Table 4.

Variables Associated with 12-Month SF-36 MCS Scores (n=196)

Variable	Bivariable Analysis (unstandardized regression coefficients (95% CI))	p-value	R-square	Multivariable Analysis (unstandardized regression coefficients (95% CI))	p-value
Gender		0.50	<0.01		0.51
- male	reference category			reference category
- female	1.36 (−2.60 to 5.31)			1.17 (−2.33 to 4.66)
Age (for each 10-year increment)	−0.21 (−1.30 to 0.89)	0.71	<0.01	−0.94 (−1.91 to 0.04)	0.06
Smoking Status		0.01	0.02		0.15
- not currently smoking	reference category			reference category
- current smoker	−4.62 (−8.28 to −0.96)			−2.37 (−5.60 to 0.86)
Fracture type		0.05	0.02		0.34
- closed	reference category			reference category
- open	−3.58 (−7.09 to −0.07)			−1.47 (−4.52 to 1.59)
Multi-Trauma		0.19	0.01		0.37
- no multi-trauma	reference category			reference category
- multi-trauma	−2.29 (−5.74 to 1.16)			−1.34 (−4.32 to 1.63)
SPOC Score (for each 14-point increment)	−3.11 (−3.83 to −2.39)	<0.01	0.27	−3.01 (−3.75 to −2.27)	<0.01

95% CI = 95% confidence interval

Legend: The unstandardized regression coefficients represent the expected differences in SF-36 MCS scores between the subgroup and the reference category. For example, in our multivariable analysis, for every increase in 10-years of age patient’s will score 0.94 less on the SF-36 MCS (95% CI = −1.91 to 0.04) at 12-months. The R-square value represents the amount of variation explained in 12-month SF-36 MCS scores by each independent variable (e.g. smoking status explained 2% of variation in 12-month SF-36 PCS scores).