Health economic considerations of screening for early type 1 diabetes

Health economics of screening for early type 1 diabetes (T1D) is an emerging area of research. Historically, screening for early T1D has been limited to prospective cohort studies of the aetiology and natural history of the disease as well as trials of secondary prevention. In the past few years, successful large-scale studies have expanded the screening to the general population, providing data needed to estimate the cost-effectiveness of such programs and their economic viability as they become part of public health preventive services. This review covers available results of health economics analyses from early estimates through state transition cohort simulation models relying on birth cohort studies to real-world experience from general population screening and, finally, predictions to a national scale. The cost-effectiveness analyses of screening for early T1D to date suggest that the financial investment in such programs is justified by the health benefits and savings achieved. Screening can be cost-effective if it reduces the incidence of diabetic ketoacidosis at diagnosis and decreases healthcare costs associated with long-term complications. However, the cost-effectiveness varies based on population prevalence of T1D, frequency of diabetic ketoacidosis at clinical diagnosis, screening test accuracy and cost as well as healthcare system efficiency. All these factors influence the HbA1c at diagnosis and glycaemic control as well as insulin requirements later in the course of the disease. Earlier interventions aiming at delaying insulin dependency may further improve the cost-effectiveness. PLAIN LANGUAGE SUMMARY: Type 1 diabetes (T1D) is one of the most frequent severe chronic diseases of childhood, increasing in numbers with age, affecting in lifetime 1 in 100 people. It is caused by the immune system attacking insulin-producing cells in the pancreas. Stage 1 of T1D is diagnosed when multiple markers of the attack (islet autoantibodies) are detected. The disease progresses to stage 2 when most of the insulin is lost and blood sugar levels become abnormal. Stage 3 is defined by very high blood sugars leading often to diabetic ketoacidosis (DKA) and need of insulin treatment to safe life. This progression happens over a period of months or years, providing an opportunity for screening to detect the disease early and slow the progression with drug therapy as well as to provide education that prevents DKA. Early diagnosis and start of insulin therapy when HbA1c is just above 6. 5% helps to avoid multiorgan complications that increase with age and account for most of the direct medical cost and lost workforce participation and productivity associated with T1D. Studies following high-risk youth for decades provided early estimates of the cost-effectiveness of screening for stage 1 and stage 2 T1D. Screening cannot be limited to relatives of people with T1D because they represent only 10-15% of new T1D diagnoses. In recent years, successful programs such as Fr1da in Germany or Autoimmunity Screening for Kids (ASK) in USA expanded the screening to the general population, providing data needed to estimate cost-effectiveness as they become part of public health preventive services. Testing for islet autoantibodies dramatically reduced the incidence of DKA at diagnosis and may decrease healthcare costs associated with long-term complications; however, an extended follow-up of screening participants is necessary. Screening for early T1D can be combined with screening for celiac disease, high cholesterol levels, or other conditions detectable by blood test, further improving cost-effectiveness. The widely accepted routine newborn screening for about 30 rare diseases, affecting 1 in 600 infants, costs 125-150 per child. In contrast, 1 in 30 children has early T1D or celiac disease that could be detected for less than 50 per child screened. Results of the programs in Germany and USA indicate that the cost-effectiveness of screening depends on population prevalence of T1D, frequency of DKA, screening test accuracy and cost as well as healthcare system efficiency. These analyses allow national-scale predictions of the number of high-risk youths and the resources necessary to successfully monitor them during stage 1 and 2. Screening at age 2 and 6 years in Germany would annually yield a similar number of children at early stage T1D to those currently diagnosed at stage 3 and reduce DKA at diagnosis by 61%. If all USA children were screened today, it is estimated that 350, 000 would be diagnosed with stage 1 and 70, 000 with stage 2 T1D. The cost-effectiveness of analyses of screening for early T1D suggest that financial investment in such programs is justified by the observed health benefits and savings.