According to a new study published in the Journal of JAMA Internal Medicine, participants in the SPRINT trial 65 or 70 years or older without diagnosed cardiovascular disease (CVD) who were taking statins at baseline had no significant differences in primary outcomes compared with those not taking statins with or without adjustment for non-random statin use.
Debate continues about the benefits and risks of statins for primary prevention, especially among older adults. Recently, older adults with moderate hyperlipidemia and hypertension who were randomized to initiate statin therapy for primary prevention, instead of receiving usual care, experienced no benefit. However, patients already taking statins were excluded from that trial. This could matter if such patients were systematically at higher risk.
To understand the impact of statins without such a potential exclusion bias, the researchers reanalyzed the Systolic Blood Pressure Intervention Trial (SPRINT). SPRINT sought to test whether a treatment program aimed at reducing systolic blood pressure (BP) to a lower goal than currently recommended would reduce cardiovascular disease (CVD) risk among patients without diabetes. Statin use was not randomized in this trial.
Accordingly, inverse probability weighted (IPW) methods were used in treatment effects and survival models to adjust for non-random statin use. This study is limited by its reliance on a nonrandomized comparison and secondary analysis for which the original trial has not powered a lack of time-varying data on statin use, and the potential inadequacy of conditioning only on observed variables to model the non-random assignment of statin use.
Moreover, given low event rates, even in a 1-sided test of the crude primary event rates, smaller differences than 3% cannot be distinguished; while for a 1-sided test of times to primary event, reductions in the hazard ratio less substantial than 0.77 cannot be distinguished. The researchers still do not have sufficient numbers of primary prevention trials to make strong recommendations about statins in intermediate-risk populations (6%-12% 10-year risk), at least on the basis of survival.
Yet even in this relatively high-risk older adult population (22%-25% 10-year risk), significant reductions in cardiovascular events were not found. Accordingly, until the Australian STAREE randomized trial of statin use among older adults concludes, the study provides some support to the concerns increasingly raised about benefits and harms of statins among older adults at higher risk of CVD, the team concluded.