# The severity of fatigue and its interplay with biological and psychological factors in people with hand osteoarthritis – Results from the Nor-Hand study

## TL;DR

This study finds that fatigue in hand osteoarthritis patients is closely linked to comorbidities, pain, anxiety/depression, and sleep issues.

## Contribution

The study introduces a network analysis approach to explore fatigue's interplay with biological and psychological factors in hand OA.

## Key findings

- Fatigue severity was moderately high, averaging 4.1 on a 10-point scale.
- Comorbidities, pain, anxiety/depression, and sleep problems were strongly linked to fatigue.
- Network relationships remained stable across sensitivity analyses.

## Abstract

Fatigue represents a concurrent yet uncommonly addressed symptom among people with hand osteoarthritis (OA). We aimed to explore fatigue severity and its interplay with other variables among hand OA patients.

We used baseline data collected in the Nor-Hand study, a cohort comprising participants with hand OA recruited at Diakonhjemmet Hospital. We measured fatigue severity by using a numeric rating scale (NRS, range: 0–10). Drawing on correlations from our dataset, existing literature, and input from a patient research partner, we estimated regularized networks to explore the interplay of fatigue. Network nodes represented variables (i.e., measures of fatigue, all bodily pain, anxiety/depression, self-efficacy, age, comorbidities, body mass index and sleep), and edges represented weighted conditional non-directional relationships between nodes. In sensitivity models, radiographic OA severity, high-sensitivity C-reactive protein, grip strength and indices of central pain sensitization were added. Network accuracy and stability were tested by bootstrapping (n = 1000).

Our sample included 300 participants (mean (standard deviation) age; 60.8 (6.2) years, 88 % women). The mean (SD) severity of fatigue was 4.1 (2.9) NRS points. Network analyses identified comorbidities, all bodily pain, symptoms of anxiety/depression, and sleep problems as central and strongly related to fatigue, independent of additional variables included in sensitivity analyses. Edge weights and node centrality estimates were considered accurate and stable based on bootstrapped confidence intervals.

Fatigue is likely significant and strongly related to comorbidities, pain, symptoms of anxiety/depression, and sleep problems among hand OA patients. Longitudinal studies using more diverse samples and comprehensive variable selections are warranted.