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Preliminary Estimates of the Prevalence of Selected Underlying Health Conditions Among Patients with Coronavirus Disease 2019

Our take —

Though preliminary, this study supports findings from Asia and Europe on the importance of underlying conditions and risk factors — particularly diabetes, lung disease, and cardiovascular disease — in predicting severe manifestations of COVID-19. Data cannot be assumed to be representative of all U.S. COVID-19 patients, and longer follow-up may change associations with severe disease. Data at a higher resolution are needed to disaggregate underlying conditions of particular interest, such as asthma.

Study design

Case Series

Study population and setting

7,162 (6%) of the 122,653 reported U.S. cases as of March 28, 2020 for whom there were reported data on the presence or absence of underlying health conditions and risk factors for severe respiratory disease. Data on these conditions and risk factors were reported to the CDC with a standardized case report form.

Summary of Main Findings

38% of patients had at least one underlying condition, the most common of which were diabetes, chronic lung disease, and cardiovascular disease. Higher proportions of patients with underlying conditions or risk factors, relative to those without, were hospitalized without ICU admission (30% vs. 8%) or admitted to the ICU (15% vs. 2%) across all age groups, among those with known outcome status. 173 (94%) of the 194 deaths among those with reported data had at least one underlying condition/risk factor.

Study Strengths

The sample size is large, though it is a small fraction of reported cases, and it includes data from nearly all regions of the U.S. The study used a standardized case report form in reporting across localities.


94% of reported cases were missing data on underlying conditions/risk factors; the 6% with available data may not be representative of all COVID-19 patients. Outcome data are preliminary and follow-up time was short, so outcomes for many patients included in this report are still unknown. Reported cases are likely biased towards more severe disease due to limited testing. Some conditions (e.g., asthma and COPD) were collapsed into a single category limiting ability to determine how many patients had each condition. The presence or absence of geographical variation in missing data was not discussed. Finally, there was no adjustment for, or stratification by, age which is clearly linked to both the number of diagnosed comorbidities and COVID-19 severity.

Value added

This is the first comprehensive examination of underlying conditions and risk factors among COVID-19 patients in the United States.