Predicting acute myocardial infarction (AMI) 30-days mortality: Using standardised mortality ratio (SMR) as the hospital performance measure.

Abstract

A standardised mortality ratio (SMR) is the hospital observed mortality divided by its predicted mortality and has been used as an indicator to monitor hospital performance. This study developed a model that predicted 30-day mortality for acute myocardial infarction (AMI) and compared the SMR among 41 Malaysian public hospitals using statistical process control charts. Data from referral centres and specialist hospitals with cardiology services were analysed. Both referral centres and specialist hospitals had comparable mortality, except for Hospitals A and B, which the study considered outliers. Two-thirds of the remaining hospitals had an SMR of above one (SMR 1.05-1.51), but the indices were still within the expected variations. The SMR coupled with a funnel plot and variable life adjusted display (VLAD) can identify hospitals with potentially higher than expected mortality rates.