Evaluation of the reliability of blood Cortisol concentration essay using Electro-ChemiLuminescence ImmunoAssay compared to liquid chromatography-tandem-mass spectrometry in patients with ulcerative colitis treated with oral Prednisone

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Corticosteroids (CS), together with aminosalicylates, are drugs of choice for the management of ulcerative colitis (UC). Patients undergoing repeated oral administrations of Hydrocortisone or Prednisone may experience a variety of adverse effects, some of which of concerning clinical relevance. With regards to Cortisol plasma levels, a specific safety endpoint in the various clinical trials concerning the use of CS in UC is represented by the morning Cortisol levels below the lower limit of the normal range during treatment. Prednisolone and its metabolites are known to be chemically similar to serum cortisol and might therefore interfere with Cortisol measurements by radioimmunoassay (RIA). Analytical methods involving chromatographic separation of Cortisol from Prednisolone and its metabolites, such as high performance liquid chromatography (HPLC), circumvent this problem of interference. This study was planned to compare serum Cortisol measurements by both conventional RIA Electro-ChemiLuminescence ImmunoAssay (ECLIA) (Cobas) and by liquid chromatography with tandem mass spectrometric detection (LC/MS-MS) in patients with acute relapse of UC treated with oral Prednisone at a stable daily dose >= 30 mg in the last two weeks. A total of 20 in-patients and out-patients followed by the Gastroenterology Unit of the Cardarelli Hospital in Naples, Italy (UOC di Gastroenterologia ed Endoscopia Digestiva, Azienda Ospedaliera A. Cardarelli, Napoli) are required to complete this study. The inclusion criteria include: both genders, age between 18 and 70 years (both included); clinical diagnosis of acute relapse of UC with extension of the disease above the rectum and indication for systemic CS treatment; and continuous treatment with oral Prednisone at a daily dose >= 30 mg for at least the two weeks preceding enrollment. Exclusion criteria include: ongoing local (enema) or systemic treatment with CS other than Prednisone; low compliance to medical treatment; presence of other diseases or treatments that are known to interfere with the evaluation of blood Cortisol concentrations as a measure of hypothalamic-pituitary-adrenal axis suppression. The study includes: 1) a “screening visit” for study presentation, informed consent signature, clinical data collection and inclusion/ exclusion criteria check; 2) a “blood drawn visit” to collect fasting blood specimen for Cortisol essay. In particular, screening visit includes the following activities: patient information and signature of the informed consent; demographic data collection and patient ID assignment; medical history and concomitant treatment data collection; physical examination and vital signs; verification of inclusion and exclusion criteria. If patients verify all the inclusion and none of the exclusion criteria, an appointment for the blood drawn visit is given. Blood drawn visit includes the following activities: AEs and concomitant treatments collection; inclusion/exclusion criteria re-check; vital signs; blood drawn in fasting conditions, at a 24 hour distance from last Prednisone dose, between 8AM and 9AM, of about 10-12 mL (about 8 mL in serum vials and about 2-4 mL in EDTA-coated vials). Blood specimens will be fresh centrifuged at about 2500 rpm for 15 minutes at +4 degrees C. After centrifugation, specimens will be divided into 4 aliquots: -one aliquot of about 200 uL of plasma (from EDTA-treated blood) to determine circulating Cortisol by LC/MS/MS assay; -one aliquot of about 1,5 mL of serum (from untreated blood) to determine circulating Cortisol by RIA ECLIA (Cobas) assay; -one aliquot of about 200 uL of plasma to be stored at -20 degrees C as backup for possible re-analysis; -one aliquot of about 1.5 mL of plasma to be stored at -20 degrees C as backup for possible re-analysis. Specimens will be stored at -20 degrees C at the investigator site (laboratory of the Gastroenterology Unit) until shipment to the laboratory for Cortisol assay. Primary evaluation parameter will be the difference between Cortisol concentrations assayed with the two methods. Data will be presented descriptively as mean, median, SD and 95% CI for the mean. As exploratory analysis, cortisol concentrations obtained with the two methods will be compared using paired t-test.

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