Low serum calcium is associated with perioperative blood loss and transfusion rate in elderly patients with hip fracture: a retrospective study

BACKGROUND: To investigate whether hypocalcemia influenced total blood loss and transfusion rate in elderly patients with hip fracture. METHODS: From our hip fracture database, patients were consecutively included between January 2014 and December 2020. Serum calcium level was corrected for albumin concentration, and hypocalcaemia was defined as corrected calcium < 2.11 mmol/L. Hemoglobin and hematocrit were obtained on admission day and postoperative day, and blood transfusions were collected. According to the combination formulas of Nadler and Gross, the total blood loss of each patient was calculated. Risk factors were further analyzed by multivariate linear regression. RESULTS: A total of 583 consecutive elderly hip fracture patients were finally included (mean age 79.32 ± 8.18 years, 68.61% female). On admission, the mean serum corrected calcium level was 2.17 ± 0.14 mmol/L, and the prevalence of hypocalcemia was 33.11% (95% CI: 29.42–37.02). When comparing patients with normal calcium, hypocalcemia patients exhibited a higher blood transfusion rate (7.69% vs 16.06%, P < 0.05), and significantly larger total blood loss (607.86 ± 497.07 ml vs 719.18 ± 569.98 ml, P < 0.05). Multivariate linear regression analysis showed that male, anemia on admission, time from injury to hospital, intertrochanteric fracture, blood transfusion and hypocalcemia were independently associated with increased total blood loss (P < 0.05). CONCLUSION: Hypocalcemia is common in elderly patients with hip fracture, and significantly associated with more total blood loss and blood transfusion. The other risk factors for increased total blood loss are male, anemia on admission, time from injury to hospital, intertrochanteric fracture, and blood transfusion. LEVEL OF EVIDENCE: Level III, retrospective study.