title: Are statin trials in diabetes representative of real-world diabetes care: a population-based study on statin initiators in Finland.
abstract: OBJECTIVE
  To assess the representativeness of the Heart Protection Study (HPS) and the Collaborative Atorvastatin Diabetes Study (CARDS) for incident statin users.
  
  
  METHODS
  A population-based analysis with linked register data.
  
  
  METHODS
  Finland.
  
  
  METHODS
  56 963 patients with diabetes initiating statin use from 2005 to 2008.
  
  
  METHODS
  We determined the proportions of real-world patients who fulfilled the eligibility criteria for HPS and CARDS trials and assessed the cardiovascular disease (CVD) event rates, assumed to reflect the background CVD risk, for those eligible and ineligible. We used descriptive statistics to identify the patient characteristics, lipid-lowering interventions and adherence to statin therapy.
  
  
  RESULTS
  Of the real-world patients, 57% (N=32 582) fulfilled the eligibility criteria for HPS (DM) and 49% (N=20 499) of those without CVD for CARDS. The patients ineligible for HPS (DM) had a higher cumulative risk for CVD events than those eligible, whereas regarding CARDS the cumulative risks were of similar magnitude. The overall CVD event rates seemed to be comparable to those in the reviewed trials. Both trials were under-representative of women and users of antihypertensive agents and metformin. 27% and 29% of real-world patients had an initial statin dose corresponding to <20 mg of simvastatin. The proportions of patients who were deemed adherent were 57% in the real world and 85% in both trials.
  
  
  CONCLUSIONS
  Only half of the real-world patients would have qualified for the HPS (DM) and CARDS, limiting their representativeness for clinical practice. Women and users of antihypertensive agents and metformin were under-represented in both trials. These deviations reflect the changes in diabetes treatment over the years and are not expected to modify the average treatment effects of statins on CVD. Prescribing of lower statin doses in clinical practice than used in the trials and lower adherence may, however, attenuate the benefits in the real world.
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, FI-20014 University of Turku, Turku, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Ruokoniemi
authors.affiliation: Service Systems Research Unit, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Reijo
authors.initials: R
authors.lastname: Sund
authors.affiliation: Service Systems Research Unit, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Martti
authors.initials: M
authors.lastname: Arffman
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, FI-20014 University of Turku, Turku, Finland.
authors.forename: Arja
authors.initials: A
authors.lastname: Helin-Salmivaara
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, FI-20014 University of Turku, Turku, Finland Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland.
authors.forename: Risto
authors.initials: R
authors.lastname: Huupponen
authors.affiliation: Social and Health Services, National Institute for Health and Welfare, Helsinki, Finland School of Health Sciences, University of Tampere, Tampere, Finland.
authors.forename: Ilmo
authors.initials: I
authors.lastname: Keskimäki
authors.affiliation: Service Systems Research Unit, National Institute for Health and Welfare, Helsinki, Finland.
authors.forename: Tuulikki
authors.initials: T
authors.lastname: Vehko
authors.affiliation: Department of Pharmacology, Drug Development and Therapeutics, FI-20014 University of Turku, Turku, Finland.
authors.forename: Maarit Jaana
authors.initials: MJ
authors.lastname: Korhonen
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D003920:Diabetes Mellitus / Q000188:drug therapy*; D005260:Female; D005387:Finland; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged
chemical_list: D000959:Antihypertensive Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: adherence; diabetes; randomised controlled trial; representativeness; statin