Development and validation of a prognostic scoring model for Mycobacterium avium complex lung disease: an observational cohort study

Abstract

BackgroundPatients with Mycobacterium avium complex (MAC) lung disease (LD) have a heterogeneous prognosis. This study aimed to develop and validate a prognostic scoring model for these patients using independent risk factors for survival.MethodsWe retrospectively analyzed the data of patients with MAC-LD from two hospitals (cohort 1, n = 368; cohort 2, n = 118). Cohort 1 was evaluated using a multivariate Cox proportional hazards model to identify independent risk factors for overall survival (OS). A prognostic scoring model composed of these factors was developed, and cohort 1 was stratified into three groups according to risk using the log-rank test. Finally, the prognostic scoring model was validated using the data of cohort 2.ResultsSeven independent risk factors for OS were selected from cohort 1, including the male sex, age ≥ 70 years, the presence of a malignancy, body mass index <18.5 kg/m2, lymphocyte count <1000 cells/μL, serum albumin levels <3.5 g/dL, and fibrocavitary disease. The areas under the receiver operating characteristic curves for the prognostic scoring model were 0.84 [95% confidence interval (CI), 0.80 − 0.89] for cohort 1 and 0.84 (95% CI, 0.75 − 0.92) for cohort 2. The 5-year OS rates of patients stratified into low-risk, intermediate-risk, and high-risk groups were 97.6, 76.6, and 30.8%, respectively (P < 0.001), in cohort 1, and 97.2, 82.3, and 45.4%, respectively (P < 0.001), in cohort 2.ConclusionsThis study is the first to develop and validate a prognostic scoring model for patients with MAC-LD. This model may prove useful in clinical settings and practical in estimating the prognosis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2544-0) contains supplementary material, which is available to authorized users.

The Rise of Non-Tuberculosis Mycobacterial Lung Disease

“…Predictors of high mortality included male gender, presence of comorbidities, and fibro cavitary disease. These findings have been validated in other studies that showed that male patients, with fibro cavitary disease, low BMI and malignancy were prognostic indicators of poor clinical outcome (41,119,120). In addition, patients with persistent infection (those who remain culture positive despite 12 months of treatment) have higher rates of death attributable to NTM infection compared to those who manage to clear NTM in the sputum (34).…”

Characteristic chest CT findings for progressive cavities in Mycobacterium avium complex pulmonary disease: a retrospective cohort study

“…The progression of the cavity leads to destruction of the lungs, which results in respiratory failure and poor prognosis. Unlike previous studies [6][7][8][9] that assessed prognostic factors but yielded recommendations that were somewhat complicated to apply in daily clinical practice, our results indicate that the combination of two simple findings can predict disease Fig. 2 Rates of progressive cavities stratified by maximum inner diameter and consolidation around the initial cavity.…”

“…Poor prognostic factors for MAC-PD include old age, low body mass index (BMI), low lung function, anemia, high blood deposition, malignancy, and hemosputum. Notably, the presence or absence of cavities is the most important factor [6][7][8][9]. Enlarged progressive cavities destroy lungs, leading to respiratory failure and poor prognosis [10,11].…”

Treatment of Mycobacterium avium Complex (MAC)

“…That decision is not difficult for cavitary MAC-LD patients because of the clear risk for disease progression and associated morbidity and mortality associated with cavitary MAC-LD. [15][16][17][18][19][20] Therefore, the risk/benefit evaluation unambiguously favors initiating therapy at the time cavitary MAC-LD is diagnosed. For patients with NB MAC-LD, that decision is not as straightforward and requires a more deliberate approach.…”

“…Those NB MAC-LD patients not started on therapy must be followed up indefinitely as there is mounting evidence for significant risk of MAC-LD-associated morbidity and mortality in patients not started on antimycobacterial therapy. 18,[21][22][23][24] There are few objective markers of MAC-LD disease progression. A recent study compared the clinical characteristics of MAC-LD patients who had a progressive course resulting in treatment initiation within 3 years of diagnosis with patients who exhibited a stable course for at least 3 years.…”