Background <p>Self-monitoring blood glucose (SMBG) is an important factor for glycemic control in people with diabetes. Many countries have implemented policies to support SMBG for better glycemic control. The long-term impact of supporting the cost of SMBG strips for glycemic control in type 1 diabetes mellitus (T1DM) and insulin-treated type 2 DM (T2DM) have been determined in only a few studies.</p> Methods <p>People with T1DM and insulin-treated T2DM for whom the cost of blood glucose strips was and was not supported were included in the present study. Longitudinal changes in HbA1c were repeatedly measured in people with T1DM and insulin-treated T2DM at baseline, and 3, 6, 9, and 12 months. The inverse probability of treatment weighting (IPTW) linear mixed effect model (LMM) analysis was used.</p> Results <p>Among people with T1DM and insulin-treated T2DM, subjects who received support for strip prescriptions showed significantly decreased hemoglobin A1c (HbA1c) levels (0.78% and 0.92% at 12 months, respectively), with significant between-group differences compared with subjects who did not receive support (<i>p</i> &lt; 0.001). When using the IPTW-LMM after adjusting for covariates, the mean reduction in HbA1c every 3 months in T1DM and insulin-treated T2DM subjects with strip prescriptions was − 0.105% (95% CI: −0.197 to − 0.014) and − 0.112% (95% CI: −0.143 to − 0.082), respectively, compared with their respective control groups without strip prescriptions.</p> Conclusions <p>In conclusion, the reimbursement policy supporting the cost of blood glucose strip prescriptions was associated with significant reduction in HbA1c levels in people with T1DM or insulin-treated T2DM.</p> Graphical Abstract <p></p>