Table 4

Multivariable-adjusted association of income with pain and activity limitation after primary total knee arthroplasty

2 years

5 years


Moderate to severe pain

Moderate to severe functional limitation

Moderate to severe pain

Moderate to severe functional limitation


Odds ratio (95% CI)

P value

Odds ratio (95% CI)

P value

Odds ratio (95% CI)

P value

Odds ratio (95% CI)

P value


≤ US$35, 000

0.61 (0.40 to 0.94)

0.02

0.78 (0.60 to 1.02)

0.07

0.77 (0.50 to 1.19)

0.24

0.91 (0.68 to 1.25)

0.56

> US$35, 000 to US$45, 000

0.68 (0.49 to 0.94)

0.02

0.96 (0.78 to 1.20)

0.75

0.90 (0.60 to 1.34)

0.60

1.09 (0.83 to 1.44)

0.52

> US$45, 000 (ref)

1.00

1.00

1.00

1.00


Data were additionally adjusted for the following variables at baseline: age category, gender, body mass index (BMI) category, Deyo-Charlson index, American Society of Anesthesiologists (ASA) class, distance, operative diagnosis, implant fixation, preoperative pain (for pain models) and preoperative functional limitation (for functional limitation models). Significant variables in each model included the following: (1) 2-year pain model: age (P = 0.03) and preoperative pain (P = 0.003); (2) 2-year activity limitation model: age (P < 0.001), gender (P < 0.001), body mass index (P < 0.001), ASA class (P < 0.001) and preoperative activity limitation (P < 0.001); (3) 5-year pain model: ASA class (P < 0.001), distance from medical center (P = 0.02) and implant fixation (P = 0.01); (4) 5-year activity limitation model: age (P < 0.001), gender (P < 0.001), body mass index (P < 0.001), ASA class (P < 0.001), Deyo-Charlson index (P = 0.02) and preoperative activity limitation (P < 0.001).

Singh and Lewallen BMC Medicine 2013 11:62   doi:10.1186/1741-7015-11-62

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