Introduction: The modified Rankin scale (mRS) is a reliable objective measure of disability and is widely applied in clinical trials. Health-related quality of life (QOL) measurements using Neuro-QOL provide validated measures of patient-reported outcomes. In a matched case-control study, we hypothesized that differences in QOL in favor of tPA would be readily detectable compared to the dichotomous mRS outcome traditionally applied in acute stroke research.
Methods: From a single-center prospective cohort study, we identified ischemic stroke patients who received intravenous tPA, admitted between August 1, 2012 and July 31, 2014, and who had 3-month QOL and mRS outcomes. Using a propensity score matching algorithm based on age and stroke severity, ischemic stroke patients who did not receive tPA were selected as controls. The mRS was assessed by structured telephone interviews and Neuro-QOL using short forms analyzing domains of upper extremity (UE), lower extremity (LE), executive function (EF), and general cognition (GC). T-scores for Neuro-QOL domains are referenced to the general population (mean 50, SD 10). We assessed differences in mRS (dichotomized 0-1 vs. 2-5) and QOL T-scores (continuous) in each domain using appropriate tests.
Results: A total of 90 patients were analyzed (45 tPA and 45 controls; median NIHSS score 7). There was no statistical difference between the two groups by age (p=0.967) and NIHSS score (p=0.855). When comparing Neuro-QOL T-scores, higher scores were reported for domains of EF (tPA: 52 vs. controls: 46; p=0.032) and LE function (tPA: 46 vs. controls: 41; p=0.008) among tPA patients compared to controls. No differences were noted for UE or GC QOL T-scores. Using the mRS, the results were not statistically significant (dichotomous: 0-1, tPA: 75.6% vs. controls: 57.8%, p=0.117).
Conclusion: Neuro-QOL offers a complementary tool for assessment of neurological function and may help identify finer grades of functional change and outcomes for stroke patients undergoing a specific therapy. The mRS requires a greater number of patients to show statistical significance while utilization of a continuous measurement of function from the patient perspective may improve statistical power in future clinical trials.