Minimal clinically important difference of the Modified Fatigue Impact Scale in Parkinson's disease

Parkinsonism Relat Disord. 2017 Oct:43:101-104. doi: 10.1016/j.parkreldis.2017.07.016. Epub 2017 Jul 20.

Abstract

Objective: Fatigue is a common and debilitating symptom of Parkinson's disease (PD) with no evidence-based treatments. While several fatigue scales are partially validated in PD the minimal clinically important difference (MCID) is unknown for any scale but is an important psychometric value to design and interpret therapeutic trials. We thus sought to determine the MCID for the Modified Fatigue Impact Scale (MFIS).

Methods: This is a secondary data analysis from 94 PD participants in an acupuncture trial for PD fatigue. Standard psychometric approaches were used to establish validity and an anchor-based approach was used to determine the MCID.

Results: The MFIS demonstrated good concurrent validity with other outcome measures and high internal consistency. MCIDs values were found to be 13.8, 6.8 and 6.2 for the MFIS total, MFIS cognitive, and MFIS physical subscores respectively.

Conclusions: The MFIS is a valid multidimensional measure of fatigue in PD with demonstrable MCID.

Keywords: Fatigue; Minimal clinically important difference; Modified Fatigue Impact Scale; Parkinson's disease; Validity.

MeSH terms

  • Acupuncture Therapy / methods
  • Adult
  • Aged
  • Aged, 80 and over
  • Cognition Disorders / etiology
  • Disability Evaluation
  • Fatigue / diagnosis*
  • Fatigue / etiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Parkinson Disease / complications*
  • Parkinson Disease / therapy
  • Physical Examination
  • Psychometrics
  • Statistics as Topic