Study objective: To investigate the relationship between two widely used, generic health-related quality of life (HRQOL) measures, Short Form-12 (SF-12) and EuroQol's EQ-5D, and potentially inappropriate drug use in an elderly cohort.
Design: Longitudinal retrospective cohort study.
Data source: Medical Expenditure Panel Survey, panel 5.
Participants: Respondents aged 65 years or older.
Measurements and main results: Participants with potentially inappropriate drug use were identified by using National Drug Codes based on the Beers updated criteria. The dependent variable, HRQOL, was measured by using self-reported scores on the SF-12 (physical component summary, mental component summary, and global rating of health) and the EQ-5D (index and visual analog scale). The HRQOL data were regressed onto scores for potentially inappropriate drug, age, sex, number of prescriptions, race, comorbidity, and previous HRQOL. Regression analysis revealed statistically significant models for all five HRQOL equations (adjusted R2=26.50-53.83%, p<0.0001). However, potentially inappropriate drug use was not a significant predictor of HRQOL in any of the models tested. Previous HRQOL, as measured by using the SF-12 (global, physical component summary, and mental component summary) and the EQ-5D (index and visual analog scale), was a significant predictor of HRQOL; number of prescriptions was also a significant predictor of HRQOL, as measured by using the SF-12 (global and physical component summary) and the EQ-5D (index and visual analog scale).
Conclusion: The results supported others showing that a significant proportion of the elderly receive care that is potentially harmful and not supported by evidence-based practice. Use of a disease-specific HRQOL scale may be more responsive to measuring the impact of potentially inappropriate drugs on patients' HRQOL.