Article

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. 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.

Langue : ANGLAIS