Kidney function and discrimination of cardiovascular risk in middle-aged men.

OBJECTIVE

To define the optimal glomerular filtration rate (GFR) cut off for discriminating the risk of myocardial infarction or cardiovascular death.

DESIGN

Prospective longitudinal observational study.

SETTING

A community-based cohort.

PARTICIPANTS

A total of 2176 nondiabetic 50-year-old men without cardiovascular disease.

METHODS

The men were followed until age 70. GFR was estimated at baseline using the Cockcroft-Gault formula. The optimal GFR cut-off points for discriminating risk of a fatal or nonfatal myocardial infarction and cardiovascular death were defined as the GFR levels maximizing integrated discrimination improvement (IDI).

MAIN OUTCOME MEASURES: Fatal or nonfatal myocardial infarction, cardiovascular death.

RESULTS

During follow-up, 264 men experienced a fatal or nonfatal myocardial infarction, and 218 died of cardiovascular disease. The IDI-defined optimal GFR cut offs in this study were 98 mL min(-1) for discriminating myocardial infarction risk and 92 mL min(-1) for discriminating risk of cardiovascular death. In Cox proportional hazard models adjusting for established risk factors, the myocardial infarction risk was substantially higher in men with GFR below versus above 98 mL min(-1) [hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.3-2.3, P < 0.001], and the risk of cardiovascular death was doubled in men with GFR below versus above 92 mL min(-1) (HR 2.1, 95% CI 1.5-3.0, P < 0.001).

CONCLUSION

The GFR cut-off point for optimal discrimination of cardiovascular risk in the general population may be higher than previously suggested.