OBJECTIVES : Increases in the total expenditure of medical service items after pricing adjustments are associated with pricing adjustments and volume changes. This study assessed if the changes in pricing or volume contribute more to the total expenditure change of medical service items for different types of medical service items after pricing adjustment.

METHODS : Medical service items with pricing adjustments between 2015 and 2017 after Shanghai initiated the dynamic pricing adjustment policy are included in the study. Four service types are identified with Shanghai medical service item codes. Prices are collected from policy documents of Shanghai Development and Reform Commission website. Annual volume was collected from Shanghai Medical Information Platform, a real-time database of all public hospital health service records in Shanghai. The Laspeyres price index (L₁) and volume index (L₂) were used to assess the contribution extent pricing and volume do respectively to total expenditure changes in 4 types of services within and across rounds.

RESULTS : Three rounds of pricing adjustments items were included: 43 in 1_st round, 47 in 2_nd round, and 573 in 3_rd round; items with 0 volume were excluded. Volume index outnumbered price index for laboratory tests items(L₂=165.78%;L₁=163.69% for 3_rd round) and Chinese traditional medicine diagnostic and treatment items(L₂=184.26%;L₁ =161.44% for 2_nd round, and L₂=150.98%;L₁ =120.12% for 3_rd round); price index outnumbered volume index for clinical diagnostic and treatment items(L₁=151.93%;L₂=141.95% for 1_st round, and L₁=144.23%;L₂ =141.23% for 3_rd round). Indexes do not exhibit an uniform trend across rounds for general medical service items.

CONCLUSIONS : Volume changes contribute more than pricing to the total expenditure change for laboratory tests and Chinese traditional medicine diagnostic and treatment items; pricing contributes more for clinical diagnostic and treatment items after pricing adjustments in Shanghai. General medical service item trends vary across rounds.