Usefulness of the C-reactive Protein Level as a Substitute for the Erythrocyte Sedimentation Rate when Calculating the BACES Score of Patients with Mycobacterium Avium Complex Pulmonary Disease.

Objective　The BACES score is calculated based on the body mass index, age, presence of cavity, erythrocyte sedimentation rate (ESR), and sex, and it is used to predict the overall and respiratory-related mortality risks in patients with nontuberculous mycobacterial pulmonary disease. ESR and C-reactive protein (CRP) levels are commonly used to assess inflammation. In this study, we aimed to evaluate the usefulness of the CRP level as a substitute for ESR when calculating the BACES score. The scores determined using this substitution are referred to as the BACCS scores.Methods　We retrospectively evaluated the medical records of 195 patients (median age, 64 years; 47 (24.1%) patients were male) with Mycobacterium avium complex (MAC) pulmonary disease who presented to our hospital between 2003 and 2019. We compared the prognostic performance of the BACCS and BACES scores for all-cause and MAC-specific mortalities.Results　According to the BACCS score, 102 (52.3%),75 (38.5%), and 18 (9.2%) patients comprised the low-, moderate-, and high-risk groups, respectively. All-cause mortality significantly differed between the low- and moderate-risk and low- and high-risk groups. The C-indices for all-cause mortality were 0.79 (95% CI, 0.73-0.86) and 0.78 (0.72-0.85) for the BACCS and BACES scores, respectively, and for MAC-specific mortality, 0.87 (0.80-0.93) and 0.84 (0.75-0.92), respectively.Conclusion　The BACCS score may serve as a practical alternative to the BACES score in routine clinical settings.