The variety and severity of the health consequences of diabetes and the large number of people that are or can be affected by the disease leave no doubt that diabetes is a major public health problem.3
A critical step toward the solution of this problem is to screen the population in search of individuals at high risk, particularly those at the early stages of impaired glucose metabolism. The World Health Organization (WHO) has set stringent conditions for any screening program that would assign a health risk to a potentially large number of asymptomatic individuals.4,5
First, the condition should be an important health problem, amenable to primary prevention, and its epidemiology and natural history should be adequately understood. Second, the screening test should be simple, safe, precise, and validated; the distribution of the values generated by the test and its risk thresholds should be known in the target population; the test should be acceptable to the population; and there should be a clear policy on the management of individuals with a positive test result. Third, there should be an effective intervention with better outcomes for those treated early rather than late as well as a clear policy to deliver such intervention; the clinical management of the condition and the health outcomes should be optimized by the health care providers before they join the screening program. Fourth, there should be strong evidence that the screening program is effective in reducing mortality or morbidity and that the entire program is clinically, socially, and ethically acceptable to health professionals and the public; the benefits of the program should clearly outweigh the harms; the cost of the screening program should be reasonable in relation to expenditure on medical care as a whole; the screening program should be adequately staffed and managed from the start; potential participants should be well informed of the consequences of testing and available treatment; and there must be flexibility for widening the eligibility criteria, reducing the screening interval, and improving the test if such changes are supported by scientific evidence.
Does screening for diabetes meet the conditions just stated? Diabetes and its associated conditions meet most of the requirements for a screening program,5
but no major national organization recommends universal screening for diabetes. The reason is that screening for diabetes does not meet some important requirements set by the WHO;5
namely, there is no evidence that a screening program would eventually reduce mortality and morbidity, no country has the infrastructure in place to handle large-scale screening and treatment programs for diabetes, and the clinical management of the disease may not be optimal throughout entire health care systems.5
The WHO, then, considers that the best approaches to screen for undiagnosed diabetes or prediabetes are (1) selective (among groups known to have risk factors for diabetes) and (2) opportunistic (among potentially high-risk individuals at the time they visit their health care providers).6
It is important to note here that recent evidence-based screening recommendations, issued by the U.S. Preventive Services Task Force (USPSTF), do not favor universal screening for diabetes either.7,8
The main reason is that the USPSTF found, with moderate certainty, that even though screening for diabetes in adults with hypertension would lead to a substantial benefit, the evidence was insufficient to determine the benefit of screening in other populations.7
On the positive side, a diagnosis of hypertension offers the opportunity for health care providers to offer a diabetes test to their patients.