A propensity-score matching study being presented at the CHEST Annual Meeting 2019 found that asthma is associated with decreased mortality in patients admitted to the hospital with myocardial infarction.
Researchers used the 2016 National Inpatient Sample to identify admissions for myocardial infarction as the primary diagnosis and included 12,926 patients with (n=6,463) and without (n=6,463) asthma.
Compared with those without asthma, patients with asthma were more likely to be male (42.1% vs. 44.6%; P=0.005), have ST-elevation myocardial infarction (STEMI; 18.5% vs. 20.0%; P=0.038) and percutaneous coronary intervention (PCI; 39.6% vs. 41.6%; P=0.019), have a lower prevalence of cancer (3.8% vs. 3.0%; P=0.15), and have slightly lower Elixhauser (10 vs. 9; P=0.017) and Charlson Comorbidity Index (CCI; 3 vs. 3; P=0.001) scores. There were no differences observed in age, race, hypertension, dyslipidemia, diabetes, smoking, drug use, HIV, anemia, peripheral vascular disease, chronic kidney disease, depression, atrial arrhythmias, admission month, weekend admission, or elective admission.
Patients with asthma had reduced inpatient mortality (OR=0.74; 95% CI, 0.62 to 0.89; P=0.001), and this remained unchanged when adjusting for sex, STEMI, PCI, cancer, CCI, and Elixhauser indices (OR=0.80; 95% CI, 0.66 to 0.97; P=0.025).
The researchers observed no interaction between asthma and sex (P=0.33) or type of myocardial infarction (P=0.69) with regard to mortality. There was also no difference in hospital length of stay (4 vs. 4 days; P=0.82) or total inpatient costs ($36,513 vs. $36,259; P=0.34) between the asthma and non-asthma cohorts.
The researchers noted that prior evidence suggests that the T-helper 2 immunopathology that is attributed to asthma may be protective against atherosclerosis and myocardial infarction, and other mechanisms associated with asthma may protect against adverse cardiac remodeling after myocardial infarction; this study appears to support previous findings.
“Understanding the immunopathology of asthma may provide mechanistic clues to improve outcomes in patients with myocardial infarction,” the authors concluded.
Tashtish N, Al-Kindi S, Yaqoob Z, et al. Asthma is associated with lower risk of mortality in patients admitted with acute myocardial infarction. Presented at the CHEST Annual Meeting 2019. October 19-23, 2019; New Orleans, Louisiana.