The minimal important difference of the ICU mobility scale

Area of Science:

• Rehabilitation medicine
• Clinical measurement
• Physiotherapy research

Background:

• The Intensive Care Unit Mobility Scale (IMS) is a validated and responsive tool for assessing patient mobility.
• Establishing the minimal important difference (MID) is crucial for interpreting clinically significant changes in IMS scores.
• Understanding the MID enhances the clinical utility and research application of the IMS.

Purpose of the Study:

• To determine the minimal important difference (MID) of the Intensive Care Unit Mobility Scale (IMS).
• To provide a benchmark for clinically meaningful improvements in patient mobility within the intensive care unit.

Main Methods:

• A prospective, multi-center observational study was conducted.
• The IMS was administered to patients at admission and discharge.
• MID was calculated using anchor-based (global rating of change) and distribution-based (SEM, effect size) methods.

Main Results:

• Anchor-based methods yielded an MID of 3 for the IMS (AUC 0.94).
• Distribution-based methods suggested an MID ranging from 0.89 to 1.40.
• A total of 184 adult patients (mean age 62.0) across surgical, trauma, and medical ICUs were included.

Conclusions:

• The study provides key clinimetric data on the IMS, specifically its MID.
• The findings improve the interpretation of IMS scores in clinical practice and research settings.
• Determining the MID enhances the scale's utility for tracking patient recovery and treatment effectiveness.