Endocrine Abstracts

Background and aims: Electrolyte imbalance is common among hospital inpatients, reflecting severity of underlying illness, but also independently contributing to excess morbidity and mortality. However, studies have largely been retrospective, with incomplete data capture. We prospectively evaluated the prevalence of major Na and Ca disorders among inpatients at the Newcastle-upon-Tyne Hospitals.

Method: With approval of the Information Guardian, we used Laboratory Medicine Cognos software to conduct a proactive audit (28 January–28 February 2016), with data released twice-weekly, typically enabling us to complete the dataset acquisition through eRecord ‘add-on requests’ for stored serum. Inclusion criteria were: serum Na ≤120 or ≥160 mmol/l, serum adjusted Ca ≤2.00 or ≥2.79 mmol/l. Patients aged <18 years, on ITU, or maternity unit were excluded.

Results: 114/4238 inpatients satisfied our criteria for major electrolyte imbalance. The most common abnormality was hypocalcaemia (1.3%) and the least common was hypernatremia (0.1%). 18 patients had hyponatraemia (0.4%) whilst 36 had hypercalcaemia (0.9%). Review of on-call logs over the corresponding period allowed us to estimate that <¼ had been discussed with Endocrinology. Twenty-two patients (19%) had persistent electrolyte disturbance at the end of the study; all Ca-related disorders. The overall mortality associated with these major electrolyte abnormalities was 18% (83% for hypernatraemia; 11% for hyponatraemia). The most common cause of hyponatremia was medication-related, whilst renal failure and malignancy accounted for the majority hypocalcaemia and hypercalcaemia, respectively. Vitamin D deficiency (pre-defined as <50 nmol/l) was coexistent in 31% of our patients with calcium disorders.

Conclusions: The incidence of major abnormalities among the general (non-ITU, non-maternity) adult inpatient population was 27/1000 inpatients per month, of which 19% were persistent. However only 21% were referred to Endocrinology. Given the high mortality of these electrolyte imbalances, the development of an eRecord alert system targeting early input from Endocrinology needs further exploration.