Table 4.

Risk of hospitalization (incidence rate ratios, 95% confidence interval) by summary physical performance score^*

Number of physical exams with poor performance	N	Model 1: Age, clinical center, race, and sex adjusted †	Model 2: Multivariate adjusted ‡	Model 3: Model 2 adjustments plus muscle density §
0	1200	1.00 (ref)	1.00 (ref)	1.00 (ref)
1	808	1.36 (1.19,1.55)	1.27 (1.10,1.45)	1.25 (1.08,1.43)
2	406	1.73 (1.47,2.04)	1.61 (1.36,1.91)	1.57 (1.32,1.86)
3	179	1.95 (1.56,2.44)	1.72 (1.36,2.17)	1.63 (1.28,2.07)
4	54	2.457 (1.71,3.56)	1.88 (1.27,2.78)	1.80 (1.20,2.69)
p for trend		<.001	<.001	<.001

^*Performance tests included include grip strength, knee extension strength, walking speed and repeat chair stands exam. Poor performance is defined as performance in lowest race and sex specific quartile of a measure or unable to complete the measure.

^†In age, clinical center, race and sex adjusted models (N=2,645), 3,299 hospitalizations occurred in 1,444 participants.

^‡Adjusted for total percent body fat, weight, age, self-rated health, sex, race, clinical center, co-morbid conditions (cerebrovascular disease, CHD, CHF, hypertension, PPAD, pulmonary disease, diabetes) In model 2, (N=2,395), 2,977 hospitalizations occurred in 1,295 participants.

^§The IRR (95% CI) for muscle density in this model was: quartile 1: 1.40 (1.15, 1.70); quartile 2: 1.25 (1.05, 1.49); quartile 3: 1.09 (0.92, 1.30); quartile 4: 1.00 (referent), p for trend = 0.008.