title: Statin utilization according to indication and age: a Danish cohort study on changing prescribing and purchasing behaviour.
abstract: OBJECTIVE
  Introduced to reduce mortality after myocardial infarction (MI), statins are now recommended for a range of other conditions, including asymptomatic individuals without cardiovascular disease or diabetes. The aim was to describe trends in Danish statin utilization according to indication and age during 1996-2009, and to analyse changing prescribing and purchasing behaviour during time intervals (driver periods) a priori defined by potential influential factors.
  
  
  METHODS
  A nationwide cohort (N=4,998,580) was followed in Danish individual-level registries. Based on a hierarchy of register markers of indications for statin prescribing, we analysed incidence and prevalence of use by age and indication (age ≥ 40). Applying Poisson regression, we calculated Incidence Rate Ratios (IRR) of statin treatment for the last year of each driver period, applying the first year as reference.
  
  
  RESULTS
  Treatment prevalence increased from 7/1000 to 187/1000, representing a shift towards lower-level indications and increased relatively more in individuals aged 75+. While treatment prevalence in MI-patients reached 780/1000, asymptomatic individuals represented 50% of incident statin-users in 2009. A marked increase in incidence of statin use occurred during 1999-2003 (IRR=3.05) across all indications, followed by a more moderate rise during 2003-2006 (IRR=1.29) and 2006-2008 (IRR=1.15) - most marked increases in asymptomatic individuals. A sudden decrease was observed in 2009 (IRR=0.82) for all indications and ages.
  
  
  CONCLUSIONS
  While patent expiry and lower prices most likely boosted the general increase in statin utilization, the gradually altered indication and age pattern seems to be driven by guidelines, influencing both reimbursement rules and general healthcare policies. A media debate on statin side effects may have modified the general attitudes.
authors.affiliation: Centre for Healthy Aging, Department of Public Health, University of Copenhagen, Denmark. hewk@sund.ku.dk
authors.forename: Helle
authors.initials: H
authors.lastname: Wallach Kildemoes
authors.forename: Mikkel
authors.initials: M
authors.lastname: Vass
authors.forename: Carsten
authors.initials: C
authors.lastname: Hendriksen
authors.forename: Morten
authors.initials: M
authors.lastname: Andersen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases; D003327:Coronary Disease / Q000188:drug therapy / Q000517:prevention & control; D003695:Delivery of Health Care / Q000458:organization & administration; D003718:Denmark / Q000453:epidemiology; D016527:Drug Costs / Q000706:statistics & numerical data; D005260:Female; D019983:Guideline Adherence / Q000706:statistics & numerical data; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000009:adverse effects / Q000191:economics / Q000627:therapeutic use*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy / Q000517:prevention & control; D016012:Poisson Distribution; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D015995:Prevalence
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors