RESUMEN
PURPOSE: Fatigue is the third most common "extraintestinal" complaint of patients with irritable bowel syndrome (IBS), but it is still poorly understood. This study aimed to review characteristics of IBS-associated fatigue and to examine pooled frequency, severity of fatigue, and correlations of related factors with fatigue in IBS via meta-analyses. METHODS: Publications were searched in eight databases from 1995 to 2014. Random effects meta-analyses were applied with standard error, weighted effect size, and correlation-based measure of effect size. RESULTS: Twenty-four studies were included in systematic review. Seventeen studies were used for meta-analyses (2 studies were excluded in the frequency of fatigue analysis due to data unavailability). Using "tiredness" to define fatigue, and Fatigue Impact Scale to assess fatigue were the most frequently used across the studies. Gastrointestinal symptoms, psychological distress, and health-related quality of life were the most common correlates with fatigue. The pooled frequency of fatigue was 54.2% [95% confidence interval (38.5, 69.4)]. Metaregression on the frequency of fatigue showed positive and significant relations with tertiary care settings, female sex, and younger age. There was a negatively moderate relationship between the severity of fatigue and health-related quality of life score (correlation-based measure of effect size: -.378). CONCLUSIONS: Fatigue is prevalent among patients with IBS and commonly co-occurs with other symptoms. This is the first study to fully examine fatigue in IBS, which shed light on the comprehensive management of fatigue in this patient group. Future research is warranted to further explore fatigue-related factors and underlying mechanisms of fatigue in IBS.