Autor:innen:
Marietta von Siemens | Klinikum der Universität München | Germany
PD Dr. Rudolf A. Jörres | Klinikum der Universität München | Germany
Prof. Dr. med. Jürgen Behr | Klinikum der Universität München | Germany
Prof. Dr. med. Peter Alter | Philipps-University Marburg | Lithuania
Johanna Lutter | Helmholtz Zentrum München GmbH | Germany
Dr. Sandra Söhler | University of Marburg | Germany
Prof. Dr. med. Tobias Welte | Hannover Medical School | Gibraltar
PD Dr. med. Henrik Watz | Pulmonary Research Institute at LungenClinic Grosshansdorf | Germany
Franziska Trudzinski | Saarland University Hospital | Germany
Prof. Dr. Winfried Rief | University of Marburg | Germany
Britta Herbig | Klinikum der Universität München | Germany
Dr. Kathrin Kahnert | Klinikum der Universität München | Germany
The diagnosis of depression, a frequent comorbidity of COPD, is often supported by questionnaires, such as the Patient Health Questionnaire 9 (PHQ-9). It is unknown to which extent its single questions are affected by the characteristics of COPD patients.
We addressed this question in 2255 GOLD grade 1-4 patients from the COSYCONET COPD cohort. The dependence on COPD severity was assessed using symptoms, exacerbation risk (GOLD A-D; mMRC), and frequent comorbidities as predictors of PHQ-9 results, while including age, gender, BMI and smoking habits as covariates.
Symptoms and exacerbation risk were associated in an additive manner, with mean elevations in the PHQ-9 sum score by 2.75 and 1.44 points, respectively. Asthma, sleep apnoea, gastrointestinal disorders, osteoporosis and arthritis were linked to increases by 0.8 to 1.3 points. Overall, the COPD characteristics contributed to the mean score by increases from 4.5 or 5.2 to 6.3 points, respectively, when either taking GOLD A as reference or the absence of comorbidities, independent of the diagnosis of mental disorder or intake of antidepressants. The presence of COPD led to an increase in the proportion of scores indicating depression from 12 to 22%. Single item analysis revealed homogenous effects regarding GOLD groups, but heterogeneous effects regarding other COPD characteristics.
These findings indicate specific effects of COPD severity, especially symptoms and exacerbation risk, on the PHQ-9 depression score, explain the high prevalence of depression in COPD. Alternatively, our findings raise the question of a bias from COPD severity on the PHQ-9, but also suggest COPD treatment effects on depression scores.