Measuring the incidence of hospital-acquired complications and their effect on length of stay using CHADx

Objectives: To use an automated Classification of Hospital Acquired Diagnoses (CHADx) reporting system to report the incidence of hospital-acquired complications in inpatients and investigate the association between hospitalacquired complications and hospital length of stay (LOS) in multiday-stay patients. Design: Retrospective cross-sectional study for calendar years 2010 and 2011. Setting: South Metropolitan Health Service in Western Australia, which consists of two teaching and three non-teaching hospitals. Main outcome measures: Incidence of hospital-acquired complications and mean LOS for multiday-stay patients. Results: Of 436841 inpatient separations, 29172 (6.68%) had at least one hospital-acquired complication code assigned in the administrative data, and there were a total of 56326 complication codes. The three most common complications were postprocedural complications; cardiovascular complications; and labour, delivery and postpartum complications. In the subset of data on multiday-stay patients, crude mean LOS was longer in separations for patients with hospital-acquired complications than in separations for those without such complications (17.4 days v 5.4 days). After adjusting for potential confounders, separations for patients with hospital-acquired complications had almost four times the mean LOS of separations for those without such complications (incident rate ratio, 3.84; 95% CI, 3.73-3.96; P