Table 4.

Predictors of having poor pain or function (WOMAC < 60) 2 years after hip replacement^* (logistic regression results).

	Poor WOMAC Pain at 2 Yrs, OR (95% CI)	p	Poor WOMAC Function at 2 Yrs, OR (95% CI)	p
Age	0.99 (0.97, 1.01)	0.14	1.01 (0.99, 1.00)	0.34
Female vs male	1.06 (0.61, 1.83)	0.36	1.25 (0.69, 2.26)	0.46
RA vs OA	3.22 (1.29, 8.07)	0.01	4.32 (1.57, 11.89)	0.005
Back pain vs no back pain	1.25 (0.75, 2.08)	0.30	1.62 (0.93, 2.82)	0.08
25 ≤ BMI < 30 vs 18.5 < BMI < 25	0.91 (0.48, 1.73)	0.78	1.36 (0.65, 2.84)	0.42
30 ≤ BMI < 35 vs 18.5 < BMI < 25	0.94 (0.46, 1.93)	0.87	1.64 (0.75, 3.56)	0.22
35 ≤ BMI < 40 vs 18.5 < BMI < 25	0.42 (0.13, 1.31)	0.13	0.78 (0.23, 2.66)	0.70
BMI > 40 vs 18.5 < BMI < 25	1.30 (0.44, 3.85)	0.63	2.93 (0.95, 8.99)	0.06
Preoperative WOMAC pain	0.99 (0.97, 1.01)	0.17	1.01 (0.98, 1.03)	0.71
Preoperative PCS	0.95 (0.91, 0.99)	0.01	^**	^**
Preoperative WOMAC function	^**	^**	0.96 (0.94, 0.99)	0.03
Preoperative MCS	0.96 (0.94, 0.98)	0.0002	0.98 (0.96, 0.999)	0.04
Education: college vs no college	0.83 (0.49, 1.41)	0.56	0.74, (0.43, 1.30)	0.30
White vs other	0.46 (0.23, 0.92)	0.02	0.66 (0.30, 1.47)	0.31
Expectation score	^**	^**	0.97 (0.96, 0.99)	0.0005
Deyo: 0 comorbidities vs 1–3+	^**	^**	0.80 (0.44, 1.47)	0.47
ASA class 2 vs ASA class 1	1.01 (0.37, 2.74)	0.99	^**	^**
ASA class 3+ vs ASA class 1	2.11 (0.67, 6.59)	0.20	^**	^**
Previous hip replacement vs no
previous replacement	1.37 (0.75, 2.50)	0.30	1.35 (0.72, 2.53)	0.35

↵* Multivariate regression controlling for age, sex, diagnosis, BMI, education, race, back pain, previous hip replacement, preoperative WOMAC pain and function, preoperative MCS and PCS, expectations score, ASA class, and number of Deyo comorbidities.
↵** Variable excluded because of nonconvergence of logistic model. WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; RA: rheumatoid arthritis; OA: osteoarthritis; BMI: body mass index; PCS: physical component scale; MCS: mental component scale; ASA: American Society of Anesthesia.