Industry payments to physicians and prescribing branded memantine and donepezil combination
ABSTRACTObjective:Once-daily extended-released memantine with donepezil (hereafter memantine/donepezil) may improve medication adherence but has a 60-fold higher cost compared to combined generic components. Little is known about factors associated with prescribing memantine/donepezil. We examined the association between pharmaceutical industry payments to physicians and prescribing memantine/donepezil in Medicare.Methods:A cross-sectional study. Using 2015-2016 Centers for Medicare and Medicaid Services Open Payments and Part D prescription databases, we identified unique physicians who prescribed ≥11 memantine/donepezil prescriptions from 2015 to 2016. Outcome variable was the number of memantine/donepezil prescriptions written per physician per year. Key independent variable was physician receipt of industry payments defined in two models: (1) number of payments, and (2) amount of payment ($100 units) for memantine/donepezil received per physician per year. Multivariable Poisson regression was used, adjusting for potential confounders.Results:Among 4,895 unique eligible physicians in 2015-2016, the median number of memantine/donepezil prescriptions per physician per year was 19.5 (25th percentile=13, 75th percentile=32). Physicians received between 0 and 75 payments per year (median=1, 25th percentile=0, 75th percentile=2.5) for memantine/donepezil, totaling an average of $92 per year (median=$10.5, 25th percentile=$0, 75th percentile=$33.20). Every 1 additional payment received was associated with a 2% increase in new memantine/donepezil prescriptions prescribed per physician per year (rate ratio [RR]=1.02, 95% confidence interval [CI]=1.02-1.02). Every $100 increase in payment for memantine/donepezil was associated with a 0.3% increase in new memantine/donepezil prescriptions prescribed per physician per pear (RR=1.003, 95% CI=1.002-1.004).Conclusions:Receipt of industry payments for memantine/donepezil was independently associated with increased likelihood of physician prescribing memantine/donepezil in Medicare.