THE IMPACT OF A LOW-NORMAL PROTEIN HIGH CALORIE DIET ON THE NEPHROLOGICAL SCENARIO AND PERCEIVED QUALITY OF LIFE OF ONCOUROLOGICAL PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract BACKGROUND AND AIMS Nutritional therapy (NT) based on controlled protein intake represents a cornerstone in the management of chronic kidney disease (CKD). However, the international guidelines do not precisely define an adequate protein intake for onconephrological patients. The aim of our study is to investigate whether a low-normal protein high calorie (LNPHC) diet in a nephrologist-nutritionist combined approach (NNCA) and aimed at CKD patients can also be effective in improving the renal function in oncological patients which developed renal disease, while maintaining a high quality of life and a healthy nutritional status. METHOD A consecutive cohort of 113 patients was enrolled in the Urological Department at San Raffaele Scientific Institute between 2018 and 2021. Inclusion criteria were: age (>18 years), eGFR (<60 mL/min/1.73 m2), Malnutritional Screening Tool (MST < 2), Urological Cancer aggressiveness (no metastatic process) and informed consent (signed). We divided the total cohort in two matched subgroups; case (CS: onco-nephrological pts with urological malignancies) and control (CT: nephrological pts) with a 2.1 ratio. Each patient underwent an initial nephrological and nutritional evaluation and was subsequently subjected to a conventional CKD LNPHC diet integrated with aproteic foods (0.7–1 g/kg/die: calories: 30–35 kcal per kg body weight/die) for a period of 6 months (+/– 2 months). The diet was based on the estimated glomerular filtration rate (CKD-EPI 2021 Creatinine formula), comorbidities and nutritional status. MST, RAPA test, body mass index (BMI), phase angle (PA), fat mass percentage (FM%), fat-free mass index (FFMI), body cell mass index (BCMI), extracellular/intracellular water ratio (ECW/ICW), waist/hip circumference ratio (WHC), lab test exams and clinical variables were examined at baseline and after 6 months. To evaluate the impact of the combined approach on perceived quality of life, multiple 8 scale assessments in a generic QoL-Short Form 36 (SF36) questionnaire were administered to patients. Statistical analysis: Kruskal–Wallis rank-sum test; data analysis: R programming language and RStudio integrated development environment. RESULTS The combined treatment produced eGFR and urea parameter improvements (49% of patients improved eGFR, 65% uremia) without negatively altering the anthropometrical outcomes. The nutritional status, as assessed by the MST, was preserved in both groups during the study. We notice specially an improvement in BMI (average deviation from ideal weight: 0.5 kg/h2 CS pts; 0.7 kg/h2 CT pts), an increase of PA [average difference (AD): 3.0°CS pts; 1.6°CT pts], BCMI (AD: 0.6 CS pts; 4.0 CT pts) and FFMI (AD: 0.1 female and 0.1 male for CS pts; 2.9 female and 1.1 male for CT pts) and a favourable decrease of WHC ratio (AD:–0.01 female and–0.02 male for CS pts; ––0.01 female and–0.01 male for CT pts), FM percentage (AD: –1.2 female and 1.2 male CS pts;–2.7 female and 2.9 male CT pts) and ECW/ICW (AD:–0.02 CS pts;–0.03 CT pts). Finally, RAPA test highlight that all patients considered themselves ameliorated after the diet period in term of lifestyle and Short-Form Health SF36 Questionnaire confirmed satisfaction for all eight domains of health including physical and mental health. CONCLUSION Our study suggests that LNPHC diet ameliorates the nephrological scenario, the metabolic complications and the nutritional perspective in uro-oncological CKD pts. Following NNCA, perceived quality of life has been pushed towards high scores and does not appear to be influenced by physical health and emotional status; however, there is a worsening in health change despite they describe their current health status as more than satisfactory. This may be explained by the fact that harsh clinical monitoring and food choice limitations may have increased the perception of the pathological condition, thereby increasing the sense of responsibility in adhering to the NT.