IGAm: A novel index predicting long-term survival in patients with early-diagnosed inherited metabolic disorders

Abstract

Abstract Objectives The childhood mortality rate for IMDs is approximately 25 % in populations with no expanded newborn screening program. Although the factors that increase mortality risk are known, an index predicting long-term survival has yet to be established. Methods Two hundred sixty patients who were hospitalized during the first month of their life were screened, and 94 patients diagnosed with IMDs were included in the study. Clinical and laboratory data were assessed to identify any independent prognostic factors for overall survival. Results Among the 38 patients with IMDs in the exitus group, the presence of dysmorphism, extremity abnormalities, respiratory distress, cyanosis, elevated transaminases, elevated INR, hypoglycemia, hypoalbuminemia, metabolic acidosis, electrolyte imbalance and anemia were associated with poorer survival. Elevated INR (Hazard Ratio [HR]: 0.17, 95 % CI: 0.03–0.87, p=0.034), hypoglycemia (HR: 0.48, 95 % CI: 0.25–0.91, p=0.026) and hypoalbuminemia (HR: 0.09, 95 % CI: 0.03–0.26, p<0.001) were the independent prognostic factors for survival after adjusting for confounding factors. For the prediction of survival, INR, glucose, and albumin were used to structure a novel index (IGAm = INR-Glucose-Albumin metabolic index). The median survival was shorter in the IGAm-high group (2 or 3 points) than in the IGAm-low group (p<0.001). Harrell’s c-index was 0.73 for the IGAm index. Conclusions The devised novel IGAm index can predict long-term survival in patients with IMDs, with a high IGAm index being associated with higher mortality in patients with IMDs.