Baseline, delta, and achieved low-density lipoprotein cholesterol levels and cardiovascular risk in patients on statin therapy: A post-hoc resampling mediation analysis of treating new targets [TNT] trial

Abstract

Clinical guidelines for monitoring low-density lipoprotein cholesterol (LDL-C) after statin therapy do not clearly define the clinical roles of baseline LDL-C, Delta LDL-C, and achieved LDL-C according to statin intensity. We performed post-hoc analysis of the Treating to New Target (TNT) study to evaluate individual LDL-C parameters after statin therapy. Primary outcome was the risk for total major adverse cardiovascular events (MACE). We use resampling multilevel mediation analysis to analyze complex relationships among LDL-C parameters based on similar statin intensities. Tertiles for resample A (matched baseline LDL-C; distinct achieved LDL), resample B (matched Delta LDL-C; distinct baseline LDL-C), and resample C (matched achieved LDL-C; distinct Delta LDL-C) were analyzed using Cox proportional hazard ratios. In original data analysis, the incidence of MACE was reduced in those with lower achieved LDL-C in total, low, and high intensity statin users (hazard ratios [HRs] = 0.990, 0.992, 0.992; respectively; allP-values < .001). In mediation analysis, resample A showed consistently high incidence for MACE in the middle tertile (HR = 1.237; 95% confidential interval [CI] = 1.008-1.517;P-value = .041) and highest tertile (HR = 1.275; 95% CI = 1.021-1.592;P-value = .032) compared to the lowest tertile. However, resamples B and C did not show consistent differences. Similarly, no consistent statistical difference in MACE according to statin intensity. Lower achieved LDL-C decreased MACE in participants with a similar baseline LDL-C after statin therapy. However, the change in absolute values of Delta LDL-C and achieved LDL-C should be interpreted in an individualized manner due to their complex collinearity, and statin intensity should also be taken into consideration.