Serum calcium–phosphorus product for predicting the risk of osteoporotic vertebral compression fractures in elderly patients: a retrospective observational study

BACKGROUND: This study retrospectively analyzed and evaluated the potential correlations of serum calcium, serum phosphorus, and calcium-phosphorus product (Ca–P product) with the incidence of osteoporotic vertebral compression fractures (OVCFs), with the aim of exploring whether the Ca–P product can be used as a serological indicator to predict the risk of OVCFs. METHODS: This study randomly enrolled 400 elderly patients in our hospital with OVCFs and 400 patients with hip and knee arthroplasty due to femoral head necrosis or osteoarthritis from August 2013 to April 2021. Age, sex, past medical history, and admission biochemical indicators, including albumin, blood urea nitrogen, serum creatinine, serum calcium and serum phosphorus, were collected for statistical analysis. RESULTS: Albumin, serum calcium, serum phosphorus, Ca–P product, corrected serum calcium and corrected Ca–P product were lower in the OVCF group than in the non-OVCF group (P < 0.05). Multivariate logistic regression analysis showed that low values of serum calcium, serum phosphorus, Ca–P product, corrected blood calcium, and corrected Ca–P product can all be risk factors for OVCF. The ROC curve showed that the Ca–P product and corrected Ca–P product were effective in predicting the risk of OVCFs. The predictive value of the Ca–P product was the best; the cutoff point was 29.88, the sensitivity was 0.72 and the specificity was 0.62. The cutoff point of the corrected Ca–P product was 30.50, the sensitivity was 0.74, and the specificity was 0.62. CONCLUSION: The Ca–P product and corrected Ca–P product can be used as serological indicators to predict the risk of OVCFs in elderly individuals. Early clinical interventions targeting this risk factor can further reduce the risk of OVCFs. Also, timely and regular testing of the serum calcium and phosphorus level is recommended and encouraged for this group of people.