LENGTH OF HOSPITAL STAY AFTER ACUTE MYOCARDIAL-INFARCTION IN THE MYOCARDIAL-INFARCTION TRIAGE AND INTERVENTION (MITI) PROJECT REGISTRY

Objectives. This study sought to identify current trends in length of stay in patients with an acute myocardial infarction and to evaluate w hich demographic, clinical, procedural and hospital-related factors ex plain the variation and reduction in length of stay observed during th e study period. Background. Hospital length of stay is an important co ntribution to cost of care. Previous studies of length of stay after a cute myocardial infarction have been performed largely on administrati ve data bases and do not reflect current practice patterns, Methods. W e used univariate and multivariate models to evaluate which demographi c, clinical and administrative factors influenced length of stay in 11 ,932 patients with acute myocardial infarction admitted to 19 Seattle- area hospitals between 1988 and 1994. Results. Length of hospital stay decreased from (mean +/- SD) 8.5 +/- 8.2 to 6.0 +/- 5.8 days during t he study period. Demographic and clinical characteristics known at the time of admission explained only 6% of variation in length of stay, w hereas hospital complications, procedure use and type of admitting hos pital explained an additional 27% of variation. The use of primary ang ioplasty and early diagnostic coronary angiography predicted a shorter length of stay; however, none of the measured variables explained the 29% reduction in length of stay that occurred between 1988 and 1994. Conclusions. Although hospital complications, procedure use and hospit al characteristics are important predictors of length of hospital stay , none of these factors explains the 29% reduction in length of stay o bserved in postmyocardial infarction patients between 1988 and 1994. I t is likely that unmeasured economic and administrative factors play i mportant roles in influencing hospital length of stay.