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Researchers examine variations in asthma medication use

Asthma is more prevalent and usually less well-controlled among poor children, especially among racial and ethnic minorities. In fact, underuse of recommended antiinflammatory medications to control persistent asthma (controller medications) is widespread among poor children insured by Medicaid managed care plans, according to a study supported by the Agency for Healthcare Research and Quality (HS09935). The researchers also found that underuse of controller medications was less likely when indicators of quality care were present (i.e., usual source of care, specialist care, and a written action plan).

A second AHRQ-supported study (National Research Service Award training grant T32 HS00063) recommends a better way to identify whether patients are being prescribed asthma medication and whether they are using a sufficient amount of the medication. Both studies are described here.

Finkelstein, J.A., Lozano, P., Farber, H.J., and others. (2002, June). "Underuse of controller medications among Medicaid-insured children with asthma." Archives of Pediatric and Adolescent Medicine 156, pp. 562-567.

Antiinflammatory (controller) medications such as inhaled corticosteroids or mast-cell stabilizers are recommended on a regular basis to control persistent asthma. However, these researchers found widespread underuse of these controller medications by Medicaid-insured children, especially those who are black, Hispanic, or have parents with less than a high school education. The researchers surveyed the parents of 1,648 children and adolescents aged 2 to 16 years with asthma, who were insured by one of five geographically dispersed Medicaid managed care plans. The survey included demographic factors, number of symptomatic days in the prior 2 weeks, and medication use. The researchers also identified the child's Physical Function Score on the American Academy of Pediatrics (AAP) Child Health Status Assessment of Asthma.

Children who had asthma symptoms such as cough, wheeze, shortness of breath, or limited activity on 5 or more days during the past 2 weeks and those who were using daily controller medications were considered to have persistent asthma. Guidelines recommend that these children (more than 2 symptom-days per week) use daily controller medications. Of the 1,083 children with persistent asthma, 73 percent underused controller therapy, 49 percent reported no controller use, and 24 percent reported less than daily use.

A model that adjusted for age, managed health care organization, and AAP Physical Function Score found that blacks and Hispanics were at substantially increased risk of underuse of controller medications, and that parental education beyond high school reduced the risk by 40 percent. Children with persistent asthma who were less likely to underuse controller medications were those who had a primary care doctor, a written action plan about which medications to use depending on symptom severity or a followup visit, or had seen an asthma specialist. The underlying reasons for underuse of controller agents remains unclear.

Glauber, J.H., and Fuhlbrigge, A.L. (2002, May). "Stratifying asthma populations by medication use: How you count counts." Annals of Allergy, Asthma, and Immunology 88, pp. 451-456.

It is important to identify asthma patients who overuse bronchodilators that quickly open the airways (an indication that their asthma is not controlled) or underuse antiinflammatory medications (the controller medications of choice) so that they can be targeted for programs to improve their use of controller medications and perhaps avert costly hospital and emergency department use. This study concludes that a novel canister-equivalent method for counting dispensed asthma medications yields different and more accurate profiles of medication underuse than simple asthma medication counts.

The investigators compared two methods for counting the use of bronchodilators and antiinflammatory medication among adult and pediatric asthma patients receiving care at one of 14 health maintenance organization practices. One approach used simple counts of dispensed medication. The alternative, canister-equivalent method standardized these medications based on variation in both potency and medication days supplied per prescription. Inhaled antiinflammatory medications vary in potency, recommended daily dose, quantity of medication per canister, and ultimately in days of medication supplied. Bronchodilators may be administered orally, by metered-dose inhaler, or by nebulizer. The canister-equivalent method determined the days supplied of a particular formulation based on the defined daily dose, that is, the amount of daily medication used at recommended doses.

Relative to simple counts, the canister-equivalent method resulted in a 40 percent increase in the population identified as having high bronchodilator use and chronic antiinflammatory medication use. When stratified by each method, 36 percent of physicians were assigned to different quartiles of the antiinflammatory:bronchodilator prescribing ratio. Specifically, nearly one-fifth of physicians placed in the lowest quartile by the simple-count method, and potentially targeted for educational outreach to improve prescribing, were placed in higher quartiles by the canister-equivalent method.

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