Relationship between height and outcomes among critically ill adults: a cohort study

Purpose: Many diagnostic and therapeutic interventions for critically ill adult patients are not performed according to patient size, but are standardized for an idealized 174-cm man (ideal body weight 70 kg). This study aims to determine whether critically ill patients with heights significantly different from a standardized patient have higher hospital mortality or greater resource utilization. Methods: Retrospective cohort study of consecutive patients admitted to 210 intensive care units (ICUs) in the United Kingdom participating in the Intensive Care National Audit and Research Centre’s Case Mix Programme Database from April 1, 2009, to March 31, 2015. Primary outcome was hospital mortality, adjusted for age, comorbid disease, severity of illness, socioeconomic status and body mass index, using hierarchical modeling to account for clustering by ICU. Data were stratified by sex, and the effect of height was modeled continuously using restricted cubic splines. Results: The cohort included 233,308 men and 184,070 women, with overall hospital mortality of 22.5% and 20.6%, respectively. After adjustment for potential confounders, hospital mortality decreased with increasing height; predicted mortality (holding all other covariates at their mean value) decreased from 24.1 to 17.1% for women and from 29.2 to 21.0% for men across the range of heights. Similar patterns were observed for ICU mortality and several additional secondary outcomes. Conclusions: Short stature may be a risk factor for mortality in critically ill patients. Further work is needed to determine which unmeasured patient characteristics and processes of care may contribute to the increased risk observed.