Bone Quality In Chinese Postmenopausal Women With Type 2 Diabetes – Impact Of Dipeptidyl Peptidase-4 Inhibitor Usage

Abstract

Objectives: To compare the bone quality in type 2 diabetes (T2D) subjects to those without T2D and evaluate the impact of dipeptidyl peptidase-4 inhibitor (DPP4-i) usage on bone quality in T2D subjects, in view of the potential effects of DPP4 and the incretins on bone biology. Methods: We conducted a cross-sectional study of post-menopausal women with T2D subjects recruited from the Hong Kong West Diabetes Registry and non-diabetic subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study, from November 2016 to June 2018. Subjects with fasting glucose 5.6–6.9 mmol/L, 2 hours post-load glucose 7.8–11.0 mmol/L in oral glucose tolerance test, or HbA1c 5.7–6.4% were classified as pre-diabetes and those with normal glucose tolerance as euglycaemia. Bone mineral density (BMD), vertebral fracture assessment (VFA), and trabecular bone score (TBS) were measured by dual X-ray absorptiometry. BMD and TBS in DPP4-i users and non-users with T2D were compared. Results: Three hundred and sixty subjects were studied: 98 with euglycaemia, 154 with pre-diabetes, and 108 with T2D. Using euglycaemia subjects as reference, pre-diabetes and T2D subjects were significantly older (euglycaemia 60.0 ± 4.4, pre-diabetes 61.8 ± 5.5, and T2D 63.1 ± 5.5 years, p < 0.001) and heavier (euglycaemia 56.1 ± 9.2, pre-diabetes 60.1 ± 10.1, and T2D 62.0 ± 10.5 kg, P < 0.001). Lumbar spine (LS) BMD among T2D subjects was significantly higher than subjects with euglycaemia after adjustment for age, height and weight (0.942 g/cm2 vs 0.876 g/cm2, P = 0.001). TBS among T2D subjects, however, was significantly lower than those with euglycaemia after adjustment for age, height, weight and LS BMD (1.26 vs 1.30, P < 0.001). Among T2D subjects, 47 were DPP4-i users and 61 were non-users. Mean duration of DPP4i usage was 3.1 ± 2.4 years. Age, height, weight, fragility fracture prevalence, HbA1c, duration of diabetes, and frequency of usage of other oral anti-diabetic agents were not significantly different between the two groups. More insulin usage was found among DPP4-i non-users. After adjustment for insulin usage, there was no difference in LS BMD or TBS between DPP4-i users and non-users. Conclusions: Hong Kong Chinese subjects with T2D had lower TBS, an indirect index of bone microarchitecture, but higher BMD when compared with those with euglycaemia. DPP4-i usage, however, did not have significant impact on BMD or TBS among T2D subjects.