Abstract
HbA1c is widely used as an efficacy index in the treatment of diabetes, and HbA1c level before administration of hypoglycemic agents, is considered one of the important predictors of hypoglycemic effect. In this study, we investigated the relationship between pre-administration HbA1c level and the HbA1c level 3 months after administration to determine the optimal interpolation method when using the HbA1c level 6 months before administration in diabetic patients treated with DPP-4 inhibitors as monotherapy.
With 221 enrolled patients, the post-administration HbA1c level that showed the best correlation with the pre-administration HbA1c level was the measured real value (correlation coefficient: 0.59). It is higher than the difference and the rate of HbA1c levels before and after administration.
Comparing the correlation with HbA1c level after administration using various pre-administration HbA1c levels indicates that the correlation coefficient was higher when the HbA1c level 6 months before administration was used than when one point of the pre-administration value was used. The highest correlation (correlation coefficient: 0.62) was shown by the backward interpolation method.
HbA1c is known to have intra-individual variation. It is considered that higher correlation with HbA1c after administration was obtained when the HbA1c level was used multiple times in the 6 months before administration because the intra-individual variations could be absorbed. Among various interpolation methods, the backward interpolation method showed the highest correlation, which is consistent with HbA1c being an indicator of blood glucose status in the past 1-2 months. This study is an exploratory study in which pre-administration HbA1c level of DPP-4 inhibitors was univariately analyzed. Univariate analysis of pre-administration HbA1c level in patients treated with DPP-4 inhibitors was conducted. It was shown that a method of retrospectively interpolating HbA1c level for 6 months before administration may be useful as a predictor of hypoglycemic effect.
