Generally speaking, what do you get when you perform an observational study based on registry data?
Nevertheless, this study does pose an interesting research question. Is intubation beneficial for in-hospital cardiac arrest? Or should we just use other means of ventilation and resuscitate accordingly.
To really answer this question, one would ideally like to see a randomized trial so that confounders are equal amongst the two groups. Otherwise we might be comparing geckos to watermelons.
Back to the study...
This was an observational cohort study of patients who had in-hospital cardiac arrest. The primary outcome was survival to hospital discharge.
Of 71,615 patients who were intubated in the first 15 minutes, 60% were matched to a patient not intubated in the same minute.
Survival was lower among patients who were intubated 16.3% vs those not intubated 19.4% (RR=0.84; 95% CI 0.81-0.87; p<.001)
So this was a huge study with a pretty p value… so it must be right?!
A few things...
You can’t overpower bias with big numbers.
This study relied on registry data which is notoriously of poor quality. Garbage in, garbage out. No amount of fancy statistics can make up for this.
Once again, this was not a randomized trial so the groups were very likely different from the start. The outcomes could very well be due to one group being sicker than the other. The authors tried to correct for this confounding by some clever propensity matching. But it must be emphasized that this is far from an exact science.
So what’s the take home?
Probably not much. But this study does lay the foundations for a proper randomized trial… hopefully only including geckos.
Andersen LW, Granfeldt A, Calloway CW, et al. Association Between Tracheal Intubation During Adult In-Hospital Cardiac Arrest and Survival. JAMA 2017;317(5):494-506.