Associations of somatic symptom disorder with pain, disability and quality of life in patients with chronic low back pain.

Literature findings have suggested that psychological factors, including anxiety, depression and somatic symptom disorder (SSD), are predictors of poor outcomes in individuals with chronic low back pain (CLBP). The aim of this study was to examine the correlations between anxiety, depression and SSD with pain, disability and health-related quality of life (HRQoL) in Greek CLBP patients. Ninety-two participants with CLBP recruited using random systematic sampling from an outpatient physiotherapy department, who completed a battery of paper-and-pencil questionnaires included items on demographic characteristics, as well the Numerical Pain Rating Scale (NPRS) for pain, the Rolland-Morris Disability Questionnaire for disability (RMDQ), the EuroQoL 5-dimension 5-level (EQ-5D-5L) for health status, the Somatic Symptom Scale-8 (SSS-8) for SSD, the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression. A Mann-Whitney test and a Kruskall-Wallis test were used for the comparison of continuous variables between two groups and among more than two groups, respectively. Moreover, Spearman correlations coefficients were used to explore the association between subjects' demographics, SSS-8, HADS-Anxiety, HADS-Depression, NPS, RMDQ and EQ-5D-5L indices. Predictors of health status, pain and disability were assessed using multiple regression analyses, whereas the level of statistical significance was set at p<0.05. The response rate was 94.6% (87 participants, 55 of whom were women) and the mean age of the sample was 59.6 years (SD=15.1). A tendency of weak negative associations was noted between scores of SSD, anxiety and depression with EQ-5D-5L indices, whereas only a weak positive correlation was found between levels of SSD with pain and disability. After examining in a multiple regression analysis, only SSD emerged as prognostic factor of poor HRQoL, greater levels of pain and disability. In conclusion, the elevated scores of SSD significantly predict worse HRQoL, intense pain and severe disability in Greek CLBP patients. Further research is needed to test our findings in larger and more representative samples of the Greek general population.