Background: Salivary cortisol is routinely used as a diagnostic test for Cushing syndrome. The diagnostic use of salivary cortisol for adrenal insufficiency (AI), however, is less established. We aimed to investigate the utility of morning basal and adrenocorticotropic hormone-stimulated salivary cortisol in diagnosing AI in Korean adults. Methods: We prospectively included 120 subjects (female, n=70) from Seoul National University Hospital. AI was defined as a stimulated serum cortisol level of <496.8 nmol/L during the short Synacthen test (SST). Serum and saliva samples were drawn between 8:00 AM and 10:00 AM. Salivary cortisol levels were measured using an enzyme immunoassay kit. Results: Thirty-four patients were diagnosed with AI according to the SST results. Age, sex, body mass index, serum albumin levels, and serum creatinine levels did not significantly differ between the normal and AI groups. Basal and stimulated salivary cortisol levels were positively correlated with basal (r=0.538) and stimulated serum cortisol levels (r=0.750), respectively (all P<0.001). Receiver operating characteristic curve analysis yielded a cutoff level of morning basal salivary cortisol of 3.2 nmol/L (sensitivity, 84.9%; specificity, 73.5%; area under the curve [AUC]=0.822). The optimal cutoff value of stimulated salivary cortisol was 13.2 nmol/L (sensitivity, 90.7%; specificity, 94.1%; AUC=0.959). Subjects with a stimulated salivary cortisol level above 13.2 nmol/L but a stimulated serum cortisol level below 496.8 nmol/L (n=2) had lower serum albumin levels than those showing a concordant response. Conclusion: The diagnostic performance of stimulated salivary cortisol measurements after the SST was comparable to serum cortisol measurements for diagnosing AI.

Aims/IntroductionDipeptidyl peptidase‐4 inhibitors might have pleiotropic protective effects on cardiovascular disease (CVD), in contrast to sulfonylureas. Therefore, we compared various CVD risk factors between vildagliptin and glimepiride.Materials and MethodsWe carried out a randomized, prospective and crossover trial. A total of 16 patients with type 2 diabetes whose glycated hemoglobin was >7% were randomized to add vildagliptin or glimepiride. After 12‐week treatment, each drug was replaced with the other for another 12 weeks. Before and after each treatment, glucose homeostasis and CVD risk factors were assessed, and the continuous glucose monitoring system was applied to calculate glycemic variability.ResultsThe mean age of the participants was 60 years, 31% were men, body mass index 25.5 kg/m2 and HbA1c 8.41%. Both vildagliptin and glimepiride significantly decreased glycated hemoglobin and glycemic variability indices. Despite the improved glucose homeostasis, favorable change of CVD markers was not prominent in both the arms, along with significant weight gain. Only plasma stromal cell‐derived factor (SDF)‐1α decreased by 30% in the vildagliptin arm. According to regression analyses, the reduction of SDF‐1α was independently associated with vildagliptin usage and serum interleukin‐6 changes, but white blood cells were not related with the SDF‐1α changes.ConclusionCompared with glimepiride, vildagliptin arrestingly decreased plasma SDF‐1α, and its clinical implications should be further investigated.