Systematic Review On The Correlation Between Lung Function Or Eosinophil Levels And Health Care Resource Utilization In Asthma


      Asthma is a very common chronic disease that can cause a significant economic burden. The objective of this review was to explore the evidence on the possible correlation between lung function or eosinophil levels and resource utilization in asthmatic patients.


      A literature search was made using keywords such as “asthma”, “eosinophil”, “respiratory function”, “resources”, and “costs”. The search was conducted in the electronic databases MEDLINE, EMBASE and PubMed from January 2000 to February 10th, 2015. To be eligible, studies had to focus on asthmatic patients, include pulmonary or eosinophil measurements, and resource utilization data.


      The review allowed retrieving 4,768 studies and 11 fulfilled the eligibility criteria. Two articles presented their results in terms of correlation coefficient that were all statistically significant. The first one determined a correlation between FEV1 and inhaled corticosteroids (ICS) use with an R-value of -0.42 and between sputum eosinophils and ICS use with an R-value of 0.3. The second article evaluated the correlation between PEF and hospitalization rates and concluded to a correlation with an R-value of -0.51. A total of 9 articles presented raw data that could be used to establish a correlation between lung function or eosinophil levels and resource utilization. Seven studies presented data that indicate an inverse correlation between FEV1 and hospitalizations with decreased hospitalization rates, when FEV1 increases. Three studies indicate decreased emergency departments visit rates when FEV1 increases. Two studies also indicate an increased emergency department visit rates, when blood eosinophil levels increase.


      The correlation coefficients found in the systematic review indicate that when lung function improves or sputum eosinophil decreases, the resource utilization decreases. Furthermore, non-correlation studies that look at the same parameters support this hypothesis and suggest there may be a correlation between emergency department’s visits and blood eosinophil levels.