Case management poststroke did not induce response shift: the value of residuals

ObjectivesTo estimate the extent to which different methods of assessing response shift lead to different conclusions about its presence.Study Design and SettingA reanalysis of a randomized clinical trial involving 190 persons poststroke to evaluate the effectiveness of a case management intervention aimed at assisting persons with stroke to make the transition from acute care to home.ResultsResponse shift was found to be nondifferential across groups and was therefore ruled out as an explanation for why the case management intervention showed no impact on patients' perceptions of their health. The results of a then-test did not show differential recalibration overtime. Factor analysis did not support reconceptualization response shift in either group but did find weak evidence for reprioritization response shift. An analysis of residuals indicated that approximately 50% of study subjects in each group experienced response shift that is probably close to reconceptualization.ConclusionA framework for assessing response shift was proposed and investigators planning trials of interventions targeting patient-reported outcomes should build into the trial methods for response shift investigation. In trials of interventions likely to induce response shift, before concluding about intervention-induced change, response shift should be ruled out by using a combination of design and statistical approaches.