Association between high-salt diet and increased risk of acute exacerbation in elderly patients with chronic obstructive pulmonary disease

Abstract

Abstract Background Lifestyle is closely linked to chronic obstructive pulmonary disease (COPD) progression and acute exacerbation risk. Older adults (aged ≥60 years) account for over 50% of global COPD cases and carry a higher exacerbation risk due to more comorbidities and poorer lung function. This study aimed to investigate the association between high-salt intake, an important modifiable lifestyle factor, and the risk of acute exacerbations of COPD (AECOPD) in older patients, and to provide evidence for targeted disease management in this high-risk population. Methods Older AECOPD patients who were successfully discharged after treatment were consecutively enrolled. The baseline was set as the outpatient review at 2 weeks post-discharge, when COPD condition and treatment regimens were collected and patients were trained in standardized morning urine collection. Follow-up lasted until another AECOPD occurrence or 12 months elapsed. Morning urine samples were collected at baseline, 4, 8, and 12 months to measure sodium levels and calculate the mean value. Daily salt intake was estimated via the INTERSALT formula, and ≥5 g/day was defined as high-salt intake. Meanwhile, AECOPD occurrence was monitored with related condition and treatment details recorded. Multivariate Cox and logistic regression models were used for data analysis. Results A total of 646 patients were divided into the high-salt group (n=461) and low-salt group (n=185). Multivariate Cox regression indicated that high daily salt intake was associated with an increased risk of AECOPD recurrence. Multivariate logistic regression further demonstrated that high daily salt intake was associated with lower FEV1/FVC ratio, FEV1%pred, and PaO2 levels during acute exacerbation, along with higher PaCO2 levels, increased risks of hospitalization and ICU admission, and prolonged hospital stays. Conclusion High daily salt intake may be associated with an increased risk of AECOPD in older patients. These findings support a potential link between high-salt diet and AECOPD risk.