Effects of tobacco smoking on recurrent hospitalisation with pneumonia: a population-based cohort study.

The incidence of and risk factors for recurrent hospitalisation for pneumonia were investigated using data from Hospital Episode Statistics, linked to a UK primary care database. Within 90 days and 1 year of follow-up, 1733 (3.1%) and 5064 (9.0%), developed recurrent pneumonia respectively. Smoking status at the time of hospitalisation with index pneumonia was associated with the risk of readmission with recurrent pneumonia within a year of discharge: current versus never smokers: adjusted subhazard ratio (sHR) 1.42, 95% CI 1.32 to 1.53, p<0.001, and ex smokers versus never smokers: adjusted sHR 1.24, 95% CI 1.15 to 1.34, p<0.001. Other independent risk factors associated with recurrent pneumonia were age, gender, deprivation and underlying comorbidities.