Actionable Insights Newsletter

Translating research to power whole health

Issue 6    |    August 2023

Adherence to diabetes medications has significant clinical and economic advantages

For patients with type 2 diabetes, adherence to any non-insulin diabetes medication can help to reduce the risk of death and hospitalization. Adherence to dual therapy may also result in total cost savings.

Enterprise Analytics Core domain(s): Cardiometabolic, cost of care, quality of care, HEDIS/STARS

Summary

Background
Uncontrolled type 2 diabetes mellitus (T2D) increases overall patient morbidity and mortality and significantly increases cost of care burden to the healthcare system in the US. Although research suggests that diabetes medication adherence remains low, there is limited real-world evidence evaluating the causal link between adherence to these treatments and health outcomes and cost of care.

Objective
To assess the causal impact of adherence to any non-insulin diabetes medication and any non-insulin dual therapy on health outcomes and cost of care.

Methods
Carelon Research analyzed data from commercial and Medicare insured Elevance Health members with T2D and integrated medical and pharmacy benefits. Medication adherence to the different regimens was calculated using proportion of days covered (PDC), and PDC was regarded as adherent when it was greater than or equal to 80 percent. Robust causal inference methods, known as marginal structural models, were used to account for the time-varying nature of adherence and control for other factors when evaluating the causal impact of adherence on health outcomes and cost of care.

Results
Of 473,438 T2D patients receiving diabetes medication, 23% received dual therapy. Of these patients, about one fifth received metformin in combination with an SGLT-2 inhibitor or GLP-1 inhibitor. After balancing differences in adherent and non-adherent groups, the impact of adherence to any diabetes medication and to dual therapy on health outcomes followed similar trends. However, adherence to dual therapy was more impactful and led to reduced total costs. Compared to non-adherence to dual therapy, adherence for at least eight months resulted in:

• Reduced risk of cardiovascular event, all-cause mortality, all-cause inpatient admissions, and all-cause emergency room visits.
  
• Reduced average monthly all-cause total costs per patient (Figure 1).
  
• Decreased medical costs offset the increased pharmacy costs (due to adherence).
  
• Significant reductions in average all-cause total healthcare costs per patient per month. 
  
• Increased likelihood of observing microvascular complication coding/diagnosis possibly due to higher frequency of provider visits.
  

Key takeaways