Several studies have evaluated the cost-effectiveness of CHW-led diabetes management programs rather than the ROI as these types of programs are often associated with improved health outcomes but also increased health care costs as the result of expanding health care access and services to underserved populations [15,25–29]. Most of these evaluations modeled the long-term cost-effectiveness, as the majority of cost savings from diabetes management programs are likely to accrue in the long run as a result of the prevention of diabetes-related complications such as amputations, blindness, kidney failure, coronary heart disease, and stroke [15,25]. Although these CHW-led interventions for diabetes differed in scope, the incremental cost effectiveness ratios for these interventions were less than the common willingness-to-pay threshold of $50,000 per quality-adjusted life year (QALY). These studies may have underestimated the societal benefits of these programs as they did not incorporate non-medical cost savings such as those that may be attributed to gains in productivity [26].
A recent cost-effectiveness analysis of the DEP and the 4 other programs that were part of the Alliance to Reduce Disparities in Diabetes found that these programs spent an average of $975 per patient in the first year and additional $520 per patient in subsequent years to improve care for diabetes patients [15]. Based on improvements in health indicators such as HbA1c, systolic blood pressure, and total cholesterol observed for participants in Alliance programs, the incremental cost-effectiveness ratio of these programs was $23,161 per QALY given the optimistic assumption that the observed improvements in health indicators were all attributable to the interventions. DEP patients achieved a 1% average reduction in mean HbA1c and this improvement was sustained over the course of the program. The UK Prospective Diabetes Study Group found that every 1% reduction in HbA1C reduces a patient’s risk of developing eye, kidney, and nerve disease by 40% and the risk of heart attack by 14% [30]. Thus, if DEP patients sustain improvements gained as a result of program participation, they may avoid serious and expensive medical complications in the future.
Ultimately, the goal of the DEP was to provide patients with improved access to diabetes care and to help them achieve improved glucose control. Improving access to chronic disease care is costly. However, employment of CHWs is a less costly alternative to employing additional clinicians, and CHWs may be more effective in assisting patients with chronic disease management particularly those from underserved and vulnerable populations. Although we did not generate a positive ROI for the DEP in this short-term analysis, the program is likely cost-effective when the low cost of the program is compared with the improvements in health outcomes we have observed.
This study had several limitations. There were observed differences in gender and ethnicity between the intervention and control groups and it is likely that risk-adjustment (including propensity scoring) did not fully accountfor underlying differences between the populations. The observed reductions in inpatient utilization and costs in the intervention group may have been due to other factors besides the DEP as the control group also achieved reductions in inpatient LOS and costs. The control group did contain a few outliers in terms of high pre-period medical costs which were retained in the analysis and these outliers may have caused reductions in costs for this group to be overstated. The observed outcomes may also be biased due to intervention contamination. Patients in the control group attended the same clinics as DEP patients and were treated by the same primary care physicians. The primary care physicians likely applied the knowledge gained from working with DEP patients and the CHWs, including how to identify and help patients address the specific barriers to diabetes self-management faced by clinic patients, to the treatment of patients who were not enrolled in the DEP. The fact that health care utilization and costs were much higher for patients in the control group in the pre-period indicates that these patients had greater severity of illness and additional comorbidities, and the observed reductions in utilization and costs for these patients may have been the result of obtaining access to a regular source of primary care through the clinics. However, the observed decrease in inpatient encounters from .18 to .08 in the post period for DEP patients as well as the observed decreases in inpatient LOS and direct costs indicate that the DEP may provide additional benefits compared to access to primary care alone in terms of avoidance costly hospitalizations for diabetes-related complications.