title: Isoniazid-resistant tuberculosis in Birmingham, United Kingdom, 1999-2010.
abstract: BACKGROUND
  There have been few studies on risk factors and treatment outcomes of isoniazid (H)-resistant tuberculosis (TB), and optimal treatment regimens are debated.
  
  
  OBJECTIVE
  : To identify risk factors for H-resistant TB, describe treatment regimens and compare these to national guidelines and describe short-term outcomes of H-resistant TB in Birmingham, UK.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Cases of H-resistant tuberculosis in Birmingham between January 1999 and December 2010 (n = 89) were compared with drug-susceptible cases (n = 2497). Treatment regimens and outcomes at 12 months from diagnosis were evaluated by case note review.
  
  
  RESULTS
  No independent predictors for H-resistant TB were found. For 76/89 (85%) patients with full treatment details available, median treatment duration was 11 months (interquartile range 9-12 months). Only 27/72 (38%) patients with H-monoresistance were treated in line with national guidelines. A further 14/72 (19%) were treated according to other recognized guidelines. Overall treatment success was 75/89 (84%). Treatment failure occurred in 6/89 (7%) patients, all developed multi-drug resistance. Poor adherence was documented in these patients and use of a non-standard regimen in one patient was not thought to have contributed to treatment failure.
  
  
  CONCLUSIONS
  No discriminating risk factors for early detection of H-resistant TB were found. Treatment regimens in clinical practice were highly varied. H-resistance can drive MDR-TB when there is evidence or suspicion of poor adherence. A low threshold for enhanced case management with directly observed therapy is warranted in this group.
authors.affiliation: From the Department of Infection and Tropical Medicine, Birmingham Heartlands Hospital, West Midlands and Department of Sexual Health, Upton Hospital, Slough, UK melindamunang@nhs.net.
authors.forename: M L
authors.initials: ML
authors.lastname: Munang
authors.affiliation: From the Department of Infection and Tropical Medicine, Birmingham Heartlands Hospital, West Midlands and Department of Sexual Health, Upton Hospital, Slough, UK.
authors.forename: M
authors.initials: M
authors.lastname: Kariuki
authors.affiliation: From the Department of Infection and Tropical Medicine, Birmingham Heartlands Hospital, West Midlands and Department of Sexual Health, Upton Hospital, Slough, UK.
authors.forename: M
authors.initials: M
authors.lastname: Dedicoat
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007538:Isoniazid / Q000627:therapeutic use*; D008297:Male; D008485:Medical Audit / Q000379:methods; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid