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, χ2 , 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.