This is yet another typically Canadian study, which is to say it’s Ian G. Stiell, et al, producing yet another high-quality risk-stratification profile for Emergency Department patients.
In this week’s episode, we find our heroes prospectively validating the Ottawa COPD Risk Scale (OCRS), a set of 10 criteria identifying COPD patients in the ED at highest-risk for short-term serious outcomes. Short-term serious outcomes, by their definition, was the occurrence of death, admission to a monitored unit, intubation, non-invasive ventilation, myocardial infarction, or hospital re-admission. Their target population was effectively patients with COPD who weren’t otherwise obviously ill, with a set of exclusion criteria for those who clearly necessitated admission on the index visit.
Within their 10 items, there are 16 points available to assign, and the expected risk of short-term outcomes ranged from 2.2% at a score of 0, up to 91.4% at a score of 10. Their validation, however, demonstrated potentially important differing results – with nearly two-fold greater risks for short-term poor outcomes in the lowest (and most common) strata. Then, at the high-end, there simply weren’t enough patients with scores >4 to come to any reliable consensus regarding the accuracy of the risk stratification. In fact, of the 65 patients with scores >4, the overall incidence of serious outcome was only 23% – while the expected risk from their derivation scale would probably be upwards of 40 or 50%. Their explanation: these higher-risk patients were all hospitalized at the index visit, thereby decreasing their expected rate of short-term serious outcome. This may, in fact, be true, but it is rather a hypothesis rather than a well-supported conclusion.
The other question, even assuming this tool is valid, is “what now?” The authors emphasize these data and risk levels are not necessarily prescriptive, but rather give the clinician an objective tool to supplement their decision-making. Will incorporating this tool this improve care delivery and outcomes? Unfortunately, it is impossible to tell. These authors have done the “easy” research, a data collection and number-crunching exercise. Determining its effect on clinical care is another, much harder step – and fraught with limitations due to generalizability from one practice setting to another. I would be wary of incorporating this into your clinical care until better data is available regarding its effect on patient-oriented and resource utilization outcomes – unless you’re ready to prospectively study it!
“Clinical validation of a risk scale for serious outcomes among patients with chronic obstructive pulmonary disease managed in the emergency department”