Hypophosphataemia in severe acute malnutrition: a prospective observational study

Micronutrient status in children aged 6-59 months with severe wasting and/or nutritional edema: implications for nutritional rehabilitation formulations

Undernutrition remains a global struggle and is associated with almost 45% of deaths in children younger than 5 years. Despite advances in management of severe wasting (though less so for nutritional edema), full and sustained recovery remains elusive. Children with severe wasting and/or nutritional edema (also commonly referred to as severe acute malnutrition and part of the umbrella term "severe malnutrition") continue to have a high mortality rate. This suggests a likely multifactorial etiology that may include micronutrient deficiency. Micronutrients are currently provided in therapeutic foods at levels based on expert opinion, with few supportive studies of high quality having been conducted. This narrative review looks at the knowledge base on micronutrient deficiencies in children aged 6-59 months who have severe wasting and/or nutritional edema, in addition to highlighting areas where further research is warranted (See "Future Directions" section).

Incidence of Refeeding Syndrome in Critically Ill Children With Nutritional Support

INTRODUCTION

Early enteral nutrition is recommended for critically ill children, potentially exposing those who are undernourished to the risk of refeeding syndrome. However, data on its incidence is lacking, and the heterogeneity of diagnostic criteria and frequent electrolyte disorders in this population make its diagnosis complex. In 2020, the American Society for Parenteral and Enteral Nutrition (ASPEN) developed consensus recommendations for identifying patients at risk and with refeeding syndrome. These state that undernourished children are considered at risk of refeeding syndrome; those who develop one significant electrolyte disorder (decrease ≥ 10% in phosphorus, potassium, and/or magnesium) within the first five days of nutritional support, combined with a significant increase in energy intake, are considered to have refeeding syndrome. The aim of this study was to determine the incidence of refeeding syndrome according to the ASPEN definition in critically ill children on nutritional support.

MATERIALS AND METHODS

A secondary analysis of two prospective cohorts conducted in a tertiary pediatric intensive care unit in France was undertaken, and additional data were retrospectively collected. Children included were those (0-18 years) admitted to the pediatric intensive care unit with a minimum of one phosphorus, potassium, and/or magnesium assay and who received exclusive or supplemental nutritional support. Undernourished children (body mass index z-score < -2 standard deviations) were considered at risk of refeeding syndrome. The ASPEN critiera were used to identify those with probable refeeding syndrome.

RESULTS

A total of 1,261 children were included in the study, with 199 children (15.8%) classified as undernourished, who were at risk of refeeding syndrome. Of these, 93 children were identified as having probable refeeding syndrome, giving an overall incidence of 7.4%. The incidence rate among at-risk children was 46.7%. Most patients (58.1%) were classified as having severe refeeding syndrome.

CONCLUSION

Refeeding syndrome remains difficult to diagnose in critically ill children, due to frequent confounding factors impacting electrolyte plasma levels. These findings suggest that refeeding syndrome incidence may be high in undernourished children, and that refeeding syndromes can be severe. Further prospective studies using the ASPEN definition and risk criteria are required.

Impact of serum phosphate changes on in-hospital mortality

Background

Fluctuations in serum phosphate levels increased mortality in end-stage renal disease patients. However, the impacts of serum phosphate changes in hospitalized patients remain unclear. This study aimed to test the hypothesis that serum phosphate changes during hospitalization were associated with in-hospital mortality.

Methods

We included all adult hospitalized patients from January 2009 to December 2013 that had at least two serum phosphate measurements during their hospitalization. We categorized in-hospital serum phosphate changes, defined as the absolute difference between the maximum and minimum serum phosphate, into 5 groups: 0–0.6, 0.7–1.3, 1.4–2.0, 2.1–2.7, ≥2.8 mg/dL. Using serum phosphate change group of 0–0.6 mg/dL as the reference group, the adjusted odds ratio of in-hospital mortality for various serum phosphate change groups was obtained by multivariable logistic regression analysis.

Results

A total of 28,149 patients were studied. The in-hospital mortality in patients with serum phosphate changes of 0–0.6, 0.7–1.3, 1.4–2.0, 2.1–2.7, ≥2.8 mg/dL was 1.5, 2.0, 3.1, 4.4, and 10.7%, respectively (p < 0.001). When adjusted for confounding factors, larger serum phosphate changes were associated with progressively increased in-hospital mortality with odds ratios of 1.35 (95% 1.04–1.74) in 0.7–1.3 mg/dL, 1.98 (95% CI 1.53–2.55) in 1.4–2.0 mg/dL, 2.68 (95% CI 2.07–3.48) in 2.1–2.7 mg/dL, and 5.04 (95% CI 3.94–6.45) in ≥2.8 mg/dL compared to serum phosphate change group of 0–0.6 mg/dL. A similar result was noted when we further adjusted for either the admission or mean serum phosphate during hospitalization.

Conclusion

Greater serum phosphate changes were progressively associated with increased in-hospital mortality.

Hypophosphatemia in critically ill patients with acute kidney injury on renal replacement therapies

Hypophosphatemia is a common but often underestimated electrolyte derangement among intensive care unit (ICU) patients. Low phosphate levels can lead to cellular dysfunction with potentially relevant clinical manifestations (e.g., muscle weakness, respiratory failure, lethargy, confusion, arrhythmias). In critically ill patients with severe acute kidney injury (AKI) renal replacement therapies (RRTs) represent a well-known risk factor for hypophosphatemia, especially if the most intensive and prolonged modalities of RRT, such as continuous RRT or prolonged intermittent RRT, are used. Currently, no evidence-based specific guidelines are available for the treatment of hypophosphatemia in the critically ill; however, considering the potentially negative impact of hypophosphatemia on morbidity and mortality, strategies aimed at reducing its incidence and severity should be timely implemented in the ICUs. In the clinical setting of critically ill patients on RRT, the most appropriate strategy could be to anticipate the onset of RRT-related hypophosphatemia by implementing the use of phosphate-containing solutions for RRT through specifically designed protocols. The present review is aimed at summarizing the most relevant evidence concerning epidemiology, prognostic impact, prevention and treatment of hypophosphatemia in critically ill patients with AKI on RRT, with a specific focus on RRT-induced hypophosphatemia.