title: A comparison of medical records and patient questionnaires as sources for the estimation of costs within research studies and the implications for economic evaluation.
abstract: Data on health care utilization may be collected using a variety of mechanisms within research studies, each of which may have implications for cost and cost effectiveness.
  
  
  
  The aim of this observational study is to compare data collected from medical records searches and self-report questionnaires for the cost analysis of a cardiac secondary prevention intervention.
  
  
  
  Secondary data analysis of the Secondary Prevention of Heart Disease in General Practice (SPHERE) randomized controlled trial (RCT). Resource use data for a range of health care services were collected by research nurse searches of medical records and self-report questionnaires and costs of care estimated for each data collection mechanism. A series of statistical analyses were conducted to compare the mean costs for medical records data versus questionnaire data and to conduct incremental analyses for the intervention and control arms in the trial.
  
  
  
  Data were available to estimate costs for 95% of patients in the intervention and 96% of patients in the control using the medical records data compared to 65% and 66%, respectively, using the questionnaire data. The incremental analysis revealed a statistically significant difference in mean cost of -€796 (95% CI: -1447, -144; P-value: 0.017) for the intervention relative to the control. This compared to no significant difference in mean cost (95% CI: -1446, 860; P-value: 0.619) for the questionnaire analysis.
  
  
  
  Our findings illustrate the importance of the choice of health care utilization data collection mechanism for the conduct of economic evaluation alongside randomized trials in primary care. This choice will have implications for the costing methodology employed and potentially, for the cost and cost effectiveness outcomes generated.
authors: School of Business and Economics, National University of Ireland, Galway, Ireland, paddy.gillespie@nuigalway.ie.
authors: Paddy
authors: P
authors: Gillespie
authors: School of Business and Economics, National University of Ireland, Galway, Ireland.
authors: Eamon
authors: E
authors: O'Shea
authors: Department of General Practice, Royal College of Surgeons, Dublin, Ireland.
authors: Susan M
authors: SM
authors: Smith
authors: Department of General Practice and Primary Care, UKCRC Centre of Excellence for Public Health Research, Queen's University Belfast, Belfast, Northern Ireland, UK and.
authors: Margaret E
authors: ME
authors: Cupples
authors: School of Medicine, National University of Ireland, Galway, Ireland.
authors: Andrew W
authors: AW
authors: Murphy
mesh_terms: D000368:Aged; D035843:Biomedical Research / Q000379:methods*; D003362:Cost-Benefit Analysis / Q000379:methods*; D005260:Female; D058006:General Practice / Q000191:economics*; D017048:Health Care Costs; D006295:Health Resources / Q000191:economics / Q000706:statistics & numerical data; D006331:Heart Diseases / Q000191:economics / Q000517:prevention & control; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D016032:Randomized Controlled Trials as Topic; D055502:Secondary Prevention / Q000191:economics; D011795:Surveys and Questionnaires
keywords: Atherosclerosis; cardiovascular disorders; health economics; primary care.