Impact of COVID-19 Infection in Patients with Inherited Metabolic Diseases: A National Multicenter Study from the French IMDs Healthcare Network for Rare Diseases

Background The COVID-19 pandemic presented unique challenges for patients with inherited metabolic diseases (IMDs), particularly due to the risk of infection-related metabolic decompensation and disruptions to specialized care. We aimed to assess the impact of COVID-19 infection on the clinical course of patients with IMDs in a National Multicenter Study from the French IMDs Healthcare Network for Rare Diseases. Results This national French study included 317 IMD patients (69 children and 248 adults) with symptomatic or asymptomatic COVID-19 infection between January 2020 and January 2023. Most COVID-19 cases were mild to moderate. The frequency of symptomatic COVID-19 was similar in adults and children (234/248 [94.3%] vs 56/64 [87.5%], p = 0.09). Children were more likely to experience a metabolic destabilization than adults during a COVID-19 infection (17/67 [25.4%] vs 33/248 [13.3%], p = 0.03). Moreover, the proportion of children admitted to the ICU was higher than that of adult patients (5/69 [7.2%] vs 4/248 [1.6%], p = 0.04). Temporary suspension or delay of IMD-specific treatment due to COVID-19 was rare, affecting 3/64 (4.7%) children and 13/229 (5.7%) adults. Severe COVID-19 outcomes were uncommon, with only one death in the adult cohort and five cases of long-term sequelae (1 child, 4 adults). Conclusions COVID-19 was generally mild to moderate in IMD patients and caused metabolic decompensation or imbalance in a minority of cases, with only rare interruptions to disease-specific treatment. COVID-19 more frequently worsened the condition of children with IMD compared to adults.