Comorbidity as a mediator of depression in adults with congenital heart disease: A population-based cohort study

Background The population of adults with congenital heart disease (CHD) has increased dramatically with a high prevalence of acquired cardiac and non-cardiac comorbidities. However, the relationship among congenital heart disease, physical comorbidities, and psychological health in this population is not well studied. Aims The purpose of this study was to investigate (a) the association between adult congenital heart disease and the occurrence of depression and (b) whether physical comorbidities mediated the association between congenital heart disease and the occurrence of depression. Methods This retrospective cohort study was followed from 1 January 2010-31 December 2013, based on the data from the National Health Insurance Research Database 2010 in Taiwan. We used mediation analysis in survival data to assess the mediated effect. The hazard ratios were adjusted by age, sex, area of residence, and estimated propensity scores. Results We recruited 2122 adult congenital heart disease patients and 8488 matched controls. Nearly half of patients diagnosed with simple congenital heart disease, 39.0% had complex congenital heart disease, and 11.2% had unclassified congenital heart disease. Adult congenital heart disease patients had a significantly higher risk of depression than matched controls (adjusted hazard ratio = 1.43 and 1.48, for all and complex congenital heart disease, respectively, p<0.05). Coronary artery disease and chronic obstructive pulmonary disease were the significant comorbidities mediating the relationship between adult congenital heart disease and depression, the proportions mediated by coronary artery disease or chronic obstructive pulmonary disease were 35.5% and 12.9%, respectively. Conclusions Helping patients to prevent psychological and physical acquired disease is imperative. Coronary artery disease is a potent mediator between congenital heart disease and depression, especially for patients with complex congenital heart disease.