GPs should monitor glycaemic control extra carefully in patients with diabetes who quit smoking, according to UK experts who found patients’ blood sugar increased after they gave up the habit – regardless of whether they put on weight.
The team’s study of UK general practice records found the patients’ worsened glucose control lasted for two-to-three years after quitting.
The study – which was funded by the National Institute for Health Research School for Primary Care Research and led by Dr Deborah Lycett at Coventry University – looked at over 10,500 adult smokers with type 2 diabetes whose records were included in The Health Improvement Network database of general practice.
Just over 3,100 of the patients (29%) quit smoking and remained abstinent for at least a year.
After taking into account potential confounders, including weight gain, patients had an average 2.29mmol/mol rise in their HbA1c levels during the first year after quitting.
Their HbA1c gradually fell again thereafter, but remained elevated for another two years when compared with continuing smokers.
The researchers concluded: ‘This study has shown strong evidence that glycaemic control worsens after cessation of smoking of smoking and that this does not appear to be primarily down to increases in bodyweight that usually follow cessation.
‘A proactive review of glycaemic control and prompt adjustment of medication is needed in this patient group both before and after smoking cessation.’