Etiological Spectrum of Hypercalcemia in a North Indian Tertiary Care Center: Emerging Role of Vitamin D Toxicity.

INTRODUCTION

Globally, primary hyperparathyroidism and malignancy account for the majority of hypercalcemia cases. However, regional epidemiological variations exist. Kashmir, a high-altitude region in North India with a high prevalence of vitamin D deficiency, has witnessed increasing use of high-dose vitamin D supplementation. This has led to growing concern about iatrogenic hypercalcemia secondary to hypervitaminosis D. This study aimed to evaluate the current etiological spectrum of hypercalcemia among hospitalized patients in Kashmir and to assess the contribution of vitamin D toxicity and its underlying causes.

MATERIALS AND

METHODS

This retrospective study included adult patients (≥18 years) admitted to a tertiary care center in Kashmir between 1 January 2025 and 30 June 2025 with corrected serum calcium >10.5 mg/dL on at least two occasions. Demographic data, biochemical parameters, and etiological diagnoses were retrieved from hospital records. Data were analyzed using descriptive statistics, and comparisons between groups were performed using the Student's t-test, Mann-Whitney U test, and chi-square test.

RESULTS

A total of 40 patients were included (mean age 62 ± 12.8 years; 52.5% female). Malignancy (including multiple myeloma and lymphoma) was the most common cause of hypercalcemia, followed by primary hyperparathyroidism (20%) and vitamin D toxicity (20%). Patients with hypervitaminosis D had markedly elevated 25-hydroxyvitamin D levels (123.5 ± 25 ng/mL) with suppressed intact parathyroid hormone (iPTH) levels. Patients with malignancy-associated hypercalcemia were significantly older than those with non-malignant causes, whereas serum 25-hydroxyvitamin D levels and iPTH were significantly higher in the non-malignant group. Review of prior regional studies demonstrated frequent administration of high-dose intramuscular cholecalciferol (600,000 IU) and repeated high-dose oral supplementation as major contributors to toxicity.

CONCLUSIONS

While malignancy and primary hyperparathyroidism remain leading causes of hypercalcemia in hospitalized patients, vitamin D toxicity now represents a significant and preventable contributor in the Kashmiri population. Greater emphasis on rational prescribing, avoidance of high-dose intermittent regimens, and appropriate biochemical monitoring is warranted to reduce iatrogenic hypercalcemia.