We propose a comparative study of urinary cortisol in a controlled simple group of patients diagnosed with fibromyalgia (FM) during a minimum time frame (3 years) vs. a normal group with the same characteristics of age and gender. Our objective is to demonstrate if urinary cortisol at lower levels than those found in the normal population, as long as FM is regarded, could help to evaluate the fatigue.
We determined the urinary cortisol in a group of 47 women with a clinical diagnosis of FM using the criteria from the American College of Rheumatology (ACR) 1990, with ages between 29 and 64 years, in whom an accurate sample was collected and cortisol was determined using an FPIA method. The results were compared with the urinary cortisol obtained in a group of 88 healthy women within the same age range as those with FM.
Urinary cortisol in FM was 65.0 microg/l (median), which was significantly lower than that of the healthy group (80.0 microg/l), p<0.001.
33.4% of patients with FM displayed urinary cortisol concentrations significantly lower than the group of women without FM.