Asthma and High Healthcare Use

Nicholas J. Gross, MD, PhD


November 05, 2010

Burden of Comorbidity in Individuals with Asthma

Gershon AS, Wang C, Guan J, To T
Thorax. 2010;65:612-618

Study Summary

It is well known that patients who have asthma use significant amounts of healthcare, including hospitalizations and unscheduled emergency department or clinic visits. However, asthma is also commonly associated with comorbidities such as obesity and depression, which are often unrecognized and may contribute to high utilization of healthcare.

Investigators in Ontario, Canada, sought to quantify the additional healthcare use related to comorbidities of patients with asthma, on the basis of national health administration data. Because residents of Canada have universal healthcare coverage, data on hospitalizations, emergency department visits, and clinic visits, and the primary complaint resulting in these visits were available. From those data, healthcare use for non-asthma events in patients with asthma was compared with that of patients without asthma.

The investigators found that individuals with "active" asthma had 200 claims per 100 individuals per year for asthma and an additional 1616 claims per 100 individuals per year for non-asthma problems. (The actual diagnoses of the nonasthmatic events were not stated.) They also had 68 emergency department visits and 26 hospitalizations per 100 individuals per year for non-asthma conditions. In comparison, patients without asthma made 942 claims for non-asthma events (58% of the number for asthmatics), 33 emergency department visits (49%), and had 16 hospitalizations (62%). Individuals whose asthma was considered "less active" used healthcare for non-asthma problems at a rate that was intermediate between that of active asthma patients and the patients without asthma. The investigators' conclusion was that "asthma comorbidity places a significant burden on individuals and the healthcare system and should be considered in the management of asthma."


Unlike in other chronic diseases such as coronary artery disease and diabetes, comorbidities tend to be overlooked in asthma, possibly because the asthma population is younger and is assumed to be relatively free of comorbidities. Yet this study finds that healthcare utilization for non-asthma reasons is almost twice as common in patients with asthma as in matched patients with other diagnoses. Gershon and colleagues suggest that comorbidities are the reason that people with asthma seek more healthcare, although alternative explanations are offered. A detailed accounting of the problems that led to the extra healthcare use would have strengthened their case and would probably point to problems associated with asthma that require extra vigilance. Perhaps a follow-up study will report those data.

I agree that comorbidities should be more frequently sought in patients with asthma. Most asthma is not optimally controlled, although we have excellent drugs, and this tends to be the case in Canada as well as in the United States.[1] Gershon and colleagues list some commonly overlooked comorbidities linked with asthma -- obesity, depression, sleep disturbances, related allergic disorders, and the adverse events associated with some asthma treatments, particularly long-term corticosteroid use. The strict adherence to treatment guidelines[2] for asthma itself should also be stressed, because poor compliance is a major reason for loss of asthma control.

Studies on common diseases that involve large numbers of patients are readily feasible in Canada where most of the population is covered by and receives all of its healthcare from the government, and where electronic medical records are the norm. In addition, the province of Ontario has a diverse but relatively stable population, making it a very suitable site for studies of the type reported here. Given the otherwise similar medical practices in Canada and the United States, the present findings are probably applicable to the US population as well.



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