Abstract P266: Low Adherence to Antihypertensive Medications Predicts a Decline in Health-Related Quality of Life Among Older Adults

Abstract

Purpose: Low adherence to antihypertensive medication is associated with poor cardiovascular outcomes and increased healthcare costs. Less is known about how low adherence relates to health-related quality of life (HRQOL) over time. We tested whether low adherence to antihypertensive medications predicts a decline in HRQOL over one year using data from the Cohort Study of Medication Adherence among Older Adults (CoSMO). Methods: A telephone survey was administered to hypertensive older adults three times at yearly intervals. Three measures of low adherence captured at first follow-up were used: pharmacy fill (low adherence defined as proportion of days covered (PDC) <0.8), self-report using the 8-item Morisky Medication Adherence Scale (MMAS-8) (low adherence defined as a score <6), and self-report using a published 4-item scale by Krousel-Wood and colleagues (K-Wood-4) (low adherence defined as a score >0). HRQOL was measured using the RAND Medical Outcomes Study 36-item tool. Low HRQOL was defined in two ways: Mental and Physical Component Summary scores (MCS and PCS, respectively) in the lowest tertile. Decline in HRQOL was defined as a 10 point decrease from first to second follow-up. Separate multivariable logistic regression models were used to obtain odds ratios (OR) and 95% confidence intervals (CI) for declines in MCS and PCS, after adjusting for sociodemographic and clinical factors. The analysis predicting a decline in MCS was restricted to those without low MCS at first follow-up (n=1234), while the analysis predicting a decline in PCS was restricted to those without low PCS at first follow-up (n=1225). Results: The sample was 58.2% female and 30.0% black with a mean age of 74.9. Among those without low MCS at first follow-up, the incidence of low MCS at second follow-up was 21.6%; the incidence of low PCS at second follow-up was 15.7% among those without low PCS at first follow-up. After adjusting for sociodemographic and clinical factors, low adherence at first follow-up as measured by the K-Wood-4 was associated with a decline in MCS over one year (OR=1.85, 95% CI 1.13, 3.05), but not with a decline in PCS (OR=0.73, 95% CI 0.47, 1.14). Neither PDC nor MMAS-8 measures predicted declines in MCS or PCS over one year. Conclusions: Low adherence to antihypertensive medication as measured by the K-Wood-4 predicts a decline in MCS, but not PCS, over one year among older adults with hypertension. Efforts to address low adherence may improve HRQOL for older adults.