Impact of Medicare prescription drug (Part D) coverage expansion on utilisation and financial burden of benzodiazepines among older adults: an interrupted time series analysis

OBJECTIVE: Benzodiazepines were excluded from Medicare Part D coverage since its introduction in 2006. Part D expanded coverage for benzodiazepines in 2013. The objective was to examine the impact of Medicare Part D coverage expansion on the utilisation and financial burden of benzodiazepines in older adults. DESIGN: Interrupted time series with a control group. SETTING: Nationally representative sample. PARTICIPANTS: 53 150 468 users of benzodiazepines and 21 749 749 users of non-benzodiazepines (an alternative therapy) from the Medicare Current Beneficiary Survey between the pre-expansion (2006–2012) and post-expansion (2013–2017) periods. INTERVENTION: Medicare Part D coverage expansion on benzodiazepines. PRIMARY AND SECONDARY OUTCOME MEASURES: Annual rate of benzodiazepines and non-benzodiazepines, average number of benzodiazepines and non-benzodiazepines and average cost of benzodiazepines and non-benzodiazepines. RESULTS: After Medicare Part D coverage expansion, the level of the annual rate of benzodiazepines increased by 8.20% (95% CI: 6.07% to 10.32%) and the trend decreased by 1.03% each year (95% CI: −1.77% to −0.29%). The trend of the annual rate of non-benzodiazepines decreased by 0.72% each year (95% CI: −1.11% to −0.33%). For the average number of benzodiazepines, the level increased by 0.67 (95% CI: 0.52 to 0.82) and the trend decreased by 0.10 each year (95% CI: −0.15 to –0.05). For the average number of non-benzodiazepines, the level decreased by 0.11 (95% CI: −0.21 to –0.01) and the trend decreased by 0.04 each year (95% CI: −0.08 to –0.01). No significant level and trend changes were identified for the average cost of benzodiazepines and non-benzodiazepines. CONCLUSIONS: After Medicare Part D coverage expansion, there was a sudden increase in the utilisation of benzodiazepines and a decreasing trend in the long-term. The increase in the utilisation of benzodiazepines did not add a financial burden to older adults. As an alternative therapy, the utilisation of non-benzodiazepines decreased following the coverage expansion.