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

Objective Previous studies have shown inconsistent results regarding 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 versus no adjustment in BIPSS. Methods This study searched the PubMed, Embase, Web of Science, Cochrane library, and WanFang databases for published data as of March 2022 on the use of prolactin adjustment in BIPSS to differentially diagnose ACTH-dependent CS. 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% CI, 88.67%-98.44%) and 91.14% (95% CI, 57.17%-99.80%), respectively. The combined sensitivity and specificity after prolactin adjustment were 99.97% (95% CI, 99.03%-100.00%) and 80.69% (95% CI, 50.27%-97.82%), respectively. After the prolactin adjustment, the sensitivity of BIPSS to diagnose Cushing disease was improved with a statistically significant difference (difference in sensitivity, 5.39%; 95% CI, 1.37%-11.26%), whereas the decrease in specificity was without a 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 Cushing disease among patient with ACTH-dependent CS. However, prolactin adjustment may not help identify ectopic ACTH syndrome in BIPSS.