Prevalence of Rheumatoid Arthritis and Drug Dispensing Patterns Among Medicaid and Medicaid-Medicare Dually Eligible Beneficiaries in Puerto Rico.

The prevalence of RA in Puerto Rico in this study is lower than reported in the mainland US, possibly due to more stringent criteria to define RA. DMARD dispensing and cost patterns are similar to those found in other studies. Claims algorithms that identify RA have higher validity when pharmacy data is included.