Nutritional Status, Dietary Intake and Immunosuppressive Therapy in Kidney Transplant Recipients: Differences Between Early and Late Post-Transplant Period—A Cross-Sectional Pilot Study

Background/Objectives: Kidney transplantation is associated with profound metabolic and nutritional changes, particularly across different post-transplant periods. This study aimed to evaluate differences in nutritional status, dietary intake, and immunosuppressive therapy between recipients in the early and late post-transplant period. Materials and Methods: This cross-sectional pilot study presents an analysis of baseline data obtained from a prospective cohort of 38 kidney transplant recipients divided into early (≤1 year post-transplantation; n = 15) and late (>1 year post-transplantation; n = 23) post-transplant groups. Nutritional status was assessed using anthropometric and laboratory measurements, bioelectrical impedance analysis (BIA), and Nutritional Risk Screening 2002 (NRS-2002). Dietary intake was assessed using the Food Frequency Questionnaire-6 (FFQ-6) and a 3-day dietary record. Information regarding immunosuppressive therapy was obtained from medical records and verified at routine clinic visits. Results: The groups did not differ significantly with respect to sociodemographic characteristics, comorbidities, anthropometric measurements, body composition, and nutritional risk. No significant differences were observed in body weight, body mass index (BMI), body composition parameters, or most laboratory measurements. Early post-transplant recipients exhibited significantly higher non-high-density lipoprotein (non-HDL) cholesterol concentrations (153.3 ± 37.5 vs. 111.1 ± 50.8 mg/dL; p = 0.040), higher tacrolimus trough concentrations (11.2 ± 5.2 vs. 4.6 ± 1.1 ng/mL; p = 0.0001), and lower serum magnesium concentrations (1.64 ± 0.13 vs. 1.94 ± 0.15 mg/dL; p = 0.009) than late post-transplant recipients. No statistically significant differences were observed for most assessed dietary habits, except for the more frequent addition of sugar to beverages among the early post-transplant group (p = 0.048). Qualitative assessment of 3-day dietary records showed a tendency toward more regular meals and greater dietary variety among early post-transplant recipients. This group also received significantly higher tacrolimus trough concentrations and higher prednisone-equivalent and mycophenolate doses than recipients in the late post-transplant period. Conclusions: In this pilot study, the observed differences between early and late post-transplant recipients concerned primarily immunosuppressive exposure and selected metabolic parameters, while no statistically significant differences were identified for most measures of nutritional status or dietary intake. Given the small sample size and the exploratory nature of the study, these findings should be considered preliminary and hypothesis-generating rather than confirmatory. Larger, adequately powered prospective studies are needed to validate these observations and further evaluate nutritional and metabolic changes across the post-transplant course.