Association of the malnutrition-inflammation score with clinical outcomes in kidney transplant recipients

Background: The combination of chronic malnutrition and inflammation, often termed malnutrition-inflammation complex syndrome or protein-energy wasting, is common in patients with chronic kidney disease. It is associated with increased mortality in patients on maintenance dialysis therapy. We assessed the association of malnutrition-inflammation score (MIS) with all-cause mortality and death-censored transplant loss or death with a functioning transplant in a sample of kidney transplant recipients.

Study design: Prospective prevalent cohort study.

Setting & participants: Data from 993 prevalent transplant recipients were analyzed. Sociodemographic parameters, laboratory data, medical and transplant history, comorbid conditions, estimated glomerular filtration rate, and MIS were tabulated at baseline and annually thereafter.

Predictor: MIS, a 30-point scale expressed per 1 standard deviation (1 SD) unit or categorized as <3 (reference), 3-5, 6-8, and >8. The MIS is derived from 10 components, each with 4 levels of severity from 0 (normal) to 3 (severely abnormal). Higher score reflects more severe degree of malnutrition and inflammation status.

Outcomes: All-cause mortality and death-censored transplant loss or death with a functioning transplant. Association of MIS with total mortality was assessed using time-dependent Cox regression analysis, and the association of MIS with death-censored transplant loss or death with a functioning transplant was assessed using semiparametric competing-risks regression analysis.

Results: Mean age was 51 ± 13 years, 57% of patients were men, and 21% had diabetes. Percentages of patients in the MIS categories <3, 3-5, 6-8, and >8 were 40%, 32%, 20%, and 8%, respectively. In multivariable time-dependent Cox regression analyses, time-varying MIS score was a significant predictor of all-cause mortality (HR per 1-SD increase, 1.59; 95% CI, 1.37-1.85), death with a functioning transplant (HR per 1-SD increase, 1.48; 95% CI, 1.23-1.78), and death-censored transplant loss (HR per 1-SD increase, 1.34; 95% CI, 1.04-1.71). Compared with MIS <3, HRs for all-cause mortality for MIS of 3-5, 6-8, and >8 were 1.53 (95% CI, 0.74-3.15), 3.66 (95% CI, 1.87-7.14), and 6.82 (95% CI, 3.34-13.91), respectively.

Limitations: Single-center study, small number of outcomes.

Conclusions: The MIS, a simple tool to assess the presence of malnutrition-inflammation complex syndrome, predicts mortality in kidney transplant recipients.