January 11, 2021
2 min read
St-Jules reports having a membership to the Academy of Nutrition and Dietetics and being a registered dietitian through the Commission of Dietetic Regulation. Please see the study for all other authors’ relevant financial disclosures.
A meta-analysis of clinical trials suggested that diet therapy focused on lowering serum phosphate levels may be safe and effective for patients on hemodialysis, but researchers emphasized that further investigation is required.
“Hyperphosphatemia is a persistent problem in individuals undergoing maintenance hemodialysis, which may contribute to vascular and bone complications,” David E. St-Jules, PhD, of the department of nutrition at the University of Nevada, Reno, and colleagues wrote. “In some dialysis centers, dietitians work with patients to help them manage serum phosphate. Given the regularity of hyperphosphatemia in this population and constraints on kidney dietitian time, the authors aimed to evaluate the evidence for this practice.”
After assessing 12 clinical trials, researchers determined diet therapy was effective because it reduced serum phosphate levels for participants in all trials compared with controls and reached statistical significance in eight of the studies.
They also found monthly diet-therapy sessions of 30 minutes lowered serum phosphate “without comprising nutrition status for up to 6 months” and demonstrated safety (mean difference in serum phosphate was -0.87 mg/dL).
Despite apparent safety and efficacy, researchers acknowledged these reductions “appeared to fade when the intervention was stopped” and the quality of studies was “low.”
“The limited number of RCTs and diversity of approaches used represents a key challenge in establishing evidence-based dietetic practice guidelines,” St-Jules and colleagues concluded of the findings, though they still contended diet therapy shows promise for this patient population.
“Overall, these findings highlight relevant opportunities for challenging, but influential, research on dietary management of [chronic kidney disease-mineral and bone disorder] CKD-MBD and signal the potential to improve serum phosphate levels in individuals on [hemodialysis] HD through additional dietetic services.”
Researchers from the University of California, Irvine, provided further insight into the findings in an accompanying editorial.
“In addition to affirming the critical importance of dietitians in multidisciplinary hyperphosphatemia management, this study also underscores the need for frequent, ongoing administration of individualized diet therapy to achieve and maintain improvements in persistent phosphate control,” Yoko Narasaki, MS, PhD, and Connie M. Rhee, MD, wrote. “Although the authors acknowledged the heterogeneity of the interventions across trials, this study emphasizes the value of utilizing combinations of dietary strategies (low-phosphate diet, avoidance of phosphate additives, training in meal preparation) with non-dietary strategies (binder and dialysis adherence, pharmacist consultation) in achieving phosphate control.”
Narasaki and Rhee urged that further studies be conducted regarding the potential cost-savings of medical nutrition therapy (MNT) for patients with kidney disease.
“Although MNT administered by a registered dietitian nutritionist is cost-effective in the management of diabetes, hypertension, and the elderly population, there have been a paucity of studies examining the potential cost-savings of MNT in patients with CKD,” they concluded. “Given the high prevalence of mineral bone disease contributing to the disproportionate burden of cardiovascular disease, skeletal complications, and death in patients on hemodialysis, this study is an important contribution to summarizing existing evidence on the nutritional management of hyperphosphatemia and the essential role of dietitians in caring for this population, as well as the need for future rigorous research in this area.”