A retrospective analysis of postoperative hypokalemia in pituitary adenomas after transsphenoidal surgery

A Simple Scoring System for Predicting the Risk of Delayed Hyponatremia After Endoscopic Transsphenoidal Surgery for Pituitary Adenomas

BACKGROUND

To identify high-risk patients for delayed postoperative hyponatremia (DPH) early, we constructed a simple and effective scoring system.

METHODS

We retrospectively analyzed 141 consecutive patients who underwent endoscopic transsphenoidal surgery from January 2019 to December 2022. Patients were divided into DPH group and nondelayed postoperative hyponatremia group based on whether hyponatremia occurred after the third postoperative day. Multivariable logistic regression analysis was conducted to determine the predictive factors of DPH, and a simple scoring system was constructed based on these predictors.

RESULTS

Among 141 patients, 36 (25.5%) developed DPH. Multivariable logistic regression analysis showed that age ≥48 years (odds ratio [OR], 3.74; 95% confidence interval [CI], 1.14-12.21; P = 0.029), Knosp grade ≥3 (OR, 5.17; 95% CI, 1.20-22.27; P = 0.027), postoperative hypokalemia within three days (OR, 3.13; 95% CI, 1.05-9.33; P = 0.040), a difference in blood sodium levels between the first and second day after surgery ≥1 mEq/L (OR, 3.65; 95% CI, 1.05-12.77; P = 0.043), and postoperative diabetes insipidus (OR, 3.57; 95% CI, 1.16-10.96; P = 0.026) were independent predictors of DPH.

CONCLUSIONS

This scoring system for predicting DPH has an area under the receiver operating characteristic curve of 0.856 (95% CI, 0.787-0.925), indicating moderate to good predictive value for DPH in our cohort, but further prospective external validation is needed.

Gender potentially affects early postoperative hyponatremia in pituitary adenoma: XGBoost-based predictive modeling

Purpose

The occurrence of hyponatremia is a prevalent complication following transnasal transsphenoidal surgery for pituitary adenoma surgery, which adversely affects patient prognosis, hospitalization duration, and rehospitalization risk. The primary objective of this study is to strengthen the correlation between clinical factors associated with pituitary adenoma and postoperative hyponatremia. Additionally, the study aims to develop a predictive model for postoperative hyponatremia in patients with pituitary adenoma, with the ultimate goal of establishing a basis for reducing the occurrence of postoperative hyponatremia following surgical interventions.

Methods

The chi-square test or Fisher test was employed for nominal data, while the t-test or Mann-Whitney test was utilized for continuous data analysis. In cases where the data exhibited statistical differences, binary logistic analysis was conducted to examine the risk and protective factors associated with postoperative hyponatremia. XGBoost was employed to construct predictive models for hyponatremia in this study. The patients were partitioned into training and test sets, and the most suitable parameters were determined through five-fold cross-validation and subsequently utilized for training on the training set. The discriminatory capability was assessed on the internal validation set.

Results and conclusions

Out of the total 280 patients included in this investigation, 82 patients experienced early postoperative hyponatremia. Among these individuals, male gender (P = 0.02, odds ratio = 1.98) was identified as a risk factor for early postoperative hyponatremia, while preoperative chloride levels (P = 0.021, odds ratio = 0.866) and surgery time (P = 0.039, odds ratio = 0.990) were identified as protective factors against postoperative hyponatremia. The XGBoost model exhibited a sensitivity of 94.2%, a specificity of 61.5%, a positive predictive value of 51.6%, a negative predictive value of 96%, and identified male gender, preoperative sodium, and preoperative cortisol as the most significant predictors. Our findings indicate that gender may have influence in the development of early postoperative hyponatremia in patients with pituitary adenomas.

Development of a preoperative index-based nomogram for the prediction of hypokalemia in patients with pituitary adenoma: a retrospective cohort study

Objective

To develop and validate a preoperative index-based nomogram for the prediction of hypokalemia in patients with pituitary adenoma (PA).

Methods

This retrospective cohort study included 205 patients with PAs between January 2013 and April 2020 in the Sun Yat-sen Memorial Hospital, Guangzhou, China. The patients were randomly classified into either a training set (N = 143 patients) and a validation set (N = 62 patients) at a ratio of 7:3. Variables, which were identified by using the LASSO regression model were included for the construction of a nomogram, and a logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) in the training set. The area under the curve (AUC) was used to evaluate the performance of the nomogram for predicting hypokalemia. Multivariate logistic regression analysis with a restricted cubic spline analysis was conducted to identify a potential nonlinear association between the preoperative index and hypokalemia.

Results

The incidence of hypokalemia was 38.05%. Seven preoperative indices were identified for the construction of the nomogram: age, type of PA, weight, activated partial thromboplastin time, urea, eosinophil percentage, and plateletocrit. The AUCs of the nomogram for predicting hypokalemia were 0.856 (95% CI [0.796–0.915]) and 0.652 (95% CI [0.514–0.790]) in the training and validation sets, respectively. Restricted cubic splines demonstrated that there was no nonlinear association between hypokalemia and the selected variables.

Conclusion

In this study, we constructed a preoperative indices-based nomogram that can assess the risk of hypokalemia after the surgical treatment of pituitary adenomas. This nomogram may also help to identify high risk patients who require close monitoring of serum potassium.