Pusat Pengajian Sains Perubatan - Tesis

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Browsing Pusat Pengajian Sains Perubatan - Tesis by Author "Abeed, Nik Nur Amirah Nik"

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    Accuracy of baseline serum cortisol in diagnosing secondary adrenal insufficiency
    (2022)
    Abeed, Nik Nur Amirah Nik
    ABTRACT Background: Adrenal insufficiency (AI) is defined as inability of adrenal cortex to secrete enough number of hormones likes glucocorticoids and mineralocorticoids. To establish the diagnosis of AI, one need to underwent Short Synacthen Test (SST). However, baseline serum cortisol may be a useful tool for screening and diagnosis of AI. The objectives of the study are to compare baseline serum cortisol at presentation with positive and negative SST and to evaluate diagnostic accuracy of baseline serum cortisol at different cut off value. Methods: This 5-year retrospective study was performed in three tertiary centres. A total of 111 subjects who underwent SST in the endocrine clinics were identified. Primary adrenal insufficiency was excluded in this study. Primary and secondary adrenal insufficiency were differentiated based on serum ACTH level taken during SST. High serum ACTH suggestive of primary AI. The SST result in subjects who fulfilled the xi criteria were reviewed. Positive SST refers to a patient who has confirm diagnosis of secondary adrenal insufficiency based on short synacthen test (serum cortisol level <550 nmol/L at 30 minutes or 60 minutes). Baseline serum cortisol was defined as a random serum cortisol sample drawn at first presentation. The association between random baseline serum cortisol and positive SST level were demonstrated by independent sample T test analysis. Diagnostic accuracy was evaluated by a receiver operating characteristic curve (ROC) analysis. Result: Of the 111 patients who underwent SST, only 103 patients who fulfilled all the criteria. From 103 patients, 53 (51%) were confirmed to have secondary AI. The ROC curve for the model assessing the diagnostic accuracy had an area under curve of 0.72 (95%CI 0.62-0.82). The cut off level of baseline serum cortisol for lower group were < 80 nmol/L and < 100 nmol/L with highest specificity of 98%, the optimal baseline serum cortisol of >400nmol/L had the highest sensitivity of 98.1%. Conclusion: Baseline serum cortisol of < 100 nmol/L is highly specific and very strongly associated with secondary Adrenal Insufficiency (AI). There is no clinical and biochemical factors associated with positive SST in this study.