Multivariate stratified analyses for cancer occurrence between biologics cohort and biologics-naive cohort. All analyses were stratified according to age, gender, disease duration, average dosage of corticosteroids or disease-modifying anti-rheumatic drugs (DMARDs) after the index date, and coexisting comorbidities, based on a modified Cox proportional hazards model in the presence of a competing risk event. Some hazard ratios (HR) were not statistically significant due to a small number of cases. *Indicates average drug use after the index date of observation. Event, new cancer occurrence; MI, ischemic heart disease, including myocardial infarction; N, number; CVA, cerebrovascular attack.