Switching statins : the impact on patient outcomes

Abstract

Little is currently known of the effect of switching statin therapy on cardiovascular outcomes. Using The Health Improvement Network database, patients who had received atorvastatin for ≥ six months were identified. They were classified as 'switch' if they were subsequently switched to simvastatin, and were matched to up to four 'control' patients who remained on atorvastatin. Time to death or first major cardiovascular event was compared, controlling for the matching co-variates, prior statin exposure and baseline cholesterol concentration. A total of 2,511 switch patients and 9,009 controls were identified. The risk of death or first major cardiovascular event was significantly associated with switching therapy (hazard ratio = 1.30, 95% confidence interval: 1.02-1.64) compared with patients who did not switch. Major cardiovascular events and stroke were also significantly associated with switching. There was no significant difference in all-cause mortality. While recognising the observational nature of database research, this study has highlighted the potential for poorer cardiovascular outcomes in patients switching statin therapy, compared with patients maintained on their current treatment. This raises concerns for policies that encourage widespread statin switching without careful consideration of individual patient circumstances and cardiovascular risk, and highlights the need for formal trials to assess the consequences of switching statin treatment.