Comorbidity of chronic back pain and depression in Germany: Results from the GEDA study, 2009 and 2010

Background: Depression and chronic back pain are two common disabling diseases. Studies suggest an association of both conditions. We aimed to determine sex- and age-specific prevalences of depression, chronic back pain and the combination of both. Furthermore, influencing factors and resulting consequences were analyzed. Methods: Data was derived by pooling two representative cross-sectional telephone surveys "German Health Update (GEDA)" 2009 and 2010 including 43,312 adults. Self-reported physician-diagnosed chronic somatic diseases including diagnosed depression and chronic back pain in the past 12 months were assessed. Age- and sex-specific prevalence was calculated. Logistic regression was used to examine their association and identify influencing factors. Sick days, missed workdays and doctor visits were compared for single disease vs. comorbidity. Results: 12-month prevalence for diagnosed depression was 6.7 %, for chronic back pain 21.1 %, and the comorbidity of both was 3.0 %. An association of depression and chronic back pain was found for both sexes and all age groups. The characteristics "female sex", "being 50-64 years of age", "low socioeconomic status" and "low social support" increased the likelihood of comorbid depression and chronic back pain. Comorbid depression and chronic back pain increased the number of sick days, missed workdays and doctor visits significantly. Conclusion: The results show a strong association of depression and chronic back pain. The direction of association cannot be determined due to the cross-sectional design of the study. Identifying patients at risk for comorbid depression and chronic back pain early on might improve treatment and reduce the economic impact.