High plasma lead levels tied to kidney allograft failure

Elevated lead (Pb) concentrations in plasma among kidney transplant recipients appear to contribute to an increased risk of late graft failure, a study reports.

The study followed 670 outpatient kidney transplant recipients with a functioning graft for ≥1 year for an average of 4.9 years to examine the potential link of plasma Pb to late graft failure. A parallel cohort of 46 end-stage kidney disease patients who were scheduled to receive kidney transplants was followed up at 3, 6, 12, and 24 months after transplantation.

Plasma Pb was log₂ transformed to estimate the association with outcomes per doubling of plasma Pb concentration. The plasma Pb concentration was also considered categorically as tertiles. Kidney graft failure was defined as restart of dialysis or retransplantation, assessed with the competing event of death with a functioning graft.

Median baseline plasma Pb at baseline was 0.31 μg/L overall. There were 78 (12 percent) kidney transplant recipients who developed graft failure during the follow up.

Multivariable-adjusted cause-specific hazards models showed that higher plasma Pb conferred an almost 60-percent higher risk of graft failure (per doubling of plasma Pb concentration: hazard ratio [HR], 1.59, 95 percent confidence interval [CI], 1.14‒2.21; p=0.006). This association was not modified by age, sex, transplant characteristics, estimated glomerular filtration rate, proteinuria, smoking status, alcohol intake, and plasma concentrations of cadmium and arsenic, among others.

In serial measurements, plasma Pb levels were significantly higher at admission for transplantation than at 3-months post-transplant (p=0.001) and subsequently remained stable over 2 years of follow-up (p=0.2).

More studies are needed to evaluate whether preventive or therapeutic interventions to decrease plasma Pb may be a useful risk-management strategy to lower the rate of kidney allograft failure.