Purpose: To evaluate the relationship between depressive symptoms and health care costs in outpatients with chronic medical illnesses in Korea, we screened for depressive symptoms in 1,118 patients with a chronic medical illness and compared the severity of somatic symptoms and health care costs.
Patients and methods: Data were compared between outpatients with depressive symptoms and those without depressive symptoms. Depression and somatic symptoms were measured by Zung's Self-rating Depression Scale (SDS) and Patient Health Questionnaire (PHQ)-15, respectively. We also investigated additional data related to patients' health care costs (number of visited clinical departments, number of visits made per patients, and health care costs). A total of 468 patients (41.9%) met the criteria for depressive disorder.
Results: A high rate of severe depressive symptoms was found in elderly, female and less-educated patients. A positive association between the severity of somatic symptoms and depressive symptoms was also identified. The effects of depressive symptoms in patients with chronic illnesses on three measures of health services were assessed by controlling for the effects of demographic variables and the severity of somatic symptoms. We found that the effects of depressive symptoms on the number of visited departments and number of visits made per patients were mediated by the severity of somatic symptoms. However, for health care costs, depressive symptoms had a significant main effect. Furthermore, the effect of gender on health care costs is moderated by the degree of a patient's depressive symptoms.
Conclusion: In summary, there is clearly a need for increased recognition and treatment of depressive symptoms in outpatients with chronic medical illnesses.
Keywords: Depression symptoms; chronic medical illness; health care costs; somatic symptoms.