Impact of COVID-19 infection in patients with inherited metabolic diseases: a National Multicenter Study from the French IMDs Healthcare Network for Rare Diseases

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. 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 experienced more frequently 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). 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. We observed that COVID-19 more frequently worsened the condition of children with IMD compared to adults in our cohort of patients.