Variation in fatigue may be poorly explained by pain: results from a longitudinal, exploratory study

Area of Science:

• Rheumatology
• Clinical Medicine
• Pain Management

Background:

• Fatigue is a common symptom in ankylosing spondylitis (AS).
• It is often assumed that fatigue in AS is primarily driven by pain.
• This assumption influences treatment strategies, focusing on pain management for fatigue relief.

Purpose of the Study:

• To examine the longitudinal correlation between fatigue and pain in AS patients.
• To determine the temporal relationship between fatigue and pain over time.
• To inform targeted treatment strategies for AS.

Main Methods:

• Longitudinal study design over 35 weeks.
• 23 patients with ankylosing spondylitis (AS) participated.
• Twice-weekly assessments of fatigue and pain via mobile phone text messages (approx. 70 measurements/patient).
• Statistical analysis included within-individual correlation and lagged linear regression.

Main Results:

• Pain explained less than 36% of fatigue variance in 70% of patients.
• The association between fatigue and pain was synchronous in 57% of patients.
• In 22% of patients, fatigue preceded pain by one week.
• In 22% of patients, pain preceded fatigue by one week.

Conclusions:

• Fatigue and pain may function as independent symptoms in some AS patients.
• Treatment strategies should consider targeting fatigue and pain separately.
• Clinical management should not assume that improving one symptom will automatically improve the other.