PROGNOSTIC CUT-OFF VALUES OF SERUM URIC ACID ASSOCIATED WITH FATAL AND NON FATAL INCIDENT MYOCARDIAL INFARCTION INDEPENDENTLY OF ARTERIAL HYPERTENSION IN A LARGE COHORT

Abstract

Objective: Searching for a prognostic cut-off value of serum uric acid (SUA) in predicting myocardial infarction (MI) in a large regional-based Italian cohort of men and women in the frame of the URRAH study (URic Acid Right for heArt Health). Design and method: The ongoing large database URRAH collects data from studies and cohorts from hypertension centres and epidemiological laboratories, including subjects with at least 1 measure of SUA and a follow-up of ∼20 years. Incident myocardial infarction (MI) was defined in 23,475 subjects on the basis of ICD10 codes and double-checked with general practitioners and hospital files. Multivariate dichotomic Cox regression models having fatal and morbid MI as dependent variables, adjusted for arterial hypertension (AH), age, sex, diabetes, hematocrit, LDL-cholesterol, smoking and chronic renal disease were preliminarily used to search for an association between SUA as a continuous variable and MI. Two prognostic cut-off values (one for fatal and one for morbid MI), identified by means of receiver operating curves (ROC) and able to discriminate between subjects doomed to develop the event, were then used as independent predictors to divide people into those <cut-off and >cut-off in further multivariate Cox models adjusted for the confounders listed above. Results: In Cox analysis, SUA as a continuous variable was a significant predictor of fatal [odds ratio, OR, 1.457 (1.029–1.240), p < 0.001] and morbid [OR 1.254 (1.111–1.306), p < 0.0001] incident MI, independently of AH. ROC showed that >5.70 mg/dl (95%CI 5.10–6.42, sensitivity 46.6, specificity 71.3, p < 0.0001) was the prognostic cut-off value for fatal MI and >4.30 mg/dl (95%CI 3.79–5.20, sensitivity 79.5, specificity 34.0, p < 0.0001) for morbid MI. These two values were accepted as multivariate predictors in Cox analyses, the hazard ratios being 1.23 (95%CI 1.04–1.68, p = 0.022) for fatal and 1.73 (95%CI 1.22–2.47, p = 0.002) for morbid MI. Conclusions: In conclusion, clear prognostic cut-off values of SUA for fatal (>5.20 mg/dl) and morbid (>4.30 mg/dl) MI do exist also after adjustment for confounders including AH.