Predicting life expectancy of older people using respiratory symptoms and smoking status: Data from the Australian Longitudinal Study of Ageing

Background and objective: Respiratory symptoms are recognizable to patients and may be markers of chronic disease and mortality risk. This risk may be easier to conceptualize if presented as remaining life expectancy (LE) rather than hazard ratios. We aimed to predict the remaining LE of older people with respiratory symptoms using data from the Australian Longitudinal Study of Ageing (ALSA).

Methods: The ALSA is a prospective longitudinal cohort of older Australians (n = 2087) with 22 years of follow-up. The symptoms analysed were cough, shortness of breath (SOB) and wheeze. The implied impact on LE was estimated using a parametric survival function.

Results: SOB predicted shorter LE irrespective of smoking status. Cough predicted shorter LE in former smokers and wheeze predicted shorter LE in current smokers. The estimated remaining LE of a 70-year-old male never smoker with no symptoms was 16.6 (95% CI: 14.8-17.7) years. The years of life lost for a 70-year-old male current smoker with cough, SOB and wheeze compared to a never smoker with no symptoms was 4.93 (95% CI: 2.87-7.36) years with only 2.99 (95% CI: 1.35-4.97) years being attributed to their current smoking and the remainder to their respiratory symptoms.

Conclusion: Respiratory symptoms predict mortality in older people. Cough in former smokers, wheeze in current smokers and all those with SOB require further investigations and disease-specific management.