Longitudinal comparison of anxiety and depression between idiopathic pulmonary fibrosis and other interstitial lung diseases: a prospective cohort study

Background and objective: Few studies have investigated the differences in the incidence of anxiety and depression among the interstitial lung diseases (ILDs). We evaluated the differences in the incidence of anxiety and depression between idiopathic pulmonary fibrosis (IPF) and non-IPF ILD, and the changes after a 1-year follow-up period. Methods The study participants were patients included in a prospective ILD cohort of Seoul National University Hospital between March 2013 and August 2018. Clinical variables were recorded at baseline and at 1 year. The Hospital Anxiety and Depression Scale was used to assess patient anxiety and depression at baseline and at 1-year follow-up. Results A total of 224 patients in the cohort participated in the study (154 [68.8%] with IPF and 70 [31.2%] with non-IPF ILD). Among them, 111 patients completed a follow-up Hospital Anxiety and Depression Scale questionnaire 1 year later (77 in the IPF group, 34 in the non-IPF group). In the IPF group, 20.8% and 27.3% of patients suffered from anxiety and 29.9% and 31.2% suffered from depression at baseline and 1-year follow-up, respectively. In the non-IPF group, 14.3% and 23.5% of patients suffered from anxiety and 24.3% and 17.6% suffered from depression at baseline and 1-year follow-up, respectively. Total score on the St. George’s Respiratory Questionnaire at baseline was associated with depression both at baseline (odds ratio 1.05; 95% confidence interval 1.02–1.08) and at 1-year follow-up (odds ratio 1.03; 95% confidence interval 1.00-1.05), even after adjusting other factors. The interaction of prevalence change of anxiety and depression at baseline and 1-year follow-up between the IPF group and the non-IPF ILD group were not statistically significant (p-value 0.878 for anxiety and 0.376 for depression, respectively). Conclusion The prevalence of anxiety and depression at baseline and at 1-year follow-up were not significantly different between patients with IPF and non-IPF ILD. St. George’s Respiratory Questionnaire total score at baseline was associated with depression at baseline and at 1-year follow-up.