Cost-effectiveness of tightly controlling Type 2 diabetes

Original articles:
Cost effectiveness of an intensive blood glucose control policy in patients with type 2 diabetes: economic analysis alongside randomised controlled trial (UKPDS 41). Gray A, Raikou M, McGuire A et al., on behalf of the United Kingdom Prospective Diabetes Study Group. Br Med J 2000; 320: 1373–8.

Cost-effectiveness of intensive insulin therapy for type 2 diabetes: a 10-year follow-up of the Kumamoto study. Wake N, Hisashige A, Katayama T et al. Diabetes Res Clin Pract 2000; 48: 201–10.

Summary
In the article by Gray et al., the subjects enrolled in the United Kingdom Prospective Diabetes Study (UKPDS) were randomized to different groups in order to estimate the cost-effectiveness of conventional vs. intensive blood glucose control. The median follow-up was 10 years, which made it possible to determine the long-term costs of Type 2 diabetes and its complications. The study included 3867 subjects with newly diagnosed Type 2 diabetes (mean age 53 years) who entered the main randomization. The glycemic goal of the conventional diet therapy group (n = 1138) was a fasting plasma glucose concentration below 270 mg/dl. The intensive treatment group was randomized to insulin (n = 1156) or sulfonylureas (n = 1573), both with a goal fasting plasma glucose concentration below 110 mg/dl.
The cost-effectiveness analysis included net costs of intensive compared with conventional management. Costs associated with visits to diabetes clinics, tests, treatment of diabetic complications and inpatient stays were included. The main clinical endpoints analyzed were death or the development of diabetic complications including coronary heart disease, cerebrovascular disease, amputation, laser treatment for retinopathy, cataract extraction and renal failure.
The results revealed lower total routine costs of $5364 per patient in the conventional therapy group vs. $6384 in the intensive therapy group (mean difference $1020, 95% CI $814–1227). When the cost of complications was analyzed, hospital admissions accounted for the largest element. The mean cost of all hospital admissions was $6260 in the conventional therapy group and $5127 in the intensive therapy group (mean difference $1133, 95% CI $233–2032). 
The 18% reduction in cost with the intensive management group was primarily the result of differences in the length of stay (9.7 days in the conventional therapy group, 8.4 days in the intensive therapy group; mean difference 1.3, 95% CI 0.2–2.3). The difference in the number of admissions was not significant. The analysis shows that the increased cost of antidiabetic treatment among the intensive therapy group was counterbalanced by the reduced costs of complications. The net costs did not differ significantly between the groups (total cost $14,483 in the conventional group and $14,099 in the intensive group).
The second component of the cost-effectiveness analysis was event-free years. This was measured as time to first event with regards to the endpoints listed above. Within-trial event-free time gained for the intensive vs. the conventional therapy group was 0.60 years (95% CI 0.12–1.10).
In the article by Wake et al., insulin-requiring Type 2 diabetic subjects (n = 110) from the Kumamoto study were randomized into two groups to evaluate the economic impact of Type 2 diabetic complications over 10 years. The first group was assigned to multiple insulin therapy and their goal was to maintain fasting blood glucose <140 mg/dl, 2-h postprandial blood glucose <200 mg/dl, HbA1c <7.0% and mean amplitude of glycemic excursions <100 mg/dl. The second group was assigned to conventional insulin therapy with the goal to maintain fasting blood glucose <140 mg/dl and avoid symptoms related to hyperglycemia or hypoglycemia. The endpoints were defined as progression of retinopathy, photocoagulation, progression of nephropathy, clinical neuropathy, macrovascular complications (the appearance of cerebrovascular, cardiovascular or peripheral vascular disease) and diabetes-related death (which includes deaths due to myocardial infarction, stroke, peripheral vascular disease, renal disease, hyperglycemia, hypoglycemia or sudden death).
Cost evaluations were based on the reimbursement fee schedule of the Japanese National Health Insurance in 1988. The medical services included inpatient care, outpatient care, medications, medical equipment and laboratory tests related to diabetes care. These costs were subdivided into costs of routine treatment and costs due to complications.
The results showed that the total treatment costs over 10 years were significantly higher for multiple insulin therapy ($27,201) than for conventional insulin therapy ($21,121) — an increase of $6080 (95% CI $3891–8268). However, the costs of complications were significantly lower in the multiple insulin therapy ($7591) vs. the conventional insulin therapy ($15,565) group by $7974 (95% CI $4694–11,253). The total costs combining treatment and complications were $34,792 ± $9639 for multiple insulin therapy and $36,685 ± $12,985 for conventional insulin therapy. The results show that conventional insulin therapy was more expensive by $1893 (95% CI -$2433 to $6220) over the 10 years of observation (Fig. 1).

Fig. 1: Comparison of annual trend of total, treatment and complication costs (undiscounted) between patients receiving intensive insulin therapy (MIT) and conventional insulin therapy (CIT) in the Kumamoto study.

When the relative risks of complications were analyzed, there were significant differences between the conventional and multiple insulin therapy groups. The multiple insulin therapy group significantly reduced their relative risks of progression of retinopathy by 67% (95% CI 49–79), photocoagulation by 77% (95% CI 47–90), progression of nephropathy by 66% (95% CI 42–80), clinical neuropathy by 64% (95% CI 45–76), macrovascular complications by 54% (95% CI 2–78) and diabetes-related death by 81% (95% CI 28–95) (Fig. 2).