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 which demographic, clinical, procedural and hospital-related factors explain the variation and reduction in length of stay observed during the study period. Background. Hospital length of stay is an important contribution to cost of care. Previous studies of length of stay after acute myocardial infarction have been performed largely on administrative data bases and do not reflect current practice patterns, Methods. We used univariate and multivariate models to evaluate which demographic, 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 the study period. Demographic and clinical characteristics known at the time of admission explained only 6% of variation in length of stay, whereas hospital complications, procedure use and type of admitting hospital explained an additional 27% of variation. The use of primary angioplasty 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 hospital characteristics are important predictors of length of hospital stay, none of these factors explains the 29% reduction in length of stay observed in postmyocardial infarction patients between 1988 and 1994. It is likely that unmeasured economic and administrative factors play important roles in influencing hospital length of stay.