Research in context
Evidence before this study
We searched PubMed in addition to manual searches of reference lists of previous studies, and identified a few studies specifically assessing the improvement of cardiovascular risk prediction by incorporation of either or both kidney measures (estimated glomerular filtration rate [eGFR] based on serum creatinine, cystatin C, or both) and kidney damage (based on albuminuria or proteinuria), exclusively or predominantly in individuals without history of cardiovascular disease at baseline. However, these studies obtained conflicting results and varied substantially in terms of study population and method, making achievement of definitive conclusions difficult and leading to inconsistent approaches about how to incorporate measures of kidney disease in assessment of cardiovascular risk across different clinical guidelines.
Added value of this study
We meta-analysed individual-level data from 24 cohorts (637 315 participants without a history of cardiovascular disease) and assessed risk prediction improvement with either or both of creatinine-based eGFR and albuminuria (albumin-to-creatinine ratio [ACR] or dipstick proteinuria) for cardiovascular mortality, coronary disease, stroke, and heart failure. Although creatinine-based eGFR and albuminuria independently improved cardiovascular prediction in general, the improvement was particularly evident for cardiovascular mortality and heart failure. ACR outperformed eGFR and most of the modifiable traditional risk factors for these two outcomes, as well as stroke. The discrimination improvement with ACR was especially evident in individuals with diabetes or hypertension but remained significant for cardiovascular mortality and heart failure even in those without either of these disorders. When the analysis was restricted to patients with chronic kidney disease (CKD), the combination of eGFR and ACR for risk discrimination outperformed most single traditional predictors, suggesting the value of their simultaneous assessment for cardiovascular risk classification.
Implications of all the available evidence
Creatinine-based eGFR and albuminuria should be taken into account for cardiovascular prediction, especially when they are already assessed for clinical purposes (eg, in individuals with chronic kidney disease, diabetes, or hypertension), or when cardiovascular mortality and heart failure are the outcomes of interest (eg, as stated by European guidelines for cardiovascular prevention). ACR could have particularly broad implications for cardiovascular prediction. In populations with chronic kidney disease, the simultaneous assessment of eGFR and ACR could facilitate improved cardiovascular risk classification, supporting current guidelines for chronic kidney disease.