Comparison of dietary intake among women on maintenance dialysis to a Women's Health Initiative cohort: results from the NKF-CRN Second National Research Question Collaborative Study.

OBJECTIVE: The objective of this study was to compare the characteristics and dietary intake of Second National Research Question (SNRQ) participants to the Women's Health Initiative-Dietary Modification (WHI-DM) Trial group and to compare the dietary intake of both groups to relevant reference norms.

DESIGN: The study design was a secondary analysis of data collected from the SNRQ and from the WHI-DM Trial.

SUBJECTS: SNRQ participants were adult women on dialysis (n = 248) from U.S. dialysis facilities. WHI-DM Trial participants (n = 48,836) were postmenopausal, 50- to 79-year-old women from 40 U.S. clinical centers.

METHODS: The 1-sample t test, χ(2), and Wilcoxon signed-rank test were used to compare the SNRQ participants to the WHI-DM group and to compare the dietary intake of both to nutrition reference norms. Differences were considered significant at a 2-tailed P ≤ .01.

MAIN OUTCOME MEASURE: Dietary intake was defined as dietary energy intake (DEI), dietary protein intake (DPI), fiber, fat, saturated fat, sodium, potassium, phosphorus, fruits, and vegetables.

RESULTS: Characteristics including age, race, weight, educational level, and cardiovascular disease differed between the SNRQ and WHI-DM groups (P < .001). SNRQ participants had lower DEI, DPI, fiber, fat, saturated fat, potassium, sodium, phosphorus, fruit, and vegetable intake than WHI-DM women (P < .001). Dietary intake of SNRQ hemodialysis (HD) and peritoneal dialysis (PD) patients differed significantly from reference norms (P < .001) except for phosphorus intake in PD patients (P = .03). WHI-DM women had higher intakes of fat and saturated fat and lower intakes of fiber, fruit, and vegetables than recommended in reference norms for the general population.

CONCLUSION: Dietary intake differed significantly between SNRQ participants and the WHI-DM group. Dietary intake of the SNRQ participants, except for phosphorus intake in PD patients, differed significantly from relevant reference norms.