Venous thromboembolism in patients with pituitary adenoma: UK multicentre cohort study.

Objective: To assess risk of venous thromboembolism (VTE) in patients with Cushing's disease (CD) compared to acromegaly and non-functioning pituitary adenomas (NFPA) and to investigate the timing and risk factors for VTE.

Design: Retrospective, observational cohort study.

Methods: Patients diagnosed with acromegaly, NFPA, or CD across three UK centres between 2010 and 2021 were included. Chi-square and Cox regression were performed to compare VTE cumulative incidence and examine associations with clinical factors.

Results: Among 827 patients (107 CD, 502 NFPA, 218 acromegaly) the cumulative incidence of VTE was 11.2% in CD, 0.4% in NFPA, and 2.7% in acromegaly. Follow-up time was similar across diagnostic groups (median ∼13.3-13.5 years, p = 0.41), allowing valid comparison of VTE incidence and Cox regression modelling. Patients with CD had significantly higher VTE risk compared to with NFPA (odds ratio (OR) 21.05, p < 0.001) and acromegaly (OR 4.48, p = 0.002). Cox regression showed that CD diagnosis (hazard ratio (HR) 46.87, p < 0.001) and history of diabetes or impaired glucose tolerance (HR 3.48, p = 0.008) were significantly associated with VTE.In patients with CD, there were 12 VTE's recorded, with most (8/12) occurring within one year of CD diagnosis. Notably, four VTEs occurred within 45 days post-transsphenoidal surgery (TSS).

Conclusion: Patients with CD exhibit a significantly elevated risk of VTE compared to those with acromegaly or NFPA, with diabetes mellitus independently associated with this risk. In CD, VTEs were more frequently diagnosed around the time of diagnosis and during the perioperative period.