Table 3:

Exploration of patient characteristics using linear random effects model, which may affect six-minute walk distance

Individual patient characteristic	Mean Change in 6MWD (meters) (95% CI)	p-value
Mean age (per 10 years)	0.2 (−27, 27)	0.988
Percent male (per 10 percent)	50 (20, 79)	0.002
Mean body mass index (per 1 unit)	−3 (14, −7)	0.550
Percent of patients with 1 or more comorbidities prior to ICU admission (per 10 percent)	−35 (−66, −5)	0.046

The 6MWD mean and 95% confidence intervals were estimated using a linear random effects model with a random intercept for study. The estimates were tested across follow-up time. This model was extended to determine if the study mean 6MWD varied as a function of the following patient characteristics reported by the eligible studies: age, percent of male patients, mean body mass index (BMI), and percent of patients with one or more comorbidities. Due to the limited availability of these patient characteristics variables, four separate models were constructed for each of the four characteristics; in each model the patient characteristic was centered for ease of interpretation. This table provides data on the estimated change in study mean 6MWD per unit change in variable explored. It is based on available data in the eligible studies, regression model with ‘age’ and with ‘percent male’ have data for all follow-up times. Regression models with ‘body mass index’ and ‘percent 1 or more comorbidities’ have data from 3, 6 and 12 month follow-up times.