Endocrine Abstracts

Objective

To investigate whether salivary cortisol could provide an alternative to serum cortisol for hypocortisolaemic patients undergoing hydrocortisone day curves.

Method

Correlational study of 58 patients receiving corticosteroid replacement therapy for primary (9) or secondary (49) hypocortisolaemia. Paired samples of saliva and serum were taken at pre-determined time points throughout a 7½ hour hydrocortisone day curve. Subjects also completed a short questionnaire enquiring about their knowledge of, and attitudes towards, steroid replacement therapy and cortisol sampling.

Results

89% of patients preferred to give a saliva sample instead of blood and 58% said that it was not easy to find a vein in their arm for cannulation. There was a modest correlation between salivary cortisol and serum cortisol at baseline (9.30 am): R=0.28, p<.04. However there was no correlation significant to p<.05 between serum and salivary cortisol values at the other time points. When comparing differences in cortisol values between baseline and other sample times there was correlations for some but not all time points.

Conclusions

Saliva samples could be self-administered away from hospital and delivered for cortisol analysis; this would provide a more realistic assessment of patient’s daily routines and would meet their preference for saliva over blood sampling. However, the absence of consistent correlations reported here suggests further research is required. Analysis of cortisol binding globulins for each subject may provide an explanation of the lack of correlation and further work is being undertaken to identify whether serum (total) or salivary (free) cortisol is the more accurate cortisol level upon which to base judgements about medication dosage for hypocortisolaemic patients.