Adherence to Dietary Recommendations Measured by Smartphone-based Recipe Nutrition Calculator in Kidney Transplant Patients

Background: Dietary restriction of protein, salt, and energy is recommended to prevent lifestyle related diseases, proteinuria, and graft dysfunction in kidney transplant patients. It is useful if the patients can evaluate meal components by themselves for each meal.

Patients and methods: A total of 26 maintenance-phase kidney transplant patients were included in the study. The mean age, sex, body mass index, number of years post-transplantation, creatinine clearance, and 24-hour urinary excretion (24 UE) of protein were recorded on a medical chart. Estimated daily protein and salt oral intake were calculated from 24 UE of nitrogen and sodium, respectively. We compared these laboratory results and patients' self-reported dietary intake using a smartphone-based recipe nutrition calculator (SRNC).

Results: Estimated daily protein and salt oral intake calculated from 24 UE of nitrogen and sodium were 55.4 ± 12.9 g/d and 8.5 ± 3.1 g/d, respectively. Estimated daily protein and salt oral intake measured by SRNC were 52.4 ± 13.8 g/day and 6.5 ± .9 g/day, respectively. The results of estimated daily protein and salt oral intake measured by SRNC were correlated to those calculated from 24 UE (R² = .287 and .217, respectively).

Conclusions: The results of estimated daily protein and salt oral intake measured by SRNC were correlated to those calculated from 24 UE in maintenance-phase kidney transplant patients. SRNC was useful as a measurement modality to evaluate the adherence to dietary guidance. Dietary therapy for these patients may have the potential to improve kidney graft function and survival.