Análise de duas medidas indiretas de adesão ao tratamento em pacientes com mieloma múltiplo em uso de imunomoduladores

Abstract

Multiple Myeloma – MM – is an incurable cancer of plasma monoclonal cells located in the bone marrow. In the early 2000s, patients' life expectancy increased by about five to ten years with the introduction of immunomodulators – IMID – (thalidomide, lenalidomide, pomalidomide). In Brazil, despite the fact that these medicines are approved for MM treatment, only thalidomide is provided free of charge through the public health system, which confers it a prominent role in the treatment of the disease in the country. Thalidomide use for extended periods raises concerns about the occurrence of adverse reactions, which may influence adherence to drug therapy. Non-adherence to medications is, often, the main obstacle to the success of pharmacotherapy in outpatients. This study aims to calculate the frequency of adherence to treatment with IMIDs in patients with MM and to determine the associated factors. The study has a cross-sectional design. The population consisted of patients, aged 18 years or older, treated at public and private health services, who had been using IMID for at least a month. Adherence to treatment was measured by two indirect measures, the Treatment Adherence Measure – TAM, a self-report scale, and the Proportion of Covered Days – PDC, a method based on dispensing dispensation records. Univariate and multivariate analyses were performed using the logistic regression method. The magnitude of association was expressed by the odds ratio (OR) with a 95% confidence interval (CI). Statistical significance was considered when p<0.05. Statistical analysis was performed by the Statistical Package for the Social Sciences® (SPSS®) software, version 25.0. Most patients with MM in the investigated outpatient clinics were elderly, declared themselves black, and received treatment in public health services. Almost 50% of patients were, at least once, hospitalized during the study period, and more than half had up to 11 years of education and received up to three minimum wages. Patients presented high rates of adherence to IMIDs measured by TAM (97.6%), and the frequency of adherence obtained by the PDC method was around 60% of adherent patients. Thalidomide was the most prescribed IMID. Adherence to thalidomide showed an inverse association with hospitalization in the last 12 months and educational level, and a direct association with income. TAM did not show validity and satisfactory reliability, requiring further studies that use more accurate measures to expand knowledge about the magnitude of the problem of non-adherence to IMIDs in clinical practice.