INTENSIVE-CARE SOCIETY APACHE-II STUDY IN BRITAIN AND IRELAND .1. VARIATIONS IN CASE-MIX OF ADULT ADMISSIONS TO GENERAL INTENSIVE-CARE UNITS AND IMPACT ON OUTCOME

Objectives-To describe the extent of variation in the case mix of adul t admissions to general intensive care units in Britain and Ireland an d investigate the impact of such variation on outcome. Design-Prospect ive, cohort study of consecutive admissions to intensive care units. S etting-26 general intensive care units in Britain and Ireland. Subject s-9099 admissions to the intensive care units studied. Main outcome me asure-Death or survival at discharge before and after adjustment of ca se mix (age, history of chronic conditions, surgical status, diagnosis , and severity of illness) according to the APACHE II method. Results- Important differences in case mix were found, with large variations be tween the units. Hospital mortality was significantly associated with most of the case mix factors investigated. Conclusions-Comparing crude death rates in hospital between intensive care units may be misleadin g indicators of performance. The collection of data on case mix needs to be standardised and differences in case mix adjusted for when compa ring outcome between different intensive care units.