Long-Term Biochemical Status and Disease-Related Morbidity in 53 Postoperative Patients with Acromegaly

Abstract

firstly, to correlate plasma IGF-I with plasma glucose-suppressed GH concentrations; and secondly, to correlate each of these biochemical parameters with morbidity [impaired glucose tolerance (IGT), diabetes, and hypertension] in postoperative patients with acromegaly. Fifty-three patients with long-term follow-up (mean, 12.7 yr; range, 1-30 yr) after transsphenoidal surgery for acromegaly and 20 healthy subjects matched for age, sex, and body mass index were evaluated for plasma glucose [by 75-g oral glucose tolerance test (OGTT)], GH (by immunoradiometric assay), plasma IGF-I (by immunoradiometric assay), and blood pressure (BP) measurements. Remission was defined by a normal IGF-I. We identified 34 acromegalics in remission and 19 with active disease. There was no statistical difference between all three groups for age, sex, BMI, and for fasting and 2-h post-OGTT plasma glucose. The time elapsed since surgery was similar in both groups of acromegalics. The OGTT-GH nadir was less than 1 micro g/liter in 31 patients in remission (91.2%) and in nine patients with active disease (47.4%). Prevalence of IGT was lower in acromegalics in remission (14.7%) in comparison with patients with active disease (47.4%; P = 0.01). Plasma IGF-I and GH nadir cut-off of 0.25 microg/liter were strong predictors of abnormal glucose tolerance (odds ratio, 13.6; confidence interval, 2.5-73.7; P = 0.003). GH nadir cut-off of 1 microg/liter and basal GH of 2.5 microg/liter failed to predict abnormal glucose tolerance. There was no statistical difference for prevalence of hypertension and systolic BP values, but diastolic BP was significantly lower in patients in remission than in those with active disease (P < 0.05). Our observations indicate that the validity of the GH threshold of 1 microg/liter post OGTT might be inadequate as a criterion of biochemical remission of acromegaly and as a marker of associated comorbidities. However, normalized IGF-I concentrations and a lower GH cut-off value less than 0.25 micro g/liter are strongly associated with a lower prevalence of IGT and lower diastolic BP in long-term postoperative acromegaly.

Diabetes mellitusin a cohort of patients with acromegaly

“…Previous reports in the literature (27) showed superior prevalence of diabetes in patients who were not cured by transsphenoidal surgery. In a study with 66 patients with acromegaly (28), normal post-surgery IGF-1 values were more suggestive of insulin sensitivity than random GH measure.…”

60 YEARS OF NEUROENDOCRINOLOGY: Acromegaly

“…Some authors proposed a 0.25 mg/l cutoff to differentiate the persistent disease activity (Serri et al 2004). An even lower cutoff was advocated by some authors who reported that 25% of postsurgical cases with normal IGF1 and nadir GH O0.14 mg/l experienced recurrence (Freda et al 2004).…”

Low insulin resistance after surgery predicts poor GH suppression one year after complete resection for acromegaly: a retrospective study

“…The insulinogenic index (IGI) is an OGTT-based estimate of early-phase insulin secretion, calculated as (insulin at 30 min − insulin at 0 min [μU/mL])/(glucose at 30 min − glucose at 0 min [mg/ dL]) [25] and as the incremental area under the insulin curve (AUCinsulin: the sum of insulin at 0, 30, 60, 90, and 120 min). Preoperative BMI and preoperative and immediate postoperative HOMA-IR, HOMApostoperative patients with active disease show elevated IGF-1 levels and a GH nadir <1.0 ng/mL [9][10][11]. In addition, some patients with active acromegaly were reported to have elevated IGF-1 levels and 24-h mean plasma GH levels within the normal range of healthy individuals [12].…”