Low Preoperative Calcium Linked to Higher Postoperative Risk among elderly orthopedic patients: Study
China: Researchers have found in a new study that lower preoperative serum calcium levels are associated with an increased risk of postoperative complications in older orthopedic patients. As orthopedic surgeries in older adults continue to rise, monitoring and correcting calcium levels before surgery may help reduce complications.
The findings were published in PLOS One by Doudou Li and colleagues from the Clinical Pharmacy Center, Department of Pharmacy at Zhejiang Provincial People’s Hospital in Hangzhou, China. The study explored whether preoperative serum calcium levels could help predict the likelihood of complications after orthopedic surgery in older adults.
Serum calcium is an essential biochemical marker that plays a major role in bone metabolism, muscle function, and overall physiological balance. Despite its importance in skeletal health, limited research has examined whether low calcium levels before surgery may influence postoperative outcomes in elderly patients undergoing orthopedic procedures.
To investigate this, the researchers conducted a multicenter cohort study involving 690 older adults who underwent orthopedic surgery. Statistical analyses, including multivariate logistic regression and generalized additive models, were used to assess the relationship between preoperative calcium levels and postoperative complications. The researchers also evaluated potential dose-response relationships and explored threshold effects.
The following were the key findings:
- Common postoperative complications observed in the study included infections, hypoalbuminemia, and electrolyte imbalances.
- Preoperative serum calcium levels were independently associated with the risk of postoperative complications.
- Higher calcium levels showed a protective effect, reducing the likelihood of adverse postoperative outcomes.
- Patients in the lowest serum calcium group had a significantly higher risk of complications compared with those in the highest calcium group.
- Individuals with lower calcium levels had approximately 79% higher odds of developing postoperative complications.
- A nonlinear relationship was identified between serum calcium levels and complication risk.
- A threshold effect was observed at around 2.4 mmol/L.
- Below 2.4 mmol/L, the risk of complications increased significantly as calcium levels decreased.
- Above 2.4 mmol/L, the association between calcium levels and complication risk was not statistically significant.
- Subgroup analyses showed that factors such as age, sex, comorbidities, medication use, cognitive status, cardiac function, and surgical complexity did not significantly influence the relationship between calcium levels and complication risk.
The researchers suggest that serum calcium may serve as an early indicator of postoperative risk in elderly orthopedic patients. Screening for low calcium before surgery could help identify high-risk individuals and enable preventive measures.
The study had several limitations. It lacked external validation, and key regulators of calcium metabolism—such as vitamin D, renal function, and parathyroid hormone—were not assessed. The follow-up period was also limited to three months, which may not capture long-term complications.
Overall, the findings indicate that routine preoperative calcium screening and correction of low levels could be a simple, cost-effective approach to reduce postoperative complications in elderly orthopedic patients. The identified threshold of 2.4 mmol/L may also help guide early calcium supplementation and risk assessment before surgery.
Reference:
Li, D., Zhang, T., Ning, Y., Miao, J., Shi, J., & Hu, Y. (2026). Preoperative hypocalcemia predicts postoperative complications in older orthopedic patients: A multicenter cohort study. PLOS ONE, 21(3), e0340876. https://doi.org/10.1371/journal.pone.0340876
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