Prevalence and Risk Factors for Depression in Korean Adult Patients with Asthma: Is There a Difference between Elderly and Non-Elderly Patients?

Depression is an important comorbidity of asthma. However, little information is available about depression and its potential impact on asthma control in Korean adult asthma patients. We aimed to estimate the prevalence and risk factors for depression in Korean adults with persistent asthma. The 127 non-elderly (20-64 yr) and 75 elderly (>= 65 yr) patients with asthma were recruited. Demographic and clinical data were extracted, and the patients completed the Asthma Specific Quality of Life (AQOL) questionnaire and asthma control test (ACT). Depression status was defined using the Korean version of the Patient Health Questionnaire-9 (PHQ-9). Depression was more prevalent in non-elderly (18.9%) than in elderly patients with asthma (13.3%). Patients with depression were significantly younger, had lower economic status, shorter disease duration, poorer asthma control, and worse AQOL scores (P < 0.05). Within the non-elderly group, younger age and shorter disease duration were significantly associated with depression (P < 0.05). Within the elderly group, a higher body mass index and current smoking status were significantly associated with depression (P < 0.05). The PHQ-9 score was significantly correlated with worse ACT and AQOL scores in both groups. In conclusion, depression is strongly associated with poor asthma control and quality of life in Korean adult asthma patients. Our results provide important clues that used to target modifiable factors which contribute to development of depression in asthma patients.