Association between baseline LDL-C level and total and cardiovascular mortality after LDL-C lowering a systematic review and meta-analysis

Abstract

IMPORTANCE: Effects on specific fatal and nonfatal end points appear to vary for low-density lipoprotein cholesterol (LDL-C)-lowering drug trials. OBJECTIVE: To evaluate whether baseline LDL-C level is associated with total and cardiovascular mortality risk reductions. DATA SOURCESAND STUDY SELECTION: Electronic databases (Cochrane, MEDLINE, EMBASE, TCTMD, ClinicalTrials.gov, major congress proceedings) were searched through February 2, 2018, to identify randomized clinical trials of statins, ezetimibe, and PCSK9-inhibiting monoclonal antibodies. DATA EXTRACTION AND SYNTHESIS: Two investigators abstracted data and appraised risks of bias. Intervention groups were categorized as "more intensive" (more potent pharmacologic intervention) or "less intensive" (less potent, placebo, or control group). MAIN OUTCOMES AND MEASURES: The coprimary end points were total mortality and cardiovascular mortality. Random-effects meta-regression and meta-analyses evaluated associations between baseline LDL-C level and reductions in mortality end points and secondary end points including major adverse cardiac events (MACE). RESULTS: In 34 trials, 136 299 patients received more intensive and 133 989 received less intensive LDL-C lowering. All-cause mortality was lower for more vs less intensive therapy (7.08% vs 7.70%; rate ratio [RR], 0.92 [95% CI, 0.88 to 0.96]), but varied by baseline LDL-C level. Meta-regression showed more intensive LDL-C lowering was associated with greater reductions in all-cause mortality with higher baseline LDL-C levels (change in RRs per 40-mg/dL increase in baseline LDL-C, 0.91 [95% CI, 0.86 to 0.96]; P =.001; absolute risk difference [ARD], -1.05 incident cases per 1000 person-years [95% CI, -1.59 to -0.51]), but only when baseline LDL-C levels were 100 mg/dL or greater (P