Association between COVID-19 and the incidence of type 1 diabetes in Portugal - a registry study

Abstract

Background: Viral respiratory infections may precipitate type 1 diabetes (T1D). A possible association between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for COVID-19, and the incidence of T1D is being determined. This study was carried out using Portuguese registries, aiming at examining temporal trends between COVID-19 and T1D.

Methods: Hospital data, comparing the incidence before and during the COVID-19 pandemic, from children and young adults diagnosed with new-onset T1D, was acquired beginning in 2017 and until the end of 2022. Data was obtained from nine different Portuguese hospital units. The impact of the COVID-19 pandemic, beginning in March 2020, was assessed comparing the annual numbers of new-onset T1D cases. The annual median levels of glucose, glycated hemoglobin (HbA1c) and fasting C-peptide at T1D diagnosis were compared. The annual number of diabetic ketoacidosis (DKA) episodes among new T1D cases was also assessed at two centers.

Results: In total, data from 574 newly diagnosed T1D patients was analyzed, including 530 (92.3%) children. The mean ages for child and adult patients were 9.1 (SD 4.4) and 32.8 (SD 13.6) years, respectively. 57.8% (331/573) were male, one patient had unknown sex. The overall median (25-75 percentiles) levels of glucose, HbA1c and fasting C-peptide at diagnosis were 454 mg/dL (356-568), 11.8% (10.1-13.4) and 0.50 µg/L (0.30-0.79), respectively. DKA at T1D diagnosis was present in 48.4% (76/157). For eight centers with complete 2018 to 2021 data (all calendar months), no overall significant increase in T1D cases was observed during the COVID-19 pandemic, i.e. 90 cases in 2018, 90 cases in 2019, 112 in 2020 and 100 in 2021 (P for trend = 0.36). Two of the centers, Faro (CHUA) and Dona Estefânia (CHULC) hospitals, did however see an increase in T1D from 2019 to 2020. No significant changes in glucose (P = 0.32), HbA1c (P = 0.68), fasting C-peptide (P = 0.20) or DKA frequency (P = 0.68) at the time of T1D diagnosis were observed over the entire study period.

Conclusion: The T1D incidence did not increase significantly, when comparing the years before and during the COVID-19 pandemic, nor did key metabolic parameters or number of DKA episodes change.

Keywords: COVID-19; Portugal; Type 1 diabetes.

Fig. 1

Number of newly diagnosed T1D patients per year (2018–2021). Note The figure only shows 2018-2021, as these were full calendar years. Also, it only includes the eight centers with complete data (i.e. Santa Maria Hospital in Lisbon, Dona Estefânia Hospital in Lisbon, Centro Hospitalar in Leiria, Hospital Santa Maria Maior in Barcelos, Hospital Espírito Santo in Évora, Centro Hospitalar Universitário do Algarve in Faro, the Pediatric Hospital in Coimbra, Hospital de Portimão e Lagos at the Algarve Coast).

Fig. 2

Number of newly diagnosed T1D patients per individual calendar month (2018–2021)

Fig. 3

Glucose levels at T1D diagnosis from 2017 to 2022

Fig. 4

HbA1c levels at T1D diagnosis from 2017 to 2022

Fig. 5

Fasting C-peptide levels at T1D diagnosis 2017 to 2022