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DEPRESSIVE SYMPTOMATOLOGY, MEDICATION PERSISTENCE, AND ASSOCIATED HEALTH CARE COSTS IN OLDER ADULTS WITH INSOMNIA
Kulkarni AS1, Patel I2, Anderson RT3, Balkrishnan R1
1The Ohio State University College of Pharmacy, Columbus, OH, USA, 2The Ohio State University, Columbus, OH, USA, 3Wake Forest University School of Medicine, Winston Salem, NC, USA
OBJECTIVE: The effect of insomnia along with the decreased cognitive functioning associated with aging is a serious concern within the elderly (65 years and older) population. We examined the association of patient health care utilization and depressive symtomatology with medication adherence in insomnia in Medicare-HMO enrolled elderly patients. METHODS: This was a retrospective, longitudinal cohort study which included elderly patients (65 and older) enrolled continuously for 1-5 years in the Medicare HMO. Medication possession ratio was used to estimate the adherence in insomnia medication. Different MPR thresholds (0.8, 0.6, 0.4 and 0.2) were used to determine non adherence. Associations between depressive symptoms, medication adherence and health care costs were assessed using ordinary least square multiple regressions. RESULTS: A total of 2068 patients with a primary diagnosis of insomnia were included in the study. Sixty percent of these patients had depressive symptomatology. The severity of comorbidity (Charlson index) was 4 and the patient perception of quality of life (Short Form-12 scores) were between 79 and 82. The prevalence of non adherence was 70% even with a low MPR of 0.2. Insomnia patients with depressive symptoms were 92% less likely to be adherent to their insomnia medications (p<0.05). After controlling other variables, we found MPR was a good predictor of total health care costs (10% increases in MPR for every 2% decrease in total health care costs, p <0.001). CONCLUSION: We found strong associations between depressive symtomatology, medication adherence, and health care costs in elderly patients with insomnia. Disease and risk management programs in managed care settings should be used to optimize the medication adherence in the elderly.