Increased risk of 2-year death in patients who discontinued their use of statins

Objective This study examined the association between statin usage (discontinued, reduced or continued) and two-year death following a 21% increase in the Pharmaceutical Benefits Scheme (PBS) consumer co-payment in Western Australia.

Methods A retrospective observational study in Western Australia using linked administrative Commonwealth PBS data and State hospital inpatient and death data (n=207,066) was undertaken. We explored the two-year all-cause and ischemic heart disease(IHD)/stroke-specific-death in individuals who discontinued, reduced or continued statin medication following the January 2005 PBS co-payment increase, overall, by beneficiary status (general population vs. social security recipients) and by a history of admission for ischemic heart disease or stroke. Non-cardiovascular (CVD)-related death was also considered.

Results In the first six months of 2005, 3.3% discontinued, 12.5% reduced and 84.2% continued statin therapy. We found those who discontinued statins were also likely to discontinue at least two other medicines compared to those who continued therapy. There were 4,607 all-cause deaths. For IHD/stroke-specific death, there were 1,317. For all non-CVD-related death, there were 2,808 deaths during the 2-year follow-up period. Cox regression models, adjusted for demographic and clinical characteristics, showed a 39%-61% increase in the risk of all-cause death for individuals who reduced or discontinued statin medication compared to those who continued their statin medication (Discontinued: Adj HR=1.61, 95% CI 1.40-1.85; Reduced: Adj HR=1.39, 95% CI 1.28-1.51). For IHD/stroke-specific death, there was an increased risk of death by 28-76% (Discontinued: Adj sHR=1.76, 95% CI 1.37-2.27; Reduced: Adj sHR=1.28, 95% CI 1.10-1.49), and for non-CVD-related death, there was an increased risk of death by 44-57% (Discontinued: Adj sHR=1.57, 95% CI 1.31-1.88; Reduced: Adj sHR=1.44, 95% CI 1.30-1.60), for individuals who discontinued or reduced their statin medication compared to those who continued.

Conclusions Patients who discontinued their statin therapy had a significantly increased risk of IHD and stroke death. Health professionals should be aware that large co-payment changes may be associated with patients discontinuing or reducing medicines to their health detriment. Factors that lead to such changes in patient medication-taking behaviour need to be considered and addressed at the clinical and policy levels.