Background Humerus fractures (HF) are one of osteoporotic fragility fractures. The risk of a humeral fracture and its prediction by measuring bone density (BMD) at different sites has not been performed. Furthermore, the predictive factors of sustaining an isolated humerus fracture as compared to the risk factors of multiple fractures, have not been examined previously.
Objectives This study aimed to determine the following unexplored areas: A) The predictors of HF by measuring BMD at different sites using a case-control approach; B) The predictors of an isolated HF compared to multiple fractures.
Methods A cohort of patients with humerus fractures attending for a DEXA scan between 2004 and 2011 were identified. The cohort was divided into two groups: patients with isolated HF versus patients with multiple fractures. Additionally, a control group which had no indication for scanning was age and sex matched with the HF cases.
Patients' characteristics including age at scan, height, weight, body fat, index of multiple deprivation (IMD) scores, BMD scores of the lumbar vertebrae (L1-L4) and the femoral neck were compared between patients with isolated HF versus multiple fractures and between cases and controls. Univariate and multivariate logistic regression models were applied to identify variables predictive of HF in the case-control group and variables predictive of isolated HF versus multiple fractures. Analyses were adjusted for possible confounders.
Results A total of 1566 patients were included in the study: 783 cases and 783 controls, inclusive of 684 (87%) females in each group. Cases included 447 patients with isolated HF (86% female) and 336 patients with multiple fractures (89% female). Results of univariate regression analyses are shown in the Table 1 below. In the case-control group, multivariate analysis adjusted for height, weight, body fat and deprivation score, revealed a significant association between having HF and lower BMD in the lumbar spine OR0.03 (95% CI0.01, 0.09) and the femoral neck OR0.01 (95% CI0.002, 0.06). In the isolated versus multiple fractures, multivariate-adjusted analysis showed a significant association between age at scan and sustaining an isolated humerus fracture: lumbar spine OR4.64 (95% CI 2.08, 10.36) and femoral neck OR11.48 (95% CI2.47, 53.34).
Conclusions This study demonstrates that humerus fractures occur with higher body fat content, lower BMD and higher deprivation. Moreover, patients with multiple fractures were older and had lower BMD. Further work on differences between patients with fractures is needed.
Disclosure of Interest None declared