Mounting evidence from clinical trials indicates that early nutrition intervention in CKD patients can improve outcomes.
As patients progress through the stages of CKD, diet plays an important role in maintaining kidney function, decreasing risk of malnutrition, and ameliorating negative cardiac and bone outcomes. Providing patients with regular and disease-specific nutrition information can be challenging in our current health-care system.
Patients often are not seen by a nephrologist or renal dietitian until they are close to starting dialysis. Endocrinologists, internists, or family physicians may be caring for patients in the early stages of CKD and could be unaware of the serious consequences of suboptimal energy and vitamin D intake and of excess phosphorus on nutritional, cardiac, immune, and bone-related outcomes of kidney patients.
Effects of poor nutrition
Nutritional concerns can begin as early as stage 3 CKD. Eustace et al demonstrated a spontaneous decline in kilocalorie intake starting between stages 2 and 3; by stage 4, more than 50% of kidney failure patients were consuming less than 20 kcal/kg/day (Kidney Int. 2004;65:1031-1040)(J Ren Nutr. 2008;18:408-414)(Cochrane Database Syst Rev. 2006;:CD10082)(Am J Kidney Dis. 2007; 49:569-580), patients who chose to not go on dialysis had significantly better nutritional status and rates of survival than those patients who elected to begin dialysis treatment.
Cianciaruso et al. conducted an interesting clinical trial comparing outcomes of patients consuming different amounts of protein—0.8 g/kg/day and 0.55 g/kg/day (Nephrol Dial Transplant. 2008;23:636-644). Results demonstrated that those patients who were compliant on the 0.55 g/kg/day took significantly less phosphate binders, allopurinol, bicarbonate, vitamin D analogs, and diuretics, while there was no significant difference between the groups’ serum concentrations of parathyroid hormone, phosphorus, or bicarbonate. Serum urea nitrogen was significantly lower in compliant patients on the 0.55 g/kg/day diet.
Nutrition intervention through education has been shown to be effective. Two groups of investigators were able to demonstrate improved outcomes in intervention groups compared with control groups. Campbell et al conducted a randomized clinical trial with 56 stage 4 CKD patients who were randomized to standard care or an intervention group in which dietitians provided instruction on diet and self-management skills (Clin Nutr. 2008;27:537-544). The intervention group had significantly improved energy intake and serum albumin concentrations compared with the control group.
Of importance to clinical practice is that the dietitians had face-to-face contact with patients only at the start of the study. Between two and 12 weeks, the dietitians followed up via telephone conversations. This is a feasible and cost-effective model for nutrition intervention.
Tracking and caring for patients with CKD can be challenging. The Veteran Affairs Medical system has a computer network that allows for tracking patients regardless of location. This enables doctors to monitor the patients who come for care as they progress through the stages of CKD and to refer them to registered dietitians for diet instruction. Private institutions and physicians may have a more difficult time monitoring and caring for patients through all the stages of CKD.
This may be due in part to a lack of communication from one institution/physician office to another. Doctors can and should refer their CKD patients to registered dietitians and expect reimbursement from the Centers of Medicare and Medicaid Services (CMS), as CKD is a reimbursable condition for medical nutrition therapy. Many insurance providers follow the lead of CMS and provide coverage to patients newly diagnosed with CKD.
Dr. Steiber is Coordinator of the Dietetic Internship/Master’s Degree Program at Case Western Reserve University in Cleveland.