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UBC Theses and Dissertations

Impact of British Columbia's reduction in generic drug prices on statin adherence Mushashi, Fidela


Background: The burden of cost of prescription medications for chronic conditions is substantial. Many patients do not take their medication as prescribed due to cost. In 2010 the government of British Columbia introduced policy changes that reduced generic prices over a period of four years. I studied the impact of five generic price reductions policy on adherence to statin medications. Methods: Using data from the British Columbia Ministry of Health through Population Data BC, I analyzed prescription claims of 433,945 residents who were on statins from 2008 to 2014. I measured medication adherence using proportion of days covered (PDC) with brand name statin users as my control group. Interrupted time series analysis was used to compare longitudinal trends before and after policy changes. Results: Residents on brand name statins on average had 89.9% (95% CI 0.8924 to 0.9059) proportion of days covered with medication prior to policy interventions. Pre-existing level of adherence to generic statins was 0.89 percentage points (-0.0007 to 0.0184) higher relative to the control. There was a sustained significant decrease of 0.05 percentage points (-0.0009 to -0.00001) per month in trend of brand name use (p=0.0473). Adherence to generics dropped by 0.02 percentage points (-0.0009 to 0.0005) relative to the control over the 24 months preceding policy interventions. After first policy intervention, adherence to brand name statins increased immediately by 1.1 percentage points (-0.0032 to 0.0245) while generics utilization decreased by 0.71 percentage points (-0.0267 to 0.0125) relative to the control. Trend in control decreased by 0.03 percentage points (-0.0026 to 0.0021). After the first policy, there was a rise in trend of generics adherence of 0.27 percentage points (-0.0006-0.0061) per month relative to the control. Further price reductions resulted in moderate improvement in adherence to generic statins. Conclusion: Findings indicate that reductions in generic drug prices in BC yielded a modest improvement in pharmaceutical claims for statins. In the future, health policy makers may want to consider fewer but larger drug price reduction interventions for a more effective impact on medication adherence.

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