Objective: To confirm the cost savings in a randomized clinical trial of the Vermedx Diabetes Information System (hereafter referred to as the Diabetes Information System [DIS]) in independently collected data using claims paid by a managed care insurer for patients with and without DIS participation.
Study Design: Longitudinal analysis of paid claims with concurrent and historical controls from October 2002 through October 2007. Methods: Using locally weighted smoothing functions and linear regression analysis before and after commencement of the DIS, we compared the total claims paid per member per month for 153 patients using the DIS versus 870 control patients.
Results: For DIS patients, paid claims increased at a rate of $8.30 (95% confidence interval [CI], $1.12-$15.48) per month before the DIS started compared with −$3.92 (95% CI, −$9.50 to $1.67) after commencement of the DIS (P = .008). For control patients, the slope changed from $6.80 (95% CI, $3.78-$9.82) to $3.16 (95% CI, −$1.06 to $7.38) (P = .17). After commencement of the DIS, the slope of the claims in the DIS group is significantly lower than that of the control group (−$3.92 vs $3.16, P = .046). The mean estimated savings range from $504 per patient in year 1 of operations to $3563 in year 4. The cumulative net savings reach $8134 in 4 years.
Conclusions: Participation in the DIS is associated with substantial reductions in claims paid, net of the costs of the intervention. The cost savings reported in the randomized clinical trial of the DIS are reproduced in an independent data set.
(Am J Manag Care. 2009;15(3):166-170)
The DIS has been described previously.4,5 The system receives laboratory results (glycosylated hemoglobin and cholesterol levels and kidney function) from clinical laboratories, maintains a registry, and produces reports for primary care providers and their patients. Reports are automatically generated whenever a laboratory test is completed and include flow sheets with guideline-based recommendations for the providers and alert letters for the patient (when results the patient (when results are above target). When test results are overdue, a reminder is sent to the patient and the practice. Population reports listing all the provider’s patients are sent to the provider quarterly, along with a report card indicating population-level performance. Reports are mailed to patients and are sent electronically or by fax to the practices. The system is not linked to any pay-for-performance incentives.
Setting and Subjects
Vermont Managed Care, Inc (VMC ) is a physician hospital organization serving 31,673 covered lives in Vermont. Practices began participation in the DIS in May 2003 through February 2008. All adults with diabetes covered by VMC were included, regardless of which practice they attended. Adults with diabetes covered by VMC and receiving primary care from participating practices were enrolled in the DIS when their practice first participated. All other adults with diabetes covered by VMC were included as control subjects.
Claims paid for all covered services from October 2002 through October 2007 were aggregated per patient per month. Patient-months with no claims were set to zero if the patient was covered that month. For DIS subjects, each patientmonth was assigned a number relative to the time the patient was first entered into the DIS. The month of DIS enrollment was assigned as zero. Negative numbers represent the number of months before starting the DIS, and positive numbers represent the number of months in the DIS. For control patients, a random month was chosen during the time of coverage to represent the “zero month.”
The DIS and control patients were compared using Wilcoxon signed rank sum test for continuous variables or χ2 test for categorical variables. The relationship between claims paid and time was estimated using nonparametric locally weighted smoothing functions6 and 2-piece ordinary least squares linear regression analysis with adjustment for clustering within members.7 Two-tailed P <.05 represented statistical significance.
This study was performed in accordance with ethical research standards. The research protocol was approved by the University of Vermont Committees for the Protection of Human Subjects.
The utilization records of 153 patients participating in the DIS and of 870 control patients were analyzed. All claims paid for the period of analysis were available, with no missing data. The DIS subjects received 193 alert letters (0.8 per patient per year) and 764 reminder letters (3.3 per patient per year). Their providers received 818 flow sheets (3.6 per patient per year) and 725 reminders (3.1 per patient per year). Overall, the system generated 2500 reports (10.7 per patient per year). The control patients and providers received none. Fifty-five percent of the subjects were male. The mean age at enrollment was 52.4 years, with 7.8% being 65 years or older at enrollment. The mean period of enrollment was 44.5 months. The DIS patients had longer periods of observation and fewer paid claims per month (Table 1). The number of subjects contributing data varied from 11 control and 21 DIS subjects at 48 months before the start of the DIS, to 860 control and 131 DIS subjects at the start of the DIS, to 89 control and 18 DIS subjects at 48 months after the start of the DIS.
The nonparametric curve of claims paid per member per month as a function of time relative to starting the DIS has a distinct inverted-U shape (Figure 1), with the peak at 9 months after the start of the DIS. For control patients, the curve continues to rise without decline.
Fitting a straight line to the data for the period before the start of the DIS (Figure 2) shows that paid claims increased at a rate of $8.30 (95% confidence interval [CI], $1.12-$15.48) per month. A second line that was fit to the data after the DIS started decreased, with a slope of −$3.92 (95% CI, −$9.50 to $1.67) per month. The difference between the 2 slopes is highly statistically significant (P = .008). For control patients, the slope changed from $6.80 (95% CI, $3.78-$9.82) to $3.16 (95% CI, −$1.06 to $7.38) per month (P = .17). The slopes of the 2 lines for the earlier period are not significantly different ($8.30 vs $6.80, P = .70).