The results of an extensive analysis of practice registers, conducted by the RCGP, found 5% of the records of patients with diabetes had 'important errors,' including misdiagnosis, misclassification or miscoding.
The research, by GP experts in diabetes and primary care informatics, audited data for around a million patients in two primary care databases and identified that overall, 85-90% of data on diabetes is fit for purpose, "but that there is room for improvement."
An audit of five practices in southeast England with a combined list size of approximately 45,000 found that: 2.2% of people diagnosed with diabetes in primary care did not have the condition; 2.1% of patients were classified with the wrong type of diabetes; and 0.9% had their type of diabetes coded as 'indeterminable'.
This means, in an average practice, for every 500 people identified with diabetes on a practice register, between 65 and 70 will need to be looked at "for some sort of error."
Of the 65-70 people, 7-16 cases will be where the wrong sort of diabetes has been diagnosed, the majority of which will be incorrectly diagnosed Type 1 diabetes when the person really has Type 2 diabetes.
About 21 people will be incorrectly diagnosed with diabetes when they do not have it, and there will be 24-37 miscodings.
"Overall the effect of the audit was to change the diagnosis of around a quarter of the people identified," the report concludes.
Stone MA, Camosso-Stefinovic J, Wilkinson J, de Lusignan S, Hattersley AT, Khunti K. Incorrect and incomplete coding and classification of diabetes: a systematic review. Diabet Med. 2010 May;27(5):491-7. PMID: 20536944