Predictive validity of the Chelsea Critical Care Physical Assessment tool (CPAx) in critically ill, mechanically ventilated adults: a prospective clinimetric study

Abstract

Purpose To investigate the predictive validity of the Chelsea Critical Care Physical Assessment tool (CPAx) at intensive care unit (ICU) discharge in critically ill adults for their 90-day outcomes. Materials and methods This prospective clinimetric study investigated four theory-driven, a-priori hypotheses in critically ill adults recruited within 72–144 h of mechanical ventilation. The primary hypothesis was a moderate accuracy (AUROC = 0.750) in predicting residence at home within 90 days. Secondary hypotheses included discrimination between hospital discharge destinations, correlation with subsequent health-related quality of life and length of ICU stay. Results We observed a good accuracy (AUROC = 0.778) of the CPAx at ICU discharge in predicting a return to home within 90 days. The CPAx score significantly increased between the discharge groups “undesirable” ≤ “rehabilitation” ≤ “home” (p < 0.001), but was not associated with 90-day health-related quality of life (physical: r = 0.261, mental: r = 0.193). Measured at baseline, CPAx scores correlated as expected with length of ICU stay (r = −0.443). Conclusions The CPAx at ICU discharge had a good predictive validity in projecting residence at home within 90 days and general discharge destinations. The CPAx might therefore have clinical value in prediction, though it does not seem useful to predict subsequent health-related quality of life. TRIAL REGISTRATION: German Clinical Trials Register (DRKS) identification number: DRKS00012983, registered on September 20, 2017 IMPLICATIONS FOR REHABILITATION The CPAx is a valid and reliable measurement instrument to evaluate critically ill adults’ physical function and activity, in addition the CPAx might be useful to predict rehabilitation needs. The CPAx had a moderate to good predictive validity with three out of four a-priori hypotheses accepted. A CPAx score of ≥18 at critical care discharge has a sensitivity of 80% and a specificity of 70% in predicting a return to home within 90 days. The CPAx might consequently be valuable to identify critically ill adults’ rehabilitation needs, to advise on their potential trajectory of recovery or to screen patients for follow-up after hospital discharge.