Table 2

 Comparison of patients with and without a primary total joint arthroplasty within three years of baseline questionnaire before and after matching. Values are numbers (percentages) unless stated otherwise

CharacteristicsExposure groups before matchingExposure groups after matching
No arthroplasty (n=1582)Arthoplasty (n=173)Standardised differenceNo arthroplasty (n=153)Arthroplasty (n=153)Standardised difference
Median (interquartile range) age (years)69 (63-77)70 (64-75)0.0869 (62-76)70 (63-75)0.08
Women1174 (74.2)125 (72.3)0.04109 (71.2)109 (71.2)0
Median (interquartile range) body mass index28 (25-32)28 (25-32)0.1428 (26-33)28 (25-33)0.09
Median (interquartile range) hip pain974 (61.6)100 (57.8)0.0889 (58.2)86 (56.2)0.04
Median (interquartile range) knee pain1378 (87.1)153 (88.4)0.04138 (90.2)134 (87.6)0.08
Living conditions:
 Lives alone510 (32.2)50 (28.9)0.0749 (32.0)42 (27.5)0.09
 Lives with others1055 (66.7)123 (71.1)0.09102 (66.7)111 (72.5)0.09
 Lives in long term care facility17 (1.1)0 (0)0.11
Income ($C):
 >20 000477 (30.2)51 (29.5)0.0143 (28.1)48 (31.4)0.07
 ≤20 000820 (51.8)86 (49.7)0.0479 (51.6)78 (51.0)0.01
 Missing285 (18.0)36 (20.8)0.0731 (20.3)27 (17.6)0.07
Education:
 High school or less1351 (85.4)140 (80.9)0.13125 (81.7)124 (81.0)0.02
 Post-secondary231 (14.6)33 (19.1)0.1328 (18.3)29 (19.0)0.02
Smoker:
 Never752 (48.8)83 (49.4)0.1075 (49.0)75 (49.0)0.01
 Former552 (35.8)70 (41.7)0.1062 (40.5)63 (41.2)0.01
 Current236 (15.3)15 (8.9)0.1016 (10.5)15 (9.8)0.01
NSAID use576 (36.4)89 (51.4)0.3184 (54.9)80 (52.3)0.05
No of comorbidities:
 072 (4.6)8 (4.6)0.07≤5 (2.0)7 (4.6)0.05
 1294 (18.6)42 (24.3)0.0733 (21.6)38 (24.8)0.05
 2502 (31.7)53 (30.6)0.0767 (43.8)47 (30.7)0.05
 3427 (27.0)37 (21.4)0.0731 (20.3)32 (20.9)0.05
 ≥4287 (18.1)33 (19.1)0.0919 (12.4)29 (19.0)0.05
Pre-existing cardiovascular disease541 (34.2)47 (27.2)0.1540 (26.1)40 (26.1)0
Diabetes249 (15.7)24 (13.9)0.0520 (13.1)22 (14.4)0.04
Depression529 (33.4)50 (28.9)0.1053 (34.6)45 (29.4)0.09
Hypertension955 (60.4)118 (68.2)0.1697 (63.4)102 (66.7)0.07
Median (interquartile range) SF-3650 (32-67)55 (40-72)0.2255 (37-67)55 (40-72)0.01
Median (interquartile range) WOMAC41 (25-53)48 (33-56)0.3145 (35-53)48 (32-56)0.01
Pre-baseline total joint arthroplasty150 (9.5)41 (23.7)0.4636 (23.5)35 (22.9)0.02

$C1.00 (£0.60; $0.96; €0.71).

NSAID=non-steroidal anti-inflammatory drug; SF-36=short form-36 general health survey; WOMAC=Western Ontario and McMaster Universities arthritis index.