Multivariable analysis of 63 contemporary patients diagnosed with Nelson's syndrome: A nationwide readmission database study

Introduction. Nelson's syndrome (NS) is a rare complication involving enlargement of an adrenocorticotropic hormone (ACTH) producing tumor in the pituitary following bilateral adrenalectomy in Cushing's syndrome. Here, we explore the epidemiology, complication profiles, and readmission statistics of 63 patients diagnosed with NS. Methods. The Nationwide Readmission Database was retrospectively queried for all patients diagnosed with NS (n = 63) or receiving total bilateral adrenalectomy (TBA) surgery (n = 275) between 2016 and 2017. Complications, demographics, and predictive factors were queried for all patients involved. Statistical analysis used Mann-Whitney U nonparametric testing was to compare basic demographics and gaussian-fitted multivariable regression analysis with post hoc odds ratios to compare patient predictors of development of NS and complication rates between the two cohorts. Results. We report the largest contemporary patient series of NS through a nationally-representative inpatient database and explore the clinical characteristics of modern NS patients. Modeling revealed that the absence of primary hypertension served as a significant predictor for NS when compared to the TBA control cohort (OR = 0.88; 95%CI = 0.79–0.99; p = 0.037). In addition, analysis of complications between NS and TBA cohorts revealed that NS patients have significantly higher rates of hypoosmolarity/hyponatremia (OR = 1.42; 95%CI = 1.19–1.71; p = 0.00021), hypopituitarism (OR = 1.94; 95%CI = 1.60–2.36; p < 0.0001), and sepsis (OR = 1.51; 95%CI = 1.14–2.00; p = 0.0046). Conclusion. Contemporary NS is a rare complication of TBA, and modern cases of NS may differ significantly from cases of NS reported in the mid-1900s. As such, a thorough understanding of patient complications and predictive factors for NS are necessary to fully guide patient management in the modern era.