Is there a correlation between an eGFR slope measured over a 5-year period and incident cardiovascular events in the following 5 years among a Flemish general practice population: a retrospective cohort study

Objectives To examine if the estimated glomerular filtration rate (eGFR) slope over a 5-year period is related to incident cardiovascular (CV) events in the following 5 years.

Design Retrospective cohort study.

Setting Primary care.

Participants All patients aged 50years with at least four eGFR measurements between 01 January 2006 and 31 December 2010 were included in the study.

Outcome measures During the follow-up period (01 January 2011 until 31 December 2015), CV events (acute myocardial infarction, stroke (cerebrovascular accident (CVA)/transient ischemic attack (TIA)), peripheral arterial disease and acute heart failure) were identified.

Methods The slope was calculated by the least square method (in mL/min/year). The following slope categories were considered: (-1 to 1), (-3 to -1) (-5 to -3), -5, (1 to 3), (3 to 5) and 5.00mL/min/year. Cox proportional hazards model was used to assess the association between eGFR slope and incidence of CV events. Survival probability from CV events was estimated per slope category.

Results 19567 patients had at least four eGFR measurements, of whom 52% was female. 12% of the -5 slope category developed a new CV event in comparison to 7.8% of the reference group and 5.4% of the 5slope category. Survival rates were worst in those with a slope -5. Patients with a slope of (-5 to -3) and -5 had an adjusted HR of 1.37 and 1.55, respectively. Most patients with a slope 60mL/min.

Conclusions Negative eGFR slopes of at least 3mL/min/year give irrespectively of the eGFR itself a higher risk of CV events compared with patient groups with stable or improved kidney function. So the eGFR slope identifies an easy to define group of patients with a high risk for developing CV events.