Endocrine Abstracts

Background: Bilateral adrenalectomy (BLA) is a treatment option for patients suffering from endogenous Cushing syndrome (CS). It consists of the surgical removal of both adrenal glands. Even though BLA offers immediate control of cortisol excess, given the risk of adrenal insufficiency, it requires life-long glucocorticoid and mineral corticoid replacement. It may lead to perioperative and long-term complications which affect patients’ quality of life (QoL). Health state utility values are essential parameters in cost-effectiveness models and should be established with a systematic literature review (SLR). The generic EQ-5D is the preferred QoL instrument by health technology assessment bodies.

Objectives: The main objective of the SLR was to identify relevant utility data of adult patients with endogenous CS after BLA to enable performing cost-effectiveness estimation in this therapeutic area. Another goal was to provide clinicians and researchers with a better understanding of the impact of BLA on patients’ QoL.

Methods: The search was conducted using electronic databases, Embase® and MEDLINE. Eligibility criteria were based on the population, interventions, comparators, and outcomes (PICO) framework. The search terms included EQ-5D, other recommended measures like HUI 1-3, SF-6D, SF-36 and other instruments which, if no relevant EQ-5D data were available, could be mapped onto EQ-5D. The quality of full-text publications was assessed using a validated checklist provided in the literature.

Results: Out of 146 records identified, 5 unique studies were eligible for inclusion. Four studies assessed the QoL of CS patients after BLA using SF-36 and one using SF-12. All included studies demonstrate consistently that CS patients after BLA had lower QoL scores compared to the general population. The most impaired domains of SF-36 were bodily pain, general health, vitality and social functioning. Both physical and mental composite score of SF-12 were deteriorated. As no EQ-5D values were identified, SF-36 and SF-12 outcomes were mapped to EQ-5D-3L using published and validated regression models. EQ-5D values as estimated for different mapping models were oscillating between 0.5 and 0.7, with median value equal to 0.65. Reference population norms for EQ-5D-3L values, matched to CS patients by age, ranged from 0.85 to 0.97, depending on the country of origin.

Conclusions: Despite control of CS, CS patients after BLA have impaired QoL. The utility value of their health state, mapping SF-36 and SF-12 results to EQ-5D, is approximately 0.65. This relatively low value may be attributable to comorbidities, especially adrenal insufficiency.