Fatigue and Quality of Life Assessment Scales: Comprehensive Clinical Guide

PART I: FATIGUE ASSESSMENT SCALES

1. Fatigue Severity Scale (FSS)

Overview

Indications

• Neurological conditions: Multiple sclerosis, Parkinson's disease, post-stroke fatigue, epilepsy
• Rheumatological diseases: Systemic lupus erythematosus (SLE), rheumatoid arthritis, fibromyalgia
• Infectious/hepatic conditions: Chronic hepatitis C, HIV/AIDS
• Psychiatric conditions: Major depressive disorder, burnout syndrome
• Other chronic conditions: Chronic fatigue syndrome (CFS/ME), cancer-related fatigue, chronic kidney disease, sleep disorders
• Rehabilitation settings: Post-surgical recovery, post-ICU patients

Precautions

• Literacy and language: Requires the patient to read and comprehend English (or translated version). Not valid in patients with significant cognitive impairment or illiteracy.
• Not a diagnostic tool: FSS identifies the severity of fatigue but does not diagnose its cause. Abnormal scores must prompt further clinical evaluation.
• Cognitive confounders: In patients with delirium, severe dementia, or acute psychiatric disturbance, self-report accuracy is compromised.
• Recall bias: The scale evaluates recent fatigue experience, so acute intercurrent illness (e.g., influenza) can artificially elevate scores.
• Not validated below age 18: The scale is validated for adults aged 18 and older; pediatric use is off-label.
• Single domain: FSS measures only the impact of fatigue - it does not capture fatigue frequency, type (physical vs mental), or causality.
• No proxy version: Cannot be reliably completed by caregivers or family members on behalf of the patient.

Procedure

• 1 = Strongly disagree
• 7 = Strongly agree

1. Motivation
2. Exercise ability
3. Physical functioning
4. Carrying out duties
5. Causes frequent problems
6. Prevents sustained physical functioning
7. Interferes with work, family, or social life
8. Among the most disabling symptoms
9. Interferes with work, family, or social life (daily activities)

• Total score = sum of all 9 items (range: 9-63)
• Mean score = total ÷ 9 (range: 1-7)
• Mean score ≥ 4.0 = clinically significant/moderate-to-severe fatigue
• Higher scores indicate more severe fatigue

Clinical Uses

2. FACIT-Fatigue Scale (Functional Assessment of Chronic Illness Therapy - Fatigue)

Overview

Indications

• Oncology: Cancer patients during/after chemotherapy, long-term cancer survivors, childhood cancer survivors, anemia of chronic disease
• Rheumatology: Rheumatoid arthritis, psoriatic arthritis, osteoarthritis, ankylosing spondylitis (axial spondyloarthritis), systemic lupus erythematosus, primary Sjogren's syndrome, systemic sclerosis/scleroderma, psoriasis
• Neurology: Multiple sclerosis, Parkinson's disease, stroke
• Hematology: Paroxysmal nocturnal hemoglobinuria (PNH), chronic immune thrombocytopenia
• Pulmonology: Chronic obstructive pulmonary disease (COPD), sarcoidosis
• Gastroenterology: Crohn's disease, ulcerative colitis
• Infectious/other: HIV/AIDS, chronic kidney disease, Gaucher disease, hidradenitis suppurativa
• General population: Validated in the general US population

Precautions

• Age restriction: Validated for patients 18 years and older.
• Recall period dependency: Asks about the past 7 days only - a period of acute illness or improved wellbeing can skew results and not represent the patient's typical fatigue burden.
• Missing data rules: At least 7 of 13 items (>50%) must be completed for a valid score. If fewer are answered, the score is not interpretable.
• Reverse scoring items: Items 7 and 8 ("I have energy" and "I am able to do my usual activities") are positively worded and must be reverse-scored - failure to apply reverse scoring is a frequent administration error.
• Not condition-specific for all domains: While validated broadly, condition-specific fatigue tools may be more sensitive for specific diseases (e.g., cancer fatigue vs. MS fatigue).
• Cognitive/language limitations: Requires adequate literacy; interview administration is available for patients who cannot self-administer.

Procedure

• 0 = Very Much (most impaired)
• 1 = Quite a Bit
• 2 = Somewhat
• 3 = A Little Bit
• 4 = Not At All (least impaired)

1. I feel fatigued
2. I feel weak all over
3. I feel listless
4. I feel tired
5. I have trouble starting things because I am tired
6. I have trouble finishing things because I am tired
7. I have energy (reverse scored)
8. I am able to do my usual activities (reverse scored)
9. I need to sleep during the day
10. I am too tired to eat
11. I need help doing my usual activities
12. I am frustrated by being too tired to do the things I want to do
13. I have to limit my social activity because I am tired

• Standard items (1-6, 9-13): Score = 4 - item response
• Reverse items (7-8): Score = item response (no subtraction)
• Sum all 13 item scores → Multiply by 13 → Divide by the number of items answered = FACIT-Fatigue Score
• Score range: 0-52
• Score < 30 = severe fatigue
• Higher scores = better quality of life / less fatigue
• Minimum clinically important difference (MCID): approximately 3-4 points

Clinical Uses

PART II: QUALITY OF LIFE SCALES

3. SF-36 Health Survey (36-Item Short Form Health Survey)

Overview

Indications

• Any chronic disease or condition requiring quality of life assessment: cardiovascular disease, cancer, diabetes, COPD, arthritis, stroke, renal disease, orthopaedic conditions
• Rheumatology: Osteoporosis (comparing QUALEFFO vs SF-36 for vertebral fracture discrimination), osteoarthritis, ankylosing spondylitis, hip/knee replacement outcomes
• Orthopaedics and trauma: Femoral neck fractures, tibia fractures, limb salvage assessment
• Urology: Post-cystectomy, urinary diversion outcomes
• Dermatology: Psoriasis, atopic dermatitis, other chronic skin conditions - used as a measure of overall quality of life
• ENT: Chronic rhinosinusitis, chronic otitis media, dysphonia, laryngeal cancer, head and neck surgery outcomes
• Psychiatry and geriatrics: Assessing functional status in older adults and psychiatric populations
• Population health studies: Large-scale epidemiological research and clinical trials
• Post-surgical evaluation: Physical and mental recovery benchmarking after surgery

Precautions

• Not disease-specific: Generic nature means it may miss condition-specific impacts; best paired with disease-specific tools when detailed condition assessment is needed.
• Ceiling and floor effects: In very healthy or very severely ill populations, responses cluster at the extremes, reducing sensitivity to change.
• Literacy required: Requires at least a 5th-grade reading level; interpreter or proxy completion may be needed.
• Cognitive impairment: May not be self-administered in patients with significant cognitive decline; interviewer-administered versions are needed.
• Time burden: 36 items takes approximately 10 minutes - longer than SF-12, and may cause patient fatigue in already unwell populations.
• Cultural validity: Scores are normed against US population data; cross-cultural comparisons require validated translated versions.
• Individual vs group use: More reliable at group level; individual-level interpretation should be done cautiously.
• SF-6D derivation: Conversion to the utility-based SF-6D for health economic studies requires separate algorithms and has shown inconsistencies in early validation.

Procedure

Transformed score = [(Raw score - Lowest possible) / Possible raw score range] × 100

• Score range per domain: 0-100
• Higher scores = better health/function
• 0 = maximum disability; 100 = no disability

• Physical Component Summary (PCS): Derived from PF, RP, BP, and GH domains
• Mental Component Summary (MCS): Derived from VT, SF, RE, and MH domains
• Both summary scores are norm-based with mean = 50, SD = 10
• Scores >50 = better than population average; <50 = below average

• Physical Functioning: α = 0.93
• Role Emotional: α = 0.83
• Energy/Fatigue: α = 0.86
• Emotional Well-Being: α = 0.90

Clinical Uses

4. SF-12 Health Survey (12-Item Short Form Health Survey)

Overview

Indications

• Brevity is required: Large-scale surveys, elderly populations, acutely ill patients, high-volume screening
• Orthopedic outcomes: Femoral neck fractures, hip and knee arthroplasty, spinal surgery
• Population surveillance: Public health monitoring, national health surveys
• Oncology: Post-treatment quality of life screening
• Neurology/Rehabilitation: Post-stroke functional outcome, neurological rehabilitation
• Urology: Bladder cancer follow-up, urinary diversion
• Psychiatry: Patient-reported mental health outcomes
• Any setting where SF-36 administration is not feasible due to time constraints or patient burden

Precautions

• Less precise for individual subscales: The SF-12 produces reliable PCS and MCS scores but gives only estimated subscale scores - less accurate at the individual domain level than SF-36.
• Not suitable for small studies: Scott-Brown's Otorhinolaryngology textbook specifically states: "The larger instrument [SF-36] gives more reliable estimates of individual levels of health and is therefore the better choice of instrument in small studies."
• Missing data: With only 12 items, a single missing answer has a proportionally greater impact on score validity.
• Ceiling and floor effects: More pronounced than in SF-36 due to fewer items per domain.
• Age validity: Validated for adults 18+; geriatric populations may need assistance with completion.
• Same literacy/language precautions as SF-36 apply.

Procedure

1. Physical functioning limitations
2. Social activity limitations
3. Role limitations (physical health)
4. Bodily pain
5. General mental health
6. Role limitations (emotional problems)
7. Energy/vitality
8. General health perceptions

• Weighted scoring (not simple summation): Each response contributes a weighted value derived from the SF-36 factor structure.
• Produces two composite scores:
  • Physical Component Summary (PCS-12)
  • Mental Component Summary (MCS-12)
• Both use norm-based scoring: Mean = 50, SD = 10
• Scores >50 = better-than-average health
• Scores <50 = below-average health
• Clinically meaningful change: 3-5 point difference is considered significant

Comparison Table: SF-36 vs SF-12

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