Table 4.
Comparison of mortality risk, swollen joints, tender joints and functional disability between cohort 1 and cohort 2 over time
| N (number of events) |
Age-adjusted and gender-adjusted, HR/SHR (95% CI) | Adjusted for baseline variables*, HR/SHR (95% CI) | Adjusted for baseline variables* and time-varying smoking, HR/SHR (95% CI) | Adjusted for baseline variables* and time-varying treatment/smoking, HR/SHR (95% CI) | |
| Mortality risk† | |||||
| Patients with IP | 1653 (291) | 0.76 (0.60 to 0.96) | 0.72 (0.56 to 0.95) | 0.73 (0.56 to 0.95) | 0.77 (0.58 to 1.02) |
| Patients with RA | 961 (178) | 0.87 (0.64 to 1.19) | 0.83 (0.59 to 1.18) | 0.85 (0.60 to 1.20) | 0.95 (0.65 to 1.38) |
| Cancer mortality risk† | |||||
| Patients with IP | 1653 (91) | 0.97 (0.64 to 1.49) | 1.06 (0.66 to 1.73) | 1.06 (0.65 to 1.72) | 1.04 (0.60 to 1.77) |
| Patients with RA | 961 (55) | 1.03 (0.60 to 1.79) | 1.25 (0.67 to 2.32) | 1.26 (0.67 to 2.35) | 1.26 (0.60 to 2.62) |
| CVD mortality risk† | |||||
| Patients with IP | 1653 (106) | 0.61 (0.40 to 0.93) | 0.58 (0.37 to 0.93) | 0.53 (0.33 to 0.84) | 0.61 (0.37 to 0.99) |
| Patients with RA | 961 (68) | 0.69 (0.41 to 1.18) | 0.61 (0.34 to 1.12) | 0.61 (0.34 to 1.12) | 0.79 (0.41 to 1.52) |
| Respiratory disease mortality risk† | |||||
| Patients with IP | 1653 (43) | 1.26 (0.67 to 2.35) | 1.33 (0.67 to 2.66) | 1.11 (0.54 to 2.28) | 1.01 (0.45 to 2.25) |
| Patients with RA | 961 (25) | 1.63 (0.75 to 3.53) | 1.50 (0.61 to 3.69) | 1.54 (0.64 to 3.72) | 1.57 (0.62 to 4.00) |
| N | Age-adjusted and gender-adjusted, relative difference (95% CI) | Adjusted for baseline variables*, relative difference (95% CI) | Adjusted for baseline variables* and time-varying smoking, relative difference (95% CI) | Adjusted for baseline variables* and time varing treatment/smoking, relative difference (95% CI) | |
| Swollen joint counts (51)† | |||||
| Patients with IP | 1653 | −34% (−39% to −29%) | −17% (−23% to −10%) | −16% (−23% to −10%) | −15% (−21% to −8%) |
| Patients with RA | 961 | −30% (−36% to −23%) | −12% (−20% to −3%) | −11% (−20% to −2%) | −5% (−14% to 6%) |
| Tender joint counts (51)† | |||||
| Patients with IP | 1653 | −3% (−11% to 5%) | 1% (−7% to 10%) | 1% (−7% to 10%) | −2% (−10% to 7%) |
| Patients with RA | 961 | 0% (−10% to 12%) | −4% (−14% to 7%) | −4% (−14% to 8%) | −5% (−15% to 6%) |
| N | Age-adjusted and gender-adjusted, mean difference (95% CI) | Adjusted for baseline variables*, mean difference (95% CI) | Adjusted for baseline variables* and time-varing smoking, mean difference (95% CI) | Adjusted for baseline variables* and time-varying treatment/smoking, mean difference (95% CI) | |
| HAQ scores† | |||||
| Patients with IP | 1651 | 0.09 (0.03 to 0.16) | 0.05 (−0.00 to 0.10) | 0.05 (−0.00 to 0.10) | 0.01 (−0.05 to 0.06) |
| Patients with RA | 960 | 0.08 (−0.01 to 0.17) | 0.01 (−0.06 to 0.08) | 0.01 (−0.06 to 0.08) | −0.05 (−0.12 to 0.02) |
Cohort 1 is the reference category for all models.
*Baseline variables controlled for age, gender, time from onset to baseline, rheumatoid factor, anticyclic citrullinated protein antibodies, smoking status, HAQ, swollen/tender joint counts (51), C reactive protein, taking sDMARDs and Disease Activity Score 28.
†Mortality risk modelled using Cox proportional hazards model, cancer/CVD/respiratory disease modelled using competing risks regression, swollen and tender joint counts modelled using population-average negative binomial regression, and HAQ score modelled using generalised estimating equations analysis.
CVD, cardiovascular disease; HAQ, Health Assessment Questionnaire; IP, inflammatory polyarthritis; RA, rheumatoid arthritis; sDMARD, synthetic disease-modifying antirheumatic drug; SHR, subhazard ratio.