Treatment outcomes of hypercalcemia that resulting in hospital admission in cancer patients treated with bisphosphonates in real-world setting

Abstract

Limited real-world studies have assessed bisphosphonates (BPs) treatment for hypercalcemia of malignancy (HCM) requiring hospital admission. We aimed to evaluate the response to BPs in terms of rate, timing and 30-day readmission. This retrospective study included adult cancer patients admitted to the hospital with hypercalcemia from January 2019 to August 2023. Medical records were reviewed to collect baseline characteristics and treatment outcomes of HCM, including complete remission (CR), defined as corrected serum calcium (CSC) normalization to 10.8 mg/dl or below, partial response (PR), defined as CSC trending down but not reaching 10.8 upon discharge, and readmission due to hypercalcemia within one month. During the study period, 505 patients were included, with a mean age of 58.2 years (± 12.5 SD); 52.3% were male, predominant cancers were breast 26.1% and lung 16.0%, with 53.9% having bone metastasis. Severe, moderate, and mild hypercalcemia were observed in 30.5%, 46.9%, and 22.6% patients, respectively. Zoledronic acid and pamidronate were administered to 75.4% and 24.6% patients, respectively. CR was achieved in 73.5% of patients, while 19.4% showed PR, and 2.6% had no response. Zoledronic acid led to faster CSC normalization (2.6 days ± 1.5 SD) compared to pamidronate (3.9 days ± 2.4 SD) (P = 0.001). Additionally, 13.7% of patients required readmission due to hypercalcemia, with a significantly lower rate associated with zoledronic acid compared to pamidronate (P = 0.042). While BPs were effective in achieving CR in most patients, a remarkable fraction required readmission, highlighting the need for additional research to identify factors predisposing patients to recurrent hypercalcemia.