Current screening for type 2 diabetes and cardiovascular risk factors may not reduce mortality and cardiovascular disease in the general population, according to USF College of Public Health’s Dr. Janice Zgibor, an associate professor in the Department of Epidemiology and Biostatistics.
Identifying and treating diabetes early are beneficial and cost-effective, however, according to Zgibor, current screening trial objectives lack in improving outcomes for those who become diagnosed.
Zgibor and her colleague David Simmons of Western Sydney University share their findings “Should we screen for type 2 diabetes among asymptomatic individuals? Yes,” in the European Association for the Study of Diabetes journal, Diabetologia.
“Trials of screening for undiagnosed diabetes among asymptomatic individuals may no longer be feasible or ethical in many countries,” Zgibor said.
Three large trials, also published Diabetologia, suggest a reduction in mortality and cardiovascular disease risk among individuals already diagnosed with diabetes.
However, Zgibor and Simmons indicate that current study trials do not adequately test whether those without diabetes should be screened and of the few population-based trials assessing the benefits of screening programs for diabetes risk, results are mixed.
“The most efficient recommendation may be opportunistic screening, where patients already seeking care, including screening, for another condition are subsequently tested for diabetes or prediabetes,” Zgibor said. “If screened positive, they are more likely to receive treatment, thus leading to improved outcomes.”
With more than 30 years of experience in diabetes research, Zigbor said that as more screening occurs, more research will be needed on how to best screen and improve risk-factor controls once diabetes is detected.
Diabetes prevalence continues to rise globally, according to the World Health Organization, affecting 422 million individuals as of 2014. It is also a leading cause of blindness, kidney failure, heart attacks, stroke and lower limb amputation.
Zgibor and Simmons analyzed ADDITION-Denmark, a population-based cardiovascular and diabetes screening program introduced in sixteen Danish countries between 2001 and 2006.
More than 150,000 individuals registered with 181 practices participating in the ADDITION-Denmark study were sent a diabetes risk score questionnaire, and if their score indicated moderate to high risk they were invited to attend for a diabetes test and cardiovascular risk assessment with their family doctor.
More than 27,000 attended for screening, and 1,533 were diagnosed with diabetes during screening. A further 1,760,000 individuals were identified for a matched no-screening control group. Participants were followed for approximately 9.5 years to 31 December 2012, when national registers were searched for vital status and cardiovascular disease (CVD) events – CVD death, non-fatal ischaemic heart disease and non-fatal stroke.
The researchers found that in the overall populations in the screening and no-screening groups, a single round of screening for type 2 diabetes and cardiovascular risk assessment was not associated with a reduction in mortality or in cardiovascular events between 2001 and 2012. Similarly, rates of cardiovascular, cancer or diabetes-related mortality were not reduced by invitation to screening.
However, a sister study found that a single round of diabetes screening and cardiovascular risk assessment was associated with a 21 percent reduction in all-cause mortality rate and a 16 percent reduction in cardiovascular disease events between 2001 and 2012 in individuals diagnosed with diabetes between 2001 and 2009.
“There is probably sufficient evidence to conclude that this systematic approach to screening should occur in primary care and that focus should now shift to trials of how to screen, methods for implementing treatment earlier, and better risk factor control in those at highest risk,” Zgibor said.