Concomitant chronic pulmonary diseases and their association with hospital outcomes in patients with anaphylaxis and other allergic conditions: a cohort study

OBJECTIVES To determine if chronic pulmonary diseases adversely impact selected outcomes in hospitalised patients who have various allergic conditions including anaphylaxis. DESIGN A population-based cohort study. PARTICIPANTS A statewide hospital inpatient discharge database from Texas, USA, covering the years 2004-2007 was analysed. Patients with anaphylaxis and other allergic conditions were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Within each group of patients (the overall group with various selected allergic conditions and the subgroup with anaphylaxis), the exposure variables were 11 chronic pulmonary diseases including asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. PRIMARY OUTCOME MEASURES Admission to an intensive care unit, a prolonged (>3 days) hospital stay, receipt of mechanical ventilation and death in hospital. Logistic regression was used to calculate adjusted OR and 95% CI for these four outcomes. RESULTS 30 390 patients with allergic conditions were identified, of whom 2410 had anaphylaxis. The following results pertain to the subcohort of patients with anaphylaxis. Median age was 50 years (range 0-95 years) and 1470 (61%) were female. The hospital mortality was 2.7%. Although asthma was not associated with hospital mortality (OR=1.27, 95% CI 0.55 to 2.90), asthmatics had more than twice the odds of non-asthmatics of receiving mechanical ventilation (OR=2.45, 95% CI 1.81 to 3.33). Chronic bronchitis, COPD, emphysema and interstitial lung diseases (ILDs) were also associated with an increased risk of requiring mechanical ventilation. Chronic bronchitis and COPD were associated with a prolonged length of stay: OR=2.69 (95% CI 1.45 to 4.98) and OR=1.86 (95% CI 1.30 to 2.66), respectively. ILD was the only chronic pulmonary disease associated with an elevated risk of hospital mortality: OR=8.71 (95% CI 1.48 to 51.20). CONCLUSIONS In this unique analysis of a large database, we found that asthma, COPD and other chronic pulmonary diseases increased the risk of adverse outcomes among hospitalised patients with anaphylaxis.