5771 - Chemotherapy associated Hyponatremia in Hematological Malignancies: A retrospective study of 189 patients treated in a single medical center

Background

Hyponatremia, usually defined as the sodium serum level < 135 mEq/l (mmol/l), is a common electrolyte disorder in the clinical practice.¹ Despite its often benign course, it can rapidly evolve into a life threatening condition mainly due to neurological symptoms. Moreover, in cancer patients, hyponatremia is significantly associated with reduced overall survival.² In cancer patients hyponatremia can occur due to malignancy as well as chemotherapy.³ Many chemotherapy drugs have been reported to induce hyponatremia.⁴ This study aims to determine which chemotherapeutic drugs used in hematological patients are mostly associated with hyponatremia.

Methods

This study analyzed retrospectively the data from 189 patients with diagnosed haematological malignancies that developed hyponatremia while undergoing chemotherapy. The period of observation was determined to start at the first day of a chemotherapy cycle until the 3^rd day after the end of a cycle. For the purpose of this study, hyponatremia was defined as serum sodium level < 135 mEq/l (mmol/l).

Results

In our cohort of 189 patients with hyponatremia the most predominant hematological malignancy was Multiple Myeloma, which was present in 56 (29.6%) of the included patients and was followed by diffuse large B-cell Lymphoma with 34 (13.2%) patients. The median age of the studied cohort was 68 years (range 33-84 years).The mean value of serum sodium was 130.4 ± 0.27 mEq/l. 42 (22.4 %) patients had hyponatremia in the 4^th cycle of the chemotherapy, with 101 (53.4%) patients developing hyponatremia in the first 4 cycles of the chemotherapy. From all patients with hyponatremia (n = 189), 43 (22.7%) received Cyclophosphamide, 38 (20.1%) Vincristine, 85 (44.9%) Cyclophosphamide and Vincristine as part of a combination, 20 (10.5%) Methothrexate, 18 (9.5%) Cisplatin and 8 (4.2%) Daratumumab.

Conclusions

Patient with hematological malignancies are at increased risk of hyponatremia possibly induced by chemotherapy. The combination regimens seem to increase the risk of developing hyponatremia substantially. In which way the occurrence of hyponatremia depends on cofactors such as infusion schemas or tumor lysis has to be evaluated in prospective studies.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.