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Il colesterolo non-HDL è buon predittore del rischio cerebrovascolare

Il colesterolo non-HDL che è facilmente calcolabile sottraendo il valore del colesterolo HDL da quello del colesterolo totale, dà una stima della concentrazione delle lipoproteine aterogene (LDL, VLDL, IDL e Lp(a)). Se ne parla da molto tempo ma, nonostante basi teoriche solide e vari studi clinici di conferma, il colesterolo non-HDL non ha avuto la fortuna che probabilmente merita come indicatore di rischio cardiovascolare. L'attenzione è sempre stata monopolizzata dal colesterolo LDL, la cui stima è generalmente basata sull'equazione di Friedewald che, benché ampiamente validata, non è certamente esente da errori soprattutto perché si basa sull'assunto di un rapporto costante tra trigliceridi e colesterolo nelle VLDL. In questo studio è stato ricalcolato il rischio di eventi cerebrovascolari nel ben noto studio CARE ed il valore del colesterolo non-HDL è risultato essere il parametro lipidico con il più alto peso predittivo. Se il colesterolo non-HDL dà una valida stima del rischio, può anche essere considerato un valido obiettivo terapeutico.

Role of non-high-density lipoprotein cholesterol in predicting cerebrovascular events in patients following myocardial infarction

Mahajan N, Ference BA, Arora N, Madhavan R, Bhattacharya P, Sudhakar R, Sagar A, Wang Y, Sacks F, Afonso L

Am J Cardiol 2012;109:1694 -1699

Although there appears to be a role for statins in reducing cerebrovascular events, the exact role of different lipid fractions in the etiopathogenesis of cerebrovascular disease (CVD) is not well understood. A secondary analysis of data collected for the placebo arm (n = 2,078) of the Cholesterol and Recurrent Events (CARE) trial was performed. The CARE trial was a placebo-controlled trial aimed at testing the effect of pravastatin on patients after myocardial infarction. Patients with histories of CVD were excluded from the study. A Cox proportional-hazards model was used to evaluate the association between plausible risk factors (including lipid fractions) and risk for first incident CVD in patients after myocardial infarction. At the end of 5 years, 123 patients (6%) had incident CVD after myocardial infarction (76 with stroke and 47 with transient ischemic attack). Baseline non-high-density lipoprotein (HDL) cholesterol level emerged as the only significant lipid risk factor that predicted CVD; low-density lipoprotein cholesterol and HDL cholesterol were not significant. The adjusted hazard ratios (adjusted for age, gender, hypertension, diabetes mellitus, and smoking) for CVD were 1.28 (95% confidence interval [CI] 1.06 to 1.53) for non-HDL cholesterol, 1.14 (95% CI 0.96 to 1.37) for low-density lipoprotein cholesterol, and 0.90 (95% CI 0.75 to 1.09) for HDL cholesterol (per unit SD change of lipid fractions). This relation held true regardless of the level of triglycerides. After adjustment for age and gender, the hazard ratio for the highest natural quartile of non-HDL was 1.76 (95% CI 1.05 to 2.54), compared to 1.36 (95% CI 0.89 to 1.90) for low-density lipoprotein cholesterol. In conclusion, non-HDL cholesterol is the strongest predictor among the lipid risk factors of incident CVD in patients with established coronary heart disease.

Am J Cardiol 2012;109:1694 -1699