Rheumatoid arthritis is associated with increased in-hospital mortality in asthma exacerbations: a nationwide study

The relationship between RA and asthma has been yielding conflicting results, with most recent studies showing a possible positive association. The study aims at the outcomes of adult patients hospitalized for asthma exacerbation in those with and without RA. We used data from the National Inpatient Sample (NIS) for the period of 2012–2014. ICD 9 code was used to identify the diagnosis. Our primary outcome was in-hospital mortality. Our secondary outcome was total asthma exacerbation hospitalizations, length of stay, and total hospital charges. Compared to those without RA, RA was associated with increased hospitalizations for asthma exacerbation (unadjusted OR 1.29, p < 0.001; adjusted OR 1.06, p = 0.002), more respiratory and systemic comorbidities, increased in-hospital mortality (unadjusted OR 1.89, p = 0.001; adjusted OR 1.60, p = 0.020), length of stay (4.5 vs 3.8; unadjusted p < 0.001, adjusted p < 0.001), and total hospital charges (30,149 vs 26,247; unadjusted p < 0.001, adjusted p = 0.048). Our study was the first to demonstrate that RA is associated with increased in-hospital mortality, length of stay, and cost using a national inpatient database. We hypothesize that in asthmatic patients with concurrent RA, their asthma may represent a distinctive subgroup that is more severe and carries a poorer prognosis, which deserves more attention and future investigation.