Impact of whole comorbidities on patients with exacerbation of chronic obstructive pulmonary disease: A Long-term Multicentre  Retrospective Study in China

Background: Exacerbation of chronic obstructive pulmonary disease results in severe adverse outcomes and mortality. However, individual susceptibility to exacerbations remains largely unknown. Our study aimed to investigate the association between comorbidities and exacerbation outcomes. Methods We included patients with the primary discharge diagnosis of exacerbation between 1 January 2008 and 30 September 2019 in China. Data on all comorbidities were collected and analysed to determine the impact of the comorbidities on 1-year exacerbation readmission, length of hospital stay, and hospital cost. Univariable and multivariable logistic regression analyses were performed, and predictive models were developed. Results A total of 15,708 participants were included, with a median hospital stay of 10 days and an average hospital stay cost of 9873.0 RMB. Overall, 2,487 (15.8%) participants were readmitted within 1 year. Twenty-five of the top 100 most frequent comorbidities were included as main variables. The most widely distributed comorbidities were hypertension (38.6%), ischaemic heart disease (16.9%), and diabetes mellitus (16.6%). In the multivariable analysis model, older age, female, diabetes mellitus, malnutrition, hyperlipidaemia, arrhythmias, heart failure, cerebrovascular disease, gastroesophageal reflux disease, osteoporosis, and prostate hyperplasia were included, and they were positively associated with an increased 1-year readmission rate (concordance index: 0.701). Eight comorbidities, together with older age and male gender, were associated with prolonged length of stay (concordance index: 0.752). Seven comorbidities together with older age and male gender were associated with higher costs (concordance index: 0.713). Conclusions Our models provide a novel tool for clinicians to determine the risk of the 1-year recurrence of severe ECOPD in hospitalised patients. The results suggest that exacerbation is closely related to systemic disease status.