Objective: To analyze differences in the pattern of statin use among 10 consecutive yearly cohorts of new users in Finland.
Study design: Retrospective cohort study based on administrative claims data.
Methods: New users of statins from January 1, 1995, to December 31, 2004, were captured from a nationwide prescription register, and the pattern of statin use was observed until December 31, 2005. The association between year of statin initiation and persistence with statin therapy during the first year of statin use was modeled using Cox proportional hazards regression analysis with multivariable adjustment. The median adherence (proportion of days covered) was computed among patients who discontinued therapy during each 365-day interval since statin initiation.
Results: In total, 490,024 new users of statins were identified. In the multivariable-adjusted model, discontinuation during the first year among initiators of statin use in 1996 and 1997 was similar to that in 1995 (hazard ratio [HR], 0.99; 95% confidence interval [CI], 0.95-1.03 in 1996; and HR, 1.01; 95% CI, 0.98-1.05 in 1997). Compared with the 1995 cohort, the 1998, 1999, 2000, 2001, 2002, 2003, and 2004 cohorts were less likely to discontinue statin use. Hazard ratios of discontinuation for the cohorts ranged from 0.91 (95% CI, 0.88-0.94) in 1998 to 0.80 (95% CI, 0.78-0.83) in 2004. There were no differences in adherence with respect to the duration of therapy among the yearly cohorts.
Conclusions: Compared with the 1995 cohort, 1-year persistence with statin therapy in Finland improved among new users of statins in 1998, and the improvement persisted up to 2004. Adherence to statin therapy remained stable among initiators from 1995 to 2004.