Diurnal cortisol variations and symptoms in patients with interstitial cystitis

Little attention has focused on systemic factors that may allow a state of chronic bladder inflammation to be established and maintained in interstitial cystitis cases. Abnormalities of the hypothalamic-pituitary-adrenal feedback system result in poorer regulation of the inflammatory response and are present in many chronic inflammatory and pain conditions, of which some have high co-morbidity with interstitial cystitis.

A total of 48 patients with interstitial cystitis and 35 healthy, age matched controls collected 24-hour urine samples and 3 days of salivary samples at 7 to 8 a.m., 4 to 5 p.m. and 8 to 9 p.m. for cortisol analysis. In addition, they completed a concurrent symptom questionnaire. Prospective symptom diaries also were completed in the month before sampling.

Mean urinary or salivary cortisol did not differ in patients and controls. However, patients with interstitial cystitis and higher morning cortisol had significantly less pain and urgency, while those with higher urinary free cortisol reported less overall symptomatology (p <0.05). Relationships with morning cortisol were also observed when controlling for co-morbid conditions known to be affected by the hypothalamic-pituitary-adrenal axis, such as fibromyalgia, chronic fatigue and rheumatoid arthritis. Patients with morning cortisol less than 12.5 nmol./l. were 12.8 times more likely to report high urinary urgency than those with values above this cutoff.

These findings imply that regulation of the hypothalamic-pituitary-adrenal axis may be associated with interstitial cystitis symptomatology and there may be different diurnal hypothalamic-pituitary-adrenal patterns in patients with interstitial cystitis who do and do not have co-morbid conditions. These findings may have treatment implications for patients with interstitial cystitis who have early morning cortisol deficiencies.