Burden of asthma with elevated blood eosinophil levels

Abstract

BackgroundAsthma is a common chronic condition with an economic burden of almost $56 billion annually in the US. Biologic markers like blood eosinophils, that help predict the risk of exacerbation could help guide more optimal treatment plans and reduce cost. The purpose of this study was to determine whether healthcare resource use and expenditures vary by eosinophil level among patients with asthma.MethodsPatients with a diagnosis of asthma defined by ICD-9-CM code 493.xx between January 2004 and July 2011 were extracted from EMRClaims + database (eMAX Health, White Plains NY). Patients were classified as mild, moderate, or severe by medication use following diagnosis, based on recommendations of National Institutes of Health Expert Panel Report 3. Patients were classified as those with elevated eosinophils (≥400 cells/μL) and normal eosinophil level (<400 cells/μL). Patients were followed for resource use, defined as hospitalizations, ER visits and outpatient visit and associated costs were calculated to assess whether an economic difference exists between eosinophil groups. Non-parametric tests were used to compare resource use and associated cost between elevated and normal eosinophil groups. Multivariate modeling was performed to assess the contribution of eosinophil level on the likelihood of study outcomes among patients with severe asthma.ResultsAmong the 2,164 patients meeting eligibility criteria, 1,144 had severity designations. Of these, 179(16 %) of patients had severe asthma of which 20 % (n = 35) had elevated eosinophils. Seventeen percent of patients with elevated eosinophils were admitted to the hospital during the follow-up period, significantly greater than patients with normal eosinophil levels (12 %; p = 0.011). Overall, compared to patients with normal eosinophil levels (n = 1734), patients with elevated eosinophil levels (n = 430) had significantly greater mean annual hospital admissions (0.51 vs. 0.21/year, p = 0.006) and hospital costs (2,536 vs. $1,091, p = 0.011). Logistic regressions showed that elevated eosinophil level was associated with 5.14 times increased odds of all cause admissions (95 % CI:1.76–14.99, p = 0.003) and 4.07 times increased odds of asthma related admissions (95 % CI: 1.26–13.12, p = 0.019).ConclusionEosinophil elevation was associated with greater healthcare resource use in patients with asthma.

Health care resource utilization and characteristics of patients with eosinophilic asthma in secondary health care in Finland

“…As early as 1975, Horn et al [15] observed that increased blood eosinophil counts correlate with increasing airway obstruction in patients undergoing a pulmonary function test. Since then, several observational studies have also revealed that increased blood eosinophils are associated with more severe airflow obstruction [16], more severe exacerbations [17–20], lower odds of achieving asthma control [17–19,21], and increased hospital costs [22,23]. Patients with eosinophilic inflammation generally respond well to inhaled corticosteroid.…”

Point-of-care blood eosinophil count in a severe asthma clinic setting

“…Disclosures: Authors have nothing to disclose. outcomes, after inhaled corticosteroid or targeting of airway eosinophilia by biologic agents 17,19 ; this makes the blood eosinophil count a feasible marker for monitoring severe asthma.…”

Mechanisms and Management of Asthma Exacerbations

“…x10 9 /ml independently predicted exacerbation risk with an odds ratio of 1.31 (95%CI 1.07 to 1.6) (44). This remained an independent predictor for exacerbations, even in those with poor asthma symptom control (45), and showed the strongest association with the most severe exacerbations that result in hospital admission (odds ratio; 5.14, 95%CI, 1.76 to 14.99) (46). Combining elevated blood eosinophils together with exhaled nitric oxide may further define those at greatest risk of future asthma exacerbations (47).…”