MEASURING OUTPATIENT RESOURCE USE AND CASE-MIX IN OPHTHALMOLOGY IN NORTH-EAST ENGLAND

Objectives-To test the extent to which two existing ambulatory case mi x measures (Ambulatory Visit Groups and Ambulatory Patient Groups) and other variables can explain resource use variations in ophthalmic out patient visits. Design-Three week prospective study of three consultan t outpatient clinics. Setting-One ophthalmic hospital (Sunderland Eye Infirmary, Sunderland, Tyne and Wear) and three outreach clinics (Sout h Tyneside District Hospital, South Shields, Tyne and Wear; Dryburn Ho spital, Durham, Co Durham; and Hartlepool General Hospital, Hartlepool , Cleveland). Subjects-325 patients who visited ophthalmic outpatient clinics. Main outcome measures-Mean consultation time and mean cost di stributions by case mix group, analysed by analysis of variance. Resul ts-Ambulatory case mix measures can explain some of the variation in r esource use for outpatient visits, but different measures differ in th e extent to which they can do so. Clinicians' behaviour also accounts for a significant amount of such variation. Simpler measures of visit type, without diagnostic or procedure information, do not explain reso urce use variations. Conclusions-Existing measures perform reasonably well, but their data requirements may preclude their introduction in t he National Health Service. Caution is required in advocating simpler measures, however. The influence of clinical practice on resource use variations is important; in this study, most differences between clini cians were not attributable to differences in case mix.