Apolipoprotein E genotypes predict attendance rates at lipid clinic

Except for the rare 22 genotype it remains largely unsettled whether apolipoprotein E genotype influences an individualʹs referral to lipid clinics. To test this hypothesis, we compared genotype distributions among 156 hypercholesterolemic and 83 hypertriglyceridemic patients attending a lipid clinic with that among 9241 individuals sampled from the Danish general population. The relative genotype frequencies of 22, 32, 42, 33, 43, and 44 were 0.005, 0.126, 0.026, 0.564, 0.251, and 0.027 in the general population, which differed from genotype frequencies in both hypercholesterolemic (χ2: P=0.01) and hypertriglyceridemic patients (χ2: P<0.001). By comparison with 33, 44 predicted a 2-fold increase whereas 32 predicted a 2-fold decrease in the attendance rate at the lipid clinic for hypercholesterolemic patients (95% confidence intervals: 1.1–4.3 and 0.2–0.9). Among hypertriglyceridemic patients, 22, 42, 43, and 44 versus 33 predicted 13-, 3-, 1 -, and 3-fold attendance rates at the lipid clinic, respectively (95% confidence intervals: 4.5–39.9, 1.2–8.4, 1.0–2.8, and 1.1–7.6). These findings are in accordance with the fact that 44 raises cholesterol levels, 32 reduces cholesterol levels, and 22, 42, 43, and 44 raise triglyceride levels in comparison with 33. These data suggest that hypercholesterolemic individuals carrying 44 and hypertriglyceridemic individuals carrying 22, 42, 43, or 44 are relatively more often referred to lipid clinics than carriers of 33.