The effect of intervening hospitalizations on the benefit of structured physical activity in promoting independent mobility among community-living older persons: secondary analysis of a randomized controlled trial

Table 6 Effect of physical activity on mobility outcomes within levels of hospital exposure

Exposure^a	Operational definition	HR (95% CI)	P value^*
	Onset of MMD
Any hospitalization	Not hospitalized	0.77 (0.62–0.95)	0.903
	Hospitalized	0.79 (0.58–1.1)
Number of hospitalizations	0	0.77 (0.62–0.95)	0.742
	1	0.85 (0.59–1.2)
	2 or more	0.66 (0.37–1.2)
Number of days hospitalized^b	0	0.79 (0.66–0.95)	0.804
	3	0.80 (0.67–0.95)
	10	0.81 (0.65–1.0)
	Recovery from MMD ^d
Any hospitalization^c
Model 1	Not hospitalized	1.2 (0.88–1.7)	0.670
	Hospitalized	1.5 (0.71–3.0)
Model 2	Not hospitalized	1.2 (0.94–1.6)	0.392
	Hospitalized	1.6 (0.90–2.9)
Model 3	Not hospitalized	1.3 (0.88–2.1)	0.477
	Hospitalized	2.0 (0.71–5.4)

Abbreviations: CI confidence interval, HR hazard ratio, MMD major mobility disability
^* Values represent statistical interaction between exposure and study group on mobility outcome
^a Assessed during the interval preceding the outcome
^b Results are provided for a range of fixed values. Three days was the median length of hospital stay, and 10 days allowed for long lengths of stay and more than one hospital admission
^c Results are not available for the number of hospitalizations or number of days hospitalized because the number of participants with more than one hospitalization during the at-risk period was small
^d All models include clinical site, age, and gender as covariates; Model 2 uses inverse probability weighting based on MMD, whereas Model 3 uses inverse probability weighting based on withdrawal/missed follow-up, as described in the Methods

ISSN: 1741-7015