Abstract 17184: Achievement Of LDL-cholesterol Reduction Targets is Associated With Reduced Cardiovascular Disease Risk Among Patients With Familial Hypercholesterolemia in a Large Electronic Medical Record Database

Abstract

Introduction: Heterozygous familial hypercholesterolemia (FH) is common but under-recognized, with an estimated prevalence of 1:200-1:500 and an associated high risk of premature cardiovascular disease (CVD). Little is known regarding the association between change in low-density lipoprotein cholesterol (LDL-C) and long-term CVD risk in FH patients. We hypothesized that FH patients who achieved LDL-C < 100 mg/dL or reduction ≥50% post-statin initiation would have reduced risk of non-fatal myocardial infarction (MI) or revascularization. Methods: Using Dutch Lipid Network criteria components, 174 “probable” and 125 “definite” FH patients with LDL-C measurements available before and after statin initiation were identified in the Vanderbilt de-identified electronic medical records (EMR) Synthetic Derivative database, 1996-2014. First non-fatal MI or revascularization was identified via validated EMR algorithm with positive predictive value=92%. Hazard ratios (HR) and 95% confidence intervals (CI) were obtained from Cox regression models in relation to LDL-C levels (≥ vs. <50% reduction or < vs. >100 mg/dL post-statin), adjusted for age, race, sex, blood pressure, smoking, and body mass index. Results: Mean (+/- SD) LDL-C levels prior to initiation of statin therapy were 207 (+/- 31) for probable and 304 (+/- 124) mg/dL for definite FH patients. Similar proportions of patients attained ≥50% reduction in LDL-C after statin initiation in both groups (24.1% and 26.4%), while 22.4% achieved LDL-C < 100 mg/dL in the probable group compared to only 4.8% in the definite group. Over median follow-up of 5.4 years, 34 probable and 19 definite FH patients experienced non-fatal MI or revascularization. The HR (95% CI) among those with post-statin LDL-C < 100 vs >100 mg/dL was 0.59 (0.23-1.52) overall, with no evidence of effect modification by probable/definite FH status (likelihood ratio test (LRT) p-value=0.58). A similar pattern was observed for LDL-C change ≥50% vs <50% (HR (95% CI) 0.58 (0.24-1.38), LRT p-value=0.44). Conclusions: In this small sample of FH patients, lowering LDL-C to <100 mg/dL suggests a reduction in CVD risk, but few attained this LDL-C target. These results warrant further research in larger populations of this understudied condition.