Mortality rate ratios (MRRs) were calculated for all causes, as well as for natural and unnatural causes of death separately. We fitted 2 statistical models to these outcomes, using the log-linear Poisson regression with the GENMOD procedure in SAS, version 9.3 (SAS Institute Inc). In the first model, we adjusted for demographic characteristics; in the second model, we adjusted additionally for somatic comorbidity. We also aimed to disentangle the effects of pure OCD and comorbid anxiety disorders, depression, and substance use disorders on mortality risk. In our sensitivity analyses, we assessed differences in the association of mortality with OCD by sex, age at death, and time since diagnosis. A more detailed description can be found in the eAppendix in the Supplement.
