Comparison of clinical features in patients with pulmonary Mycobacterium-avium complex (MAC) disease treated before and after proposal for guidelines.

We aimed to investigate the transitional pattern of the clinical features of pulmonary Mycobacterium-avium complex (MAC) disease, especially with regard to the clinical effect of treatment, in patients treated before and after the implementation of the 1998 guidelines of the Japanese Society for Tuberculosis for combined chemotherapy for pulmonary MAC disease. The clinical findings and treatments of 220 patients with pulmonary MAC disease during the past 10 years were compared by dividing the patients into two groups, each encompassing a 5-year period. During the past 5 years, we have carried out combined chemotherapy with rifampicin, ethambutol, an aminoglycoside (streptomycin or kanamycin), and clarithromycin (CAM) following the guidelines for the treatment of pulmonary MAC disease proposed in 1998, and we have achieved positive results; both the sputum conversion rate and clinical improvement of the outcome in patients with primary infectious type rose significantly. Although there were no significant differences in the background or in microbiological and radiological findings in the two groups, significant improvement was seen in the sputum conversion rate and in improvement of the clinical effect of treatment. The results of this combined chemotherapy were unsatisfactory, however, when compared with its clinical effect on pulmonary tuberculosis. Therefore, we anticipate the development of new companion drugs for pulmonary MAC disease that are as active as CAM.