Minimal (clinically) important differences for the Fatigue Assessment Scale in sarcoidosis

Respir Med. 2011 Sep;105(9):1388-95. doi: 10.1016/j.rmed.2011.05.004. Epub 2011 Jun 23.


Objective: The usefulness of any questionnaire in clinical management and research trials depends on its ability to indicate a likelihood of treatment success during follow-up. The Minimal Clinically Important Difference (MCID) reflects a clinically relevant change score. The aim of this study was to estimate the MCID for the Fatigue Assessment Scale (FAS) in patients with sarcoidosis.

Methods: Outpatients (n = 321) of the ild care team of the Department of Respiratory Medicine of the Maastricht University Medical Centre, The Netherlands, participated in this prospective follow-up study. Anchor-based and distribution-based methods were used to estimate the MCID. Based on the anchor Physical Quality of Life, a Receiver Operating Characteristic (ROC) was obtained. The distribution-based methods consisted of the Effect Size and Standard Error Measurement (SEM).

Results: The anchor-based MCID found with ROC was 3.5. The distribution-based methods showed that the corresponding change scores in the FAS for a small effect was 4.2. The SEM criterion was 3.6 points change in the FAS.

Conclusions: Based on the anchor-based and distribution-based methods, the MCID is a 4-point difference on the FAS. This MCID can be used in the follow-up of fatigue (FAS) in clinical trials and in the management of individual sarcoidosis cases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activities of Daily Living
  • Adult
  • Aged
  • Aged, 80 and over
  • Disability Evaluation
  • Fatigue / diagnosis*
  • Fatigue / etiology
  • Fatigue / psychology
  • Female
  • Follow-Up Studies
  • Humans
  • Middle Aged
  • Netherlands
  • Prospective Studies
  • Quality of Life / psychology*
  • Sarcoidosis, Pulmonary / complications
  • Sarcoidosis, Pulmonary / diagnosis*
  • Sarcoidosis, Pulmonary / psychology
  • Severity of Illness Index
  • Surveys and Questionnaires / standards*
  • Treatment Outcome