The relationship between adrenal incidentalomas and mortality risk

Abstract

Objective: To determine all-cause mortality risk in patients with and without adrenal incidentaloma.

Methods: Retrospective cohort study of patients with CT abdomen performed within 24 h of emergency room presentation at an academic medical center from January 1, 2005, to December 31, 2009, without history of adrenal disease, adrenal lab testing, or cancer. Incidentaloma cohort identified by database query of imaging reports followed by manual review and matched to no-nodule controls at 3:1 on age ± 1 year and exam date ± 3 months. Mortality ascertained by in-hospital deaths and National Death Index query. Survival analysis performed with Kaplan-Meier curves and Cox proportional hazards models.

Results: Among 42,575 adults with abdominal CT exams, 969 adrenal incidentaloma patients and 2907 no-nodule controls were identified. All 3876 individuals entered survival analysis with 31,182 person-years at risk (median follow-up 8.9 years [IQR, 6.9-10.7]). All-cause mortality was significantly higher among those with adrenal incidentalomas (353/969, 36.4%) compared with those without (919/2907, 31.6%; mortality difference 7.6 per 1000 person-years; multivariable-adjusted hazard ratio [aHR] 1.14; 95% CI, 1.003-1.29). Exploratory analyses, limited by missing covariates, found that adrenal incidentalomas were associated with significantly increased incidence of malignancy (aHR 1.61; 95% CI, 1.22-2.12), diabetes (aHR 1.43; 95% CI, 1.18-1.71), heart failure (aHR 1.32; 95% CI, 1.07-1.63), peripheral vascular disease (aHR 1.28; 95% CI, 1.95-1.56), renal disease (aHR 1.21; 95% CI, 1.01-1.44), and chronic pulmonary disease (aHR 1.22; 95% CI, 1.01-1.46) compared with controls.

Conclusions: Adrenal incidentalomas are associated with increased mortality and may represent a clinically valuable biomarker.

Key points: • Adrenal incidentalomas are associated with increased mortality. • Adrenal incidentaloma size is not predictive of mortality. • On exploratory analyses, adrenal incidentalomas are associated with chronic illnesses.

Keywords: Adrenal gland neoplasms; Cohort study; Incidental findings; Survival analysis; Tomography, x-ray computed.

Figure 1:

Study population, cohort identification and exclusion points.

Figure 2:

Kaplan-Meier survival curve for all-cause mortality by adrenal nodule presence.

Figure 3:

Kaplan-Meier survival curve by adrenal nodule presence and insurance type. Mean age labeled to highlight differences in insurance qualification by age that account for survival discrepancies between groups; Medicare generally includes Americans age ≥65 whereas Medicaid and Commercial insurance have no such age limitation.

Figure 4:

Incident outcomes diagnosed ≥6 months from initial CT exam in patients with ≥2 years clinical follow-up without outcome at baseline, by adrenal nodule presence. (a) Malignancy. (b) Diabetes mellitus. (c) Congestive heart failure. (d) Chronic pulmonary disease.