Serum β2-microglobulin at discharge predicts mortality and graft loss following kidney transplantation

Area of Science:

• Nephrology
• Transplantation Immunology
• Clinical Biomarkers

Background:

• Serum beta-2 microglobulin (β(2)M) is a known marker for kidney function and mortality in the general population.
• Elevated β(2)M post-transplant can indicate acute rejection, but its association with long-term outcomes is unclear.

Purpose of the Study:

• To investigate the association between serum β(2)M levels at discharge and long-term outcomes in primary kidney transplant recipients.
• To compare the predictive power of serum β(2)M with serum creatinine for post-transplant mortality and graft loss.

Main Methods:

• Retrospective cohort study of 2190 primary kidney transplant recipients.
• Serum β(2)M measured at discharge; median follow-up of 4.1 years.
• Statistical analysis adjusted for relevant covariates, including delayed graft function, donor type, and eGFR.

Main Results:

• The highest quintile of discharge serum β(2)M (≥5.0 mg/L) was associated with significantly increased hazard ratios for death (4.6), death-censored graft loss (4.1), and total graft loss (3.8) compared to the lowest quintile (<2.3 mg/L).
• Serum β(2)M demonstrated a stronger association with these outcomes than serum creatinine.
• These associations remained significant across various subgroups, including those with delayed graft function or different eGFR levels.

Conclusions:

• Discharge serum β(2)M is a potent, independent predictor of long-term mortality and graft loss in kidney transplant recipients.
• Serum β(2)M provides prognostic information beyond that of traditional markers like serum creatinine.
• This biomarker can aid in risk stratification and management of kidney transplant patients.