Risk Factors and Outcome in Living Kidney Donors: A Narrative Review

Background/Objectives: Candidates with cardiometabolic risk are considered for living kidney donation more frequently because of the global organ shortage. The 2017 Kidney Disease: Improving Global Outcomes (KDIGO) guidelines introduced individualized risk assessment based on composite donor profiles rather than categorical exclusion, but the long-term implications of accepting donors with potential risk factors require careful evaluation. This review synthesizes current evidence on outcomes of living kidney donors with obesity, prediabetes, hypertension, and smoking. Methods: A literature search was conducted in PubMed/MEDLINE for studies published between 1 January 2000 and 28 February 2026, including cohort studies, registry analyses, meta-analyses, and clinical guidelines evaluating living kidney donors with obesity, smoking, prediabetes, or hypertension. Priority was given to large cohorts with long-term follow-up. Over 70 publications were included in the final synthesis. Findings were synthesized narratively by risk factors and outcomes. Results: Obesity was associated with an 86% increased end-stage kidney disease (ESKD) risk and 32% increased 20-year mortality. Central adiposity measures outperformed body mass index (BMI) for predicting estimated glomerular filtration rate (eGFR) decline. Post-donation weight gain increased the risk for developing hypertension and diabetes. Smoking conferred a 7.5-fold chronic kidney disease (CKD) risk, with impaired compensatory renal adaptation after donation. Prediabetic donors showed comparable outcomes to normoglycemic donors, with 57.8% reverting to normoglycemia at 10 years. Pre-donation hypertension increased 15-year ESKD risk 3-fold, but absolute risk remained low. At 15 years post-donation, over 50% of the donors developed hypertension. Glucagon-like peptide-1 (GLP-1) receptor agonists reduce diabetes progression by 73–94% in at-risk populations, but prospective studies in donors are lacking. Conclusions: Each risk factor carries quantifiable risks for individualized stratification. These risk factors usually coexist and interact. Refinement of risk prediction models, strategies for metabolic optimization and prospective evaluation of emerging pharmacologic therapies are key priorities.