New research published in Article Online First (www.thelancet.com) and in an upcoming edition of The Lancet shows that, in the US population, screening for type 2 diabetes is cost effective when started between the ages of 30 years and 45 years, with screening repeated every 3-5 years. The study is written by Dr Richard Kahn, American Diabetes Association, Alexandria, VA, USA, and colleagues.
To date, no clinical trials have assessed the effects or cost-effectiveness of sequential screening strategies to detect new cases of type 2 diabetes. In this study, the authors used a representative sample of the US population to create a simulated population of 325 000 people aged 30 years without diabetes. They then used computer modelling (the Archimedes Model*) to compare eight simulated screening strategies* for type 2 diabetes with a no-screening control strategy. Strategies differed in terms of age at initiation and frequency of screening, and also as to whether patients were visiting their doctor specifically for diabetes screening or as part of a visit to monitor high blood pressure. The study is the first to address the effects of sequential, rather than one-off, screening. The effects of each strategy on incidence of type 2 diabetes, myocardial infarction, stroke, and microvascular complications were calculated, in addition to quality of life, costs, and cost per quality-adjusted life-year (QALY).
Compared with no screening, all simulated screening strategies reduced the incidence of heart attacks (3 events prevented per 1000 people screened) and diabetes-related microvascular complications (3 events prevented per 1000 people), and increased the number of QALYs (93� undiscounted QALYs) added over 50 years. Most strategies prevented a significant number of simulated deaths (2 events per 1000 people) over 50 years. There was little or no effect of screening on incidence of stroke (0 event prevented per 1000 people). Five of the screening strategies had costs per QALY of about US$10 500 or less, whereas costs were much higher for screening started at 45 years of age and repeated every year ($15 509), screening started at 60 years of age and repeated every 3 years ($25 738), or a maximum screening strategy (screening started at 30 years of age and repeated every 6 months; $40 778). Several strategies differed substantially in the number of QALYs gained.
Each screening strategy also resulted in an earlier diagnosis. The mean lead time in diagnosis, compared with control, varied from 1.8 years (starting at age 60, every 3 years) to 7.8 years (maximum screening). Despite the ability to detect diabetes sooner when screening is conducted more frequently, the authors found that the greater lead time for the most feasible screening strategies did not significantly improve long-term outcomes.
The five most cost-effective simulated screening strategies varied in their expected degree of benefit. Initiation of screening at 30 years or 45 years of age provided the most benefit. The appropriate choice of strategy would deliver the greatest benefit, while having a low cost per QALY.
The authors conclude: "We therefore recommend starting screening between the ages of 30 years and 45 years, with screening repeated every 3 years. The cost per QALY would be further improved if screening were combined with screening events for other disorders, such as screening for hypertension. Similarly, initiation of screening at 45 years with follow-up every 5 years would have the best cost per QALY if screening were done at the time of a visit for lipid testing."
In an accompanying Comment, Dr Guy Rutten University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht, Netherlands, points out that the population used in Kahn and colleagues' study was representative of the US population, and differences in race or ethnic origin or differences in behaviours between northern American and European or Asian people might make the results less generalisable to countries other than the USA—as might the variation in health-care costs between the USA's insurance based model compared to a system where the one system is responsible for almost all costs, such as the UK's National Health Service.
He concludes: "Today's paper provides further evidence that screening for diabetes should be combined with screening for hypertension and lipid tests. This recommendation is also in line with the current guideline for screening from the American Diabetes Association. Further input into the model of information on screen-detected people with type 2 diabetes, and separate analyses of different populations or health-care systems, might strengthen the role of the Archimedes model to provide further useful information for future guidelines about screening for diabetes."
Dr Richard Kahn, American Diabetes Association, Alexandria, VA, USA. T) +1 703 201 6065 E) rak6200@gmail.com
Dr Guy Rutten University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht, Netherlands. T) +31 6 461 363 19 E) g.e.h.m.rutten@umcutrecht.nl
For full Article and Comment, see: http://press.thelancet.com/diabscreening.pdf
Notes to editors:
*Archimedes model- The Archimedes Model is a full-scale simulation model of human physiology, diseases, behaviors, interventions, and healthcare systems. For more information see http://archimedesmodel.com/archimedesmodel.html
**For full details of each strategy, see panel page 2 of full Article
Journal
The Lancet