Validation of a Phosphorus Food Frequency Questionnaire in Patients with Kidney Failure Undertaking Dialysis

• Published in: Nutrients 2023-03, Vol.15 (7), p.1711
• Main Authors: Beer, Joanne, Lambert, Kelly, Lim, Wai, Bettridge, Ellen, Woodward, Fiona, Boudville, Neil
• Format: Article
• Language: English
• Subjects: Additives; Aged; Aged, 80 and over; agreement; Bioavailability; Calcification; Cardiovascular disease; Care and treatment; Chronic kidney failure; Consent; Consumption; Data collection; Dialysis; Diet; Diet Surveys; Dietary intake; dietary phosphorus; Dietitians; Energy Intake; Evaluation; Female; Food; Food and nutrition; food frequency questionnaire; Health aspects; Hemodialysis; Hemodialysis patients; Humans; Kidney diseases; kidney failure; Kidneys; Male; Mental Recall; Metabolism; Middle Aged; Nutrients; Nutrition Assessment; Nutrition research; Nutrition surveys; Patients; Peritoneal dialysis; Phosphorus; Phosphorus in the body; Phosphorus, Dietary; Questionnaires; Renal Dialysis; Renal failure; Reproducibility of Results; Surveys; Surveys and Questionnaires; Telemedicine; validity
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu15071711

Nutritional guidelines recommended limiting dietary phosphorus as part of phosphorus management in patients with kidney failure. Currently, there is no validated phosphorus food frequency questionnaire (P-FFQ) to easily capture this nutrient intake. An FFQ of this type would facilitate efficient screening of dietary sources of phosphorus and assist in developing a patient-centered treatment plan. The objectives of this study were to develop and validate a P-FFQ by comparing it with the 24 hr multi-pass recall. Fifty participants (66% male, age 70 ± 13.3 years) with kidney failure undertaking dialysis were recruited from hospital nephrology outpatient departments. All participants completed the P-FFQ and 24 hr multi-pass recalls with assistance from a renal dietitian and then analysed using nutrient analysis software. Bland-Altman analyses were used to determine the agreement between P-FFQ and mean phosphorus intake from three 24 hr multi-pass recalls. Mean phosphorous intake was 1262 ± 400 mg as determined by the 24 hr multi pass recalls and 1220 ± 348 mg as determined by the P-FFQ. There was a moderate correlation between the P-FFQ and 24 hr multi pass recall (r = 0.62, = 0.37) with a mean difference of 42 mg (95% limits of agreement: 685 mg; -601 mg, = 0.373) between the two methods. The precision of the P-FFQ was 3.33%, indicating suitability as an alternative to the 24 hr multi pass recall technique. These findings indicate that the P-FFQ is a valid, accurate, and precise tool for assessing sources of dietary phosphorus in people with kidney failure undertaking dialysis and could be used as a tool to help identify potentially problematic areas of dietary intake in those who may have a high serum phosphate.