A person with undiagnosed diabetes has not had the condition diagnosed by a physician by still has plasma glucose levels meet the criteria for diabetes.
The 1998 Canadian clinical practice guidelines for the management of diabetes lowered the cutoff point for an abnormal fasting blood glucose level from 7.8 to 7.0 mmol/L. Kue Young and Cameron Mustard used database linkage to study outcomes of people considered to have diabetes under the new guidelines, but not under the old, in a cohort of adults originally included in the 1990 Manitoba Heart Health Survey. The prevalence of undiagnosed diabetes was 2.2%, about one-third of all diabetes cases. Compared with normoglycemic people, individuals with undiagnosed diabetes had an additional 1.35 physician visits per year and were more likely to be admitted to hospital at least once. They also had unfavourable lipid profiles and higher blood pressure and obesity indices.
The authors conclude that undiagnosed diabetes represents a clinically and socially important burden of disease.
Undiagnosed diabetes: Does it matter?
Canadian Medical Association Journal