[Cost of lost productivity in pharmacoeconomics analysis. Part I. A systematic review of the literature].

The inclusion of indirect costs of illness in economic studies is still a subject of considerable debate. The aim of the systematic literature review was to present the Polish economic practice concerning indirect costs evaluation of healthcare interventions. MEDLINE, EMBASE, Cochrane Library and Polish Medical Bibliography (PBL) were searched. Cut-off dates were set to February and March 2009. The main specific keywords were 'indirect costs' or 'costs and cost analysis'. Nineteen studies fulfilled the inclusion criteria for this review, of a total of 2300 references. Seventeen out of 19 studies were cost of illness studies, 2 were economic analyses. Methods of indirect costs evaluation were all based on human capital approach. The work absenteeism unit time measure used to value productivity loss were average salary (9/19), Gross Domestic Product (GDP) per capita (7/19), Gross National Product per capita (1/19), GDP per active worker (1/19), sold production of industry per active worker (1/19). Mean indirect costs were ca. 58% of total costs (range: 16%-98%). In 5 studies transfer payments were added to productivity loss category. Indirect cost is rarely included in the economic analyses in Poland. Various methods of indirect costs calculation limit comparison between studies and support the need for development of robust and widely accepted methodology.