Serum Resistin in Older Patients with Hip Fracture: Relationship with Comorbidity and Biochemical Determinants of Bone Metabolism

Objectives: To determine the relationship of serum resistin concentrations to biochemical determinants of bone metabolism, comorbidity and outcomes in patients with hip fracture (HF).

Methods: In 256 consecutive patients (mean age 81.9±7.8 years; 71.1% women) serum levels of resistin (determined by ELISA), biochemical parameters of bone turnover and mineral metabolism as well as routine haematological and biochemical parameters were measured. Clinical data were recorded prospectively.

Results: In multivariate analysis cervical HF (OR=1.81; 95% CI 1.05-3.11), diabetes (OR=2.60; 95% CI 1.23-5.51) and history of stroke (OR=2.67; 95% CI 1.17-6.13) were significant independent predictors of higher resistin levels (≥16.26 ng/ml, median value). The independent correlates of serum resistin levels in patients with cervical HF were serum osteocalcin and magnesium (both negatively associated) and in patients with trochanteric HF, serum PTH, calcium and age (all positively associated). Resistin and glomerular filtration rate were the only independent (inverse) predictors of serum osteocalcin. Resistin levels on admission did not predict short-term outcomes.

Conclusions: In older patients with HF there is a significant association of higher resistin levels with cervical fracture, type 2 diabetes and history of stroke, which is partly influenced by the reciprocal interaction between resistin and osteocalcin. However, the design of the study does not prove causality and further prospective studies are needed to clarify these relationships.