Prevalence of undiagnosed type-2-diabetes mellitus and impaired fasting glucose in German primary care: Data from the German metabolic and cardiovascular risk project (GEMCAS)

Aims: Primary care physicians are gatekeepers of the healthcare system and thus responsible for screening, prevention and treatment of diabetes. Little is known about the prevalence of diabetes, impaired fasting glucose and factors that are associated with the risk of future development of diabetes and subsequent cardiovascular disease in unselected patients presenting to general practitioners. Research Design and Methods: A nationwide sample of 35,869 primary care patients screened in 2005 was used to estimate the prevalence of detected and undetected diabetes as well as of impaired fasting glucose. Logistic regressions were used to assess the prevalence, cardiovascular morbidity and the factors associated with undetected diabetes and impaired fasting glucose. Results: 1) Using a blood glucose screening algorithm the prevalence of known type 1 and type 2 diabetes mellitus was found to be 0.6 and 12.2%, respectively. Another 2.9% (23% of the diagnosed) had either undiagnosed diabetes (0.9%) or impaired fasting glucose (2.0%). 2) Undiagnosed patients had a more unfavourable cardiovascular risk profile compared to non-diabetic patients. 3) Moreover, higher age, male gender, low HDL-cholesterol and elevated triglycerides as well as a family history of diabetes were associated with unknown diabetes or impaired fasting glucose. Conclusions: Approximately 15.7% of individuals in Germany consulting a primary care physician are affected from either diabetes (known and unknown) or impaired fasting glucose and face a substantially elevated cardiovascular risk score. This study demonstrated that using a simplified blood glucose screening algorithm considering risk markers like higher age, male gender, low HDL-cholesterol, high triglycerides and a family history of diabetes may well serve as a suitable screening approach for undiagnosed diabetes and impaired fasting glucose in primary care practice.