Diagnosis-wide analysis of COVID-19 complications: an exposure-crossover study

Many studies reporting coronavirus disease 2019 (COVID-19) complications have involved case series or small cohorts that could not establish a causal association with COVID-19 or provide risk estimates in different care settings. We sought to study all possible complications of COVID-19 to confirm previously reported complications and to identify potential complications not yet known.

Using United States health claims data, we compared the frequency of all International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) diagnosis codes occurring before and after the onset of the COVID-19 pandemic in an exposure-crossover design. We included patients who received a diagnosis of COVID-19 between Mar. 1, 2020, and Apr. 30, 2020, and computed risk estimates and odds ratios (ORs) of association with COVID-19 for every ICD-10-CM diagnosis code.

Among 70 288 patients with COVID-19, 69 of 1724 analyzed ICD-10-CM diagnosis codes were significantly associated with COVID-19. Disorders showing both strong association with COVID-19 and high absolute risk included viral pneumonia (OR 177.63, 95% confidence interval [CI] 147.19-214.37, absolute risk 27.6%), respiratory failure (OR 11.36, 95% CI 10.74-12.02, absolute risk 22.6%), acute kidney failure (OR 3.50, 95% CI 3.34-3.68, absolute risk 11.8%) and sepsis (OR 4.23, 95% CI 4.01-4.46, absolute risk 10.4%). Disorders showing strong associations with COVID-19 but low absolute risk included myocarditis (OR 8.17, 95% CI 3.58-18.62, absolute risk 0.1%), disseminated intravascular coagulation (OR 11.83, 95% CI 5.26-26.62, absolute risk 0.1%) and pneumothorax (OR 3.38, 95% CI 2.68-4.26, absolute risk 0.4%).

We confirmed and provided risk estimates for numerous complications of COVID-19. These results may guide prognosis, treatment decisions and patient counselling.