Preventing Hypoglycemia Following Treatment of Hyperkalemia in Hospitalized Patients

Hyperkalemia is common in hospitalized patients, with an estimated prevalence of 1%-10%.^1,2 Hyperkalemia can lead to life-threatening cardiac arrhythmias. The risk of arrhythmias increases with serum potassium values >6.5 mmol/L, and hyperkalemia is associated with increased in-hospital mortality.³ Treatment for hyperkalemia is indicated by a combination of the absolute serum potassium level, the rate of change of potassium level, and the presence of electrocardiogram abnormalities.

Intravenous insulin stimulates the sodium/potassium-ATP pump, leading to intracellular uptake of potassium. Recommendations vary regarding the optimal dosing of insulin and dextrose for the treatment of hyperkalemia.⁴

Hypoglycemia is a common complication following treatment of hyperkalemia with insulin/dextrose. The reported incidence in hospitalized patients ranges from 6% to 75% depending on the population studied, the doses of insulin/dextrose administered, and the definition of hypoglycemia.^5-8 Hypoglycemia itself is associated with increased morbidity and mortality in hospitalized patients.⁹

The aims of this study were to describe the incidence of hypoglycemia following hyperkalemia treatment with intravenous insulin/dextrose in inpatients in a large (900-bed) UK teaching hospital and to determine the risk factors predisposing to hypoglycemia.

We conducted a retrospective, single-center cohort study reviewing the Electronic Patient Records (EPR) of all adult (aged ≥18 years) inpatients (excluding critical care) prescribed treatment for hyperkalemia with intravenous insulin from January 1, 2013, to March 1, 2017. Local hyperkalemia treatment guidelines included administration of 10 units of insulin and 100 ml of 20% glucose intravenously in accordance with national guidelines.¹⁰ The study received local approval.

Episodes occurring before May 1, 2015, were excluded because modification to the hyperkalemia prescription care bundle was implemented in April 2015 recommending standardized simultaneous insulin and dextrose administration and hourly capillary blood glucose (CBG) measurement for six hours following treatment. Episodes where no dextrose was prescribed or administered (n = 435) or where no CBG value was recorded within six hours after treatment were excluded (n = 63). All patients included in the analysis received the same insulin/dextrose treatment confirmed by electronic signature of the prescription.

Data extracted included patient demographics, laboratory values, and treatment and administration details. Pretreatment and posttreatment potassium measurements were taken within four hours before and after insulin/dextrose administration, respectively. Serum creatinine and estimated glomerular filtration rate (eGFR) measurements were taken within six hours prior to treatment. Pretreatment CBG levels were measured within two hours of insulin/dextrose administration, and the lowest value within six hours after treatment was used for the analysis. We collected data on length of stay and mortality during one-year follow-up.

Hypoglycemia and severe hypoglycemia were defined as CBG ≤3.9 mmol/l (70 mg/dL) and <3.0 mmol/l (54 mg/dL) in line with definitions used in the National Diabetes Inpatient Audit.¹¹

Descriptive statistics are reported as mean (±SD) or median (interquartile range [IQR]) values for continuous data or numbers and percentages for categorical data. All P values are two-tailed, and P values <.05 were considered to indicate statistical significance. Chi-squared test and Student t test were used to assess differences for categorical and continuous variables between groups. The statistical analysis was performed using the SPSS software, version 25 (IBM).