Reporting and Analysis of Process-of-Care Time Measures for Hyperacute Stroke Interventions

Process-of-care time measures provide important information about hyperacute stroke interventions and performance of systems of care. These measures are often highly skewed, and mean-based summary statistics may be misleading. Percentile-based statistics (eg, median) conveniently and unbiasedly summarize the proportion of patients treated within a given timeframe. Despite this, mean-based synthesis methods are primarily recommended by the Cochrane Handbook for Systematic Reviews of Interventions for meta-analyses. We aim to investigate the reporting and statistical comparison of process-of-care time measures in published hyperacute stroke trials and systematic reviews of trials and provide methodological foundation for meta-analysis in future studies.

A systematic scoping review of studies reporting or comparing time measures between events in the delivery of hyperacute stroke care was undertaken (Protocol DOI: 10.11124/JBIES-23-00136). Of 2321 studies identified through the database search, 146 studies were included. We analyzed the statistical agreement of transformation-based methods using process-of-care time data from hyperacute stroke clinical trials. We graphically and statistically compared mean- and percentile-based meta-analysis techniques for process-of-care time measures.

Overall, 49 of 146 (34%) studies reported a process-of-care time measure using only the mean/SD. Under the normal distribution assumption, impossible (negative) time values would have been observed in 40 of 49 (82%) of those studies. Transformation-based imputation methods showed moderate agreement with the true SD (Lin Concordance Correlation Coefficient=0.88). Mean-based and median-based meta-analysis provided comparable results when analyzing summary measures of between-arm treatment effects and differed substantially when analyzing individual-arm summary measures.

We recommend that stroke researchers: (1) summarize a sufficient set of process-of-care time measures using the median/interquartile range and use consistent rank-based analysis methods; (2) exercise caution in utilizing transformation-based methods to impute the mean/SD of process-of-care time measures; and (3) use median-based meta-analytical techniques for the synthesis of process-of-care time measures.