Validation of macaroni formula for estimating diet protein intake of patients with chronic kidney disease

Objective To evaluate the Maroni's formula of estimating diet protein intake (DPI) of the patients with chronic kidney disease (CKD).Methods During May 2015 to December 2016, 85 cases were enrolled in the study, including the patients with CKD of stage 3-5 hospitalized in the First Hospital of Chinese Medical University, and the patients given the maintenance hemodialysis and peritoneal dialysis in our blood purification center. The patients with no-dialysis CKD were assigned to 3 groups according to their glomerular filtration rate (GFR):A20 cases, CKD of stage 3, GFR 30-59 ml·min^-1·(1.73 m²)^-1, B20 cases, CKD of stage 4, GFR 15-29 ml·min^-1·(1.73 m²)^-1 and C20 cases, CKD of stage 5, GFR<15 ml·min^-1·(1.73 m²)^-1. For all patients with dietary education, then they were given a uniform weighing of food to record a three-day diet. On the third day, 24-h urine was collected to test 24-h urine urea nitrogen. Using the computer expert system combining Chinese and western medicine nutrition treatment, 3-day recipes were calculated to get the actual DPI. Using Maroni's formula, eDPI was calculated. The eDPI and the DPI were statistically analyzed.Results There were no significant differences in height, body mass, body mass index, 24-h urinary albumin, blood albumin, prealbumin, blood fat, cholesterol and hemoglobin among the groups (P>0.05). There was no significant difference in 24-h urine among groups A, B and C. The 24-h urine in group D was significantly reduced as compared with that in groups A, B and C (P<0.05). The intra-group comparison of groups A, B, C and D revealed no significant difference in DPI and eDPI.Conclusions There was no statistically significant difference in DPI and eDPI calculated by Maroni's formula among the patients with CKD of different stages. Maroni's formula can be used to assess the protein intake in patients with CKI.