Somatic symptom disorder in gastroesophageal reflux disease: a key factor contributing to severe symptoms and impaired quality of life

Background Somatic symptom disorder (SSD) is a common yet frequently overlooked comorbidity in patients with gastroesophageal reflux disease (GERD), compromising quality of life (QOL) and increasing healthcare utilization. Aims This study aimed to evaluate its impacts of SSD on symptom perception and QOL and to determine the risk factors for SSD in GERD patients. Methods A cross-sectional study was conducted in a tertiary gastroenterology department. A total of 209 GERD patients completed validated questionnaires assessing reflux symptoms, somatic symptoms, anxiety, depression, sleep quality, and QOL. SSD was diagnosed based on DSM-5 criteria. All patients underwent upper endoscopy and a subset completed esophageal manometry and 24-h pH-impedance monitoring investigations. Results The proportion of SSD was 30.14% (63/209). Despite having milder objective reflux burden on 24-h pH-impedance monitoring and esophageal manometry, patients with SSD reported higher reflux symptom scores [GerdQ: 9(5) vs. 8(4), p = 0.032; RSI: 12(9) vs. 4(6), p < 0.001], more severe anxiety and depression, worse sleep quality (all p < 0.001), and lower QOL [GIQLI: 94(37) vs. 121(27.5), p < 0.001] than non-SSD patients. Female gender, laryngopharyngeal reflux symptoms, anxiety, and depression were independent risk factors for SSD. SSD partially mediated the negative impacts of reflux symptoms and poor sleep on QOL (23.52% for GerdQ, 26.30% for RSI and 14.05% for PSQI). The PHQ-15 demonstrated high accuracy (AUC = 0.851) in identifying comorbid anxiety/depression with sleep disturbances at a cutoff score of 12.5. Conclusion SSD aggravates GERD symptoms and mediates impaired QOL by reflux and sleep disturbance. Screening SSD with PHQ-15 is recommended, particularly in females and those with laryngopharyngeal reflux symptoms.