Dietary Intake of Patients With Chronic Kidney Disease Entering the LORD Trial: Adjusting for Underreporting
Objective
The study objective was to determine the dietary intake of patients with chronic kidney disease before and after filtering for suspected underreporters and to investigate the impact of underreporting on the interpretation of diet data.
Design
This was a cross-sectional study.
Setting
The study included outpatients from hospitals and clinics in Northern Tasmania, Australia.
Patients
Data from 113 patients enrolled in the Lipid Lowering and Onset of Renal Disease trial were used in this study. Patients with serum creatinine greater than 120 mmol/L were included, and those taking lipid-lowering medication were excluded.
Methods
Patients completed a 4-day self-report diet diary, and FoodWorks software was used to determine their daily intake of energy, macronutrients, and specific micronutrients. Diet diaries were assessed for likely underreporting using the Goldberg cutoff approach with a ratio of energy intake to estimated resting energy expenditure of 1.27. Nutrient intakes were compared with current National Kidney Foundation’s Kidney Disease Outcomes Quality Initiative guidelines, World Health Organization recommendations, recommended daily allowances, and daily values adjusted for energy intake.
Results
Demographics of the patients were as follows: male/female, 71/42; age (mean ± standard deviation), 60 ± 15 years; body mass index, 28.6 ± 6.0 kg/m2, and serum creatinine, 223.4 ± 110.0 mmol/L. According to the criteria, 80 patients (70.8%) were underreporting their energy intake. Underreporters were more likely to be female and younger, and have a higher body mass index and elevated serum creatinine. In all patients, daily energy intake (89.6 ± 32.4 kJ/kg) was lower than recommended (125-145 kJ/kg); however, this was not the case for valid reporters (128.3 ± 23.7 kJ/kg). Protein intake was higher (0.9 ± 0.3 g/kg) than recommended (0.75 g/kg) in all patients and even higher (1.2 ± 0.3 g/kg) in valid reporters. Mean calcium, zinc, and dietary fiber intakes were all below recommendations in all patients, but these differences were not apparent in valid reporters.
Conclusion
Interpreting self-report diet diary data from patients with chronic kidney disease without attempting to exclude underreporters will lead to erroneous conclusions, especially in respect to energy, protein, dietary fiber, calcium, and zinc intakes.
⁎School of Human Movement Studies, University of Queensland, Brisbane, Australia.
†Renal Research Tasmania, Launceston General Hospital, Launceston, Tasmania, Australia.
‡School of Human Life Sciences, University of Tasmania, Launceston, Tasmania, Australia.
Address reprint requests to Jeff S. Coombes, PhD, School of Human Movement Studies, Rm 535 Connell Building, University of Queensland, St. Lucia, Queensland, Australia 4072.
This project was supported by a grant from the Clifford Craig Medical Research Trust, C. Prosser Green Trust. Pfizer Pharmaceuticals provided atorvastatin and placebo for the LORD trial.
ABSTRACT