Weight-for-age distribution and case-mix adjusted outcomes of 14,307 paediatric intensive care admissions

Abstract

AimsTo determine whether the paediatric intensive care (PIC) population weight distribution differs from the UK reference population and whether weight-for-age at admission is an independent risk factor for mortality.MethodsAdmission weight-for-age standard deviation scores (SDS) were calculated for all PIC admissions (March 2003–December 2011) to Great Ormond Street Hospital: this is the number of standard deviations (SD) between a child’s weight and the UK mean weight-for-age. Categorised into nine SDS groups, standardised mortality ratios (SMR) and logistic regression were used to assess the relationship between weight-for-age at admission and risk-adjusted mortality.ResultsOut of 12,458 admissions, mean weight-for-age was 1.04 SD below the UK reference population mean (p < 0.0001). Based on 942 deaths, risk-adjusted mortality was lowest in those with mild-to-moderately raised weight-for-age (SDS 0.5–2.5) and highest in children with extreme under- or overweight (SDS < −3.5 and SDS > +3.5). Logistic regression indicated that age, gender, ethnicity and weight-for-age are independent risk factors for mortality. South Asian and ‘other’ ethnicities had significantly increased risk of death compared to children of white and black ethnic origin.ConclusionThe PIC population mean weight-for-age is significantly lower than the UK reference mean. The extremes of weight-for-age are over-represented, especially underweight. Weight-for-age at admission is an independent risk factor for mortality. A U-shaped association between weight and risk-adjusted mortality exists, with the lowest risk of death in children who are mild-to-moderately overweight. Future studies should determine the impact of malnutrition on risk-adjusted mortality and investigate the aetiology of risk disparities with ethnicity.Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-014-3381-x) contains supplementary material, which is available to authorized users.

Obesity and Mortality Risk in Critically Ill Children

“…Some investigators, although not all, believe that obese children have higher morbidity and mortality. [2][3][4] In adults, higher BMI is associated with the development of acute respiratory distress syndrome (ARDS) 5 ; for those developing ARDS, increasing BMI was associated with prolonged stay. However, increased BMI was not associated with increased mortality.…”

“…[2][3][4]12,13 Existing studies identify a U-shaped distribution for mortality based on weight percentile, with both underweight and overweight children having increased mortality. There are other issues.…”

“…There are other issues. First, it is unknown whether these studies 2,3 reflect the population of US children. Second, all previous studies classified patients based on weight for age and did not take into account the patient's height.…”

“…It is unknown whether this approach results in misclassification of obesity. 2,3,12,13 The goal of the present study was to examine the association between obesity and pediatric ICU mortality in US children, adjusting for initial severity of illness. We also sought to determine whether height-and weight-based classifications of obesity compared with weight-forage alone would result in a different mortality distribution.…”

Big babies and big adults surprise us by their outcomes: why?

“…In a recent issue of Intensive Care Medicine, Prince et al [9] reviewed the relationship between admission weight for age and paediatric intensive care unit (PICU) outcome in a data set of 14,307 admissions to the neonatal and paediatric intensive care unit at Great Ormond Street Hospital in London. The key findings were that the mean weight for age for the PICU was significantly lower than the UK population mean; that patients with highest and lowest categories of weight for age (difference between the child's weight and the UK mean for age is more than 3.5 standard deviations) had the highest mortality; and the patients in the mild to moderately overweight for age category had the lowest mortality.…”