Malignant and Non-Malignant Causes of Hypercalcemia: A Retrospective Study at a Tertiary Care Hospital in Pakistan

Background: Hypercalcemia is a common electrolyte abnormality presenting with a variety of symptoms. The common causes are primary hyperparathyroidism and malignancy associated with hypercalcemia. However, iatrogenic hypercalcemia with the overzealous use of vitamin D has now emerged as another important cause of hypercalcemia over the past decade. Objective: This study aims to evaluate the causes of hypercalcemia, management strategies, and outcomes in patients admitted with hypercalcemia in a tertiary care hospital. Method: It is a retrospective study done at Aga Khan University Hospital (AKUH), Karachi after taking approval from the ethical review committee (ERC). Data were gathered about all patients admitted from 1st( )January 2008 to 31st( )December 2018. A total of 1142 patients were included in the study and their calcium levels were noted. Along with demographic details, data pertaining to their diagnosis and all investigations done to evaluate the causes of hypercalcemia were noted in a pre-defined questionnaire. Results: A total of 814 patients having hypercalcemia were included in the final analysis and their mean age was 60.8 ± 14.1 years. Male and female patients were 45.4% and 54.6%, respectively, and their mean hospital stay was 6.2 ± 5.8 days. The most common cause of hypercalcemia was malignant solid tumors (49.1%), followed by hematological malignancy (16.5%), hyperparathyroidism (10.9%), definite vitamin D toxicity (8%), chronic kidney disease (4.9%), chronic granulomatous diseases (4.7%), and probable vitamin D toxicity (3.5%). The oral cavity carcinoma (17.7%) was the most common solid tumor associated with hypercalcemia. Amongst hematological malignancy, multiple myeloma (14.4%) was the most common one. Out of 814 patients admitted with hypercalcemia, 601 (74%) patients recovered from hypercalcemia, while mortality was observed in 129 (16%) patients. Of those who expired, 110 (85.3%) had malignancy either solid tumor or hematological. Conclusion: Malignancy is the most common cause of hypercalcemia in admitted patients. The knowledge of hypercalcemia’s causes is of great importance so that targeted investigations can be done. Not only will it minimize the cost burden and shorten the hospitalization of patients; it will also help the physicians to decide the appropriate management accordingly. Moreover, vitamin D toxicity was also observed in a significant number of patients which highlights the common practice of using higher doses of vitamin D by physicians.