Clinical significance of the radiological severity score in Mycobacterium avium complex lung disease patients

SETTING: Practical methods for assessing the radiographic findings of Mycobacterium avium complex lung disease (MAC-LD) have not been established.

OBJECTIVE: To identify a correlation between the radiological score and semi-quantitative culture results of respiratory samples, and to assess the prognostic impact of this radiological score in MAC-LD patients.

DESIGN: We retrospectively studied 218 MAC-LD patients. Radiographic findings were classified as nodule (N), infiltration shadow (I), cavity (C) and bronchiectasis (E), scored individually according to the area occupied on six lung field divisions, and added to give the radiological severity score.

RESULTS: The radiological score positively correlated with the semi-quantitative culture score (P = 0.003). In univariate analysis, the radiological score was a significant negative prognostic factor for overall survival. On multivariate analysis, factors I, C and E were independent negative prognostic factors for overall survival. We compared the prognostic value of the total score of all four factors and the three significant factors (I, C and E) using receiver operating characteristic curve analysis; the corresponding areas under the curves were respectively 0.628 and 0.763 (P < 0.001).

CONCLUSIONS: The radiological score correlates with prognosis. The combined score of factors I, C and E may more accurately predict prognosis in MAC-LD patients.