Descriptive statistics were reported as mean ± SD, median [IQR], or n (%) as appropriate. A total of 3780 patients with COVID critical illness were included. Patients were stratified into groups according to discharge disposition (in-hospital death, subacute or long-term care facility, acute rehabilitation facility, home with services, or home independent). The change in mobility level during rehabilitation as measured by JH-HLM among discharge groups was compared using a two-way ANOVA. Dose of rehabilitation between discharge disposition groups was compared using Tukey’s multiple comparison test. Univariate analyses (Spearman’s correlation) were performed to assess associations between rehabilitation parameters and functional outcomes. Multivariate linear regression was performed to analyze the association between rehabilitation dose and discharge AM-PAC scores, which defined physical function among survivors, adjusting for pre-specified covariates including age, sex, body mass index (BMI), ICU length of stay, and receipt of mechanical ventilation.
Patients demographics are described in Table 1. The cohort was a mean 64 ± 16 years old, 41% female and mean BMI of 32 ± 9 kg/m2. Mechanical ventilation was required in 46% (n=1739), and the median hospital LOS was 12 days (IQR 7-21). A total of 2200 (58%) and 1698 (45%) patients received at least one PT and OT session, respectively. The first rehabilitation session occurred 7.5 ± 8.0 days after ICU admission. Patients received PT at a frequency of 0.22 ± 0.14 days a week and OT at a frequency of 0.18 ± 0.11 days a week, equivalent to 2.8 rehabilitation sessions per week. Mobility levels on the JH-HLM scale generally increased from the first to last session (+0.93 ± 2.1). The mean JH-HLM score for all sessions was 4.6 ± 1.7; this suggests a likely ability to transfer from a bed to a chair but not stand for up to one minute. The mean dose of physical rehabilitation was 1.8 ± 1.3 units.
Patients who died in the hospital (n = 994, 26%) were older, more likely to require mechanical ventilation, had longer durations of mechanical ventilation, and longer ICU LOS (Table 1) compared to patients who survived to hospital discharge. Compared to survivors, those who died in the hospital had an earlier start of rehabilitation, but had lower frequencies of rehabilitation, achieved lower levels of mobility, and received a lower dose of physical rehabilitation (Table 1). Stratified by discharge disposition, patients discharged to home had the highest dose of rehabilitation (F = 69, p <0.0001; Figure 1).
For 2191 patients with complete data, mean AM-PAC scores at discharge were 15.6 ± 5.9; similar to the JH-HLM mean score, this suggests requiring a lot of help for bed-to-chair transfers.11 Rehabilitation dose and AM-PAC at discharge were moderately, positively associated (Spearman’s rho [r] = 0.484, p < 0.001). Physical function at discharge as measured by AM-PAC was significantly associated with average mobility achieved in first 3 sessions (r = 0.799, p < 0.001), change in mobility from first to last session (r = 0.445, p < 0.001), and PT and OT frequency with physical function (r = 0.130, p < 0.001). Multivariate linear regression (model adjusted R2= 0.68, p <0.001) demonstrates mechanical ventilation (β = -0.86, p = 0.001), average mobility score in first three sessions (β = 2.6, p <0.001) and physical rehabilitation dosage (β = 0.22, p = 0.001) were predictive of AM-PAC scores at discharge when controlling for age, sex, BMI, and ICU LOS.