Clinical

Decline in lung function, impaired response to salbutamol in HCV+ asthmatics

Last Updated: 2004-05-24 12:45:17 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Chronic infection with hepatitis C virus (HCV) adversely affects lung function and airway responses to salbutamol in patients with asthma who fail to respond to interferon therapy, report two Japanese researchers in the June 1st issue of the American Journal of Medicine.

Drs. Hiroshi Kanazawa and Junichi Yoshikawa of Osaka City University prospectively followed 75 asthmatic patients for 6 years. Twenty were HCV-negative and 55 were HCV-positive. Of the HCV-positive group, 18 responded to a 6-month course of interferon (6 MIU three times/week) and 37 did not.

One year after interferon therapy, patients were treated in a double blind fashion with inhaled salbutamol (200 �g) or oxitropium bromide (200 �g).

During follow up, only interferon nonresponders showed a "significant decrease" in pre- and post-bronchodilator FEV1, the investigators report. Moreover, only these patients showed a steep decline in reversibility with salbutamol during follow up. In contrast, there was a steep increase in reversibility with oxitropium only in interferon nonresponders.

Significantly greater declines in the diffusing capacity of the lung for carbon monoxide were also noted during follow up in interferon nonresponders than in HCV-negative and interferon responders.

"It seems unlikely that interferon therapy directly influenced airway responses to salbutamol or oxitropium apart from its effect on HCV-induced airway responses," Drs. Kanazawa and Yoshikawa write.

"Therefore, our findings suggest that chronic HCV infection is associated with an accelerated decline in lung function and impaired responses to salbutamol in asthmatic patients," they conclude.

Am J Med 2004;116:749-752.