Monitoring Length of Stay of Acute Myocardial Infarction Patients: A Times Series Analysis Using Statistical Process Control.

Goal: Given that length of stay (LOS) of acute myocardial infarction (AMI) patients has a significant impact on the utilization of hospital resources and the health status of communities, this study focused on how best to monitor LOS of AMI patients admitted to U.S. hospitals by employing statistical process control (SPC).

Methods: Data were abstracted from the Healthcare Cost and Utilization Project Nationwide Readmissions Database between 2010 and 2016. A total of 1,491 patients were examined in the study. Patients who were admitted to nonfederal government (public) hospitals in metropolitan areas of at least 1 million residents with the primary diagnosis of AMI were abstracted. They were excluded if they developed AMI secondary to an interventional procedure or surgery, died during their index hospitalization, and were admitted and discharged on the same day. Patients were also excluded if they were discharged to short-term hospitals, nursing facilities, intermediate care facilities, home healthcare, or against medical advice. Individual moving range (I-MR) charts were used to monitor LOS of individual AMI patients in each subgroup from 2010 to 2016.

Principal findings: The results showed I-MR charts could be used to indicate statistically out-of-control signals on LOS. Specifically, I-MR charts showed that LOS decreased between 2010 and 2016. LOS appeared to be longer at teaching hospitals compared to nonteaching hospitals and varied by gender. Female patients appeared to stay longer than male patients in the hospitals.

Practical applications: The application of SPC and control charts can facilitate improved decision-making in healthcare organizations. This study shows the value of integrating control charts in administrative and medical decision-making processes. It may also help healthcare providers and managers achieve higher quality and lower cost of care.