Table 2

Baseline characteristics of cases and matched controls from a base population of 16 207 RA patients, 1985–2003

Number13 63468 170
Age (years, mean (SD))71.9 (6.0)71.8 (5.9)
Sex (% women)68.968.9
Follow-up (years, mean (SD))1.2 (1.5)1.2 (1.5)
Number of rheumatologist visits in 6 months before index date (mean (SD))1.5 (2.7)1.4 (2.5)
NSAID prescription within last 45 days55.255.7
Extra-articular RA0.20.1
DMARD prescription within past 45 days
 Anti-TNF therapy0.10.1
 Others (ciclosporin, mycophenolate mofetil, d-penicillamine)1.81.7
No of hospital admissions in year preceding index date (mean (SD))0.5 (1.0)0.4 (0.8)
No of GP visits in year preceding index date (mean (SD))7.8 (9.0)6.1 (7.7)
No of hospital specialist visits (excluding rheumatologist) in year preceding index date (mean (SD))9.9 (13.1)7.6 (10.8)
Comorbidity (from ICD-9 or drug codes)
 Chronic respiratory disease (COPD/asthma/ILD)20.312.1
 Chronic renal disease20.312.1
PPI/H2 blocker prescription within last 45 days27.920.0
  • Numbers are percentages unless otherwise stated.

  • * Each patient within the cohort could contribute more than once to the controls.

  • Patients could receive combination disease-modifying antirheumatic drug (DMARD) therapy and contribute to more than one drug category.

  • COPD, chronic obstructive pulmonary disease; GP, general practitioner; ICD, International Classification of Diseases; ILD, interstitial lung disease; NSAID, non-steroidal anti-inflammatory drug; PPI, proton pump inhibitor; RA, rheumatoid arthritis.