Should We Use Prolactin Adjustment in Bilateral Inferior Petrosal Sinus Sampling to Diagnose Cushing's Disease? A Joint Meta-Analysis of Head-to-head Diagnostic Tests Accuracy Studies.

OBJECTIVE: Previous studies have shown inconsistent results about the usefulness of prolactin adjustment in bilateral inferior petrosal sinus sampling (BIPSS) in the differential diagnosis of adrenocorticotropic hormone (ACTH) -dependent Cushing syndrome (CS). This meta-analysis compared the diagnostic accuracy of prolactin adjustment vs. no adjustment in BIPSS.

METHODS: This study searched PubMed, Embase, Web of Science, Cochrane library, and Wanfang database for published data on the use of prolactin adjustment in BIPSS to differentially diagnose ACTH-dependent CS as of March 2022. A Bayesian joint bivariate model was used in the head-to-head comparison of the diagnostic accuracy.

RESULTS: This meta-analysis included a total of 10 studies with 300 patients. The combined sensitivity and specificity for BIPSS without prolactin adjustment were 94.47% (95% credible interval, CI 88.67% to 98.44%), 91.14% (95% CI 57.17% to 99.80%), respectively. The combined sensitivity and specificity after prolactin adjustment were 99.97% (95% CI 99.03% to 100.00%), 80.69% (95% CI 50.27% to 97.82%), respectively. After the prolactin adjustment, the sensitivity of BIPSS to diagnose Cushing's disease (CD) was improved with a statistically significant difference (difference in sensitivity 5.39%, 95% CI 1.37% to 11.26%), while the decrease in specificity was without statistically significant difference (difference in specificity -9.20%, 95% CI -42.02% to 26.61%).

CONCLUSION: This meta-analysis indicated that prolactin adjustment in BIPSS might help to recognize CD among ACTH-dependent CS patients. However, prolactin adjustment may not help identify ectopic ACTH syndrome (EAS) in BIPSS.