TOPLINE:

Among adult kidney transplant recipients, plasma levels of symmetric dimethylarginine (SDMA) were associated with an increased risk for mortality, independent of kidney function.

METHODOLOGY:

• Researchers conducted a prospective cohort study to evaluate the association between plasma levels of SDMA and urea and mortality in 628 adult kidney transplant recipients (mean age, 53 years; 56% men) enrolled from a cohort study in Netherlands; they were assessed at a median of 5.2 years after transplantation.
• Plasma levels of SDMA were measured using liquid chromatography-mass spectrometry in blood samples collected after an overnight fasting period of at least 8 hours and stored at -80 °C. Other clinical assays, including the measurement of plasma urea levels, were performed using routine automated laboratory methods.
• The primary endpoint was all-cause mortality. Cause-specific mortality, including deaths attributed to cardiovascular disease, infection, malignancy, and miscellaneous causes, was also evaluated.
• Participants were followed up for a median of 5.5 years after the baseline blood sampling visit, which occurred at least 1 year after transplantation.

TAKEAWAY:

• In unadjusted analyses, both plasma levels of urea (hazard ratio [HR] per doubling, 2.21; 95% CI, 2.22-2.85) and SDMA (HR per doubling, 2.69; 95% CI, 1.95-3.70) were strongly associated with an increased risk for all-cause mortality.
• After adjustment for potential confounders, plasma levels of SDMA remained independently associated with an increased risk for mortality (HR per doubling, 3.24; 95% CI, 1.75-5.99); however, the association for urea levels was attenuated (HR per doubling, 1.75; 95% CI, 1.03-2.99).
• In adjusted models including both plasma levels of urea and SDMA simultaneously, only levels of SDMA remained significantly associated with an increased risk for mortality (HR per doubling, 2.94; 95% CI, 1.55-5.59), whereas levels of urea did not.

IN PRACTICE:

"Plasma SDMA concentrations were associated with a higher mortality risk. Interestingly, these associations strengthened upon adjustment for kidney function, suggesting that SDMA is not an inert uremic retention solute and may be involved in additional ongoing pathological processes," the authors wrote.

SOURCE:

This study was led by Daan Kremer, MD, PhD, University Medical Center Groningen, Groningen, Netherlands. It was published online on May 04, 2026, in Kidney360.

LIMITATIONS:

The observational study design prevented the establishment of causal relationships. The study population consisted predominantly of White Dutch individuals, limiting the generalisability of the findings. Additionally, the study lacked serial measurements of SDMA, and there was a potential for residual unmeasured confounding.

DISCLOSURES:

This study received a grant from Top Institute Food and Nutrition. Some authors reported receiving research funding; holding ownership interests, patents, or royalties; serving in advisory or leadership roles; or being employed by various organisations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.