Relationship between estimated glomerular filtration rate and incident cardiovascular disease in an ethnically diverse primary care cohort.

Aim: To investigate eGFR as an independent risk factor for CVD in a New Zealand primary care cohort, stratified by disease status (prior CVD, diabetes or no CVD or diabetes).

Method: The PREDICT-CVD open cohort study is a large, ethnically diverse, New Zealand primary care cohort, generated by using a web-based CVD risk assessment tool. Using encrypted identifiers, participant profiles were linked anonymously to a regional laboratory database (to determine renal function) and to national hospitalisation and mortality datasets. Analyses using a single baseline eGFR measurement were undertaken in three clinical sub-cohorts of participants: those with prior CVD (n=29,742), with diabetes (n=44,416) and with neither CVD nor diabetes (n=192,696). The association between baseline eGFR (by category ≥90, 60-89.9, 30-59.9, and <30ml/min/1.73m2) and incident CVD was analysed with Kaplan Meier plots and Cox regression models.

Results: After adjustment for traditional CVD risk factors, there was an inverse relationship between CVD risk and eGFR, up to an eGFR of 60ml/min/1.73m2 in all three clinical sub-cohorts, and up to an eGFR of 90ml/min/1.73m2 in the sub-cohort with CVD or diabetes. Compared to eGFR ≥90ml/min/1.73m2, the adjusted hazard ratios of a new CVD event for eGFR <30ml/min/1.73m2 in the CVD, diabetes and no CVD/no diabetes sub-cohorts were 2.29 (95% CI 2.00-2.61), 4.71 (3.92-5.67) and 2.78 (2.05-3.77), respectively. Compared to European/Other ethnic groups, Māori participants remained at greater adjusted risk of a new CVD event in all clinical sub-cohorts and Pacific people only in the no CVD/no diabetes sub-cohort, whereas Indian participants had a similar adjusted risk to European/Other, and Other Asian patients were consistently at lower adjusted risk. Sensitivity analyses for individuals with consecutive eGFR results (>90 days apart) yielded similar results.

Conclusion: This study has confirmed that, in a large ethnically diverse primary care cohort, eGFR is a significant independent predictor of CVD risk, and the risk varies by ethnic group.