Drug-related problems and quality of life in arthritis and low back pain sufferers

Objective: The objective of this study was to determine the relationship between drug-related problems (DRPs) and health-related quality-of-life (HRQoL) in ambulatory, community-dwelling patients with musculoskeletal disorders. Methods: A 12-month, prospective, observational study was conducted in 12 independent community pharmacies in eastern Iowa. Ambulatory patients with self-reported diagnoses of osteoarthritis, rheumatoid arthritis, or low back pain were invited to participate. During quarterly visits to the pharmacy, patients used touch-screen computers to fill out the Short Form-36 (SF-36) general health survey. Using the results of these point-of-service health status assessments, community pharmacists interviewed patients to assess for DRPs. To examine the influences of different DRP characteristics on HRQoL and controlling for potential confounders, both univariate and multivariate analyses were performed using the change in physical component summary (PCS) score and mental component summary (MCS) score of the SF-36 from baseline to 12 months as the dependent variables. In each regression, the independent variables were those significant variables from the univariate analyses, as well as the types of DRPs and their outcomes. Results: A total of 461 patients were enrolled in the study. Through 12 months, 926 cumulative DRPs were identified. Overall regression models were significant for the PCS and MCS scores, respectively. Two types of DRPs showed significant negative associations with change in PCS: wrong drug and needs additional drug therapy. One type of DRP showed significant negative association with change in MCS: needs additional drug therapy. Resolution or improvement in DRPs showed a significant positive correlation with change in MCS but not PCS. Conclusions: Two DRPs, needs additional drug therapy and wrong drug, are associated with reduced self-reported physical health in arthritis and low back pain, while the DRP needs additional drug therapy is also associated with reduced self-reported mental health. Resolution of DRPs is associated with improvement in mental health in this cohort.