Risk factors of central diabetes insipidus after transnasal adenomectomy

Background : At present, surgical intervention is a major treatment strategy for pituitary adenomas. It is commonly complicated with water and electrolyte imbalance. The prevalence of post-surgical central diabetes insipidus (CDI) may amount to 30%; however, its risk factors have not been established. Aim : To assess the rates and nosological distribution of CDI after transnasal adenomectomy and to identify its risk factors. Materials and methods : This retrospective study included 96 patients aged 20 to 65 years (median [Q1; Q3] 43 [34.5; 53.5]), who had transnasal adenomectomy in 2010-2011 due to Cushing's disease, acromegaly, prolactinoma, non-functioning pituitary adenoma. All patients underwent clinical examination and laboratory work-up before and after surgery. Their post-surgical course was assessed for 5 to 7 years. Depending on identified manifestations, the patients were categorized into the permanent CDI (n = 15) and transient CDI (n = 34); 47 patients had no CDI. Results : Cushing's disease (odds ratio (OR) 6.1, 95% confidence interval (CI) 2.3-16.1), secondary adrenal insufficiency (OR 6.8, 95% CI 2.618.3) and adrenocorticotropic hormone levels of < 15.8 pg/mL (OR 5.0, 95% CI 1.9-13.5), microadenoma (OR 4.5, 95% CI 1.7-11.5) promote transient postoperative CDI, whereas macroadenoma decrease this risk (OR 0.2, 95% CI 0.1-0.5). The transient CDI was also more common in patients with secondary hypothyroidism, cortisol level of<200 nmol/L, adenoma's volume at magnetic resonance imaging of < 0.83 cm 3 at trend level and more rare in patients with acromegaly and loss of tropic hormones before surgery at trend level as well. No significant risk factors were identified for permanent CDI, but it could be more often associated with secondary hypothyroidism, absence of any adenoma at magnetic resonance imaging and pituitary injury during the surgery and less frequent in patients with macroadenomas at trend level. Conclusion : The proportion of permanent postoperative CDI was 16% (95% CI 9-24), and that of the transient form 35% (95% CI 25-45). Cushing's disease, microadenoma, development of secondary adrenal insufficiency and adrenocorticotropic hormone levels of < 15.8 pg/mL after surgery increase the probability of transient CDI, whereas macroadenoma does decrease this risk. No significant risk factors were identified for permanent CDI.