Minimal Clinically Important Difference of the Modified Barium Swallow Impairment Profile (MBSImP) Pharyngeal Total Score in Post-Stroke Dysphagia.

Abstract

The Modified Barium Swallow Impairment Profile (MBSImP) is widely used to quantify swallowing physiology during videofluoroscopic swallowing assessment, but the minimal clinically important difference (MCID) for its pharyngeal total score in post-stroke dysphagia remains unclear. This study estimated the MCID for improvement in the MBSImP pharyngeal total score during inpatient rehabilitation. This prospective multicenter observational study included stroke survivors with dysphagia admitted for inpatient rehabilitation 2 weeks to 3 months after stroke onset. Baseline and 10-day follow-up assessments included the MBSImP pharyngeal total score, Functional Oral Intake Scale (FOIS), Penetration-Aspiration Scale (PAS), and Patient Global Impression of Change (PGIC). The FOIS was used as the primary anchor, while the PAS and PGIC were secondary anchors. Anchor-based estimates were calculated using average change, change difference, linear regression, and receiver operating characteristic analyses. Distribution-based estimates and minimal detectable change were used as complementary context for interpreting the anchor-based estimates. Sensitivity analyses were performed using stricter or collapsed anchor definitions, including collapsed FOIS categories, ≥ 2-level FOIS improvement, collapsed PAS categories, and a stricter PGIC threshold. An exploratory interaction analysis additionally examined whether the MBSImP change associated with exactly 1-level versus exactly 2-level FOIS improvement varied according to baseline FOIS level. A total of 161 participants were included. The MBSImP pharyngeal total score decreased from a median of [9.00 (7.00, 11.00)] to [4.00 (2.00, 6.00)]. The mean improvement, used for anchor-based MCID estimation, was 4.27 points. Changes in the MBSImP pharyngeal total score were significantly correlated with the FOIS, PAS, and PGIC (r > 0.3). The pooled average-change and change-difference estimates under the prespecified anchor definitions were 2.977 and 2.004 points, respectively. Under stricter or category-based anchor definitions, average-change estimates increased to 4.633-5.141 points, whereas change-difference estimates remained comparatively stable at 1.731-2.554 points. ROC-derived cutoffs were 2-3 points under the prespecified definitions and 5 points under the stricter definitions. In the exploratory FOIS analysis, there was no evidence that the contrast between exactly 1-level and exactly 2-level improvement varied by baseline FOIS level (P for interaction = 0.776); findings were similar when restricted to baseline FOIS levels 2-5 (P = 0.503). Clinically important change in the MBSImP pharyngeal total score depended on the anchor definition and intended interpretation. Under the prespecified anchor definitions, average-change estimates were approximately 3 points, whereas stricter functional or swallowing-safety improvement definitions showed estimates close to 5 points. In contrast, change-difference estimates were comparatively stable at approximately 2 points across anchor definitions.