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The novel coronavirus disease 2019 (COVID-19) pandemic has limited endoscopy utilization, causing significant health and economic losses. We aim to model the impact of polymerase chain reaction (PCR) testing into resuming endoscopy practice.
Methods
We performed a retrospective review of endoscopy utilization during the COVID-19 pandemic for a baseline reference. A computer model compared 3 approaches: strategy 1, endoscopy for urgent indications only; strategy 2, testing for semiurgent indications; and strategy 3, testing all patients. Analysis was made under current COVID-19 prevalence and projected prevalence of 5% and 10%. Primary outcomes were number of procedures performed and/or canceled. Secondary outcomes were direct costs, reimbursement, personal protective equipment used, and personnel infected. Disease prevalence, testing accuracy, and costs were obtained from the literature.
Results
During the COVID-19 pandemic, endoscopy volume was 12.7% of expected. Strategies 2 and 3 were safe and effective interventions to resume endoscopy in semiurgent and elective cases. Investing 22 U.S. dollars (USD) and 105 USD in testing per patient allowed the completion of 19.4% and 95.3% of baseline endoscopies, respectively. False-negative results were seen after testing 4700 patients (or 3 months of applying strategy 2 in our practice). Implementing PCR testing over 1 week in the United States would require 13 and 64 million USD, with a return of 165 and 767 million USD to providers, leaving 65 and 325 healthcare workers infected.
Conclusions
PCR testing is an effective strategy to restart endoscopic practice in the United States. PCR screening should be implemented during the second phase of the pandemic, once the healthcare system is able to test and isolate all suspected COVID-19 cases.
The first case at our institution was confirmed on March 14, 2020. During the initial weeks of the COVID-19 pandemic, laboratory testing for the severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) was provided by the Florida Department of Health only, and turnaround result time ranged between 4 and 10 days.
Parallel to the exponential number of patients requiring hospitalization for COVID-19, most hospitals, clinics, and endoscopy centers across the world started limiting endoscopy services to emergent and urgent procedures only. A recent survey showed no consensus among gastroenterologists regarding the best timing to perform semiurgent procedures for non–life-threatening conditions amid the COVID-19 pandemic.
Deferring semiurgent procedures may lead to delays in the diagnosis of critical conditions (eg, localized pancreatic cancer), closing a narrow window of opportunity for endoscopic treatment (eg, ablation of Barrett’s esophagus with dysplasia and resection of advanced colon adenomas), and has already led to substantial economic losses.
On March 24, 2020 our institution’s laboratory started performing real-time polymerase chain reaction (PCR) testing for SARS-CoV-2, with results available within 3 to 4 hours. This was possible using a combination of commercially acquired and in-house developed reagents and working with providers early in the COVID-19 outbreak. The following day all hospitalized patients were tested. Five days later a policy to test all patients within 48 hours before having an outpatient endoscopic or surgical procedure was implemented.
The primary objective of this study was to use a decision tree analysis to compare different approaches for COVID-19 testing in patients requiring semiurgent and elective endoscopy. We first modeled the impact of this policy at our institution and then extrapolated to all cases performed in the United States. The secondary objective was to identify clinical determining factors under which different strategies are more effective and safer to resume outpatient endoscopy workflow.
Methods
A retrospective review of endoscopic procedures performed at our institution was conducted over a 1-week period (ie, March 4-10, 2019). This represents our baseline practice outside of the COVID-19 pandemic period. We recorded patient demographics, procedure type, and indication of all procedures scheduled during that time. Procedure indication was grouped into 3 categories: emergent/urgent (procedure that should be performed within 24 hours), semiurgent (procedures that should be performed between 24 hours and 7 weeks), and elective (procedures that could be performed within 8 or more weeks). The classification of procedures was adapted from a survey of gastroenterologists who had to cancel procedures during the COVID-19 pandemic (Supplementary Table 1, available online at www.giejournal.org).
During the week of March 23 to 29, 2020, our institution started a policy to cancel all semiurgent and elective procedures. On March 24, PCR testing for SARS-CoV-2 became available in-house, and testing was performed systematically. We performed a second review of procedures performed between March 30, 2020 and April 5, 2020. During this week all patients were tested within 48 hours before their planned endoscopic procedure. This represents our baseline practice during the COVID-19 pandemic period (Table 1).
At our institution we used the assay Cobas SARS-CoV-2 test (Roche Molecular Systems, Inc, Basel, Switzerland), a TaqMan probe-based, real-time, reverse transcription-PCR assay designed for qualitative detection of SARS-CoV-2 RNA from human nasopharyngeal and oropharyngeal swabs.
Fact sheet for healthcare providers, coronavirus disease 2019 (COVID-19), Cobas SARS-CoV-2, Molecular Systems, Inc U.S. Food and Drug Administration, 2020.
A third research group evaluated a similar PCR assay and comparatively investigated the diagnostic value and consistency of CT in patients with COVID-19.
Clinical probabilities follow a beta distribution. Cost variations follow a normal distribution. Lower and upper values are 2 standard deviations from mean estimate.
Estimating the infection and case fatality ratio for coronavirus disease (COVID-19) using age-adjusted data from the outbreak on the Diamond Princess cruise ship, February 2020.
Authors’ calculation. Real-time PCR using Cobas severe acute respiratory syndrome–coronavirus 2 test.3 Reported sensitivity of 95% when there were at least 689.3 copies/mL.6 In a small cohort of symptomatic admitted patients viral load at admission was ∼150,000 copies/mL.23 Emergency use authorization by U.S. Food and Drug Administration.
Authors’ calculation. Real-time PCR using TaqMan One-Step from Shanghai Huirui Biotechnology Co, Ltd or Shanghai BioGerm Medical Biotechnology Co, Ltd. Authorization by China Food and Drug Administration.
There is significant variability in PPE definition. High-risk PPE included an N95 mask, covered with second surgical mask ($.14), shield, gown, shoe covers, and double set of gloves. Low-cost alternatives are designed on a regular basis.29
There is significant variability in PPE definition. High-risk PPE included an N95 mask, covered with second surgical mask ($.14), shield, gown, shoe covers, and double set of gloves. Low-cost alternatives are designed on a regular basis.29
Office of the Assistant Secretary for Planning and Evaluation, U.S. Department of Health & Human Services Colonoscopy-related costs, Medicare fee-for-service beneficiaries who received a screening or diagnostic colonoscopy, 2015.
Office of the Assistant Secretary for Planning and Evaluation, U.S. Department of Health & Human Services Colonoscopy-related costs, Medicare fee-for-service beneficiaries who received a screening or diagnostic colonoscopy, 2015.
Office of the Assistant Secretary for Planning and Evaluation, U.S. Department of Health & Human Services Colonoscopy-related costs, Medicare fee-for-service beneficiaries who received a screening or diagnostic colonoscopy, 2015.
PPE, Personal protective equipment; PCR, polymerase chain reaction; HCPCS, Healthcare Common Procedure Coding System.
∗ Clinical probabilities follow a beta distribution. Cost variations follow a normal distribution. Lower and upper values are 2 standard deviations from mean estimate.
† Authors’ calculation. Real-time PCR using Cobas severe acute respiratory syndrome–coronavirus 2 test.
Emergency use authorization by U.S. Food and Drug Administration.
‡ Authors’ calculation. Real-time PCR using TaqMan One-Step from Shanghai Huirui Biotechnology Co, Ltd or Shanghai BioGerm Medical Biotechnology Co, Ltd. Authorization by China Food and Drug Administration.
¶ There is significant variability in PPE definition. High-risk PPE included an N95 mask, covered with second surgical mask ($.14), shield, gown, shoe covers, and double set of gloves. Low-cost alternatives are designed on a regular basis.
A decision tree model was created comparing 3 potential strategies using PCR COVID-19 testing to triage and perform endoscopic procedures at our hospital. The strategies compared in Figure 1 are as follows:
•
Strategy 1: Patients requiring an emergent/urgent endoscopy (within 24 hours) are tested. Endoscopy is performed regardless of result. High-risk personal protective equipment (PPE) and decontamination after procedure is used for each emergent/urgent endoscopy.
All other procedures (semiurgent and elective) are postponed.
•
Strategy 2: Patients requiring emergent/urgent and semiurgent procedures are tested within 48 hours before the planned endoscopic procedure. All emergent/urgent cases are completed regardless of PCR result using high-risk PPE. Semiurgent cases with a negative result proceed to endoscopy using low-risk PPE. Semiurgent cases with a positive result are postponed. All elective procedures are postponed.
•
Strategy 3: PCR test is performed on all patients within 48 hours. All emergent/urgent cases are completed regardless of PCR result using high-risk PPE. Semiurgent and elective cases with a negative result proceed to endoscopy using low-risk PPE. Semiurgent and elective cases with a positive result are postponed.
Figure 1Decision tree for novel coronavirus disease 2019 PCR testing before endoscopy (not all stage transitions are shown. PCR, Polymerase chain reaction.
Our economic model focused on short-term outcomes over 7 days. We did not measure the added benefit of identifying an asymptomatic patient with COVID-19 who presented for an elective procedure. We did not measure the impact of respiratory failure developed during endoscopy, the need to perform endotracheal intubation during endoscopy, or mortality associated with COVID-19. Our analysis did not include the risk of patients contracting COVID-19 from their visit to our endoscopy center.
Outcomes
The primary outcomes were the added cost of PCR testing per patient and the total number of procedures performed using each strategy. Secondary outcomes were the number of patients with COVID-19 who underwent endoscopy without high-risk PPE (for a false-negative result), healthcare staff infected, number of healthy patients who had their procedure postponed (for a false-positive result), and economic revenue for the endoscopy center. The analysis was completed under 3 disease scenarios (with prevalence at the time of writing, 5% and 10%).
We estimated that performing an endoscopic procedure on a false-positive case under urgent circumstances would translate into wasting high-risk PPE in 4 staff members (ie, physician, nurse, anesthetist, and technician). Cases with semiurgent and elective indications and a positive test result would be postponed. On the other end, a case with a false-negative test result would undergo endoscopy with the use of low-risk PPE.
When current estimates that SARS-CoV-2 has an infective rate (R0) of 1.5 to 3.5 in the community are used, performing such endoscopic procedures could infect a similar number of healthcare workers.
We assumed that the probability of transmitting COVID-19 was independent of the endoscopic procedure requested. Clinical probabilities were obtained from different sources (Table 2). The presumed prevalence of COVID-19 was calculated from reports from Duval County, Florida on April 2, 2020. We used a reverse calculation using a corrected infection fatality rate (cIFR) of 1.3% (95% confidence interval [CI], .38-3.6) (Supplementary Material A and Supplementary Table 2, available online at www.giejournal.org).
Estimating the infection and case fatality ratio for coronavirus disease (COVID-19) using age-adjusted data from the outbreak on the Diamond Princess cruise ship, February 2020.
Primary analysis was performed using cost estimates from the Centers for Medicare & Medicaid Services data for hospital outpatient department payments in 2020.
Office of the Assistant Secretary for Planning and Evaluation, U.S. Department of Health & Human Services Colonoscopy-related costs, Medicare fee-for-service beneficiaries who received a screening or diagnostic colonoscopy, 2015.
Because Medicare payments vary geographically, depending on local operating costs, we varied our baseline costs by using a sensitivity analysis through the ranges shown in Table 2. Ranges were derived by adding 25% or subtracting 25% from the baseline estimate. Secondary analysis was performed using costs for ambulatory surgery centers in 2020 (Supplementary Table 3, available online at www.giejournal.org).
The cost of PPE was separated into low-risk and high-risk, which was calculated based on the recommendations of the Milan endoscopy group (Supplementary Table 4, available online at www.giejournal.org).
Compared with the Milan recommendations, the American Gastroenterological Association Institute advocates for high-risk PPE (ie, N95 masks and double gloves) for all upper and lower GI procedures.
We selected the former because American Gastroenterological Association recommendations were written assuming the absence of widespread rapid testing for COVID-19.
Only direct costs for a third-party payer perspective were considered, which were adjusted to the 2020 U.S. dollar (USD). We did not perform any adjustments for inflation or discounting. Additional details of cost calculations are provided in Supplementary Material B (available online at www.giejournal.org).
Sensitivity analysis and statistical considerations
The robustness of the model was tested by performing probabilistic sensitivity analysis modifying important clinical probabilities and cost estimates. Clinical probabilities followed a beta distribution, and costs ranges followed a normal distribution.
•
We performed a second-order Monte Carlo simulation with 1000 computer iterations of our model.
By using tracker variables, the number of endoscopies performed was compared among the 3 strategies. Sensitivity analysis was done with Bayes revision.
•
Threshold analysis was performed to determine clinical limits under which all cases are performed with adequate PPE (ie, no false-negative cases).
•
Tornado diagrams were created to compare the weight of different variables (PCR testing performance, costs of anesthesia, and endoscopic procedures, etc) into the final estimates of our model.
•
Using published reports, we estimated the number of needed colonoscopies, EGDs, flexible sigmoidoscopies, ERCPs, and EUSs in United States for 1 week in 2020, assuming COVID-19 had not developed.
We projected the effects of the 3 strategies in resuming endoscopic procedures toward that goal (Supplementary Table 5, available online at www.giejournal.org).
Patients presenting early in our model may have recovered from COVID-19 and could be considered for endoscopy a few days later. The World Health Organization recommends at least 14 days of quarantine and the U.S. Centers for Disease Control and Prevention at least 3 days after fever resolution.
World Health Organization. Considerations for quarantine of individuals in the context of containment for coronavirus disease (COVID-19) Interim guidance 19 March 2020.
For simplicity of the analysis, these patients were deemed poor endoscopy candidates throughout the rest of the study period. Given the relatively short period of time analyzed, we did not perform half-cycle corrections.
When estimates were unavailable or significant discrepancies were found in published literature, 3 authors (S.A.H., P.T.K., and M.B.W.) discussed and agreed on a final estimate. The decision tree was generated and analyzed using decision analysis software (TreeAge Pro, Williamstown, Mass, USA). Our study protocol was approved by the Mayo Clinic Institutional Review Board (protocol 20-003245).
Results
During the COVID-19 pandemic, the weekly endoscopy volume at our institution decreased to 12.7% of baseline. The main difference was seen in elective procedures: Only 2 elective cases were performed during the week corresponding to the COVID-19 pandemic compared with 296 during that week in 2019.
Baseline analysis of the 3 different strategies for asymptomatic endoscopy candidates during the COVID-19 pandemic showed that PCR testing is a safe and effective intervention to resume endoscopy in semiurgent and elective cases. Our analysis showed that testing under strategy 3 allows completing more endoscopies than the other 2 strategies (Table 2). Implementing strategies 2 and 3 translates into expending 22 and 105 USD, respectively, in PCR testing per patient but allows an increase to 19.4% and 95.3% of baseline endoscopies. At the current disease prevalence (122 cases per 100,000 individuals), implementing all 3 strategies over 1 week is unlikely to diagnose a true-positive case (Table 3), and false negatives would also be exceedingly rare given the low population prevalence, even with moderate test sensitivity.
Table 3Estimates of different strategies over a 1-week period (361 endoscopies per week)
Adding Medicare payments for procedure, anesthesia, and extras (management, laboratories, electrocardiogram, imaging, pathology, etc) (details in Supplementary Material B).
(U.S. dollars)
Δ Return – intervention (U.S. dollars)
True positive
False positive
False negative
Staff infected
Current prevalence (122 per 100,000 cases)
Strategy 1
29 (8.0)
3610
29 (8.0)
44,764
41,604
0
1
0
0
Strategy 2
72 (20.0)
7942
70 (19.4)
97,831
89,889
0
4
0
0
Strategy 3
361 (100.0)
37,905
344 (95.3)
453,055
415,150
0
18
0
0
5% Prevalence
Strategy 1
29 (8.0)
3610
29 (8.0)
44,764
41,604
1
1
0
0
Strategy 2
72 (20.0)
7942
68 (18.9)
96,026
88,084
3
3
1
1-2
Strategy 3
361 (100.0)
37,905
303 (83.9)
436,810
398,905
15
17
3
4-10
10% Prevalence
Strategy 1
29 (8.0)
3610
29 (8.0)
44,764
41,604
2
1
1
1-2
Strategy 2
72 (20.0)
7942
66 (18.4)
93,860
85,918
6
3
1
2-4
Strategy 3
361 (100.0)
37,905
290 (80.3)
420,204
382,299
30
16
6
9-22
∗ Adding testing, personal protective equipment (low and high risk), and room decontamination (details in Supplementary Table 4).
† Adding Medicare payments for procedure, anesthesia, and extras (management, laboratories, electrocardiogram, imaging, pathology, etc) (details in Supplementary Material B).
In our initial model all patients scheduled for a semiurgent or elective procedure who tested positive for COVID-19 would be rescheduled. This translated into 1, 4, and 18 cases canceled unnecessarily for false-positive results. If physicians deemed the procedure should still be completed, high-risk PPE equipment for 4, 16, and 72 workers would be wasted, or the equivalent of 204, 816, and 3672 USD per week, respectively (estimate includes unnecessary room decontamination) (Table 3).
Secondary analysis using reimbursement rates for ambulatory surgery centers did not change the cost of PCR implementation or test performance. Reimbursement for endoscopy decreased to 50% to 60% compared with hospital outpatient rates: 25,992 USD, 59,204 USD, and 280,858 USD per week for strategies 1, 2, and 3, respectively.
Sensitivity analysis
Our results were consistent over 1000 reiterations of the Monte Carlo simulation (Fig. 2). False-negative results were only seen after testing 4700 patients, or 3 months using strategy 2 in our practice (assuming disease prevalence remains stable). If disease prevalence increased to 5%, there was 1 false-negative result every week under strategy 2 and 1 false-negative result every 3 days under strategy 3. This translates into 1 to 10 infected healthcare workers over a 1-week period (Table 3).
Figure 2Percentage of endoscopy cases performed under each testing strategy. Monte Carlo simulation over 1000 iterations. COVID-19, Novel coronavirus disease 2019.
Sensitivity analyses showed that the economic revenue for the hospital is greatly impacted by the cost of colonoscopies, EGDs, extras (eg, laboratories, pathology, and imaging), and ERCPs. The revenue for the hospital is much less impacted by test performance (ie, true-positive, true-negative, false-positive, and false-negative values) (Supplementary Fig. 1, available online at www.giejournal.org).
Implementing nationwide PCR testing using strategies 1, 2, and 3 would require investing 6, 13, and 64 million USD weekly under each strategy. This would yield a return of 75, 165, and 767 million USD to providers (Table 4). Assuming these patients undergo endoscopy with low-risk PPE and the R0 rate is 1.5 to 3.5, that means 26, 65, and 325 healthcare workers would be infected for each strategy, respectively.
Table 4Procedures performed in the United States each week under different strategies
Testing patients for SARS-CoV-2 with PCR before endoscopy is an effective preventive strategy to resume endoscopy practice in different clinical scenarios. At the present rate of infection in low-prevalence populations, such as our center, this intervention seems safe over a 3-month period.
Despite the potential gains of PCR testing in all patients requiring endoscopy during the COVID-19 epidemic, we cannot overemphasize the importance of following adequate PPE use protocols. We recommend reviewing “Coronavirus (COVID-19) outbreak: what the endoscopy department should know”
The biggest determining factor in the safety and effectiveness of this intervention is by far disease prevalence. With our current prevalence (56-635 cases per 100,000 residents), an asymptomatic healthy individual has higher odds of having a false-positive result than a true-positive result. With the progression of the pandemic, this difference will likely narrow and invert. There are many uncertainties regarding the behavior of the COVID-19 pandemic if the incidence continues to increase. Clinical judgment should prevail over any laboratory test in deciding the best timing for endoscopy. For example, a 5- or 10-year surveillance colonoscopy should still be postponed in a patient with underlying medical conditions despite having negative PCR results. Stool-based testing should be offered as an alternative to average-risk individuals seeking colorectal cancer screening.
Our 3 prevalence scenarios evaluate a sizeable spectrum of the COVID-19 pandemic. Even though some computer models suggest the prevalence of COVID-19 may reach an excess of 214 million Americans (65% of the total population), this represents cumulative prevalence counting patients that have been exposed and recovered.
Considering the clinical duration of COVID-19 is usually 2 to 3 weeks, our point estimates are well above maximum incidences reported in New York, Spain, and Italy at the time of writing (460, 187, and 171 per 100,000 residents, respectively). Without widespread testing in the population, the best estimates of disease prevalence are calculated retrospectively based on mortality rates. Such estimates lag days or weeks from actual prevalence. With current social distancing strategies, new cases will appear, although at a lesser rate, potentially matching recovery rates.
We speculate that the transmission rate in the endoscopy unit is similar to that in the community. Most calculations of R0 originate from experience in China in a community setting.
The transmission rate within the endoscopy unit remains unknown, and the R0 range used (1.5-3.5) is likely an overestimate. Case reports show that appropriate use of PPE (either with surgical masks or N95 masks), hand hygiene, and other standard procedures can reduce transmission rates up to zero (0/41 healthcare workers exposed in Singapore).
On the other hand, nonclinical personnel (eg, front desk, transportation) will be infected if they do not follow the same procedures.
The quality of any decision tree analysis depends on the quality of probabilities and input data to the computer model. A number of external factors affect diagnostic performance, including sampling operations, specimen source (oral, nasal swab), sampling timing (asymptomatic, symptomatic, recovery phase), and detection kit selected.
We consider our estimates on PCR accuracy to be conservative and lower than that reported by the manufacturer in vitro. The test manufacturer reported a level of detection close to about 100 to 200 copies/mL of sample.
Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study.
Current estimates on PCR testing sensitivity and specificity of the SARS-CoV-2 assays are based on analytical validations. These measurements reflect performance against contrived samples (ie, spiked samples) and control material. There are no estimates of “clinical sensitivity” in patients with symptomatic COVID-19 and subclinical SARS-CoV-2 infection. The Wuhan study did not evaluate the cause for pulmonary infiltrates in those patients with negative PCR and positive CT findings (ie, infection with another virus or bacteria, inappropriate timing, testing misuse or malfunction).
For this reasons we allowed a broad CI for sensitivity and specificity. These estimates should be measured in a prospective fashion with patients at different ends of the clinical spectrum (both timing and disease severity). We are conducting a prospective analysis of cases tested in our institution for that purpose.
Of all potential outcomes of the test, false-negative results are the most relevant for isolation and personal protection. Exposing a healthcare worker to SARS-CoV-2 because of PCR testing limitations has significant ethical implications. The most common reported cause for a false negative is low viral load.
It is conceivable that a false-negative patient has a lower viral load and likely is less contagious (lower R0 factor). These strategies should be avoided at institutions or geographic areas where the prevalence of active cases approaches 5%.
We assumed that the hospital or endoscopy center would be responsible for the costs of the SARS-CoV-2 PCR test. In the United States, Medicare services and most insurance programs reimburse the cost of COVID-19 testing (paying between 36 and 51 USD per test). These reimbursement programs will favor more comprehensive testing strategies.
On the other end of the spectrum, false-positive results can lead to potential waste of valuable PPE and other resources used in disinfection and isolation. Postponing a semiurgent or elective case for a false-positive test result would be preferred. Alternatively, performing a second PCR or antibody testing (IgG serum) are potential options.
Strengths and limitations
The most critical estimates were PCR test performance and procedure classification. We were cautious to allow a broad range of sensitivity and specificity for PCR test performance including worst case scenarios. Additionally, we performed a systematic retrospective review of cases performed in March 2019 and 2020. Our analysis accounts for clinical uncertainties and valid statistical measures with a second-order Monte Carlo simulation.
One limitation was the inability to include the effect of respiratory symptoms and patients with active disease into our model. We presumed that symptomatic patients may proceed straight to a general provider and miss their scheduled endoscopy. Both patient and providers may contract COVID-19 from other healthcare workers in the endoscopy lab. We did not account for periodic screening of healthcare workers, and this population represents 10% to 20% of all positive cases.
Our study did not evaluate emerging tests for serologic exposure (IgM/IgG) and the potential that these patients may be immunized to future infections. As data emerge on the accuracy of these tests, a strategy combining rapid viral PCR and serology should be studied.
Despite the sensitivity analysis and Monte Carlo simulation, our model represents a simplification of a complex and dynamic process. We agree that the definition of endoscopy candidate is a broad umbrella term that covers diverse conditions.
The benefits of COVID-19 testing have significant geographic variability. Our hospital serves a population that extends beyond Duval County. Several healthcare systems exist in our geographic area, at least 4 of which offer testing for SARS-CoV-2. The costs of a testing program encompasses more than direct costs of testing. Testing and phone calls disrupt workflow in fast-paced ambulatory endoscopy centers. Economic models from the societal perspective are still needed. These include the cost of infections transmitted to patients coming to the endoscopy center, days missed from work by infected healthcare workers and caregivers, and cost of healthcare worker deaths (3-5 per week across the United States on strategy 3 assuming a cIFR of 1.3%).
Estimating the infection and case fatality ratio for coronavirus disease (COVID-19) using age-adjusted data from the outbreak on the Diamond Princess cruise ship, February 2020.
They describe a transition through 4 different phases (Table 5). We consider this intervention to be ideally implemented in phase 2: once each center is able to safely diagnose, treat, and isolate COVID-19 cases and their contacts. The value of PCR testing grows as the prevalence of COVID-19 increases, with an inversion of the false positive-to-true positive ratio (with the caveats of false negatives discussed above).
Table 5Coronavirus response phases and roadmap to reopening endoscopy services
Phase
Status
Population strategy
Endoscopy interventions
1: Slow the spread, ie, “flattening the curve”
Community transmission progresses rapidly in each state. Increasing infections and deaths.
Social distancing for all (closing schools, restaurants, malls, gyms, etc). Quarantines, gatherings, and travel bans. Transition to work from home. Public to wear masks. Scale up health infrastructure to safely manage the outbreak and take care of the sick.
Transfer endoscopy staff to first response line. Endoscopy rooms and ventilators used for COVID-19 patients. Treat all cases as potential positive. Restrict endoscopy to emergent and urgent indications. PPE and room decontamination based on risk stratification.
Able to test and isolate all COVID-19 suspected cases. Reduction in new cases for 14 days. Sufficient critical care capacity.
Resume schools and business Social distancing for high-risk populations (adults >60 years old, underlying health conditions). Comprehensive surveillance systems.
PCR testing (strategy 2 or 3) according to local resources and disease prevalence. Rooms and teams conditioned to scope COVID-19 patients. Telemedicine and online appointments. PPE and room decontamination based on risk stratification.
Upscaling this intervention across the country will increase healthcare workers’ exposure to SARS-CoV-2. By our estimates, this means that 325 or more healthcare workers across the country will potentially become infected in the endoscopy unit on a weekly basis. Although constituting a fundamental aspect of the strategy, testing alone is not sufficient enough to reopen practice. Testing should be integrated into an institution-wide plan that coordinates the notification of results before returning to the procedure, ensures isolation, and promotes follow-up monitoring. Additional strategies that can be implemented from the endoscopy unit are suggested in Table 5.
Finally, our findings are applicable to ambulatory surgery centers and other facilities like dialysis or infusion centers. Further computer models should estimate the infection risk in such institutions and potential gains of PCR testing with different patient populations (eg, chronically immunosuppressed). Our model was designed for healthcare institutions in high-income countries but is likely prohibitive in countries with limited testing and other resources. In such instances, symptomatic patients, patients with exposure to confirmed cases, and healthcare workers remain the priority in testing.
Conclusion
This economic analysis shows that PCR testing is an effective strategy to restart endoscopic practice in the United States. Our findings support strategy 3, which involves testing all patients, performing urgent endoscopy irrespective of testing result, and endoscopy in the remaining SARS-CoV-2–negative cases, but the extent of testing will rely on local resources and disease prevalence. The implementation of PCR screening is ideal for the second phase of the COVID-19 pandemic, once the health system is able to test and isolate all suspected COVID-19 cases and critical care capacity is secured. Further research is needed to measure PCR performance in vivo over different clinical scenarios while, in parallel, we continue to develop effective medical treatments.
Acknowledgment
We thank Matthew J. Binnicker, PhD, for technical assistance in reviewing our diagnostic accuracy estimates.
Supplementary Material A: Calculations for Novel Coronavirus Disease 2019 Prevalence in Duval County (Florida, USA) as of April 2, 2020 Afternoon
Corrected infection fatality rate (cIFR) in Diamond Princess ship was 1.3% (95% confidence interval [CI], .38%-3.6%) and cIFR in China was .6% (95% CI, .2%-1.3%). Both adjusted for delay from confirmation to death.
Fact sheet for healthcare providers, coronavirus disease 2019 (COVID-19), Cobas SARS-CoV-2, Molecular Systems, Inc U.S. Food and Drug Administration, 2020.
Reverse calculation using reported deaths yields 538 infected patients (95% CI, 194-1842) using Diamond Princess ship cIFR (an homogeneous older population) and 1167 infected patients (95% CI, 538-3500) using China cIFR (less homogeneous, larger sample). Prevalence calculated with cIFR estimated to be 56 (95% CI, 20-192) infected patients per 100,000 residents and 122 (95% CI, 56-365), respectively.
Supplementary Material B: Additional Cost Calculations
Emergency cases
All candidates were tested. All received endoscopy without waiting for results and managed as potential novel coronavirus disease 2019 (COVID-19) positive.
Input cost = cost of polymerase chain reaction (PCR) test + cost of personal protective equipment (PPE) high risk + cost of decontamination after each case. Output reimbursement = Medicare payment for procedure + payment for anesthesia + payment for extras (management, laboratories, electrocardiogram, pathology, imaging, emergency department care for patients who had adverse events).
Semiurgent and elective cases
Testing was based on strategy (1, 2 or 3) selected. Management depended on result of the test. For COVID-19 positive (true positive and false positive), procedure was postponed; hence, input cost = cost of PCR test and output reimbursement = 0. For COVID-19 negative (true negative and false negative), procedure was completed; hence, input cost = cost of PCR test + cost of PPE low risk.
Output reimbursement = Medicare payment for procedure + payment for anesthesia + payment for extras (management, laboratories, electrocardiogram, pathology, imaging, emergency department care for patients who had adverse events).
If done with COVID-19 cases, the room was cleaned only at the end of the day. Cost of decontamination once a day was considered zero.
Supplementary Figure 1The revenue for the hospital is much less impacted by the test performance (ie, true-positive, true-negative, false-positive, and false-negative values). flexsig, Flexible sigmoidoscopy; PCR, polymerase chain reaction; PPE, personal protective equipment.
Adapted from Bilal M, Simons M, Rahman AU, et al. What constitutes urgent endoscopy? A social media snapshot of gastroenterologists’ views during the COVID-19 pandemic. Endoscopy 2020.2
EGD: ampullary adenoma Isolated weight loss GERD/heartburn Dyspepsia/noncardiac chest pain Established dysphagia Barrett’s (regardless of dysplasia) Esophageal varices evaluation or follow-up banding Iron-deficiency anemia Endoscopic submucosal dissection for early gastric cancer PEG tube placement Colon/FlexSig: possible FIT or fecal FIT-DNA test Chronic diarrhea Colorectal cancer screening Colon EMR Ulcerative colitis with dysplasia ERCP: biliary stent replacement Pancreatic stent removal EUS: concerns for submucosal mass (GIST, leyomioma, lipoma) Double duct sign without a discrete mass Concerns for neuroendocrine tumor Celiac plexus block Pancreatic cyst evaluation DBE: small-bowel tumor
∗ Adapted from Bilal M, Simons M, Rahman AU, et al. What constitutes urgent endoscopy? A social media snapshot of gastroenterologists’ views during the COVID-19 pandemic. Endoscopy 2020.
Supplementary Table 2Estimated prevalence of novel coronavirus disease 2019 infected patients per 100,000 residents, Duval County, Florida, USA, April 2, 2020
Confirmed severe acute respiratory syndrome–coronavirus 2 positive
Extras (average evaluation, pathology, labs, radiology, and management)
215
215
Reimbursement for ambulatory surgery centers is approximately 50%-60% of hospital outpatient departments. All costs are adjusted to U.S. 2020 dollars. Cost variations follow a normal distribution. Lower and upper values are 2 standard deviations from the mean estimate.
PPE, Personal protective equipment; HCPCS, Healthcare Common Procedure Coding System.
Low risk defined as no symptoms, no contact with severe acute respiratory syndrome–coronavirus 2–positive person, nonstay in high-risk area during the previous 14 days.
Intermediate risk defined as the presence of symptoms with no history of contact with positive person and nonstay in high-risk area during previous 14 days OR no symptoms but contact with positive person or stay in high-risk area during the previous 14 days.
High risk defined as at least 1 symptom and 1 of the following: contact with positive person or stay in high-risk area during the previous 14 days.
Endoscopy personnel
Surgical mask
Upper GI endoscopy → consider as high risk
N95 mask
Hairnet
Hairnet
Goggles
Lower GI endoscopy → consider as low risk
Goggles and/or face shield
Single-use gown
Long-sleeved water resistant gown
Gloves
Two pairs of gloves
Patient
Surgical mask
Surgical mask
Gloves
Decontamination endoscopy rooms
Standard disinfection at the end of procedure day
At the end of each procedure
∗ Low risk defined as no symptoms, no contact with severe acute respiratory syndrome–coronavirus 2–positive person, nonstay in high-risk area during the previous 14 days.
† Intermediate risk defined as the presence of symptoms with no history of contact with positive person and nonstay in high-risk area during previous 14 days OR no symptoms but contact with positive person or stay in high-risk area during the previous 14 days.
‡ High risk defined as at least 1 symptom and 1 of the following: contact with positive person or stay in high-risk area during the previous 14 days.
Peery AF, Crockett SD, Murphy CC, et al. Burden and cost of gastrointestinal, liver, and pancreatic diseases in the United States: update 2018. Gastroenterology 2019;156:254-72.
iData Research. An astounding 19 million colonoscopies are performed annually in the United States. Available at: https://idataresearch.com/an-astounding-19-million-colonoscopies-are-performed-annually-in-the-united-states/. Accessed March 31, 2020.
Distribution adapted from Medicare beneficiaries
2020 Projected annual cases (average of lower and higher estimate)
Lower estimate using annual population growth (see below)
Upper estimate using annual procedure growth (see below)
One week 2020 projected cases (annual/52.1)
Lower estimate
Upper estimate
Colonoscopy
10,964,034
61.90
19,000,000
.6190040
19,501,337
19,456,000
19,546,673
373,997
373,128
374,867
EGD
6,069,647
34.27
10,518,327
.3426782
11,109,285
10,770,767
11,447,804
213,054
206,562
219,546
Flexible sigmoidoscopy
313,045
1.77
542,488
.0176738
556,802
555,508
558,096
10,678
10,654
10,703
EUS
196,144
1.11
339,906
.0110738
385,108
348,063
422,154
7,386
6,675
8,096
ERCP
169,510
.96
293,750
.0095701
307,400
300,800
313,999
5,895
5,769
6,022
Total
17,712,380
100.00
30,694,471
1.0000000
31,859,932
31,431,138
32,288,726
611,011
602,787
619,234
Volume increase based on U.S. annual population growth
Volume increase based on Medicare annual procedure reports
Peery AF, Dellon ES, Lund J, et al. Burden of gastrointestinal disease in the United States: 2012 update. Gastroenterology 2012;143:1179-87.
Estimated increase 2017-2020
2009
2010
Difference
Estimate increase 2017-2020
1.024
Colonoscopy/flexible sigmoidoscopy
3,330,829
3,336,136
.0015908
1.004772
EGD
2,833,863
2,895,999
.0214558
1.064367
ERCP
284,391
288,715
.0149767
1.04493
EUS
59,604
64,274
.0726577
1.217973
∗ Peery AF, Crockett SD, Murphy CC, et al. Burden and cost of gastrointestinal, liver, and pancreatic diseases in the United States: update 2018. Gastroenterology 2019;156:254-72.
• All endoscopes and reusable accessories should be disinfected according to standard guidelines.
• Endoscopies of intermediate-/high-risk patients should preferably be performed in a negative pressure room. Delay the next procedure with 30 minutes to allow airborne particles to vanish. If no negative pressure room is available, the room should be kept empty for at least 1 hour.
• Discourage reuse.
Adapted from Repici A, Maselli R, Colombo M, et al. Coronavirus (COVID-19) outbreak: what the department of endoscopy should know. Gastrointest Endosc. Epub 2020 Mar 14.
References
Holshue M.L.
DeBolt C.
Lindquist S.
et al.
First case of 2019 novel coronavirus in the United States.
Estimating the infection and case fatality ratio for coronavirus disease (COVID-19) using age-adjusted data from the outbreak on the Diamond Princess cruise ship, February 2020.
Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study.
DISCLOSURE: The following authors disclosed financial relationships: J. E. Corral: Travel, food, and beverage compensation from Abbvie, Intercept Pharmaceuticals, Janssen Scientific, Boston Scientific, and Cook Medical. M. B. Wallace: Consultant for Virgo Inc, Cosmo/Aries Pharmaceuticals, Anx Robotica, Covidien, GI Supply, Endokey, Endostart, Boston Scientific, and Microtek; researchgrantrecipient from Fujifilm, Boston Scientific, Olympus, Medtronic, Ninepoint Medical, and Cosmo/Aries Pharmaceuticals; stockholder in Virgo Inc; food and beverage compensation from Synergy Pharmaceuticals, Boston Scientific, and Cook Medical. All other authors disclosed no financial relationships.
If you would like to chat with an author of this article, you may contact Dr Wallace at [email protected]
The first case of SARS-CoV-2 infection in India was reported on January 30, 2020, from Kerala.1 The disease since then has increased manifold to reach figures of over 45,000 infections across the country, making a significant impact on healthcare with drastic changes in clinical practice. Multiple society guidelines have been published since the outbreak of the virus, with a major focus on screening and precautions for patients undergoing endoscopy. Continuing hospital services in a smooth and effective manner while taking care of patients’ and caregivers’ safety remains a priority.
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