In an earlier post, I noted an article that had done a systematic review finding 115 publications attempting to create or validate clinical prediction rules for chest pain. Well, here’s number 116.
The ACI-TIPI (Acute Cardiac Ischemia Time-Insensitive Predictive Instrument) is computerized analysis software that generates a score regarding the likelihood of cardiac ischemia based on age, gender, chest pain and EKG variables. It’s actually a product marketed and sold by Philips. These authors tried to evaluate how predictive this instrument was for predicting 30-day events, with an interest in identifying a group that could be safely discharged from the Emergency Department.
In an institution with 55,000 visits a year, the authors recruited only 144 chest pain patients – which is the first red flag. It doesn’t matter how good your prediction rule is if you only recruit 144 patients – your confidence intervals will be terrible, and their sensitivities for identifying 30 day cardiac outcomes are 82-100% at best. And, yes, they did say if the ACI-TIPI score is <20, it had a purportedly useful negative predictive value.
So, I suppose this paper doesn’t really tell us much – and even if the data were better, I’m not sure the sensitivity/specificity of this ACI-TIPI calculation would meet a useful clinical threshold to reduce low-risk hospitalizations any better than clinical gestalt. I’ll be back with you when I find risk-stratification attempt 117….
“Prognostic utility of the acute cardiac ischemia time-insensitive predictive instrument (ACI-TIPI)”
www.intjem.com/content/4/1/49