INTER‐PROVIDER COMPARISON OF PATIENT‐REPORTED OUTCOMES: DEVELOPING AN ADJUSTMENT TO ACCOUNT FOR DIFFERENCES IN PATIENT CASE MIX

ABSTRACT This paper describes the development of a methodology for the case‐mix adjustment of patient‐reported outcome measures (PROMs) data permitting the comparison of outcomes between providers on a like‐for‐like basis. Statistical models that take account of provider‐specific effects form the basis of the proposed case‐mix adjustment methodology. Indirect standardisation provides a transparent means of case mix adjusting the PROMs data, which are updated on a monthly basis. Recently published PROMs data for patients undergoing unilateral knee replacement are used to estimate empirical models and to demonstrate the application of the proposed case‐mix adjustment methodology in practice. The results are illustrative and are used to highlight a number of theoretical and empirical issues that warrant further exploration. For example, because of differences between PROMs instruments, case‐mix adjustment methodologies may require instrument‐specific approaches. A number of key assumptions are made in estimating the empirical models, which could be open to challenge. The covariates of post‐operative health status could be expanded, and alternative econometric methods could be employed. © 2013 Crown copyright.