Gastroesophageal reflux disease (GERD) and asthma are common as independent conditions, and GERD is present in 34 to 90 percent of patients with asthma. Little is known about the way these two conditions co-exist or the way GERD exacerbates asthma. Various antireflux treatments, including medical and surgical management, have been shown to improve asthma control in some patients. Multiple tests are available to confirm a diagnosis of GERD, including barium radiographs and upper gastrointestinal endoscopy. O'Connor and colleagues evaluated a variety of methods for diagnosing GERD to determine which is most cost-effective.

The study population consisted of middle-aged adults with moderate to severe asthma and heartburn at least once a week. A cost-effectiveness analysis was performed on 11 different diagnostic strategies using a combination of 24-hour pH monitoring and omeprazole therapy, or omeprazole alone. The strategies were divided into three categories: pH testing followed by omeprazole; omeprazole followed by pH testing; and omeprazole alone. In the first category, patients with positive pH test results were given 20, 40 or 60 mg of the study medication daily for three months. During this time, peak expiratory flow (PEF) rates were monitored. If PEF rates did not improve by at least 20 percent, the dosage was increased for the next three months. PEF rate improvements of 20 percent or more were considered a positive response to treatment in all three groups. In the second category, patients were given 20 or 40 mg of omeprazole for three months. If PEF rates improved, GERD was thought to be an exacerbating factor. If their asthma did not respond to the medication, pH testing was done, and the dosage was adjusted for the next three months. In the third category, patients took one of the three dosages of omeprazole for three months. If the asthma did not respond, the dosage was increased to a maximum of 60 mg per day. The outcome measure was inclusion or exclusion of GERD as an exacerbating factor in asthma.

Costs for each strategy included the cost of medication, testing and office visits. Effectiveness for each strategy was defined as the percentage of patients in whom GERD was correctly identified or excluded as an exacerbating factor. The most cost-effective strategy consisted of 20 mg per day of omeprazole for three months, followed by a 24-hour pH test in patients who did not respond to the medication. If the pH test was positive for GERD, the dosage was increased to 40 or 60 mg per day until a response was obtained.

The authors conclude that giving patients 20 mg per day of omeprazole is the most cost-effective way to see if GERD increases asthma symptoms. If the patient does not respond to this management, a 24-hour pH test is indicated to confirm the presence of GERD. If the pH test demonstrates reflux disease, the dosage of omeprazole should be increased up to 60 mg per day.