Developing the Patient Health Questionnaire-8 for a greater impact on the quality of life of patients with functional dyspepsia compared to Somatic Symptom Scale-8

(2020) 20:359 Yuan et al. BMC Gastroenterol https://doi.org/10.1186/s12876-020-01508-4 RESEARCH ARTICLE Open Access Developing the Patient Health Questionnaire‑8 for a greater impact on the quality of life of patients with functional dyspepsia compared to Somatic Symptom Scale‑8 Chaoqun Yuan1†, Guizhen Yong2†, Xi Wang1, Ting Xie1, Chunyan Wang1, Yuan Yuan1 and Guobin He1* Abstract Background: To develop the Patient Health Questionnaire-8 (PHQ-8) as a more reliable approach than the Somatic Symptom Scale-8 (SSS-8), evaluating somatization which might be a critical factor influencing the quality of life (QoL) in patients with functional dyspepsia (FD). Also, the effects of somatization on QoL of FD patients were assessed by these two approaches. Methods: Herein, 612 FD patients completed a questionnaire involving 25 items. 8/25 items were selected to develop the PHQ-8 by four methods of discrete degree, correlation coefficient, factor analysis, and Cronbach’s α coefficient. Reliability and validity of the PHQ-8 and the SSS-8 were compared by principal component and confirmatory factor analyses. The effects of somatization, depression, and anxiety on the Nepean Dyspepsia Index (NDI) for QoL were explored by Pearson’s correlation coefficient and linear regression analysis. Results: The Cronbach’s α coefficient for the PHQ-8 and the SSS-8 was 0.601 and 0.553, respectively, and the cumulative contribution rate of three extracted factors for the developed PHQ-8 and SSS-8 was 55.103% and 51.666%, respectively. Somatization evaluated by the PHQ-8 (r = 0.309, P < 0.001) and the SSS-8 (r = 0.281, P < 0.001) was found to be correlated to NDI. The model used for the PHQ-8 showed that the values of goodness-of-fit index (GFI) and adjusted GFI (AGFI) were 0.984 and 0.967, respectively, which indicated that the model fitted well. Linear regression analysis unveiled that somatization (β = 0.270, P < 0.001), anxiety (β = 0.163, P < 0.001), and depression (β = 0.136, P = 0.003) assessed by the PHQ-8 were correlated to NDI. In addition, somatization (β = 0.250, P < 0.001), anxiety (β = 0.156, P < 0.001), and depression (β = 0.155, P = 0.001) evaluated by the SSS-8 were correlated to NDI. Conclusions: PHQ-8 showed a superior reliability and validity, and somatization assessed by the developed PHQ-8 showed a greater influence on the QoL of FD patients as compared to the SSS-8. Our findings suggested that the *Correspondence: † Chaoqun Yuan and Guizhen Yong contributed equally to this work 1 Department of Gastroenterology, Affiliated Hospital of North Sichuan Medical College, No. 67 Wenhua Road, Shunqing, Nanchong 637000, Sichuan, China Full list of author information is available at the end of the article © The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Yuan et al. BMC Gastroenterol (2020) 20:359 Page 2 of 10 developed PHQ-8 may show improvement in a reliable assessment of the effects of somatization on FD patients in lieu of the SSS-8. Keywords: Patient health questionnaire-8, Functional dyspepsia, Somatization, Somatic Symptom Scale-8, Reliability, Validity, Quality of life Background Pathogenesis and subtypes of functional dyspepsia Functional dyspepsia (FD) is characterized by bothersome epigastric pain or burning, postprandial fullness, or early satiation without evidence of structural disease. According to the statistics, the prevalence of FD is as high as 20–30% [1, 2]. The underlying pathogenesis includes diverse mechanisms, such as infectious causes represented by Helicobacter pylori (H. pylori) [1–6], diet factor [1, 7, 8], gastric acid [1, 9, 10], delayed gastric emptying, impaired proximal gastric accommodation [1, 11–13], visceral hypersensitivity [1, 14–16], duodenal inflammation [1, 17, 18], genetic factors [19, 20], and psychosocial factors (such as anxiety, depression, and stress) [19–25]. Moreover, these factors may interact with each other under the participation of brain-gut axis [1, 3, 15]. Thus, FD is a disorder of gut-brain interaction and classified into three subtypes based on Rome IV criteria: (1) epigastric pain syndrome (EPS): upper abdominal pain and/or burning discomfort of upper abdomen; (2) postprandial distress syndrome (PDS): postprandial fullness and early satiety; (3) the overlapped group of EPS and PDS [2]. FD patients with common somatization symptoms In addition, FD patients often have dizziness, back pain, sleep disorders, fatigue [26], and other symptoms of digestive system that cannot be explained by biochemical and structural abnormalities. Clinically, these symptoms are known as somatization symptoms [27, 28]. Somatization is defined as a chronic mental disorder characterized by the presence of one or more frequently changing somatic symptoms, involving multiple systems and organs of the body [29]. Those symptoms often induce patients’ incorrect understanding or excessive attention, imposing a huge economic burden on the society [30]. Somatization can coexist with other medical disorders, such as anxiety and depression, rendering them complex and changeable [31]. Additionally, it affects the severity of dyspepsia and the quality of life (QoL) of FD patients [32, 33]. Somatization plays a more significant role in dyspepsia symptom severity (DSS) as compared to that in gastric sensitivity, anxiety, and depression in FD patients [21]. It is an independent risk factor for impaired QoL of FD patients, and a 5-year follow-up study demonstrated that proximal gastric accommodation, gastric emptying, and H. pylori infection were not found as risk factors [33]. Therefore, assessment of somatization is highly essential for studying FD patients. Limitations of questionnaires for somatization The symptoms of somatization disorder were widely assessed by the Patient Health Questionnaire-15 (PHQ15) developed by Kroenke et al. [34]. However, PHQ-15 includes a number of items overlapped with gastrointestinal symptoms in FD patients (...truncated)