title: Increased risk of tuberculosis in patients with rheumatoid arthritis.
abstract: OBJECTIVE
  To quantify the risk of tuberculosis (TB) in an unselected sample of patients with rheumatoid arthritis (RA) compared to the risk in the general population.
  
  
  METHODS
  The incidence of TB in the general population of Spain was obtained from the National Network of Epidemiological Surveillance reports. The incidence of TB was ascertained from a cohort of 788 patients with RA selected randomly from the registries of 34 participating centers throughout Spain. A patient was considered a TB case only if information about disease symptoms, microorganism identification, and TB treatment were confirmed in the clinical records. The relative risk of TB in RA was calculated by dividing the standardized mean incidence of TB from 1990 to 2000 in the RA cohort by the mean incidence of TB in Spain during the same years.
  
  
  RESULTS
  The mean incidence of TB in the general population of Spain from 1990 to 2000 was 23 cases per 100,000. Seven cases of TB were identified in the RA cohort, yielding a mean annual incidence (1990-2000) of 134/100,000 patients. The incidence risk ratio of pulmonary TB in patients with RA compared to the general population is 3.68 (95% CI 2.36-5.92).
  
  
  CONCLUSIONS
  We found a 4-fold increased risk of TB infection in patients diagnosed with RA. These results might help to interpret the magnitude of the problem attributable to the introduction of new therapies in RA.
authors.affiliation: Hospital Clínico San Carlos, Madrid, Spain. lcarmona@ser.es
authors.forename: Loreto
authors.initials: L
authors.lastname: Carmona
authors.forename: César
authors.initials: C
authors.lastname: Hernández-García
authors.forename: Cristina
authors.initials: C
authors.lastname: Vadillo
authors.forename: Esperanza
authors.initials: E
authors.lastname: Pato
authors.forename: Alejandro
authors.initials: A
authors.lastname: Balsa
authors.forename: Isidoro
authors.initials: I
authors.lastname: González-Alvaro
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Belmonte
authors.forename: Xavier
authors.initials: X
authors.lastname: Tena
authors.forename: Raimon
authors.initials: R
authors.lastname: Sanmartí
mesh_terms: D001172:Arthritis, Rheumatoid / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology; D015331:Cohort Studies; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D018570:Risk Assessment; D013030:Spain / Q000453:epidemiology; D014397:Tuberculosis, Pulmonary / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology