C-reactive protein and 5-year survival in type 2 diabetes: the Casale Monferrato Study

Objective: to determine to what extent plasma CRP values influence 5-year all-cause and cardiovascular mortality in type 2 diabetic persons, independently of albumin excretion rate (AER) and other cardiovascular risk factors, and its incremental usefulness for predicting individual risk of mortality. Research Design and Methods: Measurements of CRP were performed in 2381/3249 (73.3%) persons, as part of the population-based Casale Monferrato Study. Its association with 5-years all-cause and cardiovascular mortality was assessed with multivariate Cox proportional hazards modeling. The C statistic and measures of calibration and global fit were also assessed. Results: Results are based on 496 deaths in 11.717 person-years of observations (median follow-up 5.4 years). With respect to subjects with CRP≤3 mg/l, those with higher values had an adjusted hazard ratio (HR) =1.51 (95% CI 1.18-1.92) of all-cause mortality and an HR=1.44 (95% CI 0.99-2.08) of cardiovascular mortality. In normoalbuminuric people, respective HRs of CRP were 1.56 (1.13-2.15) and 1.65 (1.00-2.74), AER being neither a modifier nor a confounder of CRP association. In analysis limited to diabetic persons without CVD, adjusted HRs were 1.67 (95% CI 1.24-2.24) for all-cause mortality and 1.36 (95% CI 0.83-2.24) for cardiovascular mortality. The improvement in individual risk assessment was marginal when measured with various statistical measures of model discrimination, calibration and global fit. Conclusions: CRP measurement is independently associated with short-term mortality risk in type 2 diabetic people, even in normoalbuminuric people and in those without a previous diagnosis of CVD; its clinical usefulness in individual assessment of 5-years risk mortality, however, is limited.