[THE RELATIONSHIP AMONG BRONCHIAL HYPERSENSITIVITY, BRONCHIAL HYPER REACTIVITY, AND BRONCHIAL HYPERRESPONSIVENESS IN ASTOGRAPH].

BACKGROUND

Bronchial hyperresponsiveness testing is useful for diagnosing and predicting the risk of bronchial asthma attacks. The Astograph is a tidal breathing method often used in as bronchial provocation testing in Japan. The minimum methachorine dose (Dmin) indicates bronchial sensitivity and is used mainly as an index of bronchial hyperresponsiveness. However, Dmin does not measured hyperresponsiveness, it cannot be compared directly with PC20 in standard methods using FEV1.

METHODS

We investigated the relationship among sensitivity, reactivity, and hyperresponsiveness with the Astograph. We recruited 142 patients with confirmed or suspected bronchial asthma from outpatient clinic at St. Marianna University School of Medicine, Yokohama City Seibu Hospital. We calculated Dmin, SGrs/Grscont, PD35Grs, and PD15Grs compared them as bronchial hyperresponsiveness indices.

RESULTS

Subjects had suspected asthma (n=103), or required assessment of asthma remission (n=39). There were significant relationships between logDmin and logPD35Grs (r=0.838, p<0.001), and between parameters and SGrs/Grscont (log PD35Grs r=-0.504, p<0.001, strong, logDmin: r=-0.191, p=0.023, weaker). Among subjects positive for hypersensitivity, (Dmin<10), 38 (36.5%) showed negative hyperresponsiveness (PD35Grs>25). PD15Grs was a strongly and significantly correlated with Dmin and PD35Grs. The ROC curve to detect PD35Grs<25, showed that the cutoff of PD15Grs was 10.7 (AUC 0.983, sensitivity 0.984, specificity 0.905).

CONCLUSION

In Astograph, evaluation of bronchial hyperresponsiveness, we focused on relationship differences between sensitivity and reactivity, and hyperresponsiveness. We revealed the usefulness of the PD15Grs evaluation method.