Measuring physical activity, sedentary behaviour and physical function in survivors of critical illness in the year after hospital discharge: a prospective, observational study

Background/Aims Survivors of critical illness often face significant morbidity, including challenges in resuming daily activities and physical function after hospital discharge. Evaluating physical activity and physical function has the potential to provide insights into morbidity and quality of life following critical illness, and this has been described as a research priority. The aim of this study was to assess and describe physical activity, sedentary behaviour and physical function in survivors of critical illness over a 1-year period following discharge from intensive care units. Methods A total of 14 patients discharged from hospital following intensive care unit admission were invited to attend up to four assessments: within 2 weeks, at 6 weeks, 6 months and 1 year, following hospital discharge. Seven-day accelerometer-based physical activity (mean daily step counts, different intensities of physical activity and sedentary behaviour), modified shuttle walk test and handgrip strength were assessed at each timepoint. Results were compared against research guidelines, normative data and minimal clinically important differences for the specific tests. Results Out of 165 eligible ICU survivors, 19 individuals were recruited and 14 provided data (median age: 54 years (interquartile range IQR 20 years); eight men, six women; median intensive care unit length of stay: 9.00 IQR: 4.50 days; median mechanical ventilation duration: 58.50 IQR: 132.75 hours; median Acute Physiologic Chronic Health Evaluation score: 15.50 IQR 15.50). They all performed below population norms or research guidelines for mean daily step counts (763–7744 steps), Modified Shuttle Walk Test (40–800 metres) and handgrip strength (8–52 kg) across the 12-month study period, with most improvements below minimal clinically important differences. Conclusions Physical activity and physical function varied among patients after discharge from hospital following critical illness, and remained low during the first year post-discharge. While accelerometry and handgrip dynamometry appear to be safe and feasible assessments, there were challenges with data collection; for example, participants using mobility aids could not perform the Modified Shuttle Walk Test. The findings could be used to inform strategies that could support patients to appropriately increase their physical activity levels during recovery after critical illness. Implications for practice Measurement of physical activity, sedentary behaviour, and physical function can provide valuable insight into the recovery trajectory in survivors of critical illness following hospital discharge. Researchers and allied health professionals should work together to develop and test interventions to improve physical activity, sedentary behaviour and physical function across the recovery trajectory in this population.