Performance Evaluation of Scoring Systems for Predicting Post-Operative Hypertension Cure in Primary Aldosteronism

Samuel Matthew O'Toole; Catherine Hornby; Wing-Chiu Candy Sze; Mark John Hannon; Scott Alexander Akker; Maralyn Rose Druce; Mona Waterhouse; Anne Dawnay; Anju Sahdev; Matthew Matson; Laila Parvanta; William Martyn Drake

Disclosures

Clin Endocrinol. 2021;95(4):576-586. 

In This Article

Abstract and Introduction

Abstract

Objective: Hypertension cure following adrenalectomy in unilateral primary aldosteronism is not guaranteed. Its likelihood is associated with pre-operative parameters, which have been variably combined in six different predictive scoring systems. The relative performance of these systems is currently unknown. The objective of this work was to identify the best performing scoring system for predicting hypertension cure following adrenalectomy for primary aldosteronism.

Design: Retrospective analysis in a single tertiary referral centre.

Patients: Eighty-seven adult patients with unilateral primary aldosteronism who had undergone adrenalectomy between 2004 and 2018 for whom complete data sets were available to calculate all scoring systems.

Measurements: Prediction of hypertension cure by each of the six scoring systems.

Results: Hypertension cure was achieved in 36/87 (41.4%) patients within the first post-operative year, which fell to 18/71 (25.4%) patients at final follow-up (median 53 months, P = .002). Analysis of receiver operating characteristic area under the curves for the different scoring systems identified a difference in performance at early, but not late, follow-up. For all systems, the area under the curve was lower at early compared with late follow-up and compared to performance in the cohorts in which they were originally defined.

Conclusions: No single scoring system performed significantly better than all others when applied in our cohort, although two did display particular advantages. It remains to be determined how best such scoring systems can be incorporated into the routine clinical care of patients with PA.

Introduction

Primary aldosteronism (PA) is the most common cause of secondary hypertension[1] and is associated with excess cardiovascular morbidity compared to patients with essential hypertension.[2,3] PA results from renin-independent aldosterone secretion; unilateral disease is amenable to surgical intervention and the expectation of biochemical cure.[4]

Whilst post-operative normalization of the renin-angiotensin-aldosterone system (biochemical cure) corrects any associated abnormalities of hypokalaemia and alkalosis, the restoration of normotension without the need for anti-hypertensive medications (hypertension or clinical cure) is less certain. Hypertension cure rates range between 32% and 42% 6 months post-operatively in international series[4–7] and are even more varied with longer-term follow-up.[8–11] The likelihood of persistent hypertension post-operatively has been associated with a number of factors, including sex,[4–7,12–14] age,[6] hypertension duration,[5–7,12–15] anti-hypertensive usage[4–7,12,13,15–17] and target organ damage.[12,14,17,18] It should be noted that the rates of clinical improvement through improved hypertension control and reduction in anti-hypertensive burden exceed hypertension cure, and are meaningful outcomes to patients, but are more subjective and difficult to objectively define.

The accurate pre-operative identification of PA patients most likely to derive clinical benefit from adrenalectomy is vital for shared decision-making. It allows patients to give truly informed consent based on an individualized assessment of the potential benefit of adrenalectomy and provides both patients and clinicians a realistic expectation of outcome.

To address this issue, six pre-operative scoring systems that predict complete clinical cure (i.e., normotension without anti-hypertensive medications) in PA post-adrenalectomy have been proposed and are summarized in Table 1: the Aldosteronoma Resolution Score (ARS),[7] Primary Aldosteronism Surgical Outcome (PASO),[12] Nomogram-Based Predictive Score (NBPS)[14] and those proposed by Utsumi,[6] Wachtel[8] and Morisaki.[5] All incorporate sex and hypertension duration, with variable inclusion of other parameters including body mass index, anti-hypertensive medications, evidence of target organ damage, adrenal nodule size, age, presence of diabetes mellitus and aldosterone-to-renin ratio. Whilst each performs well within the population in which it was defined, whether they do so in other populations is less clear and their comparative performance is unknown. These reasons have contributed to their limited uptake into routine clinical practice.

In this study, we examine the performance of the six available pre-operative prediction scoring systems within a single PA cohort.

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