Table 2.
Final model hazard ratios and β coefficients before shrinkage
| Predictors | Adjusted hazard ratio (95% CI)* | β coefficient |
|---|---|---|
| Age (years) | 1.00 (1.00 to 1.01) | −0.0005886 |
| Female sex | 0.96 (0.83 to1.11) | −0.0412595 |
| Methotrexate dose (mg/day) | 1.01 (0.93 to 1.09) | 0.0111752 |
| Body mass index | 0.99 (0.98 to 1.00) | −0.0100983 |
| Smoking status: | ||
| Non-smoker, NR, former smoker | Reference | - |
| Current smoker | 1.06 (0.89 to 1.25) | 0.0545787 |
| Alcohol consumption (units/week): | ||
| Non-drinker | Reference | - |
| Low (1-14) | 0.93 (0.73 to 1.17) | −0.0745235 |
| Moderate (15-21) | 0.79 (0.52 to 1.19) | −0.2376144 |
| Hazardous (>21) | 1.11 (0.79 to 1.56) | 0.1062592 |
| Former drinker | 0.95 (0.74 to 1.22) | −0.0555338 |
| Inflammatory conditions: | ||
| Rheumatoid arthritis | Reference | - |
| Psoriasis or psoriatic arthritis | 1.14 (0.96 to 1.36) | 0.1339634 |
| Polymyalgia rheumatica or giant cell arteritis | 0.99 (0.75 to 1.31) | −0.0111359 |
| Connective tissue diseases* | 1.34 (0.87 to 2.07) | 0.2919058 |
| Other seronegative spondyloarthritis† | 1.30 (0.91 to 1.87) | 0.2636568 |
| Comorbidities: | ||
| Diabetes mellitus | 1.25 (1.02 to 1.53) | 0.2225364 |
| Chronic kidney disease stage 3 | 2.01 (1.63 to 2.49) | 0.7005654 |
| Drugs: | ||
| Hydroxychloroquine | 0.90 (0.72 to 1.11) | −0.1073611 |
| 5-aminosalicylate or sulfasalazine | 0.92 (0.76 to 1.12) | −0.0791611 |
| Other glucocorticoid sparing drugs‡ | 1.11 (0.66 to 1.85) | 0.1000699 |
| Statin | 1.11 (0.93 to 1.32) | 0.1021201 |
| NSAID or high dose aspirin (≥300 mg/day) | 0.97 (0.83 to 1.12) | −0.0334514 |
| Paracetamol (acetaminophen) | 1.17 (0.98 to 1.40) | 0.1608563 |
| Proton pump inhibitor | 1.02 (0.88 to 1.18) | 0.0170423 |
| Antiepileptic§ | 1.68 (0.92 to 3.05) | 0.5164347 |
| Blood test abnormalities: | ||
| Cytopenia or raised liver enzyme levels within first six months of first primary care methotrexate prescription | 2.97 (2.57 to 3.41) | 1.086389 |
NR=not recorded; NSAID=non-steroidal anti-inflammatory drug.
One unit of alcohol equals 10 mL or 8 g of pure alcohol.
*
Includes lupus, systemic sclerosis, myositis, and small vessel vasculitis.
†
Includes ankylosing spondylitis, reactive arthritis, and inflammatory bowel disease associated inflammatory arthritis.
‡
Includes leflunomide, azathioprine, 6-mercaptopurine, ciclosporin, tacrolimus, and mycophenolate mofetil.
§
Includes carbamazepine, levetiracetam, and valproate.