Potassium and survival outcomes in asthma patients: evidence from a retrospective cohort study

Asthma is a chronic respiratory disease with multifactorial influences. Although potassium intake has been linked to outcomes in other chronic conditions, its association with all-cause mortality in adults with asthma remains unclear. This study aimed to investigate the association between potassium intake and survival outcomes in patients with asthma.

This retrospective cohort study analyzed data from 6,279 asthma patients in the National Health and Nutrition Examination Survey (NHANES) using weighted methods. Cox proportional hazards regression models were employed to examine the association between potassium and all-cause mortality, with sequential adjustments for demographic characteristics (Model 1), clinical and biochemical factors (Model 2), and comorbidities (Model 3). Kaplan-Meier curves were used to estimate survival probabilities. Subgroup analyses were performed to assess consistency across covariates. Restricted cubic spline (RCS) and threshold analyses were applied to explore non-linear associations and identify intake thresholds.

Serum potassium was not significantly associated with all-cause mortality in Models 2 and 3 (P>0.05). In contrast, dietary potassium intake showed a consistent inverse association with mortality across all models. In Model 3, participants in the highest intake quartile had a 37% lower risk of death compared to the lowest quartile [hazard ratio (HR) =0.64; 95% confidence interval (CI): 0.46-0.89; P=0.008]. RCS revealed an inverse relationship, while threshold analysis indicated a reduced mortality risk associated with potassium intake below 3,192 mg/day (HR =0.78; 95% CI: 0.68-0.89; P<0.001).

Higher potassium intake was associated with improved survival outcomes in asthma patients, with a threshold effect observed.