Endocrine Abstracts

Introduction: Fragility fractures are increasingly recognized as a complication of diabetes mellitus (DM). Disease duration, poor glycemiccontrol, diabetes complication, and glycemic variability may be associated with increased risk.

Aim: To investigate the association between glycemic control and hip fracture (HF) risk in a cohort of diabetic patients.

Methods: This retrospective cohort study included all patients 50 years and older with ICD-9 diagnosis of DM or HbA1c measurement ≥6.5% between 2001–2016 from Southern Israel, insured by Clalit Health Services. Data included demographic and clinical information, as well as use of anti-diabetic and anti-osteoporotic medication. Association between mean HbA1c in the last year of follow-up (prior to HF or end of follow-up for patients without HF) and hip fracture risk was analyzed using logistic regression.

Results: Our cohort comprised 51381 patients. During median follow up of 8.5 years (IQR 4.75–13.16), 1377 patients (2.67%), experienced HF, 69% of which were females. Patients with HF had longer diabetes duration than patients without HF; 8 years (IQR 5–13 years) vs. 7 years (IQR 5–12) P<0.0001. Mean age at last year of follow-up (before fracture for HF patients) was 71.71±10.329 in non-fracture patients, and 80.34±9.59 in patients who experienced HF (P<0.0001). Mean HbA1c in the last year of follow up was higher in those who experienced HF, 7.9 (IQR 6.8–9.65) vs. 6.82% (IQR 6.26–7.77) respectively, P<0.0001. Patients with HF had higher rates of use of insulin, sulfonylureas, glinides and combination anti diabetic medications, lower rates of use of DPP4 inhibitors but no difference in the use of thiazolidinediones or metformin. Use of bisphosphonates (BP), vitamin D and calcium supplements were higher in the year prior to fracture among patients who suffered a HF, however, the absolute treatment rate with BP was low (12% in HF patients). Multivariate analysis adjusted for gender, age, Charlson index, duration of diabetes and glycemic variability (coefficient of variation of A1c values over the follow-up years) showed that the adjusted odds ratio (OR) for HF (reference group 6.5%≤HbA1c<7.5%) was 0.390 (0.309–0.491) for HbA1c<6.5%, 1.685 (1.389–2.044) for 7.5%≤HbA1c<8.5%, 2.765 (2.208–3.462) for 8.5%≤HbA1c<9.5%, and 9.19 (7.507–11.25) for HbA1c≥9.5% (P<0.0001 for all comparisons).

Conclusion: Worse glycemic control was exponentially associated with an increased HF risk.