Assessment of Fatigue: Review and Future Directions

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Assessment of FatigueReview and Future
Directions

• Zeeshan Butt, Ph.D.
• Research Scientist, Center on Outcomes, Research,
  and Education (CORE)/ENH
• Research Assistant Professor, Northwestern
  University Feinberg School of Medicine
• z-butt_at_northwestern.edu
• AGS/NIA/Hartford Conference Idiopathic Fatigue
  of Aging
• September 5, 2008

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Overview

• Self-report
• Fatigue measurement
• Existing instruments
• Future directions PROMIS

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Fatigue

• Clinically important, but non-specific symptom
• present across a number of chronic illnesses
  and health conditions
• Given the subjective nature of fatigue,
  self-report
• may be the best way to assess the symptom.

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Fatigue Self-report

• Subjective nature suggests reliance on
  self-report
• Several validated tools exist for measuring
  fatigue
• no instrument is the clear gold-standard method
• Many instruments tend to assess fatigue as
  multidimensional concept
• dimensions temporal characteristics, severity,
  impact
• manifestations physical, cognitive, emotional,
  behavioral

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Multidimensional Scales

• Fatigue Assessment Instrument
• Fatigue Impact Scale
• Fatigue Symptom Inventory
• Multidimensional Assessment of Fatigue
• and the Global Fatigue Index
• Multidimensional Fatigue Inventory
• Multidimensional Fatigue Symptom Inventory
• Piper Fatigue Scale

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Revised Piper Fatigue Scale (PFS)

• Subscale
• Behavioral/severity(6 items)
• Affective meaning(5 items)
• Sensory(5 items)
• Cognitive/mood(6 items)

Sample Question To what degree is fatigue you
are feeling now causing you distress? (0no
distress, 10great deal of distress) To what
degree would you describe fatigue which you are
experiencing now as being (0pleasant,
10unpleasant) To what degree are you now
feeling (0lively, 10listless) To what
degree are you now feeling (0able to think
clearly, 10unable to think clearly)
Piper et al. Oncol Nurs Forum. 199825677-684.
22 items with 4 subscales
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Fatigue Symptom Inventory (FSI)

• Dimension
• Intensity(4 items)Interference(7
  items)Duration(2 items)Daily pattern(1
  item)

Sample Question Rate your level of fatigue on
the average in the last week (0not at all
fatigued, 10as fatigued as could be)Rate how
much, in the past week, fatigue interfered with
your normal work activity (0no interference,
10extreme interference)Indicate how much of
the day, on average, you felt fatigued in the
past week (0none of the day, 10the entire
day)Indicate which of the following best
describes the daily pattern of your fatigue
(0not fatigued, 1worse in morning, 2worse in
afternoon, 3worse in evening, 4no consistent
pattern)
14 items assessing 4 dimensions
Hann et al. Qual Life Res. 19987301-310.
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Fatigue Measurement

• Many instruments tend to assess fatigue as a
  multidimensional concept

BUT, there may be little difference in scores
produced by items rated for intensity vs.
frequency
Chang, Cella et al, 2003, Palliat Supp Care
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Fatigue Measurement
AND results of bi-factor analysis suggests that
fatigue measurement is sufficiently unidimensional
THIS IS GOOD NEWS!!! (stay tuned)
Lai et al, 2006, Qual Life Res
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Single-ItemAssessments
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Single-Item Assessments
Greater levels of fatigue associated with worse
overall health-related quality of life, F(4, 524)
70.88, p lt 0.0001.
Butt et al., 2008, JNCCN
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Single-Item Assessments
On a 0-10 scale where 0 means no fatigue and 10
means the worst fatigue imaginable, how would you
rate your fatigue at its worst over the past 3
days?
Butt et al., 2008, JPSM
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Unidimensional Scales

• Brief Fatigue Inventory
• Fatigue Severity Scale
• Functional Assessment of Chronic Illness Therapy
  Fatigue
• Global Vigour and Affect
• Schedule of Fatigue and Anergia

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Brief Fatigue Inventory (BFI)
Please rate
As bad as you can imagine
No fatigue
Your fatigue right NOW Your level of fatigue
during the past 24 hours Usual Worst How much,
during the past 24 hours, fatigue has interfered
with General activity Mood Walking
ability Normal work Relations with other people
0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0
1 2 3 4 5 6 7 8 9 10
Completely interferes
Does not interfere
0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1
2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3
4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10
Mendoza et al. Cancer. 1999851186-1196.
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Sample FACIT-F Subscale Items

• Fatigue component
• I feel fatigued
• I feel weak all over
• I feel listless
• (washed out)

Response format 0
Not at all 1 a little bit
2 somewhat 3 quite a bit
4 very much
Yellen et al. J Pain Symptom Manage.
19971363-74.
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FACIT-FatigueExamples
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Fatigue in Men and Women over 50
Cella et al., 2002, Cancer
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Fatigue Across the Lifespan
LESS fatigue
Across both groups, there was evidence for
increased fatigue with age (F(6, 1797) 3.53, p
lt 0.01) but no group x age interaction (p gt 0.25).
MOREfatigue
Butt et al., under review
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Changes in Hemoglobin and Fatigue
13.1 (Hb)
13.1 (Hb)
? Fatigue -6.1
? Fatigue 9.5
13.3 (Hb)
FACIT Fatigue Subscale
10.8 (Hb)
10.5 (Hb)
? Fatigue 4.8
10.8 (Hb)
10.9 (Hb)
? Fatigue 3.9
10.6 (Hb)
Agnihotri, Telfer, Butt, et al. (2007) JAGS
0
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Week
Note Minimally important difference on the
FACIT Fatigue subscale is 3 points.
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FACIT-F, SF-36 and MAF in RA anti-TNF Trial
(N625)
Cella et al., 2005, J Rheumatol
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PROMIS
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PROMIS

• The NIH Patient-Reported Outcomes Measurement
  Information System (PROMIS) Roadmap initiative is
  a 5-year cooperative group program of research
  designed to develop, validate, and standardize
  item banks to measure patient-reported outcomes
  (PROs) that are relevant across common medical
  conditions.

http//www.nihpromis.org
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Broad Objectives

• Develop and test a large bank of items measuring
  PROs, including fatigue
• Create a CAT for efficient assessment of PROs
  across a range of chronic diseases
• Create a publicly available, adaptable and
  sustainable system allowing clinical researchers
  access to a common item repository and CAT

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PROMIS Process
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IRT

• Item Response Theory (IRT) models enable
  reliable and precise measurement of PROs
• Fewer items needed for equal precision
• Making assessment briefer
• More precision gained by adding items
• Reducing error and sample size requirements
• Error is understood at the individual level
• Enabling practical individual assessment

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Proficiency of a Fatigue IB
Items (response category measure)
Patients (frequency distribution)
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Uses for Item Banks

• Short Forms
• 5-7 Items in each HRQL Area
• Constructed to cover full range of trait
• OR
• Multiple forms constructed to only cover a narrow
  range of trait (eg., high, medium, or low)

• Computerized Adaptive Testing (CAT)
• Custom individualized assessment
• Suitable for clinical use
• Accuracy level chosen by researcher

Gershon et al, Exp Rev Pharmoecon Outcomes Res.
(2003)
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CAT Simulation - Fatigue
0 10 20 30 40
50 60 70 80
90 100
Item Meas SE
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Comparison of Measurement Precision Full-length
Item Bank vs. CAT vs. Short-form
7-item Short-form 7-item CAT Full-length item Bank
Standard Error
No Fatigue
Severe Fatigue
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Precision Comparison 3 short-forms
Short Form -- High End (i.e., severe
fatigue) Short Form Lower End (i.e., no/mild
fatigue) Short Form Cover the whole fatigue
continuum
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PROMIS

• is a fully encompassing replacement for existing
  instruments
• ...allows cross-walk to FACIT-Fatigue, SF-36
  vitality, etc.
• offers flexibility to researchers

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Conclusions

• Fatigue is best assessed by self-report.
• Many instruments assess fatigue as a
  multi-dimensional concept
• Fatigue is sufficiently unidimensional, from a
  measurement perspective.
• This measurement property allows for IRT-based
  measurement applications.

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Conclusions

• PROMIS allows for flexible assessment of fatigue
  with use of psychometrically robust short forms
  and CAT.
• Fatigue as a vital sign?
• May be useful to consider fatigue as a measurable
  property -- like temperature, blood pressure, etc
  not a disease- or treatment-specific variable.

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Questions?

• Zeeshan Butt, Ph.D.
• Research Scientist, Center on Outcomes, Research,
  and Education (CORE)
• Research Assistant Professor, Northwestern
  University Feinberg School of Medicine
• 224-364-7596
• z-butt_at_northwestern.edu

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PROMIS Fatigue Short-Form
Garcia et al (2007) Journal of Clinical Oncology