In this randomized controlled trial of a primary care based diabetes decision support system, patients in the intervention group had significant reductions in utilization of hospital and emergency care. The estimated return on investment for VDIS to a payer is at least 3.7 and is even greater among seniors and men.
Although this is a randomized study, randomization by cluster (practice) allowed the two groups to be somewhat different in age and gender at baseline. However, the subgroup analyses show that the overall effect is unlikely to be due to these differences.
The analysis is limited by the unavailability of data from hospitals and emergency rooms in New York State. This undoubtedly falsely lowers the estimates of utilization. However, in a randomized trial, this effect is similar in both groups. The higher proportion of control subjects among Vermont residents suggests that the relative difference between intervention and control groups would have been even larger if we had access to New York data.
All of the analyses of the effect of VDIS or Vermedx® on utilization have limitations. The initial analysis of the randomized population5
was free of bias, but subject to recall error. The insurance claims data were not subject to recall error, but were not randomized and applied to only one payer.3
The hospital data presented here are randomized and apply to all payers without recall error, but exclude an unknown number of admissions and emergency room visits. The current study excludes certain costs, such as physicians’ office visits, medications and supplies, and laboratory testing, which may be higher in the intervention group due to improved patient monitoring and care. Although randomized, the two groups did differ at baseline (). However, these differences favored the control group suggesting that any potential bias has the effect of reducing the apparent effect of the intervention.
Although each study is limited, together they comprise a consistent body of evidence that VDIS or Vermedx® reduces health care utilization of adults with diabetes. The results further support previous research that shows provider-centered interventions, such as diabetes registries and clinical decision support, improve outcomes and reduce costs 8-12
For instance, Bu et al
. estimated that over a 10 year period, diabetic registries saved $14.5 billion ($1,016 per enrolled patient), and clinical decision support systems saved $10.7 billion ($752 per enrolled patient)9
, suggesting a savings of similar magnitude to VDIS.
The mechanism by which VDIS or Vermedx® reduces utilization is uncertain. The cost savings are unlikely to be related to prevention of cardiovascular complications because glycemic control, cholesterol level, blood pressure, and self-care behavior remained unchanged between the control and intervention groups.6
However, the intervention facilitates communication between patient and PCP and may stimulate more scheduled contact with the PCP and thereby reduce the need for emergency care. It is also possible that communications from the provider (in the form of reminder and alert letters generated by VDIS) are reassuring to the patient, raising the threshold for urgent visits to the emergency room. Further studies are needed to better understand the mechanism of cost reduction.