State of the science in inflammation and stroke recovery: A systematic review.

Most of the 11 included studies were pilot data with small sample sizes; one had only 18 patients and another only 20. Several studies were single-center, and the authors note the findings may not generalize to larger or more diverse populations. Patient selection, baseline stroke severity, time since stroke, and the functional measures used varied widely across studies, making direct comparison difficult. In most studies, inflammatory biomarkers were measured only once at admission, so the time course of inflammation during rehabilitation could not be tracked. There was insufficient longitudinal data across the 11 studies to perform multi-time-point outcome analyses. The resistive training study that showed no increase in inflammation had baseline markers already within or near normal limits, limiting generalizability to patients with greater baseline inflammation. The time course of inflammation post-stroke is described as limited and conflicting across studies, with one finding IL-6 rising and another finding it falling over the same rehabilitation period.

One author (ST) is cofounder and consultant for Q32Bio, a company developing complement inhibitors. The remaining authors declare no conflict of interest. No funding source is named in the text.

Do not read the CRP and IL-6 associations as a basis for changing rehabilitation timing or intensity. These are observational correlations from small, heterogeneous studies, and the one trial showing no increase in inflammation after 12 weeks of training was a pilot of 20 patients whose baseline markers were already near normal. The conflicting findings on whether IL-6 rises or falls during rehabilitation mean there is no consistent picture of what inflammation is doing during your patient's recovery.