Custom weight centiles for large PICU population in Australia and new zealand: Low and high admission weights dominate and low weight increases mortality.

Abstract

Aims & Objectives: Single-centre studies have shown a preponderance of low weight-for-age patients admitted to PICU, and the lowest weight may have increased mortality. We aimed to develop centile charts for a specific ICU population in all Australia and New Zealand (A&NZ), and relate mortality to centile. Methods With a dataset of 117240 admissions to ICU 2004-2016 from-2 months preterm to 16 years (40% readmissions, 57% male), centile charts for all ages were developed by a standard method. Standard deviation scores (weight Z-scores) and centiles were applied to each admission and included in Paediatric Index of Mortality (PIM) models. Results Compared with general population data, low admission weights predominate at all ages >0 year corrected, both sexes. High weights also dominate >6 months old. Median weight is low from 0-12 months (p<0.0001), otherwise approximates to the general population. The graphs show the custom centiles for females compared to the general population, and weight distributions for males at age 6 months and 10 years. The weight distributions are displaced towards lower weight by up to 0.4 Z-scores for cardiac medical, cardiac surgical and general surgical, compared with medical admissions, also in 2004-2010 compared with 2011-2016, and in readmissions compared with first admissions (all p<0.0001). In custom PIM models, admissions with weight >70th centile had reduced mortality, odds ratio 0.995 per centile, and those with weight <20th centile had increased mortality, odds ratio 1.025 per centile (both p<0.001), and PIM performance improved. (Figure prsented). Conclusions Low weight centiles are prevalent in PICU and are associated with higher mortality.