title: Forecasting drug utilization and expenditure in a metropolitan health region.
abstract: BACKGROUND
  New pharmacological therapies are challenging the healthcare systems, and there is an increasing need to assess their therapeutic value in relation to existing alternatives as well as their potential budget impact. Consequently, new models to introduce drugs in healthcare are urgently needed. In the metropolitan health region of Stockholm, Sweden, a model has been developed including early warning (horizon scanning), forecasting of drug utilization and expenditure, critical drug evaluation as well as structured programs for the introduction and follow-up of new drugs. The aim of this paper is to present the forecasting model and the predicted growth in all therapeutic areas in 2010 and 2011.
  
  
  METHODS
  Linear regression analysis was applied to aggregate sales data on hospital sales and dispensed drugs in ambulatory care, including both reimbursed expenditure and patient co-payment. The linear regression was applied on each pharmacological group based on four observations 2006-2009, and the crude predictions estimated for the coming two years 2010-2011. The crude predictions were then adjusted for factors likely to increase or decrease future utilization and expenditure, such as patent expiries, new drugs to be launched or new guidelines from national bodies or the regional Drug and Therapeutics Committee. The assessment included a close collaboration with clinical, clinical pharmacological and pharmaceutical experts from the regional Drug and Therapeutics Committee.
  
  
  RESULTS
  The annual increase in total expenditure for prescription and hospital drugs was predicted to be 2.0% in 2010 and 4.0% in 2011. Expenditures will increase in most therapeutic areas, but most predominantly for antineoplastic and immune modulating agents as well as drugs for the nervous system, infectious diseases, and blood and blood-forming organs.
  
  
  CONCLUSIONS
  The utilisation and expenditure of drugs is difficult to forecast due to uncertainties about the rate of adoption of new medicines and various ongoing healthcare reforms and activities to improve the quality and efficiency of prescribing. Nevertheless, we believe our model will be valuable as an early warning system to start developing guidance for new drugs including systems to monitor their effectiveness, safety and cost-effectiveness in clinical practice.
authors.affiliation: Department of Drug Management and Informatics, Stockholm County Council, Stockholm, Sweden. bjorn.wettermark@sll.se
authors.forename: Björn
authors.initials: B
authors.lastname: Wettermark
authors.forename: Marie E
authors.initials: ME
authors.lastname: Persson
authors.forename: Nils
authors.initials: N
authors.lastname: Wilking
authors.forename: Mats
authors.initials: M
authors.lastname: Kalin
authors.forename: Seher
authors.initials: S
authors.lastname: Korkmaz
authors.forename: Paul
authors.initials: P
authors.lastname: Hjemdahl
authors.forename: Brian
authors.initials: B
authors.lastname: Godman
authors.forename: Max
authors.initials: M
authors.lastname: Petzold
authors.forename: Lars L
authors.initials: LL
authors.lastname: Gustafsson
mesh_terms: D002391:Catchment Area, Health; D016527:Drug Costs / Q000639:trends; D004363:Drug Utilization / Q000639:trends*; D005544:Forecasting; D005102:Health Expenditures / Q000639:trends*; D006801:Humans; D016014:Linear Models; D013548:Sweden; D019037:Urban Health Services / Q000191:economics / Q000639:trends*