Intended for healthcare professionals


Covid-19: Infection raises risk of diabetes and heart disease diagnoses in following weeks, study finds

BMJ 2022; 378 doi: (Published 22 July 2022) Cite this as: BMJ 2022;378:o1838
  1. Jacqui Wise
  1. Kent

Patients who contract covid-19 are at increased risk of being diagnosed with cardiovascular disorders and diabetes in the three months following infection, although the risk then declines back to baseline levels, a large UK study has found.1

Researchers from King’s College London say patients recovering from covid-19 should be advised to consider measures to reduce diabetes risk including adopting a healthy diet and taking exercise.

The GP medical records from more than 428 650 covid-19 patients were matched with the same number of controls and followed up to January 2022. All patients with pre-existing diabetes or cardiovascular disease were excluded from the study, published in the open access journal PLOS Medicine.

According to the analysis, diabetes mellitus diagnoses were increased by 81% in acute covid-19 and remained elevated by 27% from 4 to 12 weeks after infection (adjusted rate ratio 1.81, 95% confidence interval 1.51 to 2.19).

Acute covid-19 was associated with a sixfold increase in cardiovascular diagnoses overall (adjusted rate ratio 5.82, 95% CI 4.82 to 7.03). This included an 11-fold increase in pulmonary embolism, a sixfold increase in atrial arrhythmias, and a fivefold increase in venous thromboses.

The risk of a new heart disease diagnosis began to decline five weeks after infection and returned to baseline levels or below from 12 weeks to one year.

Lead study author Emma Rezel-Potts said, “While it is in the first four weeks that covid-19 patients are most at risk of these outcomes, the risk of diabetes mellitus remains increased for at least 12 weeks. Clinical and public health interventions focusing on reducing diabetes risk among those recovering from covid-19 over the longer term may be beneficial.”

The researchers said that people without pre-existing cardiovascular disease or diabetes who become infected with covid-19 do not appear to have a long term increase in incidence of these conditions.

The observational nature of the study means the researchers can’t say whether the short term increase in risk is directly because of covid infection or if undiagnosed cardiovascular disease and diabetes may be more prevalent among covid-19 cases. Alternatively, covid-19 infection may have aggravated or altered the natural history of pre-existing disease.

Another possibility is that patients recovering from covid-19 had higher rates of GP consultations and this increased medical surveillance could be associated with more frequent opportunities for diabetes to be diagnosed. However, illness from diabetes could itself lead to increased consultations.

Although the researchers matched the controls for age and sex they did not have sufficient data for alcohol use, diet, physical activity, and lipid parameters. They also had no data on deprivation, although the controls were matched for family practice. Patients diagnosed with covid-19 were generally less healthy than controls and this might, in part, account for differences in cardiometabolic outcomes.

Commenting on the study, Kevin McConway, emeritus professor of applied statistics at the Open University, said the study was good in many ways. But he said, “Though the cases and the controls were matched in terms of some factors, it wouldn’t have been possible to match them on everything that is potentially relevant. The covid cases, for example, had a higher tendency to be overweight than the controls, and had on average more pre-existing health conditions. So maybe the observed difference in risk is because of, in part or entirely, these other differences between the groups, rather than the covid itself.”

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