In yet another exercise in asking the wrong questions, these authors put forth a rather great deal of effort to regurgitate a vast quantity of mostly meaningless data.
Neurologists, generally those well-supported by Genentech and Boehringer Ingelheim (as in this article), are keen to expand the use of tPA beyond the license criteria. One of the easiest targets is the giant cohort of stroke patients excluded from treatment for low NIHSS. In some respects, it seems reasonable to discard an ordinal cut-off in a measure of stroke severity having a non-linear relationship with disability. But, when media coverage describes an expansion of tPA to mild stroke patients as “saving hundreds of millions of dollars” or “having no downside”, even the hypothetical best intentions have clearly gone awry.
This is a retrospective review of the Get With the Guidelines-Stroke registry, a voluntary, prospective quality improvement project used by hospitals in the U.S. Between 2010 and 2012, 7,621 patients were treated with IV tPA for AIS having an NIHSS of 5 or less, with 5,910 having data for analysis. Ranging from 192 patients with an NIHSS to 0 to 1,800 having NIHSS of 5, treatment complications were fairly consistent: 1.3% died, 1.8% suffered sICH, 0.2% suffered serious systemic hemorrhage, and 1.8% suffered other serious complications (e.g., angioedema).
So, of course, for a treatment with no demonstrated efficacy in this population, the authors conclude a number-needed-to-harm somewhere between 30 and 50 “provide[s] reassurance about the safety of IV rtPA in patients with low NIHSS scores”.
Interestingly, this data is essentially an update of the authors’ prior work, published using the 2003 to 2009 GTWG-Stroke registry data. That publication provided a helpful data supplement comparing outcomes of tPA-treated patients with non-tPA-treated patients with NIHSS 5 or less. Within the limitations of such a comparison, tPA treatment was associated with significantly increased odds of death, decreased discharges to home, and decreased ambulation at discharge. The authors have in no way muddled this article with such negativity, nor did they perform any sort of gross comparison between the ambulatory and independence outcomes in the present study with the prior, non-treated population – as they are essentially identical.
But, when you’re fed free money from your sponsors, including free airfare to Chicago, why report or suggest anything that might disrupt the narrative?
“Outcomes in Mild Acute Ischemic Stroke Treated With Intravenous Thrombolysis: A Retrospective Analysis of the Get With the Guidelines–Stroke Registry”
http://www.ncbi.nlm.nih.gov/pubmed/25642650