Goldberg Shmuel, Schwartz Shepard, Izbicki Gabriel, Hamami Ronit Belisha, Picard Elie
Department of Pediatric Pulmonology, Pediatric Respiratory Medicine, Shaare Zedek Medical Center, PO Box 3235, Jerusalem 91301, Israel.
Chest. 2005 Oct;128(4):2408-11. doi: 10.1378/chest.128.4.2408.
The exercise test is one of the most widely used challenge tests for asthma. It is not clear if the sensitivity of this test is lower when patients with asthma are not symptomatic. Since asthma activity is season dependent, with lower activity in the summer, we sought to determine if the percentage of positive exercise test results for asthma is lower in the summer as well.
In this retrospective study, the proportion of positive exercise test results for asthma during each of the four seasons of the year, over a 5-year period, was compared.
The study was conducted at the pediatric respiratory clinic and pulmonary function laboratory of Shaare Zedek Medical Center.
The study group consisted of 532 consecutive patients, all 17 years of age, who were referred for exercise testing for evaluation of suspected asthma. All had normal baseline FEV1 levels, and none received maintenance asthma treatment.
Spirometry was performed before and after a standard exercise regimen. A decrease of > or = 10% in FEV1 after exercise was considered positive; 141 patients (26%) had a positive test result. The percentage of positive results in the summer (July to September quartile) was 12.9%, less than half the percentage of positive results during any of the other three quartiles (January to March, 28.9%, p < 0.05; April to June, 30.6%, p < 0.05; October to December, 29.1%, p < 0.05).
This study shows that the percentage of positive exercise challenge test results in the summer is half that of any other season. It is likely that the lower percentage of positive results for asthma in the summer reflects the lower sensitivity of the test during this season due to decreased asthma activity. We suggest performing exercise challenge testing only when patients are symptomatic. Physicians caring for patients with symptoms suggestive of exercise-induced asthma whose exercise test results are negative while asymptomatic should consider repeat exercise testing when their patients are symptomatic.
运动试验是哮喘最常用的激发试验之一。目前尚不清楚当哮喘患者无症状时该试验的敏感性是否较低。由于哮喘活动具有季节依赖性，夏季活动水平较低，我们试图确定夏季哮喘运动试验阳性结果的比例是否也较低。
在这项回顾性研究中，比较了5年期间一年四个季节中每个季节哮喘运动试验阳性结果的比例。
该研究在沙雷兹德克医疗中心的儿科呼吸诊所和肺功能实验室进行。
研究组由532例连续患者组成，均为17岁，因疑似哮喘接受运动试验评估。所有患者基线FEV1水平正常，均未接受哮喘维持治疗。
在标准运动方案前后进行肺功能测定。运动后FEV1下降≥10%被视为阳性；141例患者（26%）试验结果为阳性。夏季（7月至9月季度）阳性结果的比例为12.9%，不到其他三个季度中任何一个季度阳性结果比例的一半（1月至3月，28.9%，p<0.05；4月至6月，30.6%，p<0.05；10月至12月，29.1%，p<0.05）。
本研究表明，夏季运动激发试验阳性结果的比例是其他任何季节的一半。夏季哮喘阳性结果比例较低可能反映了由于哮喘活动减少，该季节试验的敏感性较低。我们建议仅在患者有症状时进行运动激发试验。对于有运动性哮喘症状提示但无症状时运动试验结果为阴性的患者，医生应考虑在患者有症状时重复进行运动试验。
