We identified 1,068,104 long-stay Medicare enrollees in NHs nationwide who generated 145,254,104 prescription records during the study observation. shows the characteristics of the study population and the baseline prescribing of the study medications. In 2005, over 80% of the study NH residents lived in states that would offer complete supplemental coverage of benzodiazepines after implementation of Part D, and 16% lived in states offering partial coverage; only Tennessee did not offer any supplemental coverage (n=15,733). A comparison of age and gender showed similar distributions across the three policy groups.
Characteristics of the Study Population, 2005
At baseline, the prevalence of the study medications varied by the state’s supplemental coverage policy. In January 2005, the proportion of study NH residents on benzodiazepine therapy was 26.0% in the no coverage state, 15.6% in complete coverage states and 16.4% in partial coverage states, p<.001. The proportion of study NH residents on non-benzodiazepine sedative/hypnotics was 4.4% in the complete coverage states, 4.0 in the partial coverage states and 6.4% in the no coverage state, p<.001. The prevalence of antipsychotic use was 26.6% in the complete coverage state, 33.4% in the partial coverage state, and 29.9% in the no coverage state, p<.001. Lastly, the baseline prescribing of other anxiolytics ranged from 3.3% to 3.7% among the three groups, p=.564.
shows the changes that occurred in the monthly prevalence of benzodiazepine use and potential substitutes during the observation period. Times-series analyses showed a large and significant decrease of 10 percentage points (27% to 17%) in the proportion of benzodiazepine recipients immediately following the implementation of Part D in the no coverage state (−.10 change in prevalence; 95% confidence interval [CI], −.11- −.09, p<.0001). This large change did not occur in the partial coverage states (−.01 change in prevalence; 95% CI, −.014- −.006, p<.001) or the complete supplemental coverage states (−.01 change in prevalence; 95% CI, −.014- −.004, p<.001). The average monthly number of benzodiazepine prescriptions dispensed per user did not change before and after Part D in any of the three state reimbursement policy groups (data not shown).
Monthly Use of Benzodiazepines and Potential Substitutes, January 2005-June 2007
Times-series analyses of the reimbursable anxiolytics, sedative/hypnotics, and antipsychotics showed some evidence of potential substitution for the benzodiazepines in the no coverage state after implementation of Part D (see ). For instance, the use of other anxiolytics immediately increased significantly in 2006 (+.02 change in prevalence; 95% CI, .005-.03, p=.007) in the no coverage state relative to 2005. The average monthly number of antipsychotics and other anxiolytics dispensed also increased immediately in 2006 in the no coverage state relative to 2005; antipsychotics, +.66 change in monthly fills; 95% CI, .65-.67, p<.0000; and other anxiolytics, +.57 change in monthly fills; 95% CI, .55-.58, p=.0002. In comparison, these changes did not occur in the other states (data not shown).
shows the falls and fracture outcomes for the subgroup of newly-admitted NH residents. Overall, this group experienced 9426 incident fractures (4632 pre-Part D and 4794 post-Part D) and 23,601 incident falls (10,722 pre-Part D and 12,879 post-Part D) while observed. Before implementation of Part D, the rates of fractures were similar to or lower in the no coverage state compared to the rates in the other states. For instance, in 2005 the rate of hip fractures was 6.4 per 100 person-years in the no coverage state compared to 8.9 per 100 person-years in the complete supplemental coverage state and 9.6 per 100 person-years in the partial coverage state, p=.007. After Part D, the rates of fractures increased significantly in the no coverage state compared to the rates in the other states. For instance, the rate of hip fractures doubled from 6.4 in 2005 to 12.4 in 2006 per 100 person-years in the no coverage state. In comparison, there were modest increases of 8.9 in 2005 to 9.9 in 2006 per 100 person-years in the complete supplemental coverage state, and 9.6 to 10.7 per 100 person-years in the partial coverage state, p=.002. The incidence rate of falls showed a similar pattern, although all three groups experienced increases after Part D.
Fracture Outcomes Pre- and Post-Part D, 2005-2006
Multivariate analyses for fracture outcomes showed some significant changes in the hazards ratios after implementation of Part D, but none were in the previously hypothesized direction. Where the large decrease in benzodiazepine use occurred (no coverage state), the hazard ratio for incident hip fractures in NHs increased from 0.74 (95% CI, 0.53-1.0) before Part D to 1.60 (95% CI 1.05-2.45, p=.030) after Part D, compared to the states with stable benzodiazepines use (complete coverage states), see . The hazard ratios for falls did not change. In the partial coverage states with no change in benzodiazepine use, the hazard ratios for falls decreased from 1.09 (95% CI, 1.01-1.17, p=.04) to .99 (95% CI, 0.89-1.09) relative to the rates in complete coverage states, although the hazard ratios for hip fractures did not change.
Adjusted* Hazard Ratios of Fracture Outcomes Pre- and Post-Part D, 2005-2006