CONVERSION RATE FOR COVID19 IN NEW YORK CITY: IMPACT OF SOCIAL DISTANCING AND UNIVERSAL MASKING

ABSTRACT

We reported the results of our multicenter cohort study in all patients who presented for endoscopy between March 1 and May 17 and were evaluated before their endoscopy for SARS-CoV2 and were followed after their endoscopy for COVID-19 status. This cohort enabled us to calculate the conversion rate from COVID-19 negative to positive during the study period and evaluate the change in conversion rate with the implementation of social distancing and masking at the population level in New York City. Data were retrieved from electronic medical records systems of six tertiary care centers in New York City. We identified all adult patients who had endoscopy between March 1, and May 17, 2020. Conversion was defined as having a negative COVID-19 status before endoscopy and a positive status afterwards. Participants COVID-19 status was defined based on SARS-CoV2 PCR test or a combination of symptoms (Fever plus at least one of dyspnea, cough, dysgeusia, or anosmia). Patients were evaluated before endoscopy and then by phone or telehealth visit afterwards. Spline regression was used to evaluate the conversion rate before and after adoption of social distancing (March 20, 2020) and mandatory masks (April 15, 2020) in New York City. Of the 1467 patients presenting for endoscopy during the study period, we had follow-up data on 1222 patients (51% outpatient and 49% inpatient endoscopies). Overall, 78 participants (6.38 %) converted after endoscopy (74 with a positive PCR, and 4 with symptoms as defined above), at a median of 23 days after endoscopy (IQR 11 to 42 days). Patients had a mean age of 62±15 years, and were 62% male (n=48). Multivariable analysis demonstrated that date of endoscopy, institution, and presence of cardiovascular disease were the independent predictors of conversion after endoscopy, with cardiovascular disease associated with a more than 2 fold increase in the risk of conversion (OR=2.1, 95%CI 1.2-3.6, p=0.009). The range of conversion from the six institutions varied widely (1 to 11%, p=0.035). Overall, participants whose endoscopies were performed later during the study period had a lower risk of conversion (OR for one week=0.87, 95%CI 0.80-0.94, p=0.001). Before social distancing, conversion rate was 8.4% on average and was increasing by 2.3% per week (p<0.001). After social distancing, the conversion rate was 6.7% on average, and started to decrease by 4.2% per week (p<0.001). After mandatory masks, the conversion rate was 2.2% on average but has started to increase slowly by 0.9% per week (p<0.001;see figure 1). These findings do support decrease in conversion rate amongst New Yorkers who presented for endoscopy with the implementation of social distancing and mandatory masking. We believe the slow but significant increase in conversion rates by the end of May reflects the relative loosening in social distancing in New York City.(Figure Presented)