Morning cortisol production in coronary heart disease patients.

Background: The circadian cycle of the endogenous anti-inflammatory system (EAIS) is characterized by a morning increase in cortisol production. Circulating interleukin-6 (IL-6) activates the EAIS. A circadian variation in the onset of myocardial infarction, sudden death, stable angina (SA) and unstable angina (UA) has been reported. The aim of this study was to determine morning cortisol production in coronary heart disease (CHD) patients.

Materials And Methods: Serum cortisol and IL-6 were measured in 129 patients with either SA (n = 65) or UA (n = 64) and 40 healthy volunteers. Blood samples were taken between 9 : 00 h and 12 : 00 h. The upper normal range of cortisol (25 microg dL-1) was used as a reference to classify patients.

Results: Forty-eight patients had elevated cortisol levels (ECL) (32.5 +/- 5.4 microg dL-1), while 81 patients had normal cortisol levels (NCL) (15.7 +/- 5.9 microg dL-1). In NCL patients, IL-6 levels (26.6 pg mL-1, ranged from 0.2 to 183.7) were significantly higher (P < 0.004) than in ECL patients (9.70 pg mL-1, range 0.07-56.5). Forty-eight patients with UA belonged to the NCL group of patients, while only 16 UA patients belonged to the ECL group (chi(2) = 0.000). Thirty-two patients with SA belonged to the ECL group, and 33 to the NCL group (chi(2) = 0.08).

Conclusions: Patients with 'inappropriately' normal morning cortisol production had high IL-6 levels. 'Inappropriately' normal cortisol, detected in 75% of UA and 50% of SA patients, may be insufficient for limiting inflammation. These findings have novel clinical implications and suggest new therapeutic approaches in the treatment of these patients.