Impact of ICU-acquired weakness on post-ICU physical functioning: a follow-up study

Luuk Wieske, Daniela S Dettling-Ihnenfeldt, Camiel Verhamme, Frans Nollet, Ivo N van Schaik, Marcus J Schultz, Janneke Horn, Marike van der Schaaf

Intensive Care Unit - acquired weakness (ICU-AW) is thought to mediate physical impairments in survivors of critical illness but few studies have investigated this thoroughly. The purpose was to investigate differences in post-ICU mortality and physical functioning between patients with and without ICU-AW at 6 months after ICU discharge. ICU patients, mechanically ventilated ≥2 days, were included in a single center prospective observational cohort study. ICU-AW was diagnosed when the average Medical Research Council (MRC) score was <4 in awake and attentive patients. Post-ICU mortality was recorded until 6 months after ICU discharge; in surviving patients physical functioning was assessed using the Short-Form Health Survey (SF-36) physical functioning (PF) domain. The independent effect of ICU-AW on post-ICU mortality was analyzed using a multivariable Cox proportional hazards model. The independent effect of ICU-AW on the PF domain score was analyzed using a multivariable linear regression model. 156 patients were included, of whom 80 with ICU-AW. Twenty-three patients died in the ICU (20 with ICU-AW); during the 6 months follow-up after ICU discharge another 25 patients died (17 with ICU-AW). PF scores were available for 96 survivors (39 patients with ICU-AW). ICU-AW was independently associated with an increase in post-ICU mortality (HR 3.6 (95% CI: 1.3 to 9.8); p:0.01) and with a decrease in physical functioning (β: -16.7 points (95% CI: -30.2 to -3.1); p:0.02). ICU-AW is independently associated with higher post-ICU mortality and with clinically relevant lower physical functioning in survivors at 6 months after ICU discharge.