Diurnal Range and Intra-patient Variability of ACTH Is Restored With Remission in Cushing's Disease.

CONTEXT

Single ACTH measurements have limited ability to distinguish patients with Cushing's disease (CD) from those in remission or with other conditions.

OBJECTIVE

To investigate the changes in ACTH levels before and after transsphenoidal surgery (TSS) to identify trends that could confirm remission from CD and help establish ACTH cutoffs for targeted clinical trials in CD.

DESIGN

Retrospective analysis of CD patients who underwent TSS from 2005 to -2019.

SETTING

Referral center.

PATIENTS

CD patients (n = 253) with ACTH measurements before and after TSS.

INTERVENTIONS

TSS for CD.

MAIN OUTCOME MEASURES

Remission after TSS.

RESULTS

Remission was observed in 223 patients after TSS. Those in remission had higher ACTH variability at AM (P = .02) and PM (P < .001) time points compared to nonremission. The nonremission group had a significantly narrower diurnal range compared to the remission group (P = <.0001). A decrease in plasma ACTH of ≥50% from mean preoperative levels predicted CD remission after TSS, especially when using PM values. The absolute plasma ACTH concentration and ratio of preoperative to postoperative values were significantly associated with nonremission after multivariable logistic regression (adj P < .001 and .001, respectively).

CONCLUSIONS

Our findings suggest that ACTH variability is suppressed in CD, and remission from CD is associated with the restoration of this variability. Furthermore, a decrease in plasma ACTH by 50% or more may serve as a predictor of remission post-TSS. These insights could guide clinicians in developing rational outcome measures for interventions targeting CD adenomas.