Serum acylcarnitine to amide ratio as a predictive biomarker for the progression of pulmonary disease caused by <i>Mycobacterium avium</i> Complex

<title>Extract</title> <italic>Mycobacterium avium</italic> complex pulmonary disease (MAC-PD) is increasingly recognized as a clinically burdensome infection with substantial heterogeneity in its clinical course, particularly among individuals with non-cavitary disease, who often present with mild radiological findings that differ markedly in their progression. The need for early risk-stratification biomarkers remains a major challenge [1–3]. Current predictors, including acid-fast bacilli smear status, erythrocyte sedimentation rate (ESR), and BACES (body mass index, age, cavity, erythrocyte sedimentation rate, and sex) score, have limited capacity to distinguish rapid progressors (RP) from non-progressors (NP) at the time of diagnosis. Given that metabolomic shifts reflect the downstream effects of inflammatory and metabolic stress responses, we hypothesized that specific serum lipid signatures measured at diagnosis could identify patients at risk for early disease acceleration.