title: Changes and predictors for change to thiazolidinedione prescribing in UK primary care following the rosiglitazone safety warning.
abstract: OBJECTIVE
  To investigate switching from thiazolidinediones, and predictors for switching treatment, after publication of a meta-analysis reporting an increased risk of myocardial infarction associated with rosiglitazone use.
  
  
  METHODS
  Using the Health Information Network (THIN) UK primary care database, the number of people with type 2 diabetes prescribed either thiazolidinedione, rosiglitazone (n = 10,062) or pioglitazone (n = 4454), and the rate of switching from thiazolidinediones (n = 3301 and 1106, respectively), were computed for each month, May 2006 to January 2008. The probability of switching post-publication, May 2007 to January 2008, was modelled by logistic regression in a forward stepwise model. Variables included demographics, history of ischaemic heart disease (IHD), heart failure (HF) or stroke, risk factors for IHD, glucose-lowering and cardiovascular drug use, HbA(1c) and diabetes duration.
  
  
  RESULTS
  There was a sharp increase in switching from both thiazolidinediones in summer 2007; rosiglitazone prescription numbers then decreased while pioglitazone prescribing increased. Switching from rosiglitazone was associated with IHD [adjusted odds ratio (OR) 1.72; 95% confidence intervals (CI) 1.47-2.00], insulin treatment (OR 5.10; 95% CI 3.21-8.10), HF (OR 2.26; 95% CI 1.62-3.18), a recent sulphonylurea prescription (OR 1.33; 95% CI 1.17-1.51) gender (OR men vs. women 0.79; 95% CI 0.70, 0.90) and duration of therapy. Switching from pioglitazone was associated with HF (OR 3.05; 95% CI 1.77-5.26), duration of therapy, and number of glucose-lowering treatments.
  
  
  CONCLUSIONS
  Prescribing habits for both thiazolidinediones changed immediately following the safety warning. IHD was associated with switching from rosiglitazone; otherwise reasons for change appear to be complex, not directly related to the findings of the meta-analysis.
authors.affiliation: Grimsdyke House, London, UK. gillian.hall@gchall.demon.co.uk
authors.forename: G C
authors.initials: GC
authors.lastname: Hall
authors.forename: H T
authors.initials: HT
authors.lastname: Smith
authors.forename: B
authors.initials: B
authors.lastname: Curtis
authors.forename: A D
authors.initials: AD
authors.lastname: McMahon
mesh_terms: D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D057915:Drug Substitution; D064420:Drug-Related Side Effects and Adverse Reactions; D005194:Family Practice / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D000077205:Pioglitazone; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D012307:Risk Factors; D000077154:Rosiglitazone; D056737:Safety-Based Drug Withdrawals; D045162:Thiazolidinediones / Q000009:adverse effects* / Q000627:therapeutic use*; D006113:United Kingdom
chemical_list: D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D000077154:Rosiglitazone; C089946:2,4-thiazolidinedione; D000077205:Pioglitazone