Comorbidity patterns of respiratory symptoms and diseases and their impact on all-cause and respiratory mortality: Prospective cohort study.

BACKGROUND

Respiratory symptoms and diseases often co-occur and may increase mortality risk.

OBJECTIVE

This study aims to identify patterns of respiratory multimorbidity and assess their links with mortality.

METHODS

We conducted a prospective cohort study using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2011, linked to mortality records through 2019. Participants aged ≥40 years were classified using latent class analysis based on respiratory symptoms, diseases, and spirometry patterns. Cox models were used to estimate the relationship between respiratory clusters and all-cause and respiratory mortality.

RESULTS

Five clusters were identified. Compared with the minimal-symptom group (Cluster 4), the severe obstructive cluster (Cluster 5) had the highest risk of all-cause mortality (HR=1.355, 95% CI: 1.040-1.767) and respiratory mortality (HR=12.956, 95% CI: 4.870-34.465). The chronic cough-phlegm cluster (Cluster 1) also showed elevated risks for all-cause (HR=1.297, 95% CI: 1.001-1.680) and respiratory mortality (HR=4.605, 95% CI: 1.468-14.441). The restrictive lung cluster (Cluster 3) was associated with higher all-cause mortality (HR=1.295, 95% CI: 1.055-1.589), especially among participants with cardiovascular disease (HR=2.013, 95% CI: 1.346-3.010). No significant associations were found for the asthma-wheezing cluster (Cluster 2) after full adjustment.

CONCLUSION

Individuals with severe airflow obstruction or chronic cough and phlegm have the highest risk of death. Restrictive lung patterns also predict higher mortality, particularly when combined with cardiovascular disease. Early identification and integrated care are crucial for respiratory multimorbidity.