Lancet: Model shows optimal diabetes screening age, frequency

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In a simulated model, researchers found that five screening strategies for type 2 diabetes proved cost effective, but the strategy that proved most clinically beneficial and cost effective was screening that began at age 45 and was repeated every three to five years, according to a study published online March 30 in the Lancet.

“To date, no clinical trials have assessed the cost effectiveness of sequential screening strategies to detect new cases of type 2 diabetes,” the authors wrote.

Richard Kahn, MD, of the American Diabetes Association in Alexandria, Va., and colleagues simulated a population (Archimedes model) of 325,000 people aged 30, without diabetes, from a representative sample of the U.S. population to evaluate eight screening strategies for type 2 diabetes.

Screening strategies differed in terms of age at initiation, frequency of screening and whether patients visited their doctor specifically for diabetes screening or for the monitoring of high blood pressure or lipid control. All screening strategies continued until the age of 75 years. A no-screening group was used as a control.

The eight strategies were:

  • Screen the entire population for type 2 diabetes starting at age 30 years. For those not diagnosed, repeat screening every 3 years;
  • Start screening at age 45 years and repeat every year;
  • Start screening at age 45 years and repeat every 3 years;
  • Start screening at age 45 years and repeat every 5 years;
  • Start screening at age 60 years and repeat every 3 years;
  • Screen only when the person's blood pressure is greater than 140/90 mm Hg. Repeat screening every year at the corresponding visit for blood pressure monitoring;
  • Screen only when the person's blood pressure is greater than 135/80 mm Hg. Repeat screening every 5 years at the corresponding visit for blood pressure monitoring;
  • Start screening at age 30 years and repeat every 6 months (maximum screening).

Compared with no screening, the use of all screening measures reduced the rates of MI and diabetes-related microvascular complications (3-9 events prevented per 1,000 people screened). Screening also added over 50 years of life, 93-194 undiscounted quality-adjusted life-years (QALYs).

Additionally, most of the strategies prevented simulated deaths (2 to 5 events per 1,000 people), but had little effect on incidence of stroke  (0 to 1 events prevented per 1,000 people).

Five of the eight strategies had costs per QALY of $10,500 or less. The three costliest strategies were:

  • Screening beginning at 45 years and repeated each year -- $15,509;
  • Screening at 60 years and repeated every three years -- $25,738; and
  • Screening at 30 years and repeated every six months -- $40,778.

“Several strategies differed substantially in the number of QALYs gained,” the authors wrote. “Costs per QALY were sensitive to the disutility assigned to the state of having diabetes diagnosed with or without symptoms.”

While the researchers found that these strategies led to an earlier diagnosis, long-term outcomes did not significantly improve. Results showed that the average time of early diagnosis varied from 1.8 years when screening began at age 60 and repeated every three years, and 7.8 years when maximum screening tactics were used.

“The appropriate choice of strategy would deliver the greatest benefit, while having a low cost per QALY,” the authors wrote. The best strategy, they found, is to initiate screening at 45 years with follow-up every five years. This strategy would have the best cost per QALY if screening were done at the time of a visit for a lipid or blood pressure test.

In an accompanying editorial, Guy Rutten, MD, of the Julius Center for Health Sciences and Primary Care in Utrecht, Netherlands, said that because results were based on the U.S. population, this could make them “less generalizable” compared to other countries due to differences in race, ethnic origin and behaviors.

In addition, he concluded that Kahn et al’s findings “provide further evidence that screening for diabetes should be combined with screening for hypertension and lipid tests.”