Table 3.

Risk factors for lower extremity ulcers in patients with rheumatoid arthritis (RA)

Variable	Value*	Hazard Ratio [95% confidence interval (CI)]
At RA incidence
Age (per 10 year increase)	55.9 (± 15.7)	1.73 (1.47, 2.04)**
Sex, female	556 (68)	1.22 (0.77, 1.94)
Calendar year of RA incidence in 1995–2007 (vs. 1980–1994)	464 (57)	2.14 (1.27, 3.58)**
Erythrocyte sedimentation rate (ESR) at RA incidence date (per 10 mm/1hr increase)	32.7 (±25.7)	1.05 (0.94, 1.18)
Highest ESR in 1st year of RA (per 10 mm/1hr increase)	105 (13)	1.03 (0.94, 1.12)
Rheumatoid factor positive	537 (66)	1.63 (1.05, 2.53)**
Current smoker	178 (22)	1.46 (0.92, 2.34)
Ever smoker	449 (55)	1.02 (0.66, 1.58)
At RA incidence or at any time during follow-up
History of body mass index (BMI) ≥30 kg/m2	388 (48)	1.12 (0.73, 1.71)
History of BMI<20 kg/m2	190 (23)	1.68 (1.03, 2.75)**
Rheumatoid nodules	267 (33)	2.14 (1.39, 3.31)**
Radiological erosions/destructive changes	433 (53)	1.59 (1.03, 2.47)**
Severe extra-articular RA***	90 (11)	1.96 (1.11, 3.47)**
Large joint swelling	639 (79)	1.58 (0.89, 2.82)
Ever 3 ESR ≥60 mm/hour	105 (13)	2.39 (1.40, 4.07)**
Arthroplasty or synovectomy	190 (23)	1.36 (0.86, 2.15)
Ever exposure to medications
Methotrexate	469 (58)	1.58 (1.01, 2.47)**
Hydroxychloroquine	480 (59)	1.09 (0.70, 1.70)
Other DMARDs	258 (32)	1.36 (0.84, 2.19)
Biologic agents	137 (17)	1.95 (0.99, 3.83)
Systemic glucocorticosteroids	627 (77)	1.54 (0.93, 2.54)
Comorbidities
Hypertension	709 (87)	1.94 (0.76, 4.93)
Diabetes mellitus	154 (19)	1.56 (0.96, 2.51)
Cardiovascular disease	231 (28)	1.51 (0.92, 2.47)
Peripheral vascular disease	28 (3)	1.29 (0.52, 3.25)
Venous thromboembolism	69 (8)	2.16 (1.07, 4.36)**

^*mean (± standard deviation) or n(%)

^**statistically significant at p< .05

^***as defined in reference 10