Increasingly, government mandates require insurance coverage of blood glucose monitors and test strips for patients with type 1 and type 2 diabetes. No data exist on the effects of such coverage on self-monitoring of blood glucose (SMBG), medication compliance, or blood glucose control. We evaluated whether a policy providing free blood glucose monitors increased SMBG and whether initiating SMBG was associated with increased regularity of medication use and improved glucose control (hemoglobin A1c [HbA1c] level).
Using interrupted time-series analysis and controlling for preintervention trends, we determined changes in rates of SMBG 2 years before and after the policy among 3219 continuously enrolled patients with diabetes receiving drug therapy within a multispecialty medical group (part of a health maintenance organization) serving approximately 300 000 patients. We also compared changes over time in regularity of medication use (mean days between dispensings) and mean HbA1c level among initiators and noninitiators of SMBG.
The policy resulted in a small, significant increase in SMBG among insulin-treated patients (n = 1428). Among sulfonylurea-treated patients (n = 1791), the monthly initiation rate of SMBG increased by 14 new patients per 1000 (95% confidence interval [CI], 10 to 17), a doubling of the expected initiation rate. Test strip consumption increased during the first 6 months after the policy by 17.9 strips per cohort member (75% relative increase by 6 months; 95% CI, 50% to 101%). Compared with noninitiators of SMBG, initiators (n = 593) showed sudden, significant improvements in regularity of medication use by 6 months after initiation (−19.5 days between dispensings among those with low refill regularity [95% CI, −27.7 to −11.3]; −9.7 days among those with moderate regularity [95% CI, −12.3 to −7.1]), and in glucose control (−0.63% mean HbA1c level [as percentage of total hemoglobin] among those with poor baseline glycemic control [HbA1c >10%; 95% CI, −1.14% to −0.12%]).
Providing free glucose monitors improved rates of self-monitoring in this health maintenance organization population, possibly by offering an initial incentive for patients to engage in more desirable patterns of care. Initiating SMBG was associated with increased regularity of medication use and a reduction in high blood glucose levels.