Use of ADH antagonists results in lower hospital resource usage: a retrospective cohort study

Abstract

• Hyponatraemia is the electrolyte disturbance most commonly encountered in clinical practice (affecting 10-30% of hospitalised patients) and can be a marker of morbidity in many contexts, increasing mortality rates regardless of cause. 1• The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of hypotonic hyponatraemia, 2 responsible for approximately 30% of all patients with hyponatraemia.• Data from the US suggest that patients with hyponatraemia have a greater overall consumption of healthcare resources, and that hyponatraemia is associated with an increased length of hospital stay, [3][4][5] and increased direct medical costs. 6• The overall annual cost of hyponatraemia in the US alone has been estimated at $1.6-3.6 billion 7 -there are no comparable cost data for the UK.• The UK Consensus Statement recommends pharmacological therapy (demeclocycline or tolvaptan) for patients with mild/moderate hyponatraemia secondary to SIADH without severe symptoms, after fluid restriction has been attempted or deemed inappropriate. 8• The aim of this study was to understand how hyponatraemia secondary to SIADH is currently treated in England, and to understand the associated resource use.• A retrospective analysis of a patient cohort identified in IMS Hospital Treatment Insights (HTI) through hospital admission diagnosis codes from 1 January 2010 through to 31 October 2013 was conducted.• The HTI database, comprising details of all admissions and outpatient appointments to NHS hospitals in England, contains records on 3.3 million English patients from a source population of 13 million.• Adult patients were included if they had a new World Health Organization (WHO) ICD-10 diagnostic code for 'Hypo-osmolality and hyponatraemia' (E87.1) and/or a diagnostic code for SIADH (E22.2) during the study period.• Exclusion criteria were patients <18 years of age or with no age recorded, or co-morbid conditions associated with hyponatraemia: liver cirrhosis; liver disease with ascites; heart failure; unspecified adrenocortical insufficiency; hypothyroidism; and type 1 diabetes.• Study outcomes were captured through relevant WHO ICD-10 codes and comprised hospital admissions, outpatient visits, length of hospital stay, and in-hospital mortality.• In total, 37,425 patients were given a clinical code for SIADH or hyponatraemia ( Figure 1); >60% of patients were ≥68 years of age.• Of the patients with a diagnosis of hyponatraemia and/or SIADH, 1.8% were given demeclocycline, 0.3% were given tolvaptan, and 97.9% were not given any recorded pharmacological treatment. When pharmacological treatment was given, it was usually as monotherapy.• Mean time from diagnosis to initiation of therapy was similar for both demeclocycline and tolvaptan (10.2 days).-Median time was 3 days longer with tolvaptan at 8 days.• Patients receiving tolvaptan had a shorter mean (11.1 vs 19.3 days) and median (10 vs 14 days) length of hospital stay than those given demeclocycline.• Time to readmission and readmission rates at ...

Management of Persistent Hyponatremia Induced by Long-acting Injectable Risperidone Therapy

“…However, hyponatremia secondary to syndrome of inappropriate antidiuretic hormone (SIADH) is a well-known associated adverse effect of these medications [ 2 ]. If water deprivation and hypertonic saline fail to correct the patient’s hyponatremia, treating SIADH in-patients with tolvaptan compared to demeclocycline could be a more effective approach [ 3 ]. Cases of antipsychotic-induced hyponatremia have been reported in the literature.…”