The effect of COVID-19 pandemic on new-onset adult diabetes and its one-year follow-up

Bidirectional detrimental relationships between COVID-19 infection and diabetes have been described globally. However, new-onset diabetes in adults and its follow-up during the pandemic have not been sufficiently investigated. In this study, new-onset autoimmune and type 2 diabetes cases during the pandemic were compared to those before the pandemic, and the clinical course of new-onset diabetes during the pandemic was examined. In this single-center retrospective cohort study, clinical and laboratory characteristics of new-onset diabetes patients before the pandemic (n = 161) and during the pandemic (n = 144) were evaluated between March 2018 and March 2022. A 1.85-fold increase in new-onset adult diabetes cases was observed during the pandemic compared to pre-pandemic period (p = 0.010), while the proportion of autoimmune and type 2 diabetes (T2D) did not change. During the pandemic, there was a 6.2-fold increase in autoimmune diabetes presented with DKA (p = 0.003). Insulin was preferred 1.7 times more frequently as initial treatment during the pandemic (p = 0.014), and mean HbA1c (p = 0.003) and C-peptide (p = 0.010) were higher. Clinical and laboratory data did not differ between PCR (+) and PCR (-) patients. At one-year follow-up, while only HbA1c decreased in the autoimmune diabetes; in T2D group fasting glucose, HbA1c, C-peptide, and lipid profile were significantly improved. The pandemic led to increased new-onset adult diabetes presented with DKA. However, clinical and laboratory features were similar between PCR positive and negative cases. PCR-confirmed COVID-19 may not adversely affect the medium-term clinical course of new diabetes in adults. •Observed a 1.85-fold increase in new diabetes cases during the pandemic.•Increased initiation of insulin as primary treatment during pandemic.•Elevated HbA1c levels indicative of worsened glycemic control in pandemic.•Higher frequency of diabetic ketoacidosis presentations in pandemic era.•No significant impact of COVID-19 PCR test positivity on diabetes diagnosis rates.