PT  - JOURNAL ARTICLE
AU  - Wang, Ying-Chih
AU  - Hart, Dennis L.
AU  - Stratford, Paul W.
AU  - Mioduski, Jerome E.
TI  - Baseline Dependency of Minimal Clinically Important Improvement
AID  - 10.demo/ptj.20100229
DP  - 2011 May 01
TA  - Demo Journal of Physical Therapy
PG  - 675--688
VI  - 91
IP  - 5
4099  - http://demo.highwire.org/content/91/5/675.short
4100  - http://demo.highwire.org/content/91/5/675.full
AB  - Background Minimal clinically important improvement (MCII) is the smallest outcome measure change important to patients. Research suggests that MCII is dependent on patients' baseline functional status measures.Objective The purposes of this study were: (1) to confirm whether MCII is dependent on patients' admission scores and (2) to test whether MCII is dependent on selected demographic characteristics.Study Design and Setting This was a prospective, longitudinal, observational cohort study of 6,651 patients with orthopedic knee impairments treated in 332 outpatient rehabilitation clinics in 27 states in the United States.Outcome Measures Patient self-reports of functional status (FS) from the Lower Extremity Functional Scale were assessed using a computerized adaptive testing application (0–100 scale).Methods An anchored-based longitudinal method, with a 15-point Likert-type scale (−7 to +7), was used to provide a global rating of change (GROC). The MCII threshold for the GROC was defined at a cut-score of +3 or greater and was determined using nonparametric receiver operating characteristic curve analysis for each of the following variables: sex, symptom acuity, age group, and quartile of baseline FS scores.Results The results showed that MCII was dependent on patient baseline and demographic characteristics. Patients who were male, were younger, had more-acute symptoms, or had lower FS scores at admission required more FS change to report meaningful change.Limitations As this study was a secondary analysis, how the length of treatment mediated the relationship between the independent and dependent variables was unclear.Conclusions Although a single MCII index may provide a standard cut-score defining the smallest FS change that is meaningful to patients, researchers and clinicians should be aware that MCII is context specific and not a fixed attribute. Current results may help researchers, clinicians, and policy makers to interpret FS change related to the importance of the change to the patient.