In this study, US researchers sought to “address two unresolved issues regarding the appropriate use of statins”, namely what benefit, if any, elderly patients receive from high-intensity versus moderate-intensity statin therapy (as elderly patients as a group are generally underrepresented in clinical trials), and secondly, whether statins of equivalent cholesterol-lowering intensity have different clinical effects.
The retrospective study involved a cohort of Medicare patients (n=18,311) who were discharged after acute coronary syndrome (ACS) and received a prescription for a statin within 90 days of hospital discharge. Patients were classified into drug and dose categories based on the first statin prescription they filled after hospital discharge. “High-intensity” doses were those that would be expected to lower LDL-cholesterol levels by >40% (atorvastatin, >10mg; lovastatin, >40mg; rosuvastatin, >5mg; simvastatin, >40mg; fluvastatin and pravastatin, any dose). Subsequent to this first prescription, the investigators assessed whether patients changed medication doses, switched statins or discontinued therapy; details on concurrent medications and co-morbidities were also collected. The study’s primary endpoint was the composite of death or hospitalisation for recurrent ACS.
Of the 18,311 ACS patients included in the study, 3,066 were prescribed a high-intensity statin and 15,245 were prescribed a moderate-intensity statin within 90 days of hospital discharge. The main results were as follows:
• Patients treated with moderate- and high-intensity statins had equivalent risks of death or readmission for ACS, even after adjusting for other prognostic variables (adjusted hazard ratio 1.02, 95% CI 0.96–1.08, p=NS).
• Patients treated with moderate-intensity atorvastatin, fluvastatin, pravastatin and simvastatin had rates of death or recurrent ACS equivalent to those of patients treated with high-intensity atorvastatin.
• All high-intensity statins appeared as effective as high-intensity atorvastatin (however, the 95% confidence intervals were wide).
The authors note several limitations to their study, including the possibility of confounding by indication (higher-risk patients given high-intensity statins), and the limitations of their data (cohort consisted of mainly female patients with a high prevalence of co-morbid conditions, which limits general extrapolation). They conclude that “elderly post-ACS patients treated with high- and moderate-intensity statins in typical care settings appear to have similar rates of death and recurrent ACS”. They also state that their “analysis of high-intensity statins is suggestive of a class effect for these drugs as well, but thus far too few patients in routine practice have been treated with these medications to make robust conclusions”.
National Electronic Library for Medicine 08/03/2007