A Comparison of Vitamin D Levels and Hip Fracture Severity in Elderly Patients With and Without Type 2 Diabetes Mellitus: A Retrospective Clinical Study.

INTRODUCTION

Evidence shows that poor glycemic control and diabetes are strongly associated with poor bone quality and fragility fractures. This study was conducted to record vitamin D (VD) levels and assess hip fracture severity in elderly hip-fractured patients with and without type 2 diabetes mellitus (T2DM).

METHODS

We examined 114 patients over 65 years old with low-energy hip fractures, classified as extracapsular or intracapsular. Severe fractures were defined by Garden's classification for subcapital fractures and the AO/Orthopaedic Trauma Association classification for intertrochanteric fractures. Patients were divided into two groups: 49 with standard glycemic control (Group A) and 65 with impaired control (Group B). We measured parathyroid hormone (PTH), 25-hydroxyvitamin D, bone mineral density (BMD), hemoglobin A1c (HbA1c), serum albumin (ALB), and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Gender and age had no significant differences. In Group A, 73.5% had osteoporosis, and 26.5% had osteopenia; in Group B, the figures were 66.2% and 33.8%, respectively (p = 0.402). VD levels were similar, with Group A averaging 10.03 ± 5.43 ng/mL and Group B 10.01 ± 5.09 ng/mL (p = 0.986). Group A's mean PTH level was 79.71 ± 57.64 ng/mL, while Group B's was 59.42 ± 45.57 ng/mL (p = 0.018). Among patients with diabetes, 60% were on oral medications, 6.2% on insulin alone, and 16.9% received a combination of treatments. Elderly diabetes patients with hip fractures, those using insulin, or those newly diagnosed with T2DM had lower VD levels. Based on regression analysis, VD is expected to decrease by 0.029 for every unit increase in PTH, concerning all the participants (95% confidence interval: 0.011-0.048). HbA1c and HOMA-IR levels showed significant differences (p < 0.001). Patients with diabetes experienced more unstable fractures (75.4% in diabetics vs. 67.3% in nondiabetics), though fracture type and severity were not statistically significant. More comminuted fractures were noted in patients on oral antidiabetic medications alongside insulin usage and those with less than five years of antidiabetic therapy. ALB levels were similar, with malnutrition prevalent in 75.5% of Group A and 75.4% of Group B patients. Patients with diabetes with malnutrition exhibited lower VD levels compared to those with normal ALB (p = 0.038). Patients with diabetes with poor glycemic control (HbA1c > 6.5%) had higher VD (10.09 ± 4.93 vs. 9.82 ± 5.57 ng/mL) and PTH (58.9 ± 49.99 vs. 50.73 ± 34.01 ng/mL) levels compared to those with adequate control (p values not significant).

CONCLUSIONS

Our study confirmed the paradox that patients with T2DM had increased BMD compared to age-adjusted nondiabetic counterparts. The difference in hip fracture severity was not statistically significant. ALB levels were similar, with malnutrition prevalent in both groups, although diabetic patients with malnutrition are correlated with lower VD levels. VD levels were similar in both groups, but PTH levels were significantly higher in nondiabetics. The relationship between T2DM and PTH remains controversial and needs further investigation. Clinicians should note that low VD levels do not accompany elevated PTH in patients with diabetes, and elevated PTH may indicate poorly controlled T2DM. VD deficiency, hypoalbuminemia, and impaired glycemic control are interconnected issues in elderly patients with low-energy hip fractures.