Adherence to thalidomide in patients with multiple myeloma: A cross-sectional study in a Brazilian metropolis.

PURPOSE: The treatment of multiple myeloma (MM) has advanced with the introduction of immunomodulators (IMiDS). Thalidomide is the IMiD available in Brazil with free access to MM patients. Adherence to treatment with IMiDs is essential for a successful therapy. The study proposed to describe adherence to thalidomide treatment in patients diagnosed with MM in onco-hematological outpatient clinics. METHODS: This is a cross-sectional study with patients over 18 years of age diagnosed with MM undergoing thalidomide treatment. Adherence was measured by the Proportion of Days Covered (PDC), which is an indirect method of measuring adherence that uses database-related medication dispensing information. Patients with PDC ≥90 were classified as adherent. The association between adherence and independent variables was assessed in univariate and multivariate analyses using logistic regression. RESULTS: A total of 65 patients with a median age of 62.6 years were identified. The median PDC was 93.7%. The frequency of adherence to thalidomide was 56.9%. Adherence to thalidomide showed a negative association with hospitalization in the last 12 months (OR = 0.202; 95% CI = 0.060-0.687) and with higher schooling (OR =0.161; 95% CI = 0.039-0.667) and a positive association with higher income (OR = 5.115; 95% CI = 1.363-19.190). CONCLUSION: Most patients from onco-hematological outpatient clinics in a metropolitan region of southeastern Brazil showed high adherence to thalidomide, which was independently associated with higher income, hospitalization, and higher schooling. More studies are required to understand better the determinants of adherence to thalidomide in the country.