Introduction: African American (AA) women have been reported to have higher mortality after stroke. Our prior analysis of the NINDS dataset also showed poorer outcomes after tPA for AA compared to Caucasian (C) females. Small numbers of AA patients available in a well characterized dataset and large differences in baseline factors hamper definitive conclusions about race-based outcomes. We developed analytical techniques for small samples that explicitly consider baseline factors rather than adjust or control for them. We applied these techniques to two stroke datasets and analyzed them separately and together with NINDS.
Methods: pPREDICTS uses the placebo arms of all eligible stroke RCTs to generate a pseudo-control outcome model. The novel feature is generation of multi-dimensional statistical intervals to compare whether an individual trials outcome differed from this pooled sample at the trials specific baseline NIHSS and age. pPAIRS performs post-hoc Euclidean matching of subjects based on chosen factors and excludes outliers when no close match is found, generating a more homogenous population. We applied these techniques to assess outcomes of tpa-treated females from the NINDS, Tulane, and University of Alabama-Birmingham datasets. Matching factors were baseline NIHSS, age, glucose, race and stroke subtype. Outcomes were mRS 0-1, 0-2 and mortality at discharge or 90 days.
Results: Pooled results from individual sites are reported here. Comparison of outcomes from each site with the pPREDICTS model did not show better outcomes for the newer datasets compared to NINDS. mRS 0-2 for tPA-treated AA females was near the p=.05 threshold for poorer outcomes compared to pooled controls. After outlier exclusion, 80 matched AA and C females were found by pPAIRS. After matching, median baseline NIHSS were similar: 12.5 for AAs and 11.5 for C (p = 0.64). Final mRS 0-1 and mRS 0-2 for AA females were lower: 22.5% and 30% vs. 40% (p = 0.03) and 46.3% for C (p = 0.05). Mortality was 10% in AA and 7% in C (p=0.6).
Conclusion: We confirmed in this larger pooled sample that AA females have a poorer functional outcome following tPA after baseline matching. Factors associated with these poor outcomes are being assessed and will be presented. A prospective study is warranted.