Development and Relative Validity of the Chronic Kidney Disease Short Food Frequency Questionnaire (CKD SFFQ) to Determine Diet Quality and Dietary Habits among Adults with Chronic Kidney Disease

The Role of Dietary Acid Load on Progression of Estimated Glomerular Filtration Rate Among Individuals Diagnosed With Chronic Kidney Disease

OBJECTIVE

Individuals with chronic kidney disease (CKD) are at an increased risk for developing metabolic acidosis. Metabolic acidosis has been shown to worsen kidney function and exacerbate systemic inflammation. Diets high in protein foods can exacerbate metabolic acidosis as protein foods tend to be more acidic, while fruits and vegetables are more alkalotic. The main objective of this systematic review was to determine if higher consumption of fruits and vegetables in adults with CKD stages 1-5 reduces the rate of decline of estimated glomerular filtration rate.

METHODS

Searches of Cumulated Index to Nursing and Allied Health Literature (CINAHL -Elton B. Stephens Company [EBSCO]), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (National Library of Medicine), Scopus (Elsevier), and Web of Sciences (Clarivate) identified 1,451 articles published between January 2015 and June 2023.

RESULTS

After independent review, 7 total studies were included. Six of the studies found an association between dietary acid load and progression of CKD.

CONCLUSIONS

Dietary counseling focusing on decreasing dietary acid load may be beneficial for individuals with CKD.

Associations between diet quality, demographics, health conditions and spice and herb intake of adults with chronic kidney disease

Scant literature has been able to demonstrate an association between dietary habits and spice and herb consumption, especially for those who have chronic kidney disease. The objectives of this study were to 1) determine the frequency and quantity of spices and herbs consumed and 2) determine the associations between diet quality and its food components, demographics, and health conditions with spice and herb frequency and variety consumption of adults with chronic kidney disease. A cross-sectional online study was conducted with adults with various stages of chronic kidney disease (n = 71). Participants responded to an online demographic, diet and spice and herb questionnaire on RedCap. Diet quality was determined through the diet questionnaire. Descriptives, frequencies and Spearman correlations were conducted using SPSS v28 with a significance of p<0.05. Most participants were in chronic kidney disease stage 3 (42.3%) with a majority (98.6%) self-identifying as non-Hispanic white. On average, participants consumed black pepper more than once daily (47.9%) with the spice quantity at 5 g. The median diet quality score was 38.5 (range 31.5-48.5). Positive associations were identified with overall diet quality scores and certain spices such as basil (r = 0.33; p<0.01) and cinnamon (r = 0.37; p<0.002). Further associations were seen with food groups, self-identifying as white and health conditions with spice frequency and variety of spices and herbs consumed. Overall, positive associations were observed with diet quality and spice and herb intake, in which higher diet quality scores would indicate higher consumption of spices and herbs. Further research should focus on diet quality and spice and herb consumption in reducing progression of this disease.

Elevated Inflammation and Poor Diet Quality Associated with Lower eGFR in United States Adults: An NHANES 2015-2018 Analysis

Chronic kidney disease is prevalent within the United States likely due to dietary habits. The purpose of this study was to examine the relationship between the high-sensitivity c-reactive protein (hs-CRP) and diet quality (DQ) and their effect on the eGFR. A cross-sectional secondary data analysis study was conducted among adults (n = 6230) using NHANES 2015-2018 data. DQ was determined by the Healthy Eating Index-2015 (HEI-2015). Multivariable linear regressions were conducted based on eGFR (≥90 or <60 mL/min/1.73 m2) after adjustments for age, race/ethnicity, hypertension, diabetes mellitus, cardiovascular disease, and kidney disease awareness. All analyses were performed in SAS version 9.4 with a statistical significance of p < 0.05. Results showed that participants who had an eGFR of <60 mL/min/1.73 m2 were older and had a higher prevalence of hypertension and diabetes and had higher hs-CRP compared to participants with an eGFR ≥ 90 (p < 0.005). Of participants with an eGFR < 60, 27% reported that they were aware they had kidney disease. Regardless of the eGFR at baseline, there was a negative interaction effect on the DQ scores and hs-CRP on the eGFR (p < 0.05). Independently, for participants with an eGFR < 60, their DQ scores had a positive significant relationship on their eGFR (p = 0.03), whereas their hs-CRP had a negative significant relationship on thier eGFR (p < 0.001). For participants with an eGFR < 60, age, hypertension, and kidney disease awareness influenced this relationship (p < 0.001). Overall, low DQ and elevated hs-CRP contributed to a reduction in kidney function. Efforts to improve dietary intake and strategies to reduce inflammation and improve kidney function are necessary.

Barriers to and Strategies for Dietary Adherence: A Qualitative Study Among Hemodialysis/Peritoneal Dialysis Patients and Health Care Providers

OBJECTIVES

The objectives of this study were: (1) investigate hemodialysis (HD)/peritoneal dialysis (PD) patients' barriers to dietary adherence, (2) identify strategies to overcome these barriers, and (3) examine dialysis providers' perceptions toward patients' barriers to dietary adherence and strategies to overcome these barriers.

METHODS

A qualitative descriptive approach was conducted from February-May 2022. A total of 21 HD/PD participants and 11 health care providers participated in individual interviews. HD/PD participants also responded to a 57-item food frequency questionnaire. Six months of serum laboratory values were obtained from the medical charts. Content analysis methodology was used to identify themes. Mann-Whitney U tests were conducted to examine diet quality and laboratory values of the HD and PD participants using SPSS v.27 with statistical significance of P < .05.

RESULTS

The median (interquartile range) diet quality score for HD/PD patients was 36 (26-43) with no differences observed between the patient populations. Mann-Whitney U tests showed no differences between serum laboratory values between the patient populations. Barriers identified by the HD/PD patients were communication/patient education and dietary habits. Barriers identified by the health care providers were communication/patient education and socioeconomic status. Strategies to overcome these barriers were enhancing communication between all parties involved in the care and tailoring educational information to the patient's background.

CONCLUSIONS

Communication and patient education were themes identified among both health care providers and patients. Therefore, open communication among the patients and providers and enhancement of the nutrition education handouts may improve dietary adherence.

Nutritional Epidemiology and Dietary Assessment for Patients With Kidney Disease: A Primer

Nutritional epidemiology seeks to understand nutritional determinants of disease in human populations using experimental and observational study designs. Though randomized controlled trials provide the strongest evidence of causality, the expense and difficulty of sustaining adherence to dietary interventions are substantial barriers to investigating dietary determinants of kidney disease. Therefore, nutritional epidemiology commonly employs observational study designs, particularly prospective cohort studies, to investigate long-term associations between dietary exposures and kidney disease. Due to the covarying nature and synergistic effects of dietary components, holistic characterizations of dietary exposures that simultaneously consider patterns of foods and nutrients regularly consumed are generally more relevant to disease etiology than single nutrients or foods. Dietary intakes have traditionally been self-reported and are subject to bias. Statistical methods including energy adjustment and regression calibration can reduce random and systematic measurement errors associated with self-reported diet. Novel approaches that assess diet more objectively are gaining popularity but have not yet fully replaced self-report and require refinement and validation in populations with chronic kidney disease. More accurate and frequent diet assessment in existing and future studies will yield evidence to better personalize dietary recommendations for the prevention and treatment of kidney disease.

Using a Short Food Frequency Questionnaire to Evaluate Macronutrients, Fiber, Phosphorus, Potassium, and Calcium in Adults with Stages 3-5 Chronic Kidney Disease

The progression of chronic kidney disease (CKD) can be directly or indirectly accelerated by a poor diet and the diet's influence on risk factors for this disease. There have been no food frequency questionnaires (FFQs) developed for the assessment of diet in patients with CKD in Taiwan. This study analyzed the validity of a short FFQ (SFFQ) with 42 items for estimating patient intake of macronutrients, fiber, phosphorus, potassium, and calcium against 3-day dietary records (3-day DRs) in Taiwanese patients with stages 3-5 CKD. In an interview, 107 participants with the help of a dietician filled out an SFFQ and reviewed a 3-day DR the patients had filled out prior to the interview. Partial Pearson correlation coefficients between SFFQ and 3-day DR were 0.722, 0.619, 0.593, 0.572, 0.450, 0.611 and 0.410 for protein, fat, carbohydrate, fiber, phosphorus, potassium, and calcium, respectively, after adjusting for energy intake. Cross-classification analysis revealed 63.5-83.2% similarity in cross-tool estimated intakes of macronutrients, fiber, phosphorus, potassium, and calcium in the same quartiles or adjacent ones. Bland-Altman plots revealed good agreement between the two tools along different intake levels. In conclusion, the newly developed SFFQ had moderate relative validity in estimating the usual intake of key nutrients related to nutrition management of patients with late-stage CKD, suggesting it can be used to assess dietary intakes in a population with CKD, especially in those residing in an Asian region.