Author + information
- Katherine L. Bailey, BS,
- Aditya Mantha, BS, MS,
- Yas Sanaiha, MD,
- Lauren Mathias, MD,
- Peyman Benharash, MD and
- Ramin Ebrahimi, MD∗ (, )@LosAngelesVA
- ↵∗Greater Los Angeles VA Medical Center, 11301 Wilshire Boulevard, Los Angeles, California 90073
Inflammatory autoimmune conditions are associated with accelerated atherosclerosis and increased risk of cardiovascular disease (1,2). Autoimmune vasculitides (AVs) are characterized by immune-mediated inflammation leading to ischemia of dependent tissue. Coronary artery involvement in these disorders poses risk of myocardial infarction requiring revascularization by percutaneous intervention (PCI) (3,4).
Readmission following PCI is a major quality indicator, and data regarding PCI outcomes in patients with AV is generally lacking. The present study assessed the influence of AV on 30-day readmission among patients undergoing PCI.
Adults undergoing PCI were identified with the International Classification of Diseases-9th Edition-Clinical Modification system (ICD-9-CM) (00.66) in the 2010 to 2014 National Readmissions Database. AV conditions included polyarteritis nodosa, hypersensitivity vasculitis (HV), granulomatosis with polyangiitis, giant cell arteritis, thrombotic angiitis, Takayasu arteritis, Goodpasture syndrome, and Kawasaki disease (ICD-9-CM 446.0 to 446.7). Patients undergoing isolated PCI between January and November from 2010 to 2014 were enrolled to enable 30-day follow-up. Patients who underwent concomitant surgery were excluded from analysis.
The primary outcome was 30-day readmission defined as inpatient admission to a hospital within the Healthcare Cost and Utilization Project sample. Secondary outcomes included in-hospital mortality, length of stay (LOS), index cost, readmission LOS, and readmission cost. Multivariate linear and logistic regression analyses were used to adjust for demographics including age, sex, income quartile, health insurance, and comorbidities using the Elixhauser Index. Hospital characteristics included in the models were bed size, teaching status, and geographic population density. A p value of <0.05 was defined as statistically significant. Data analysis was performed with STATA version 14.0 software (StataCorp, College Station, Texas). The Institutional Review Board of the University of California, Los Angeles exempted this study.
Of the 2,465,697 patients undergoing PCI, 2,350 (<1%) had AV. The most common diagnoses among AV patients were giant cell arteritis (n = 1,138), granulomatosis with polyangiitis (n = 566), and HV (n = 171) (Table 1). AV patients were more likely to be older (69.5 vs. 64.8 years of age; p < 0.001), female (53% vs. 33%; p < 0.001), with higher comorbidity score (4.7 vs. 2.9; p < 0.001). Congestive heart failure (30% vs. 19%; p < 0.001), pulmonary disease (17% vs. 13%; p < 0.001), and chronic kidney disease (31% vs. 14%; p < 0.001) were also more prevalent in AV versus non-AV patients.
Unadjusted results revealed 30-day readmission (20.8% vs. 12.1%; p < 0.001), index LOS (5.8 vs. 3.7 days; p < 0.001), and index costs ($27,551 vs. $21,927; p < 0.001) to be higher in AV than non-AV patients. In-hospital mortality (3.1% vs. 2.0%; p < 0.05) was increased among AV compared with non-AV patients.
After multivariable adjustment, readmission at 30 days (odds ratio: 1.23; 95% confidence interval: 1.03 to 1.51; p < 0.05) remained higher in the AV versus non-AV cohort. In-hospital mortality, LOS, and cost of the index admission were not significantly different after adjustment. On readmission, AV patients were most commonly diagnosed with angina/chronic ischemia (11%), congestive heart failure (7.9%), peripheral vascular complications (7.2%), and acute myocardial infarction (6.4%). Among AV patients, HV was associated with the highest proportion of 30-day readmission (31%), whereas Kawasaki disease (9%) and Takayasu arteritis (6%) had the least.
To our knowledge, the present study is the largest analysis of outcomes after PCI in the setting of autoimmune vasculitis and reveals several important findings: 1) the 30-day readmission rate was higher in patients with AV compared with non-AV; and 2) in-hospital mortality, index hospitalization cost, and LOS were not significantly different between AV and non-AV groups after adjustment.
Thirty-day readmission rates among AV patients exceeded those reported previously for the general population (5). This may be due to the chronic inflammatory state and its untoward consequences such as diabetes, hypertension, and dyslipidemia. Susceptibility to infection as a result of immune suppressive therapy and overall resultant fragility of such patients may also play a role. Other adverse outcomes associated with AV include aneurysm formation, dissection, aortic incompetence, and stenosis, which exacerbate atherosclerotic disease burden (2). Notably, AV patients presented with a broader spectrum of pathologies on readmission including mesenteric ischemia, cardiomyopathy, and respiratory insufficiency than non-AV patients.
The present study has several important limitations. Follow-up is limited to inpatient readmissions occurring within 1 calendar year, thus creating separate samples from January to November. The NRD lacks disease activity, laboratory, perioperative, and medication usage data, including corticosteroids and systemic immunosuppressant therapy.
AV is associated with an increased 30-day readmission and total cost after undergoing primary PCI. Further investigations are necessary to better understand causes of increased readmission post-PCI in this vulnerable population.
Please note: Dr. Benharash has been a consultant for Baxter. Dr. Ebrahimi has been a consultant to Amarin, Novo Nordisk, and Janssen. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. This work was presented as a moderated poster presentation at Transcatheter Cardiovascular Therapeutics in Denver, Colorado, October 29 to November 2, 2017.
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