The Framingham predictive instrument in chronic kidney disease

Abstract

Objectives: We sought to determine the utility of the Framingham equations in individuals with chronic kidney disease (CKD).

Background: The Framingham equations predict incident coronary disease. The utility of these equations is unknown in CKD.

Methods: We pooled individuals without pre-existing coronary disease age 45 to 74 years from the ARIC (Atherosclerosis Risk In Communities) and CHS (Cardiovascular Health Study) trials with CKD, defined by an estimated glomerular filtration rate of 15 to 60 ml/min/1.73 m(2). Using gender-specific models, we determined 5- and 10-year risk of incident myocardial infarction and fatal coronary disease, and evaluated discriminative and calibration ability of the Framingham equations for predicting coronary events.

Results: There were 577 women and 357 men with CKD. Thirty-five men (9.8%) and 30 women (5.2%) and 74 men (20.7%) and 56 women (9.7%) had cardiac events within 5 and 10 years, respectively; 5-year events were predicted in 6.0% and 1.9% and 10-year events in 13.9% and 4.8% of men and women, respectively. For 5-year events, C-statistics assessing discrimination were 0.62 and 0.77, while 10-year C-statistics were 0.60 and 0.73 for men and women, respectively. Calibration was also poor, with Framingham scores generally underpredicting events in individuals with CKD at 5 and 10 years. Discrimination was significantly improved by refitting models with population-specific coefficients, while recalibration improved prediction in women.

Conclusions: The Framingham instrument demonstrates poor overall accuracy in predicting cardiac events in individuals with CKD, although refit models can substantially improve discrimination. Calibration in women can be moderately improved with adjustment for higher event rates. Development of CKD-specific equations is needed.