Objectives: The aims of this study were to evaluate whether hidden chronic renal insufficiency (CRI) may be considered an independent cardiovascular risk factor in patients with hypertension and to calculate cardiovascular risk in this population.
Methods: A total of 756 hypertensive patients of ages from 35 to 74 years (mean 57.0 years; 58.2% women) and without evidence of cardiovascular disease were studied and followed during 10 years. Their glomerular filtration rate (GFR) was estimated using the simplified MDRD (result of the Modification of Diet in Renal Disease study) and Cockcroft-Gault formulas. Hidden CRI was identified by a GFR <60 mL/min/1.73 m(2) with normal serum creatinine concentration (<1.4 mg/dL men; <1.3 mg/dL women).
Results: Of the patients with hidden CRI using the MDRD equation, 22% presented cardiovascular events (RR, 1.60; 95% confidence interval (CI), 1.06-2.43; p < 0.05). While the estimated coronary risk using the original Framingham function was similar in patients with and without hidden CRI (18.2%), using the REGICOR function it was higher in those with CRI (7.7 vs. 7.2%, p < 0.05). Logistic regression analysis showed that smoking, male sex, age, and diastolic blood pressure were predictors of cardiovascular events. The presence of hidden CRI was not a statistically significant predictor using either the MDRD (OR, 1.37; 95% CI, 0.72-2.61; p = 0.340) or the Cockcroft-Gault (OR, 1.05; 95% CI, 0.50-2.23; p = 0.893) formulas.
Conclusions: The hypertensive population of 35-74 years in age with hidden CRI showed a higher incidence of cardiovascular events, but hidden CRI may not be considered an independent cardiovascular risk factor.