Tolerability and efficacy of Mycobacterium avium complex pulmonary disease treatment in elderly patients.

Background: Mycobacterium avium complex pulmonary disease (MAC-PD) is considered to be increasing worldwide. In Japan, the number of elderly MAC-PD patients requiring treatment is also expected to increase due to the aging society. However, reduced organ function in elderly patients makes it often difficult to continue or complete multidrug treatment due to adverse drug reactions (ADRs). Therefore, this study aimed to identify clinical factors associated with treatment tolerability, efficacy, and ADRs in elderly MAC-PD patients.

Methods: We retrospectively reviewed the medical records of 102 patients with MAC-PD aged ≥ 75 years between January 2014 and March 2023. Forty-six patients were treated with multidrug regimens (treatment group), and 56 were observed without treatment (observation group). The treatment group was divided into the treatment continuation group (n = 28) who were treated without interruption for ≥ 12 months, and the treatment interruption group (n = 18). A comparative study was conducted in each group to examine tolerability, efficacy, and ADRs.

Results: A two-drug regimen of ethambutol (EB) and macrolides without rifampicin (RFP) was associated with treatment continuation (p = 0.026). The treatment continuation group was superior to the observation group regarding symptoms change, sputum conversion rate, and chest computed tomography scores. The most common ADRs were gastrointestinal disorders, which may be related to RFP. Treatment efficacy of the two-drug regimen was non-inferior, and no cases of macrolide resistance were observed.

Conclusions: The two-drug regimen of EB and macrolide without RFP may be a tolerable and effective treatment for elderly MAC-PD patients.