OBJECTIVE

2

To provide evidence for further improving the rules governing the renewal round of national centralized drug procurement with volume-based purchasing （VBP） program for insulin.

METHODS

2

Based on publicly available policy documents， selection outcomes， and interview data， policy text analysis， descriptive statistical analysis， the Wilcoxon signed-rank test， and thematic analysis were used to compare the procurement rules and selection outcomes between the initial and renewal rounds of the national VBP programs for insulin， and to examine the mechanisms linking rule adjustments to changes in selection outcomes.

RESULTS

2

Compared with the initial round， the renewal round retained the six procurement groups and 11 bidding units， reduced the maximum valid bid price by 40%， and introduced competitive bidding selection， revival selection， and a price line for Category A products. A total of 42 products were selected in the initial round and 49 in the renewal round， including 37 that remained selected， 5 that exited， and 12 that were newly selected in the renewal round. Within the same procurement groups， the price range decreased significantly in the renewal round compared with the initial round （

P

＝0.031）， whereas the difference in average price between the two was not statistically significant （

P

＝0.063）. Domestic manufacturers were more likely to enter the A1 category， whereas multinational manufacture

rs were more likely to remain in categories B/C. Mechanism analysis suggested that the price line shaped the boundary of selected prices， while the classification and volume-allocation rules linked manufacturers’ bidding decisions to expected procurement volumes， potentially altering bidding incentives and corresponding to changes in the distribution of selection outcomes.

CONCLUSIONS

2

The renewal round of the insulin VBP program established an interrelated mechanism involving price boundaries， volume-based incentives， and supply constraints through the use of price lines， product classification， and contracted volume allocation. These rule adjustments corresponded to changes in the structure of selected products， price distributions， and manufacturer classifications. Future policy refinement should strengthen the coordination among reasonable price ranges， volume-based incentives， and supply performance.