Corona Daily 194: Covid and Diabetes: A Two-Way Relationship?

We knew all this time that the coronavirus is more dangerous for those with diabetes. Now intriguingly it appears the relationship may be both ways. Covid-19 has caused diabetes newly in some patients. Some patients had their blood sugar higher when they were ill with covid. By the time they left the hospital, the level had returned to normal. Others went home with full-blown diabetes.

Beside attacking the lungs, Covid and in particularly long covid can cause several complications including blood clots, neurological disorders, kidney and heart damage. Now onset of diabetes may soon be added to this list. In Type 1 diabetes, (earlier called insulin-dependent or juvenile diabetes), pancreas doesn’t make insulin. This is usually diagnosed in children and younger people, and constitutes only 10% of the diabetic population. In Type 2 diabetes, very widespread, cells don’t respond normally to insulin, which is called insulin resistance. Pancreas can’t keep up trying to make more insulin to provoke cells to respond. Blood sugar rises causing all sorts of health problems. Covid may cause either type.

A year ago, in Wuhan, doctors had noticed elevated blood sugar in covid patients. Some patients who got diabetes after covid had obesity. Dexamethasone, a drug I mentioned yesterday, also causes elevated blood glucose levels. But in some cases, none of these factors were present. And some cases developed diabetes months after recovering from covid.

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John Kunkel, a 47-year-old American banker, was hospitalized in July. In a follow-up visit, his blood sugar level was dangerously high. He was readmitted and diagnosed with Type 2 diabetes. He has since had five emergency room visits and three hospital stays. He recently lost his job as a result. John is still puzzled. He had no pre-existing health issues before covid.

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An analysis published in the journal Diabetes, Obesity and Metabolism said 14.4% of people hospitalized with severe covid-19 developed diabetes. The data was collected from more than 3700 patients across eight different studies. At present researchers don’t know whether the cases are temporary or permanent.

To find out more, Francesco Rubino, a diabetes surgery professor at King’s college London and his colleagues launched a global registry of patients with covid related diabetes. God forbid, if you have had covid, and developed diabetes after that, please register here.

Some of the cases in the database provide an additional mystery. Usually, Type 1 patients may burn through their fat stores, Type 2 may experience severe dehydration and coma as the body pumps excess blood sugar into urine. The two types have different symptoms.

In some patients with Covid-19, the complications cross types. Scientists feel this may be a new hybrid form of diabetes. Professor Rubino is especially concerned about reports of diabetes diagnosed among patients who were asymptomatic or had only mild symptoms.

Diabetes has already reached alarming levels in many countries including India and the USA. When not managed, it can cause a number of complications including heart disease, stroke, blindness, kidney failure and nerve damage.

After the 2003 SARS pandemic, Chinese researchers had tracked 39 patients with no history of diabetes, who after being hospitalized with SARS had developed acute diabetes. For 33 patients, the diabetes was temporary. For four patients it lasted several months, and two patients had it after two years.

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If the suspicions about the bidirectional link between Covid-19 and diabetes turn out to be true, it is another reason everyone needs to continue taking care to avoid getting infected.

Ravi