Table 1

Results of interrupted time series analyses of the impacts of government price regulation and deregulation on Laspeyres price index, monthly average purchase volumes and spending for price-regulated, price-unregulated and all antineoplastic medications, as well as group differences, 2011–2016

	Baseline level	Baseline trend	Postregulation level change	Postregulation trend change	Change at 12 months after regulation	Postderegulation level change	Postderegulation trend change	Change at 12 months after deregulation
Lp price index
All medications	0.993***	−0.004*	−0.057***	0.001	−0.032	−0.005	0.001	−0.013
Price-regulated medications	0.988***	−0.004*	−0.082***	0.001	−0.058*	−0.003	0.002	0.000
Price-unregulated medications	1.006***	−0.003***	0.002	0.001	0.029*	−0.013*	0.000	−0.043*
Difference between groups	−0.015	−0.002	−0.081***	0.001	−0.071	0.005	0.002	0.043*
Hospital purchase volume (thousand DDD)
All medications	38.086***	0.915	1.938	−0.525	−4.881	−0.176	−0.311	−4.218
Price-regulated medications	58.502***	1.447	3.325	−0.862	−7.878	−1.605	−0.527	−8.455
Price-unregulated medications	10.242***	0.193	0.004	−0.068	−0.879	1.798	−0.017	1.573
Difference between groups	48.252***	1.258	3.273	−0.798	−7.097	−3.370	−0.510	−10.003
Hospital purchase spending (million CNY)
All medications	11.129***	0.168	−0.092	−0.083	−0.854	0.257	−0.063	−0.945
Price-regulated medications	12.628***	0.239	−0.778	−0.178	−2.821	−0.323	−0.013	−0.912
Price-unregulated medications	9.085***	0.073	0.832	0.048	1.806	1.052	−0.132	−0.992
Difference between groups	3.614***	0.158*	−1.570**	−0.219**	−4.508*	−1.301*	0.117	0.122

Price-regulated medications: 30 antineoplastic products with price regulation in 2012 and deregulation in 2015. Price-unregulated medications: 22 antineoplastic products without price regulation or deregulation.
*p≤0.05; **p≤0.01; ***p≤0.001.
CNY, Chinese yuan (¥1=US$0.155 in 2011); DDD, defined daily dose; Lp, Laspeyres.