Association between posttest dexamethasone and cortisol concentrations in the 1 mg overnight dexamethasone suppression test
Association between posttest dexamethasone and cortisol concentrations in the 1 mg overnight dexamethasone suppression test
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DOI：
10.1530/ec-12-0047
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发表时间：
2012-11-01
影响因子：
2.9
通讯作者：
Bjorgaas, Marit R.
中科院分区：
文献类型：
--
作者：
Asvold, Bjorn O.;Grill, Valdemar;Bjorgaas, Marit R.
试验后地塞米松和皮质醇浓度的比较可提高地塞米松抑制试验(DST)对库欣综合征的评价。特别是，如果试验后皮质醇水平在DST中通常达到的范围内地塞米松水平不同，这将是合理的。因此，我们使用分数多项式回归，研究了53名没有库欣综合征的受试者在接受1 mg隔夜DST测试后，800h地塞米松和皮质醇水平之间的关系。血浆地塞米松水平与皮质醇水平呈正相关(P&0.001)，回归直线显示地塞米松水平与地塞米松水平呈显著负相关(P<0.05)，地塞米松水平与皮质醇水平无相关性(P=0.55)。总而言之，接受1 mg隔夜DST测试的受试者通常能达到8800小时的血浆地塞米松-5nmol/L，而这些受试者的血浆皮质醇与血浆地塞米松没有差别。这表明，常规比较地塞米松和皮质醇水平可能不是改善1毫克DST性能的有用方法。然而，地塞米松测量可能会识别出血浆地塞米松水平不够低的受试者，因此在重新测试DST结果可能为假阳性的受试者时可能是有价值的。
It has been suggested that comparison of posttest dexamethasone and cortisol concentrations may improve the evaluation of the dexamethasone suppression test (DST) for Cushing's syndrome. In particular, this would be reasonable if posttest cortisol differs by dexamethasone levels within the range that is usually attained in the DST. Using fractional polynomial regression, we therefore studied the association between posttest 0800 h dexamethasone and cortisol levels in 53 subjects without Cushing's syndrome who were tested with the 1 mg overnight DST. Plasma dexamethasone was associated with plasma cortisol (P < 0.001), and the regression line suggested a strong negative association related to dexamethasone levels 5.0 nmol/l, there was no association between dexamethasone and cortisol levels (P = 0.55). In conclusion, subjects tested with the 1 mg overnight DST usually attain an 0800 h plasma dexamethasone >5 nmol/l, and plasma cortisol does not differ by plasma dexamethasone in these subjects. This suggests that routine comparison of dexamethasone and cortisol levels may not be a useful approach to improve the performance of the 1 mg DST. However, dexamethasone measurements may identify subjects with inadequately low plasma dexamethasone and may therefore be of value when retesting subjects with possibly false-positive DST results.