Increased risk of serious pneumococcal disease in patients with asthma

Background

Individuals with asthma have been reported to be at increased risk of invasive pneumococcal disease (IPD). These findings need to be confirmed in a different population-based study setting.

Objective

We assessed whether serious pneumococcal disease (SPD), defined as an IPD, pneumococcal pneumonia, or both, was associated with asthma status.

Methods

This is a retrospective case-control study using criteria-based methods for ascertaining SPD, as well as asthma. Subjects were residents of Rochester, Minnesota, who had SPD between 1964 and 1983 (the primarily pre–pneumococcal vaccine era) and their age- and sex-matched control subjects using 1:2 matching. Potential cases and control subjects were identified by using the Rochester Epidemiology project database and confirmed by medical record reviews. All cases and control subjects were merged with the database comprising the entire pool of Rochester residents with and without asthma between 1964 and 1983.

Results

A total of 3941 records of potential patients with SPD were reviewed, and we identified 174 cases of SPD (51% male subjects and 94% white subjects). SPD was associated with a history of asthma among all ages (odds ratio, 2.4; 95% CI, 0.9-6.6; P = .09) and among adults (odds ratio, 6.7; 95% CI, 1.6-27.3; P = .01), controlling for high-risk conditions for IPD and smoking exposure. The population-attributable risk percentage was 17% in the adult population.

Conclusion

Adults with asthma might be at increased risk of SPD.

Key words: Asthma, invasive pneumococcal disease, epidemiology, risk, microbial infection, pneumococcal pneumonia, adults, Rochester Epidemiology Project

Abbreviations used: ICD, International Classification of Diseases, IPD, Invasive pneumococcal disease, OR, Odds ratio, PAR%, Population attributable risk percentage, SPD, Serious pneumococcal disease