Influence of metabolic syndrome superposition on familial combined hyperlipoproteinemia cardiovascular complication rate

INTRODUCTION Familial combined hyperlipoproteinemia (FCHL) is a very common and aggressive genetic mixed hyperlipoproteinemia, with many features similar to that of the metabolic syndrome (MS). We aimed to evaluate whether the presence of the MS per se could account for a significant part of the elevated cardiovascular disease (CVD) risk associated with FCHL. MATERIAL AND METHODS A retrospective cross-sectional evaluation of MS features' influence on CVD prevalence in a large sample of adult Italian FCHL affected patients (64 familial clusters; 867 subjects) was carried out. RESULTS Age is associated with early cardiovascular complications, both in men (OR 1.08, 95% CI: 1.05-1.11, p < 0.0001) and in women (OR 1.09, 95% CI: 1.04-1.13, p = 0.0001). No MS component appears to be related to cardiovascular complications in men, whilst only low plasma high-density lipoprotein cholesterol (HDL-C) shows such a relation in women. Among non-MS parameters, only low-density lipoprotein cholesterol (LDL-C) and lipoprotein(a) (Lp(a)) plasma levels are significantly associated with early cardiovascular complications in male FCHL patients (LDL-C: OR 2.24, 95% CI: 1.02-4.91, p = 0.04; Lp(a): OR 4.64, 95% CI: 1.85-11.62, p = 0.001), but not in women (LDL-C: OR 1.83, 95% CI 0.53-6.34, p = 0.34; Lp(a): OR 3.65, 95% CI: 0.89-14.97, p = 0.07). CONCLUSIONS Our data support the hypothesis that MS is not associated with a higher prevalence of cardiovascular complications in FCHL affected subjects, probably because of the strongest risk increase associated with the FCHL itself.