Asthma as a Risk Factor for Invasive Pneumococcal Disease

The risk of invasive pneumococcal disease among persons with asthma is unknown. An estimated 7 percent of Americans suffer from asthma and as the prevalence of this disease increases, its association with pneumococcal disease becomes more important. This study examines the connection between the two conditions. For the purpose of the study, asthma was divided into low-risk (not requiring admission to hospital) and high-risk asthma (requiring admission to a hospital or emergency department and long-term use of asthma-related medication). A total of 635 people aged 2 to 49 years with invasive pneumococcal disease were identified and 6,350 controls. Of these, 114 and 518, respectively, had asthma.

The key findings of the study were:

  • Persons with asthma had an increase by more than a factor of two in the risk of invasive pneumococcal disease even after adjustment for other risk factors.
  • Among those without coexisiting conditions, the annual incidence of invasive pneumococcal disease was 4.2 episodes per 10,000 people with high-risk asthma and 2.3 episodes per 10,000 people with low-risk asthma, as compared to 1.2 episodes per 10,000 people without asthma.