Table 2

Univariable and multivariable analysis (imputed data, 49 datasets)—HRs for acquiring bDMARD refractory disease

Univariable HRMultivariable HRMultivariable HR (including IMD)*
Registration year (2011–2014 vs 2001–2008)15 (11 to 20); p<0.00115 (10 to 21); p<0.00117 (11 to 24); p<0.001
Women (vs men)1.3 (1.1 to 1.5); p=0.0041.3 (1.1 to 1.5); p=0.0091.2 (1.0 to 1.5); p=0.04
Age, years (>50 vs ≤50)0.6 (0.5 to 0.7); p<0.0010.6 (0.5 to 0.7); p<0.0010.6 (0.5 to 0.7); p<0.001
Disease duration, years (>10 vs ≤10)0.7 (0.6 to 0.8); p<0.0010.8 (0.7 to 0.95); p=0.0080.8 (0.7 to 0.9); p=0.004
RF positive (vs negative)1.1 (0.9 to 1.3); p=0.31.1 (1.0 to 1.3); p=0.11.1 (0.9 to 1.3); p=0.2
Erosions on X-ray (vs negative)0.8 (0.7 to 1.0); p=0.011.0 (0.8 to 1.1); p=0.81.0 (0.8 to 1.1); p=0.7
Methotrexate at registration (vs none)1.1 (0.9 to 1.2); p=0.31.0 (0.9 to 1.2); p=0.61.0 (0.9 to 1.2); p=0.9
On steroids at registration (vs none)1.0 (0.8 to 1.1); p=0.61.0 (0.9 to 1.2); p=0.51.1 (0.9 to 1.2); p=0.4
Tender joint count (per joint)1.02 (1.01 to 1.02); p=0.0011.0 (1.0 to 1.0); p=0.31.0 (1.0 to 1.0); p=0.3
Swollen joint count (per joint)1.0 (1.0 to 1.0); p=1.01.0 (1.0 to 1.0); p=0.91.0 (1.0 to 1.0); p=1.0
Patient global assessment (cm)1.1 (1.1 to 1.1); p<0.0011.1 (1.0 to 1.1); p=0.0071.1 (1.0 to 1.1); p=0.02
ESR (mm/h)0.996 (0.994 to 0.999); p=0.0031.0 (1.0 to 1.0); p=0.61.0 (1.0 to 1.0); p=0.3
DAS28 (whole unit)1.1 (1.0 to 1.1); p=0.11.0 (0.8 to 1.2); p=0.81.0 (0.8 to 1.3); p=0.8
HAQ (whole unit)1.2 (1.1 to 1.3); p=0.0051.3 (1.1 to 1.5); p=0.0011.2 (1.1 to 1.4); p=0.003
Total comorbidities† (vs none)
 1 comorbidity1.0 (0.9 to 1.2); p=0.61.1 (0.9 to 1.3); p=0.31.1 (0.9 to 1.3); p=0.2
 2 comorbidities1.2 (0.9 to 1.4); p=0.21.2 (0.9 to 1.4); p=0.21.1 (0.9 to 1.4); p=0.2
 3+ comorbidities1.3 (1.0 to 1.8); p=0.091.3 (0.9 to 1.8); p=0.11.2 (0.9 to 1.7); p=0.3
Smoke status (vs never smoked)
 Current smoker1.5 (1.3 to 1.7); p<0.0011.5 (1.2 to 1.7); p<0.0011.4 (1.2 to 1.7); p<0.001
 Ex-smoker1.0 (0.8 to 1.1); p=0.71.1 (0.9 to 1.3); p=0.41.0 (0.8 to 1.2); p=1.0
Obese (body mass index ≥30)1.3 (1.1 to 1.5); p=0.0011.2 (1.0 to 1.4); p=0.0471.2 (1.0 to 1.4); p=0.04
SF-36: Physical Component Score0.97 (0.95 to 0.99); p=0.01
SF-36: Mental Component Score0.98 (0.96 to 1.0); p=0.11.0 (1.0 to 1.0); p=0.41.0 (1.0 to 1.0); p=0.5
IMD (excluding Northern Ireland)
(all other patients as referent)
 Lowest quintile (more deprived)1.4 (1.2 to 1.7); p<0.0011.2 (1.0 to 1.4); p=0.03
  • Results are presented as HRs with 95% CIs.

  • *Patients with IMD data, excluding Northern Ireland (n=12 711).

  • †Total comorbidities—hypertension, ischaemic heart disease, stroke, lung disease, renal disease, diabetes, depression, liver disease.

  • bDMARD, biologic disease-modifying antirheumatic drug; DAS28, 28-joint Disease Activity Score (higher score indicates worse health); ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire (higher score indicates worse health); IMD, index of multiple deprivation; RF, rheumatoid factor; SF-36, 36-item Short Form Survey for quality of life (higher score indicates improved health); TNFi, tumour necrosis factor-alpha inhibitor.