Statins are recommended for treatment of dyslipidaemia when drug treatment is considered indicated according to the baseline cardiovascular risk, after lifestyle interventions have been tried.
A Cochrane review [Abstract] 1 included 18 studies (19 trial arms) with a total of 56 934 subjects to assess the effects, both harms and benefits, of statins in people with no history of cardiovascular disease (CVD; study populations where 10% or less had a history of CVD). Fourteen studies recruited patients with specific conditions (raised lipids, diabetes, hypertension, microalbuminuria). The mean age of the participants was 57 years (range 28-97 years), and 60.3% were male. The studies observed outcomes ranging from 1 to 5.3 years.
All-cause mortality was reduced by statins (RR 0.86, 95% CI 0.79 to 0.94; 13 studies, n=48 060) as was combined fatal and non-fatal CVD endpoints (RR 0.75, 95% CI 0.70 to 0.81; 9 studies, n=23 805), combined fatal and non-fatal coronary heart disease (CHD) events (RR 0.73, 95% CI 0.67 to 0.80; 14 studies, n=48 049) and combined fatal and non-fatal stroke (RR 0.78, 95% CI 0.68 to 0.89; 10 studies, n=40 295). Benefits were also seen in the reduction of revascularisation rates (RR 0.62, 95% CI 0.54 to 0.72; 7 studies, n=42 403). Total cholesterol and LDL cholesterol were reduced in all trials but there was evidence of heterogeneity of effects. No excess of combined adverse events, cancers, myopathy, rhabdomyolysis, haemorrhagic stroke, liver enzyme elevation, renal dysfunction and arthritis were found, although not all trials reported fully on adverse events. An increased risk of incident diabetes was found in the 2 studies reporting this outcome. Patient perceived quality of life was reported in only one trial, which showed limited benefit.
A study 2 included 2134 participants representing 71.8 million American residents potentially eligible for statins in primary prevention from the National Health and Nutrition Examination Survey. A 10-year risk-based approach (≥7.5% 10-year risk) yielded a number needed to treat (NNT) over 10 years of 21 (range 9 to 44) (15.0 million Americans, 95% CI 12.7to 17.3 million). Whereas for a benefit-based approach (based on predicted absolute risk reduction over 10 years [ARR10] ≥2.3% from RCT data) the NNT was 25 (range 9 to 44) (24.6 million Americans (95% CI 21.0-28.1 million).
A retrospective cohort study 3 assessing the primary prevention of cardiovascular events and mortality in old and very old adults included 46 864 people. In participants without diabetes, the hazard ratios for statin use in 75-84 year olds were 0.94 (95% Cl 0.86 to 1.04) for atherosclerotic CVD and 0.98 (0.91 to 1.05) for all cause mortality, and in those aged 85 and older were 0.93 (0.82 to 1.06) and 0.97 (0.90 to 1.05), respectively. In participants with diabetes, the hazard ratio of statin use in 75-84 year olds was 0.76 (0.65 to 0.89) for atherosclerotic CVD and 0.84 (0.75 to 0.94) for all cause mortality, and in those aged 85 and older were 0.82 (0.53 to 1.26) and 1.05 (0.86 to 1.28), respectively.
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