Factors influencing in-hospital death for pediatric patients with isolated methylmalonic acidemia: a nationwide inpatient database analysis

BACKGROUND: Patients with isolated methylmalonic acidemia (MMA) usually experience recurrent episodes of acute metabolic decompensation or metabolic stroke, require frequent hospitalization, and have a relatively high mortality rate. The aim of our study was to assess factors predicting the in-hospital death of pediatric patients with isolated MMA. We performed a retrospective study using data from the Hospital Quality Monitoring System, a national inpatient database in China collected from 2013 to 2017. All patients under 18 years old with a diagnosis of isolated MMA were included. Demographic, hospital-related, and clinical features were collected. Poisson regression was performed to identify potential influencing variables associated with in-hospital death. RESULTS: From 2013 to 2017, among 2317 admissions for pediatric patients diagnosed with isolated MMA, 1.77% had the outcome of death. In the univariate analysis, patients aged under 1 year had a higher risk of death than did those aged 1 year or older (odds ratio [OR] = 2.63, 95% confidence interval [CI]: 1.36–5.07). There was a higher risk of in-hospital death for patients admitted through emergency departments or via referrals than for those admitted through other routes (OR = 3.76, 95% CI: 1.84–7.67). Deaths were higher in hospitals with volumes of less than 50 patients with isolated MMA during the five study years (OR = 2.92, 95% CI: 1.46–5.83). Moreover, the risk of in-hospital death gradually decreased over time (OR = 0.72, 95% CI: 0.57–0.90). In the multivariate analysis, the abovementioned associations with the risk of in-hospital death remained statistically significant. However, no significant associations were observed between specific clinical signs and in-hospital death in either the univariate or the multivariate analysis. CONCLUSIONS: Younger age, admission to hospitals with low patient volumes, and admission through emergency departments or referrals are associated with higher risk of in-hospital death. The co-existence of specific clinical signs appears to have no effect on in-hospital death.