Endocrine Abstracts

The aim of this retrospective study was to assess hydrocortisone replacement therapy in patients with adrenal insufficiency, by correlating hydrocortisone regimens and doses to that of serum and urine cortisol levels.

Method: We studied the case notes of 83 patients, whose records contained the results of at least one valid hydrocortisone day curve and 24 h urine free cortisol level. Twenty-seven patients were on twice daily, and 56 were on thrice daily regimen.

Optimal hydrocortisone replacement therapy was defined as that dose which achieved 24 h urine free cortisol, and morning, afternoon and evening serum cortisol levels within normal reference range.

Results: There were 32 (50%) patients on thrice-daily hydrocortisone regimen who achieved optimum cortisol levels at all times as compared to only 4 (15%) on twice daily regimen.

Optimal cortisol replacement was achieved in 78% and 75% patients on hydrocortisone 10+5+5 mg, and 10+10+5 mg respectively; other thrice daily regimens did not achieve optimal replacement.

The average serum cortisol levels at 1300 h and 1700 h were significantly lower in patients on twice daily as compared to thrice-daily regimen, however there was no significant difference in the average serum cortisol levels of the two regimens at all other times.

The 24 h urine cortisol levels were within reference range for patients on total daily cortisol dose between 15 and 25 mg, however the levels were low in those receiving total cortisol dose of 10 mg/day, and high in patients receiving total daily dose greater than 25 mg.

Conclusion: The thrice-daily hydrocortisone regimen is superior to twice-daily regimen, and the appropriate recommended total daily hydrocortisone dose is 15–25 mg/day, in three divided doses. The 24 h urine cortisol profile is a reasonable measure for assessment of the total daily dose, but not the frequency or the regimen of cortisol replacement.