Dyspnea As Predictor Of All-Cause Mortality: Reduction In Risk Over Time In A Prospective Cohort Study

Background: It has been suggested that risk in longitudinal studies may drop with time, but clear-cut documentation has been sparse. The purpose of this investigation was to determine risks at several time points in a recently completed/published longitudinal study to further evaluate this hypothesis. Methods: A population-based sample of 11,533 Bangladeshsis aged 18 to 75 was recruited and followed for 11-12 years and all-cause mortality was evaluated in those with and without baseline dyspnea. Dyspnea, the exposure, was ascertained by trained physicians by questionnaire. Kaplan-Meier survival curves and Cox Proportional Hazard models were used to determine differences between groups at 3, 6, and 11-12 years. Results: The Kaplan-Meier curves revealed a clear increase in mortality between dyspnea versus no dyspnea groups at the 3, 6, and 11.2 year time periods. The logrank test was significant with a p value less than 0.01 for all three time periods. At 3 years (3-yrs) the unadjusted hazard ratio (HR) was...