Abstract

Background and objectives: Renal transplantation is considered the preferred treatment in end-stage renal disease. Despite improved short-term graft survival over recent years, long-term graft survival after renal transplantation has not improved. Research in this field is traditionally dominated by immunological evaluation and treatment, however non-immunological causes including diet and lifestyle are often overlooked. In the general population the Mediterranean Diet is associated with better cardiovascular and renal outcomes. We investigated whether adherence to the Mediterranean Diet is associated with graft failure in a large cohort of renal transplant recipients (RTR). Methods: In this prospective observational cohort study we included all adult RTR with a functioning graft for ≥ 1 year who visited the outpatient clinic. Dietary intake was assessed using a validated Food Frequency Questionnaire of 177 food items. RTR missing dietary data were excluded, leaving 632 RTR eligible for analyses. Adherence to the Mediterranean Diet was calculated using the nine-point Mediterranean Diet Score (MDS) by Trichopoulou based on intake of legumes, nuts, soy products, cereals, fruit, vegetables, meat , dairy, fish, alcohol and fat. Cox regression was used to analyze the association of MDS on death-censored graft failure. Results: Mean ± SD age was 53 ± 13 years, 57% were male. Mean MDS was 4.7 ± 1.7. During median [IQR] follow-up of 5.3 [4.5-6.0] years, 76 RTR developed graft failure. MDS was inversely associated with graft failure (HR 0.88 [95%CI 0.77-0.99] per MDSpoint increase). Adjustment for potential confounders including age, sex, time after transplantation, primary renal disease, eGFR, urinary protein excretion, smoking status and physical activity did not materially alter this association (HR 0.84 [95%CI 0.73-0.98] per MDS-point increase). When divided in tertiles, risk of graft failure was twice as high in RTR in the lowest tertile of MDS compared to RTR in the highest tertile of MDS (HR 2.0 [95%CI 1.05- 3.84]), independent of potential confounders. Conclusions: Higher adherence to the Mediterranean Diet is associated with lower risk of graft failure, independent of potential confounders. These findings suggest increasing Mediterranean Diet adherence may be a novel measure to improve long-term graft survival in RTR.