New-onset diabetes in many Covid-19 patients during hospital admission may only be transitory and may return to normal after discharge from the hospital, according to a new study published in the Journal of Diabetes and Its Complications.¹

In this study, researchers from Massachusetts General Hospital in Boston, United States retrospectively reviewed the electronic health records (EHR) of patients who were hospitalized with Covid-19 between March and September 2020. These patients had evidence of diabetes based on either previous history or outpatient use of insulin prior to admission or blood glucose level ≥300 mg/dL on two hospital days during the hospitalization for Covid-19.

A total of 1902 patients were hospitalized with Covid-19 during the study period. Of these 594 were found to have diabetes. Majority of patients (~93%) with previous diabetes had type 2 diabetes, while   2.1% had type 1 diabetes and 2.5% had gestational diabetes. Few patients had secondary diabetes (1.4%), while some had pancreatic diabetes (0.6%). Seventy-seven of these did not have diabetes prior to this hospitalization and were newly diagnosed with diabetes mellitus during their hospital stay for Covid treatment.

Thirty-three patients with new diagnosis of diabetes were prediabetic before hospital admission. Compared to patients with a known diagnosis of diabetes, those with a new diagnosis of diabetes were younger. Also, newly diagnosed diabetes was less common in those of non-Hispanic White race/ethnicity.

An interesting observation was that patients with new onset of diabetes had lower baseline blood glucose and/or glycosylated hemoglobin (HbA1c), but had higher levels of inflammatory markers such as C-reactive protein, ferritin, lactate dehydrogenase, aspartate and alanine aminotransferase. These findings were not seen in patients with old diabetes. They also required fewer doses of insulin during the initial days of their hospitalization. Although they were likely to be hospitalized for a longer duration of time and had higher probability of ICU admission, no association with diabetic ketoacidosis or death was noted for this group of patients compared to patients with pre-existing diabetes.

Ten out of the 77 patients who were newly diagnosed with diabetes during hospitalization and three were not available for follow-up. Thirty-six of the remaining 64 patients continued to have high blood glucose levels om follow-up at roughly one year after hospital discharge, while 26 (40.6%) of the newly diagnosed patients returned to pre-diabetes or normoglycemic state, while two patients could not be classified. Only 8% of patients needed insulin for glycemic control after one year.

Hyperglycemia is a common finding in hospitalized patients with Covid-19 and its presence is a risk factor for severe disease with need for hospitalization, ICU admissions, mechanical ventilation, and death. This study has shown that compared to patients with pre-existing diabetes, many of the newly diagnosed patients have more severe Covid-19 and fewer complications related to hyperglycemia as evident by the raised inflammatory markers.

What this study also shows is that nearly 41% of patients with newly diagnosed diabetes reverted to normal blood glucose levels demonstrating that the rise in blood glucose levels, which commonly occurs in Covid patients without previous diabetes is transient and can be attributed to the acute hyperinflammatory stress caused by the SARS-CoV-2 infection and therefore may not require antihyperglycemic medications for long. The study recommends regular follow-up and close monitoring of such patients after hospital discharge to see if the hyperglycemia returns to normoglycemia or is persistent.

Reference

1. Cromer SJ, et al. Newly diagnosed diabetes vs. pre-existing diabetes upon admission for COVID-19: associated factors, short-term outcomes, and long-term glycemic phenotypes. J Diabetes Complications. 2022 Feb 4;108145. doi: 10.1016/j.jdiacomp.2022.108145.