Table 1.
Baseline characteristics among patients with RA at diagnosis and age-matched and sex-matched controls
| RA (n=6591) | No RA (n=6591) | P value | |
| Baseline characteristics | |||
| Age (years) | 58.67 (15.54) | 58.67 (15.54) | NA |
| Male sex | 2142 (32.5) | 2142 (32.5) | NA |
| Ethnicity* | <0.001 | ||
| White | 4883 (91.6) | 4418 (94.6) | |
| Asian | 255 (4.8) | 147 (3.1) | |
| Black | 128 (2.4) | 69 (1.5) | |
| Mixed | 26 (0.5) | 18 (0.4) | |
| Other | 36 (0.7) | 18 (0.4) | |
| Smoking status* | <0.001 | ||
| Never smoked | 1853 (30.0) | 2247 (35.8) | |
| Active smoker | 1348 (21.9) | 1187 (18.9) | |
| Ex-smoker | 2968 (48.1) | 2838 (45.2) | |
| Clinical measurements | |||
| BMI (kg/m2)* | 27.67 (5.97) | 27.23 (5.56) | <0.001 |
| Systolic BP, mm Hg* | 130.86 (16.19) | 131.10 (15.95) | 0.084 |
| Diastolic BP, mm Hg* | 76.82 (9.68) | 77.31 (9.46) | 0.003 |
| Total cholesterol (mmol/L)* | 5.07 (1.13) | 5.20 (1.12) | <0.001 |
| LDL cholesterol (mmol/L)* | 2.96 (1.00) | 3.05 (1.01) | 0.005 |
| HDL cholesterol (mmol/L)* | 1.47 (0.45) | 1.50 (0.44) | <0.001 |
| Positive RF or anti-CCP antibodies* | 1885 (28.1) | 159 (2.4) | <0.001 |
| CRP (mg/L)* | 20.0 (32.7) | 7.4 (16.8) | <0.001 |
| Comorbidities | |||
| Chronic kidney disease (stage III–V) | 618 (9.4) | 614 (9.3) | 0.923 |
| Diabetes (any) | 735 (11.2) | 635 (9.6) | 0.004 |
| Type 1 | 44 (0.7) | 26 (0.4) | 0.025 |
| Type 2 | 691 (10.5) | 609 (9.2) | <0.001 |
| Atrial fibrillation | 237 (3.6) | 185 (2.8) | 0.009 |
| Myocardial infarction | 202 (3.1) | 169 (2.6) | 0.079 |
| Stroke | 254 (3.9) | 180 (2.7) | <0.001 |
| Heart failure | 108 (1.6) | 65 (1.0) | 0.001 |
| Medication use† | |||
| ACE inhibitor | 1415 (21.5) | 1359 (20.6) | 0.203 |
| Angiotensin receptor blocker | 536 (8.1) | 528 (8.0) | 0.816 |
| Calcium channel blocker | 1297 (19.7) | 1184 (18.0) | 0.007 |
| Beta-blocker | 1260 (19.1) | 1294 (19.6) | 0.452 |
| Anti-platelet agents | 1374 (20.8) | 1371 (20.8) | 0.962 |
| Lipid lowering medication | 1811 (27.5) | 1731 (26.3) | 0.078 |
| NSAID | 1962 (29.8) | 430 (6.5) | <0.001 |
| Glucocorticoids | 2001 (30.4) | 899 (13.6) | <0.001 |
| Methotrexate | 992 (15.1) | 8 (0.1) | <0.001 |
| csDMARD | 1263 (19.2) | 90 (1.4) | <0.001 |
| bDMARD | 19 (0.3) | 0 (0.0) | <0.001 |
Data are mean (SD) or n (%). P values from χ2 test or t-test are provided.
*The following variables had missing values (n): ethnicity in RA: n=1263; no RA: n=1921; smoking status in RA: n=422; no RA: n=319; BMI in RA: n=520; no RA: n=701; blood pressure in RA: n=191; no RA: n=221; cholesterol in RA: n=1678; no RA: n=2162; CRP in RA: n=2172; no RA: n=4499; one or more RA antibodies were measured in RA: n=3550, no RA: n=992.
†Any prescription on or within 3 months prior to the first diagnosis code in primary care.
anti-CCP, anti-cyclic citrullinated peptide; bDMARD, biological disease-modifying anti-rheumatic drug; BMI, body mass index; BP, blood pressure; CRP, C reactive protein; csDMARD, conventional synthetic disease-modifying anti-rheumatic drug; HDL, high-density lipoprotein; LDL, low-density lipoprotein; NSAID, non-steroidal anti-inflammatory; RA, rheumatoid arthritis.