Prediabetes After Kidney Transplant Increases Cardiovascular Risk

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Prediabetes after kidney transplantation is associated with an increased risk of cardiovascular events, similar to that seen with posttransplant diabetes mellitus (PTDM), reports a study in Kidney International.

The researchers present long-term follow-up data on 603 kidney transplant recipients, enrolled in a multicenter study of the clinical evolution of prediabetes and PTDM. Patients underwent serial oral glucose tolerance tests for up to 5 years; median follow-up was 8.38 years. The presence of prediabetes and PTDM was determined at 12 months after transplantation, due to the reversibility of these conditions at earlier times. The association of prediabetes with later fatal or nonfatal cardiovascular events was assessed.

At 12 months, 27% of patients were classified as having prediabetes and 16% as having PTDM. Patients with these conditions were older, more likely to be men, and more likely to be obese. Of the total 116 cardiovascular events, 73 occurred more than 12 months after transplantation.

The incidence of events after 12 months was 17% in patients with prediabetes and 20% in those with PTDM, compared to 7% in patients with normal glucose metabolism. Incidence rates were 0.023, 0.028, and 0.0095 events/person-year, respectively. On multivariate analysis, both abnormalities were associated with a twofold increase in cardiovascular events: hazard ratio 2.41 for prediabetes and 2.24 for PTDM. Prediabetes at 3 months and glycated hemoglobin at 12 months were unrelated to cardiovascular events. Neither prediabetes nor PTDM was a risk factor for total mortality.

Prediabetes or PTDM occurs in 20% to 30% of patients after renal transplantation. Although PTDM is a known risk factor for cardiovascular disease, less is known about the impact of prediabetes.

This cohort study finds a 27% incidence of prediabetes 12 months after kidney transplantation, along with a 16% incidence of PTDM. Both conditions are associated with an increased risk of fatal or nonfatal cardiovascular events, in a group of patients already at high risk.

“Since prediabetes is potentially a reversible condition, there is an opportunity to prevent cardiovascular disease in this population,” the researchers write. They add that the oral glucose tolerance test is “a simple tool” to identify patients at risk that “should be included in clinical practice” [Porrini E, et al. Prediabetes is a risk factor for cardiovascular disease following renal transplantation. Kidney Int 2019; 96: 1374–1380].