Recommendations for the nutrition management of phenylalanine hydroxylase deficiency

The effectiveness of a phenylalanine-restricted diet to improve the outcome of individuals with phenylalanine hydroxylase deficiency (OMIM no. 261600) has been recognized since the first patients were treated 60 years ago. However, the treatment regime is complex, costly, and often difficult to maintain for the long term. Improvements and refinements in the diet for phenylalanine hydroxylase deficiency have been made over the years, and adjunctive therapies have proven to be successful for certain patients. Yet evidence-based guidelines for managing phenylalanine hydroxylase deficiency, optimizing outcomes, and addressing all available therapies are lacking. Thus, recommendations for nutrition management were developed using evidence from peer-reviewed publications, gray literature, and consensus surveys. The areas investigated included choice of appropriate medical foods, integration of adjunctive therapies, treatment during pregnancy, monitoring of nutritional and clinical markers, prevention of nutrient deficiencies, providing of access to care, and compliance strategies. This process has not only provided assessment and refinement of current nutrition management and monitoring recommendations but also charted a direction for future studies. This document serves as a companion to the concurrently published American College of Medical Genetics and Genomics guideline for the medical treatment of phenylalanine hydroxylase deficiency

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Nutritional Therapy Improves Growth and Protein Status of Children with a Urea Cycle Enzyme Defect

Background Poor growth has been described in patients with urea cycle enzyme defects treated with protein-restricted diets, while protein status is seldom reported. Objective To assess the effects of nutritional therapy with a medical food on growth and protein status of patients with a urea cycle enzyme defect. Methods A 6-mo multicenter outpatient study was conducted with infants and toddlers managed by nutrition therapy with Cyclinex-1 Amino Acid-Modified Medical Food with Iron (Ross Products Division, Abbott Laboratories, Columbus, OH). Main outcome variables were anthropometrics and plasma amino acids (selected), albumin, and transthyretin concentrations. Results Seventeen patients completed the study. Mean (±SE) baseline age was 11.30 ± 3.20 months (median 4.40 months; range 0.22–38.84 months). Length and weight z-scores increased significantly during the 6-month study. Head circumference increased, but not significantly. Three patients were stunted and two were wasted (−2.0 z-score) at baseline while at study end, only one patient was both stunted and wasted. The majority of patients increased in length, head circumference, and weight z-scores during study. Mean (±SE) plasma albumin concentration increased from 34 ± 2 g/L at baseline to 38 ± 1 g/L at study end. Plasma transthyretin increased from a mean (±SE) of 177 ± 13 mg/L at baseline to 231 ± 15 mg/L at study end. No correlation was found between plasma NH3 concentrations and medical food intake. Plasma NH3concentration was positively correlated with the percentage of Food and Agriculture Organization/World Health Organization/United Nations recommended protein ingested. Conclusions Intakes of adequate protein and energy for age result in anabolism and linear growth without increasing plasma NH3 concentrations. Medical food intakes did not correlate with plasma NH3 concentrations

Nutritional Therapy Improves Growth and Protein Status of Children with a Urea Cycle Enzyme Defect

Background Poor growth has been described in patients with urea cycle enzyme defects treated with protein-restricted diets, while protein status is seldom reported. Objective To assess the effects of nutritional therapy with a medical food on growth and protein status of patients with a urea cycle enzyme defect. Methods A 6-mo multicenter outpatient study was conducted with infants and toddlers managed by nutrition therapy with Cyclinex-1 Amino Acid-Modified Medical Food with Iron (Ross Products Division, Abbott Laboratories, Columbus, OH). Main outcome variables were anthropometrics and plasma amino acids (selected), albumin, and transthyretin concentrations. Results Seventeen patients completed the study. Mean (±SE) baseline age was 11.30 ± 3.20 months (median 4.40 months; range 0.22–38.84 months). Length and weight z-scores increased significantly during the 6-month study. Head circumference increased, but not significantly. Three patients were stunted and two were wasted (−2.0 z-score) at baseline while at study end, only one patient was both stunted and wasted. The majority of patients increased in length, head circumference, and weight z-scores during study. Mean (±SE) plasma albumin concentration increased from 34 ± 2 g/L at baseline to 38 ± 1 g/L at study end. Plasma transthyretin increased from a mean (±SE) of 177 ± 13 mg/L at baseline to 231 ± 15 mg/L at study end. No correlation was found between plasma NH3 concentrations and medical food intake. Plasma NH3concentration was positively correlated with the percentage of Food and Agriculture Organization/World Health Organization/United Nations recommended protein ingested. Conclusions Intakes of adequate protein and energy for age result in anabolism and linear growth without increasing plasma NH3 concentrations. Medical food intakes did not correlate with plasma NH3 concentrations

Improved Growth and Nutrition Status in Children with Methylmalonic or Propionic Acidemia Fed an Elemental Medical Food

Background: Failure-to-thrive (FTT) has been described in patients with organic acidemias treated with low protein diets. Objective: To determine if patients with methylmalonic (MMA) or propionic acidemia (PA) can achieve normal growth and nutrition status. Methods: A 6-month multicenter outpatient study was conducted with infants and toddlers treated with Propimex-1 Amino Acid-Modified Medical Food With Iron (Ross Products Division, Abbott Laboratories, Columbus, OH). Main outcome measures were anthropometrics, protein status indices, plasma retinol, and α-tocopherol. Results: Sixteen patients completed the study. Mean baseline age was 0.54 ± 0.02 years (range 0.03–3.00 years). By study end, mean National Center for Health Statistics (NCHS) weight centile increased from 26 to 49%; mean crown-heel length centile from 25 to 33%; and mean head circumference centile from 43 to 54%. Mean (± SE) protein and energy intakes by \u3c6-month-old, 6 \u3c 12-month-old, and 1\u3c 4-year-old patients were 15.3 ± 0.9 g and 645 ± 10 kcal; 18.3 ± 1.1 g and 741 ± 92 kcal; and 25.1 ± 2.46 g and 1062 ± 100 kcal, respectively. Plasma glycine concentrations were significantly and negatively correlated with energy intake (r=−0.77, p\u3c0.0005). No correlation was found between dietary protein intakes and plasma ammonia concentrations. Protein status indices, retinol and α-tocopherol concentrations were within reference ranges at study end. Conclusions: Propimex-1 improved growth and nutrition status in patients with MMA or PA in just 6 months when fed in sufficient amounts. Providing energy and protein for patients with FTT at intakes recommended for catch-up growth may have resulted in even better growth