Prevalence and risk characteristics of COVID-19 in outpatients: A cross-sectional study of New York-area clinics

Outpatients can be at heightened risk of COVID-19 due to interaction between existing non-communicable diseases in outpatients and infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study measured the magnitude of COVID-19 prevalence and explored related risk characteristics among adult outpatients visiting medicine clinics within a New York state-based tertiary hospital system. Data were compiled from 63,476 adult patients visiting outpatient medicine clinics within a New York-area hospital system between March 1, 2020, and August 28, 2020. The outcome was a clinical diagnosis of COVID-19. Crude and adjusted prevalence ratios (PR) of a COVID-19 were analyzed using univariable and multivariable Poisson regression with robust standard errors. The prevalence of COVID-19 was higher among these outpatients (3.0%) than in the total population in New York State (2.2%) as of August 28, 2020. Multivariable analysis revealed adjusted prevalence ratios significantly greater than one for male sex (PR=1.10), age 40 to 64 compared to <40 (PR=1.19), and racial/ethnic minorities in comparison to White patients (Hispanic: PR=2.76; Black: PR=1.89; and Asian/others: PR=1.56). Nonetheless, factors including the advanced age of ≥65 compared to <40 (PR=0.69) and current smoking compared to non-smoking (PR=0.60) were related to significantly lower prevalence. Therefore, the prevalence of COVID-19 in outpatients was higher than that of the general population. The findings also enabled hypothesis generation that routine clinical measures comprising sex, age, race/ethnicity, and smoking were candidate risk characteristics of COVID-19 in outpatients to be further verified by designs capable of assessing temporal association.