Incidence of Hyponatremia in Patients With Indwelling Peritoneal Catheters for Drainage of Malignant Ascites

IMPORTANCE: Indwelling peritoneal catheters (IPCs) are frequently used to drain tense, symptomatic, malignant ascites. Large-volume drainage may lead to hyponatremia owing to massive salt depletion. To date, no studies have examined the epidemiology of hyponatremia after placement of an IPC. OBJECTIVE: To evaluate the incidence of hyponatremia after IPC placement, the risk factors associated with its development, and how it is managed. DESIGN, SETTING, AND PARTICIPANTS: This cohort study retrospectively reviewed the medical records of 461 patients who had IPCs placed during the period between 2006 and 2016 at a tertiary care hospital in Boston, Massachusetts, of whom 309 patients met the inclusion criteria. Data analysis was performed from June to November 2019. MAIN OUTCOMES AND MEASURES: Main outcomes were the incidence of hyponatremia (with a serum sodium level <135 mEq/L) after IPC placement, the risk factors for its development, and how it was managed. We also examined the clinical course of a subset of 21 patients with hypovolemic hyponatremia. RESULTS: Of the 309 eligible patients with laboratory results both before IPC placement and 2 days or more after IPC placement, 189 (61.2%) were female, and the mean (SD) age was 59 (12) years. The overall incidence of hyponatremia after IPC placement was 84.8% (n = 262), of whom 21 patients (8.0%) had severe hyponatremia. The mean (SD) decrease in serum sodium level before vs after IPC placement was 5 (5.1) mEq/L and decreased by 10 mEq/L or more among 52 patients (16.8%). Patients with hyponatremia prior to IPC placement had an 8-fold higher adjusted odds of having persistent hyponatremia after IPC placement (odds ratio, 7.9; 95% CI, 2.9-21.7). Patients with hepatopancreatobiliary malignant neoplasms were more likely to develop hyponatremia (78 of 262 patients with hyponatremia [29.8%] vs 7 of 47 patients without hyponatremia [14.9%]). Hyponatremia was either unrecognized or untreated in 189 patients (61.2%). CONCLUSIONS AND RELEVANCE: Although the placement of an IPC is often a palliative measure, hyponatremia is common and is often untreated or unrecognized. Patients at highest risk, such as those with hyponatremia at baseline and those with hepatopancreatobiliary malignant neoplams, should be evaluated carefully prior to IPC placement and may warrant closer monitoring after placement. In all cases, hyponatremia should be evaluated and managed within the context of a patient’s overall goals of care.