Bone turnover in patients with endogenous Cushing's syndrome before and after successful treatment.
We investigated bone turnover and its restoration in a large number of patients in the active phase and after cure of endogenous Cushing's syndrome. Furthermore, the usefulness of serum osteocalcin and collagen breakdown products as potential markers of active Cushing's syndrome was also evaluated.


BACKGROUND
Suppressed bone formation is one of the most characteristic features of Cushing's syndrome (CS). Despite numerous previous reports, many aspects of the disturbed bone metabolism of these patients are unexplored. In this study, we investigated the time course of bone marker changes after the cure of CS as well as correlations between bone markers and serum cortisol concentrations.


METHODS
Eighty-seven patients with CS were studied. Patients were followed up to 48 months after surgical cure. Serum osteocalcin (OC) and collagen breakdown products (CTX) were measured with immunochemiluminescence method and compared to the results of 161 healthy controls.


RESULTS
OC showed a negative, while CTX displayed a positive correlation with serum cortisol. Patients with diabetes mellitus and myopathy had significantly lower serum OC levels compared to those without these complications. The area under the curve of OC obtained by receiver-operating characteristics analysis for the discrimination of patients with CS from healthy controls was 0.9227. Postoperative OC increased rapidly from the first few days or weeks reaching its maximum at the sixth month and remained stable after the 24th postoperative month.


CONCLUSIONS
Our study demonstrated significant correlations between serum cortisol and both bone formation and resorption markers in the active phase of CS. We propose that OC may serve as a sensitive biologic marker of glucocorticoid activity in endogenous CS during its active phase and it may reflect the clinical cure of the disease.
Szappanos
A
A
2nd Department of Medicine, Semmelweis University, Budapest, Hungary.
Toke
J
J
Lippai
D
D
Patócs
A
A
Igaz
P
P
Szücs
N
N
Füto
L
L
Gláz
E
E
Rácz
K
K
Tóth
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016723:Bone Remodeling / Q000502:physiology*; D024042:Collagen Type I / Q000097:blood; D003480:Cushing Syndrome / Q000097:blood / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D010455:Peptides / Q000097:blood; D011184:Postoperative Period; D016896:Treatment Outcome; D055815:Young Adult
D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D006854:Hydrocortisone