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Can Screening for Diabetes Reduce CVD and Mortality in General Population?

Even though screening the general population does not impact mortality or CVD incidence, it did have benefits for those diagnosed with diabetes.

Health check programs for chronic disease have been introduced in a number of countries. However, there are few trials assessing the benefits and harms of these screening programs at the population level. In a post hoc analysis, they evaluated the effect of population-based screening for type 2 diabetes and cardiovascular risk factors on mortality rates and cardiovascular events.

This register-based, non-randomized, controlled trial included men and women ages 40–69 years without known diabetes who were registered with a general practice in Denmark (n = 1,912,392). Between 2001 and 2006, 153,107 individuals registered with 181 practices participating in the Anglo–Danish–Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care (ADDITION)-Denmark study were sent a diabetes risk score questionnaire. Individuals at moderate-to-high risk were invited to visit their GP for assessment of diabetes status and cardiovascular risk (screening group). The 1,759,285 individuals registered with all other general practices in Denmark constituted the retrospectively constructed no-screening (control) group. Outcomes were mortality rate and cardiovascular events (cardiovascular disease death, non-fatal ischemic heart disease or stroke). The analysis was performed according to the intention-to-screen principle.

Among the screening group, 27,177 (18%) individuals attended for assessment of diabetes status and cardiovascular risk. Of these, 1,533 were diagnosed with diabetes. During a median follow-up of 9.5 years, there were 11,826 deaths in the screening group and 141,719 in the no-screening group (HR 0.99 [95% CI 0.96, 1.02], p = 0.66). There were 17,941 cardiovascular events in the screening group and 208,476 in the no-screening group (HR 0.99 [0.96, 1.02], p = 0.49).

However, the screening program for type 2 diabetes and CV risk factors was not associated with a reduction in the rate of mortality or CV events in the overall Danish population. Over a median follow-up of 9.5 years, there were 11,826 deaths in the screening group and 141,719 deaths in the no-screening group (HR = 0.99; 95% CI, 0.96-1.02). There were 17,941 CV events in the screening group and 208,476 CV events in the no-screening group (HR = 0.99; 95% CI, 0.96-1.02).

In a third study, Adina L. Feldman, MSc, PhD, AFHEA, of the MRC Epidemiology Unit at University of Cambridge, and colleagues analyzed data from 142,037 residents participating in a community-based public health program in Vasterbotten County, Sweden. Residents were invited to clinical examinations that included diabetes screening by an OGTT, at ages 30, 40, 50, and 60 years. Between 1992 and 2013, researchers identified 1,024 screening-detected cases of diabetes and 8,642 clinically detected cases using registry data (including 4,506 prior screening participants). For those with screening-detected diabetes, average age at diagnosis was, on average, 4.6 years younger when compared with those with clinically detected diabetes. Additionally, those with clinically detected diabetes had overall worse health outcomes when compared with those with screening-detected diabetes (HR for all-cause mortality = 2.07; 95% CI, 1.63-2.62), according to researchers.

From the results, it was concluded that a population-based stepwise screening program for type 2 diabetes and cardiovascular risk factors among all middle-aged adults in Denmark was not associated with a reduction in rate of mortality or cardiovascular events between 2001 and 2012. But there was a positive effect for those diagnosed with diabetes.

Practice Pearls:

  • Screening does lead to an earlier diagnosis of diabetes and reduces mortality and risks of complications, in particular cardiovascular disease.
  • Screening also leads to earlier diagnosis of renal disease and retinopathy, in those who are diagnosed with diabetes.
  • Screening for prediabetes could also be very helpful in getting people to change lifestyles.

 

References:

Simmons RK, et al. Diabetologia. 2017;doi:10.1007/s00125-017-4323-2.

Simmons RK, et al. Diabetologia. 2017;doi:10.1007/s00125=017-4299-y.  Download full text PDF