Did paying drugs misuse treatment providers for outcomes lead to unintended consequences for hospital admissions? Difference-in-differences analysis of a pay-for-performance scheme in England

Abstract

Aims: To estimate how a scheme to pay substance misuse treatment service providers according to treatment outcomes affected hospital admissions. Design: A controlled, quasi-experimental (difference-in-differences) observational study using negative binomial regression. Setting: Hospitals in all 149 organisational areas in England for the period 2009–2010 to 2015–2016. Participants: 572 545 patients admitted to hospital with a diagnosis indicating drug misuse, defined based on International Classification of Diseases 10th Revision (ICD-10) diagnosis codes (37 964 patients in 8 intervention areas and 534 581 in 141 comparison areas). Intervention and comparators: Linkage of provider payments t..