Serum Albumin Level Before Kidney Transplant Predicts Post-transplant BK and Possibly Cytomegalovirus Infection

Introduction: Opportunistic viral infections cause extensive morbidity and mortality in kidney transplant recipients (KTRs). Low serum albumin levels before and after transplant have been associated with negative outcomes. However, it is uncertain whether serum albumin levels before transplantation are associated with the risk for post-transplantation opportunistic BK polyomavirus (BKV) or cytomegalovirus (CMV).

Methods: We reviewed all KTRs transplanted at our institution between 1 January 2005 and 31 December 2015 with serum albumin measured within 45 days before transplantation in a retrospective observational cohort study. Selected patients were stratified into 3 groups: normal albuminemia (≥3.5 g/dl), moderate hypoalbuminemia (3.49-2.5 g/dl), and severe hypoalbuminemia (<2.5 g/dl). Patients were observed for post-transplantation BKV or CMV according to standard of care.

Results: We included 1717 patients in this study; 72.3% had normal serum albumin, 26.3% had moderate hypoalbuminemia, and 1.5% had severe hypoalbuminemia. Moderate and severe hypoalbuminemia incurred a higher risk for BKV compared with normal serum albumin levels in univariable analysis (moderate hypoalbuminemia: hazard ratio [HR] = 1.5; 95% confidence interval [CI], 1.14-1.90; P = .003); severe hypoalbuminemia: HR = 2.15; 95% CI, 1.01-4.56; P = 0.05). Although not significant after multivariable adjustment, there was still 18% increased risk in moderate hypoalbuminemia and 64% in severe hypoalbuminemia for BKV compared with the normal albumin group. Moderate hypoalbuminemia was associated with a higher risk for CMV infection than normal serum albumin levels in multivariable analysis, although it was not statistically significant (HR = 1.15; 95% CI, 0.36-3.64; P = 0.81).

Conclusions: These findings suggest that pretransplantation hypoalbuminemia is associated with a higher risk for post-transplantation BKV and possibly CMV. More intense screening is warranted for these viruses in recipients with pretransplant hypoalbuminemia.