Biochemical evaluation of disease activity after pituitary surgery in acromegaly: a critical analysis of patients who spontaneously change disease status.
BACKGROUND
The definition of biochemical cure in acromegaly involves both the normalization of IGF-1 and a glucose-suppressed GH level of < 1 ng/ml. These criteria were reached by several consensus meetings, although no evidence-based recommendations as to the optimal time to perform biochemical evaluations were made, nor was the fact that several patients may change biochemically upon long-term follow-up taken into consideration.


OBJECTIVE
To identify and characterize biochemical changes in the follow-up of acromegaly.


METHODS
One hundred and twenty-six acromegalic patients seen at a referral centre were followed prospectively (6-108 months) with regard to glucose-suppressed GH levels and IGF-1 concentrations.


RESULTS
Eighty-nine patients did not change biochemical status, whereas in 37 (29.3%), one or more changes were identified, mostly during the first year. When glucose-suppressed GH values were discordant with the IGF-1 results, the likelihood of biochemical status modification was significantly greater than when such results were concordant [concordant 19.4%, discordant 57.6%, odds ratio (OR) = 5.6, 95% confidence interval (CI) = 2.3-13.3, P = 0.0001]. Among the changing patients, four out of the nine subjects initially considered as cured remained so at the last follow-up, whereas five became discordant; of the nine initially categorized as active, only three kept such a status at the last evaluation, whereas five became GH discordant and one achieved full biochemical criteria of cure; of 17 initially GH-discordant patients, seven remained so upon the last evaluation, whereas six became concordantly active and four concordantly cured.


CONCLUSIONS
A significant proportion of acromegalic patients change biochemical status upon long-term follow-up after surgery. Most of these changes occur within the first postoperative year and are more likely to take place if the initial GH postglucose and IGF-1 levels are discordant.
Department of Endocrinology, Hospital de Especialidades, Centro Medico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.
Ana Laura
AL
Espinosa-de-Los-Monteros
Ernesto
E
Sosa
Sonia
S
Cheng
Raquel
R
Ochoa
Carolina
C
Sandoval
Gerardo
G
Guinto
Victoria
V
Mendoza
Irma
I
Hernández
Mario
M
Molina
Moisés
M
Mercado
D000172:Acromegaly / Q000378:metabolism* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005947:Glucose / Q000378:metabolism; D019382:Human Growth Hormone / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010902:Pituitary Gland / Q000378:metabolism / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D016896:Treatment Outcome
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D005947:Glucose