Pneumonia in young adults with asthma: impact on subsequent asthma exacerbations

Background: Recent studies of community-acquired pneumonia (CAP) have recognized acute cardiac complications-such as myocardial infarction, arrhythmia, or congestive heart failure (CHF)-as frequent complications during the acute process. As well, a prolonged vulnerability to exacerbations of underlying comorbidities-such as CHF and COPD-has been observed following CAP. We hypothesized that young adults with underlying asthma could also be adversely impacted over a prolonged time period following CAP. Methods: Using a retrospective matched-cohort design and data from a US private healthcare claims repository (>15 M persons annually), we selected all adults 18-49 years of age with evidence of asthma as their only comorbidity for inclusion in the source population. Then, from the source population, we matched one comparison patient to each CAP patient based on index date, age, sex, and selected markers for health status (eg, history of asthma-related healthcare encounters), and evaluated subsequent outpatient and inpatient encounters for asthma exacerbations. Results: Asthma exacerbations were identified twice as often in the 12 months subsequent to acute CAP. Cumulative incidence proportions for asthma exacerbations requiring hospitalization or emergency department care after 12 months of follow-up were 19.9% for those previously hospitalized with CAP versus 9.0% for matched comparison patients (difference, 10.9%; p<0.001), and were 12.4% for non-hospitalized CAP patients versus 7.7% for matched counterparts (difference, 4.7%; p<0.001). Conclusion: Our analysis provides further evidence that acute CAP has a prolonged impact on respiratory health.