Prevalence of hypokalaemia: the experience of a large academic hospital

The effect of potassium supplementation and concomitant medications on potassium homeostasis for hospitalized patients

PURPOSE

Hospitalized patients receive potassium (K+) supplementation for hypokalemia, with clinicians often estimating a rise in serum K+ levels of 0.1 mEq/L per 10 mEq delivered. However, there is limited evidence to support this expectation. Patients also concomitantly take medications that may alter K+ levels, and it is not known to what degree these may impact interventions to correct K+ levels via supplementation. The objective of this study was to identify the impact of oral and/or intravenous K+ supplementation on serum K+ levels, including the influence of selected concomitant medications, in adult hospitalized patients.

METHODS

A single-center, retrospective descriptive study of adult hospitalized patients receiving K+ supplementation at a tertiary hospital between 2021 and 2022 was conducted. Patients were included if they received at least one dose of potassium chloride while admitted to the general medicine ward. The primary outcome was the daily median change in serum K+, normalized per 10 mEq of supplementation administered. The secondary outcome was the impact of selected concomitant medication use on supplement-induced changes in serum K+.

RESULTS

A total of 800 patients and 1,291 daily episodes of K+ supplementation were evaluated. The sample was approximately 53% women, was 78% white, and had a median age of 68 years. The overall daily median change in serum K+ level was 0.05 mEq/L per 10 mEq of supplementation delivered. Patients received a median of 40 mEq of supplementation per day, primarily via the oral route (80.6%). Among the concomitant medications assessed, loop diuretics significantly dampened the impact of K+ supplementation.

CONCLUSION

Supplementation of K+ in non-critically ill hospitalized patients is variable and dependent on concomitant medication use.

Incidence, Risk Factors and Prognosis of Hypokalaemia in Patients with Normokalaemia at Hospital Admission

Background

Hypokalaemia (K+<3.5 mmol/L) is observed in 20% of hospitalised patients. Previous studies have often dealt with the symptoms, prevalence and risk factors in hospitalised patients. Very few studies have dealt with hospital-induced hypokalaemia. The aim was to determine the incidence, predisposing risk factors and prognosis of patients developing hypokalaemia after admission.

Materials and Methods

A prospective observational study was performed for two months. Patients with at least two potassium values after admission and normal K values at admission were considered for inclusion. Clinical features, diagnoses, laboratory reports and treatment details, including antibiotics, were noted.

Results

A total of 653 patients were studied; 138 (21.1%) developed hypokalaemia. Diabetes, ischaemic heart disease (IHD), heart failure, chronic kidney disease, hypertension, chronic liver disease and chronic obstructive pulmonary disease (COPD) were the most associated comorbidities. Urea, creatinine, transaminases and neutrophilia at admission differed significantly between those with and without hypokalaemia groups. Most patients developed mild hypokalaemia (78.2%). Hypokalaemia developed mostly on the second (22.4%) and third (24.6%) days of hospitalisation. Antibiotics were used in 60% of patients. The potassium values returned to normal within 2.5 ± 1.9 days. Three patients subsequently developed hyperkalaemia.

Conclusion

Patients admitted under general medicine mostly developed mild hypokalaemia, even if they had multiple risk factors for developing hypokalaemia. Inpatient hypokalaemia had an incidence of 21%. An overwhelming majority (~88%) had at least one risk factor. Hypokalaemia was not attributed to causing mortality in any patient.

Association between preoperative hypokalemia and postoperative complications in elderly patients: a retrospective study

Background

Hypokalemia is a common form of electrolyte disorder, which has a higher incidence in hospitalized patients and is closely related to perioperative complications and prognosis. Due to decreased skeletal muscle mass which causes total body potassium reduction, and increased comorbidities, the elderly are more susceptible to hypokalemia.

Objective

To investigate preoperative hypokalemia in elderly patients and its effect on postoperative complications.

Methods

Data were retrospectively collected from the elderly patients who underwent elective surgery from April 2018 to March 2019 and had preoperative blood gas data available. Patients, with age 60 to 100 years, were divided into hypokalemia group (potassium level < 3.5 mmol/L) and normokalemia group (potassium level between 3.5 and 5.5 mmol/L) according to preoperative blood gas analysis. Hypokalemia can be divided into mild (potassium level 3.0 to 3.5 mmol/L), moderate (potassium level 2.5 to 3.0 mmol/L) and severe (potassium level < 2.5 mmol/L), respectively. The risk factors of preoperative hypokalemia and its impact on postoperative complications and prognosis were primary outcomes. Secondary outcomes included postanesthesia care unit (PACU) stay time and hospital length of stay (LOS).

Results

Of 987 participants, 436 (44.17%) developed preoperative hypokalemia, among them 357 (81.88%) mild, 87 (16.74%) moderate and 6 (1.38%) severe. Multivariate logistic regression showed that female gender (OR, 1.851; 95% CI, 1.415–2.421), pre-existing hypokalemia at admission (OR, 4.498; 95% CI, 2.506–8.071), and oral laxative twice or more (OR, 1.823; 95% CI, 1.266–2.624) are risk factors of preoperative hypokalemia. Gynecological and biliopancreatic surgery were more common in hypokalemia group than normokalemia group (P <  0.001, P <  0.05). There was no significant difference in postoperative complications, PACU stay time, LOS, and 30-day mortality between the two groups (all P >  0.05).

Conclusions

Female gender, pre-existing hypokalemia at admission, and oral laxative twice or more are independent risk factors for preoperative hypokalemia in elderly patients. However, postoperative complications and 30-day mortality were not increased, which may be related to monitoring blood gas analysis and prompt correction of potassium levels during surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03445-1.

Global Trends (1961-2017) in Human Dietary Potassium Supplies

Background: Potassium (K) is an essential mineral and major intracellular electrolyte involved in the regulation of blood pressure, muscle contraction and nerve transmission in humans. Major dietary sources of K include fruits and vegetables, starchy roots and tubers, and whole grains. The aim of this study was to assess and report: (i) the sufficiency of K in national food systems globally, (ii) to quantify the contribution from food groups, and (iii) to explore spatial and temporal trends in the period of 1961–2017. Methods: Food supply and demography (1961–2017), K composition and K requirement data were combined to estimate per capita human dietary supplies of potassium (DSK), adequate intake of K (AIK) and K sufficiency ratio (KSR) at national, regional, continental and global levels. Results and Discussion: Globally, the mean ± SD. DSK (mg capita⁻¹ d⁻¹) increased from 2984 ± 915 in 1961 to 3796 ± 1161 in 2017. There was a wide range in DSK between geographical regions and across years, with particularly large increases in east Asia, where DSK increased from <3000 to >5000 mg capita⁻¹ day⁻¹. Roots and tubers contributed the largest dietary source of K, providing up to 80% of DSK in most regions. At the global level, throughout the 57-year period, the population-weighted KSR was <1 based on the 2006 Institute of Medicine AIK recommendation, while it was >1 based on the 2019 National Academies of Science and the 2016 European Union AIK recommendation. While KSR ≥ 1 shows sufficiency of DSK, KSR < 1 does not indicate K deficiency risk. Conclusion: Due to the absence of a Recommended Daily Allowance (RDA) for K, this study used the ratio of DSK:AIK (i.e., KSR) to assess dietary K sufficiency. Estimates of dietary K sufficiency are, therefore, highly sensitive to the AIK reference value used and this varied greatly based on different institutions and years. To quantify the risk of dietary K deficiency, bridging the data gap to establish an RDA for K should be a global research priority.

Potassium deficiency decreases the capacity for urea synthesis and markedly increases ammonia in rats

Our study provides novel findings of experimental hypokalemia reducing urea cycle functionality and thereby severely increasing plasma ammonia. This is pathophysiologically interesting because plasma ammonia increases during hypokalemia by a hitherto unknown mechanism, which may be particular important in relation to the unexplained link between hypokalemia and hepatic encephalopathy. Potassium deficiency decreases gene expression, protein synthesis, and growth. The urea cycle maintains body nitrogen homeostasis including removal of toxic ammonia. Hyperammonemia is an obligatory trait of liver failure, increasing the risk for hepatic encephalopathy, and hypokalemia is reported to increase ammonia. We aimed to clarify the effects of experimental hypokalemia on the in vivo capacity of the urea cycle, on the genes of the enzymes involved, and on ammonia concentrations. Female Wistar rats were fed a potassium-free diet for 13 days. Half of the rats were then potassium repleted. Both groups were compared with pair- and free-fed controls. The following were measured: in vivo capacity of urea-nitrogen synthesis (CUNS); gene expression (mRNA) of urea cycle enzymes; plasma potassium, sodium, and ammonia; intracellular potassium, sodium, and magnesium in liver, kidney, and muscle tissues; and liver sodium/potassium pumps. Liver histology was assessed. The diet induced hypokalemia of 1.9 ± 0.4 mmol/L. Compared with pair-fed controls, the in vivo CUNS was reduced by 34% (P < 0.01), gene expression of argininosuccinate synthetase 1 (ASS1) was decreased by 33% (P < 0.05), and plasma ammonia concentrations were eightfold elevated (P < 0.001). Kidney and muscle tissue potassium contents were markedly decreased but unchanged in liver tissue. Protein expressions of liver sodium/potassium pumps were unchanged. Repletion of potassium reverted all the changes. Hypokalemia decreased the capacity for urea synthesis via gene effects. The intervention led to marked hyperammonemia, quantitatively explainable by the compromised urea cycle. Our findings motivate clinical studies of patients with liver disease.