Table 2 Best-fitting Cox regression model of time to joint replacement surgery

Age (at cohort entry)

1.19

1.10, 1.28

Age (at cohort entry) squared

1.00

1.00, 1.00

Female sex

0.80

0.66, 0.96

Recipient of social assistance at cohort entry

0.89

0.59, 1.35

Baseline urban residence

1.03

0.82, 1.28

Baseline regional employment rate^a

1.00

0.98, 1.01

Baseline regional family income^a

1.00

0.99, 1.01

Baseline regional percent university graduates^a

1.00

0.99, 1.01

Extra-articular RA manifestations (time-dependent)

1.08

0.91, 1.28

Rheumatology visits at baseline (log-transformed)

1.24

1.11, 1.38

Rheumatology visits in follow up, time dependent (log-transformed)

0.98

0.84, 1.15

High health care use at baseline

1.11

0.91, 1.35

Prior joint replacement

2.55

1.90, 3.43

Baseline comorbidities

 Myocardial infarction

0.86

0.48, 1.56

 Diabetes

0.99

0.76, 1.28

 Osteoporosis

0.79

0.63, 0.99

 Cerebrovascular disease

1.27

0.40, 4.02

 Acute renal failure

1.16

0.68, 1.97

 Chronic renal failure

1.60

0.90, 2.84

 Coronary artery disease

1.01

0.81, 1.27

 COPD-asthma

0.96

0.77, 1.18

 Any type of cancer

1.01

0.72, 1.41

 Osteoarthritis

2.15

1.81, 2.55

 Charlson Comorbidity

0.92

0.85, 1.00

Drug use prior to cohort entry

 Anti-TNF

1.00

0.35, 2.85

 MTX

1.27

0.94, 1.70

 Other DMARDs

1.13

0.88, 1.45

 Systemic corticosteroids

1.15

0.97, 1.38

 COXIBs

0.97

0.82, 1.15

 NSAIDs

0.87

0.73, 1.03

Time-dependent cumulative drugs in follow up (years)

 Anti-TNF

1.13

0.99, 1.29

 Other biologic drugs

1.37

0.61, 3.08

 Systemic corticosteroids

1.01

0.94, 1.08

 COXIBs

1.20

1.11, 1.30

 NSAIDs

1.31

1.20, 1.43

Cumulative MTX in first year (months)

0.94

0.92, 0.96

Cumulative other DMARDs in first year months)

0.97

0.95, 0.99