Discordant biological parameters of remission in acromegaly do not increase the risk of hypertension or diabetes: a study with the Liege Acromegaly Survey database

Acromegaly: diagnostic challenges and individualized treatment

INTRODUCTION

Acromegaly is due in almost all cases to a GH-secreting pituitary tumor. GH and IGF-1 excesses lead to its multi-system clinical manifestations and comorbidities. Acromegaly is under-diagnosed and typically presents with advanced disease. When early or mild, clinical recognition and biochemical confirmation are especially challenging. Individualized treatment may optimize patient outcome.

AREAS COVERED

This review covers challenges to diagnosing acromegaly and reviews therapies for acromegaly with a focus on those aspects that can be individualized.

EXPERT OPINION

The first step in diagnosing acromegaly is recognizing it clinically. To improve this, increase awareness and education of the general population and healthcare professionals about the acromegaly phenotype is needed. Once suspected clinically, IGF-1 measurement is the initial step in making the biochemical diagnosis. GH may be < 1.0 µg/L after oral glucose suppression in early/mild cases. GH and IGF-1 should be considered in concert. Providers should be aware of conditions that can alter GH and IGF-1 levels and each assay's performance. An individualized treatment approach is best employed. Surgery is preferred as initial treatment and medical therapy as initial adjuvant therapy. In individualizing therapy, the advantages and disadvantages of each option and predictors of response to them should be considered.

Management policy for postoperative acromegaly patients with normal IGF-1 and high GH levels on oral glucose tests

PURPOSE

Acromegaly patients occasionally achieve either of the remission criterion of IGF-1 or GH level postoperatively; however, treatment for patients with discordant IGF-1 and GH levels remains unclear. This study aimed to clarify the clinical courses and features of postoperative patients with normal IGF-1 and high GH levels and support their management.

METHODS

Overall, 110 acromegaly patients underwent initial surgery and a 75-g oral glucose tolerance test (OGTT) 3 months postoperatively. Of the 110, 23 patients with normal IGF-1 and nadir GH levels of ≥ 0.4 µg/L on OGTT (high-GH group) were categorized into three subtypes based on their repeated examinations thereafter: late-remission type (nadir GH level on OGTT of < 0.4 µg/L later), recurrence type (elevated IGF-1 and GH levels later), and persistent type (normal IGF-1 levels and constantly high nadir GH levels on OGTTs).

RESULTS

Proportion of patients in the high-GH group was 23.6%, and they were distributed as follows: late-remission type (n = 10), recurrence type (n = 5), and persistent type (n = 8). There were significantly more women (P = 0.0178) than men in the late-remission type, and patients in the persistent type had significantly larger tumors (P = 0.0110) and higher preoperative GH levels (P = 0.0018) than those that achieved complete remission 3 months postoperatively.

CONCLUSION

Careful monitoring without additional medications is recommended at first in acromegaly patients with normal IGF-1 and high GH levels considering the possibility of recurrence in the future.

Interpreting growth hormone and IGF-I results using modern assays and reference ranges for the monitoring of treatment effectiveness in acromegaly

Standard treatment for acromegaly focuses on the achievement of target absolute levels of growth hormone (GH) and insulin-like growth factor (IGF-I). The appropriateness of these targets when measured using modern assay methods is not well defined. This paper reviews biochemical status assessed using methods available at the time and associated clinical outcomes. GH measurements were shown to provide an indication of changes in tumor size, and failure of GH suppression after glucose stimulation is associated with tumor recurrence. IGF-I levels were more closely associated with changes in symptoms and signs. Reduced GH and IGF-I concentrations were shown to be associated with increased longevity, although the degree of increase has only been analyzed for GH. Lowering of GH and IGF-I has consistently been associated with improved outcomes; however, absolute levels reported in previous studies were based on results from methods and reference ranges that are now obsolete. Applying previously described absolute thresholds as targets (e.g. "normal" IGF-I level) when using current methods is best applied to those with active acromegaly symptoms who could benefit from further lowering of biochemical markers. In asymptomatic individuals with mild IGF-I or GH elevations, targeting biochemical "normalization" would result in the need for combination pharmacotherapy in many patients without proven benefit. Measurement of both GH and IGF-I remains an essential component of diagnosis and monitoring the effectiveness of treatment in acromegaly; however, treatment goals based only on previously identified absolute thresholds are not appropriate without taking into account the assay and reference ranges being employed. Treatment goals should be individualized considering biochemical improvement from an untreated baseline, symptoms of disease, risks, burdens and costs of complex treatment regimens, comorbidities, and quality of life.

Discordant biochemical parameters of acromegaly remission do not influence the prevalence or aggressiveness of metabolic comorbidities: a single-center study

Purpose

The discrepancy between the biomarkers of disease's activity in acromegalic patients (GH and IGF-1) is almost frequent representing a challenge for the development of comorbidities in the long term. The aim of this study was to evaluate the prevalence and severity of metabolic comorbidities (diabetes, hypertension, and dyslipidemia) in surgically treated acromegalic patients with disease control and discordant GH and/or IGF-1 levels compared with those with concordant values.

Patients and methods

Retrospective monocentric observational study on acromegalic surgically treated patients with biochemical remission (group A) or mild discordant GH or IGF-1 levels (group B). Metabolic complications and medical therapy were assessed at diagnosis and at the last follow-up visit. Severity of the disease was set for drug titration or shift to another molecule or more than before.

Results

There were 18 patients that met the inclusion criteria [group A: nine patients; group B: nine patients, follow-up 7 years (IQR 5.0;11.25)]. The prevalence of female patients was significantly higher in the remission group compared with the discordant group (p < 0.02). Considering metabolic complications, at the last follow-up, 61.1% was affected by hypertension, 33.3% by diabetes, and 61.1% by dyslipidemia, without differences between groups. Drug characteristics (dose, shift, number) during the follow-up did not differ significantly between groups.

Conclusion

Metabolic complications, mainly dyslipidemia, are frequent in cured acromegalic patients, but GH/IGF-1 discrepancy does not seem to represent a risk factor for their presence or persistence. More extended studies are needed to confirm our results in a long-term period.

Sex difference in patients with controlled acromegaly-A multicentre survey

OBJECTIVE

Active acromegaly is subject to sex differences in growth hormone (GH) and Insulin like growth factor 1 (IGF-I) patterns as well as clinical features but whether this also pertains to controlled disease is unclear.

DESIGN

In a cross-sectional, multi-centre study, 84 patients with acromegaly (F = 43, M = 41), who were considered controlled after surgery alone (n = 23) or during continued somatostatin receptor ligand (SRL) treatment (n = 61), were examined.

METHODS

Serum concentrations of GH, insulin, glucose and free fatty acid (FFA) were measured during an oral glucose tolerance test (OGTT) together with baseline serum IGF-I and completion of two HR-Qol questionnaires (acromegaly quality of life questionnaire [AcroQol] and Patient-assessed Acromegaly Symptom Questionnaire [PASQ]).

RESULTS

The mean age at the time of the study was 57 (±1.1) years and the majority of females (were postmenopausal. Females had significantly higher fasting GH but comparable IGF-I standard deviation scores (SDS). Using fasting GH < 1.0 µg/L as cut off, disease control was less prevalent in females (F: 56% vs. M: 83%, p = .007) whereas a comparable figure was observed using IGF-I SDS < 2 (F:79% vs. M:76%, p = .71). Compared with males, female patients showed impaired AcroQol physical score (p = .05), higher fasting FFA (p = .03) and insulin concentrations during the OGTT (p = .04).

CONCLUSION

In patients with acromegaly considered controlled, postmenopausal females exhibited higher GH levels than males despite comparable IGF-I levels, which also translated into impaired metabolic health and well-being. Our findings point to the relevance of including GH measurements in the assessment of disease control and suggest that disease-specific sex differences prevail after treatment.

The prevalence of acromegaly is higher than previously reported: Changes over a three-decade period

OBJECTIVE

To study time-related changes in the prevalence and patient characteristics of acromegaly, as well as to assess the impact of changes in treatment on disease control.

METHODS

A total of 107 patients with acromegaly were identified by healthcare registries and subsequently validated by patient chart review over a three-decade period (1992-2021). A systematic literature review focusing on the incidence and prevalence of acromegaly was performed identifying 31 studies.

RESULTS

The prevalence of acromegaly significantly increased throughout the study period (R²  = 0.94, p < .001) and was 122 cases/10⁶ persons in 2021 whereas the annual incidence remained constant at 4.6 cases/10⁶ persons. The age at the first sign of acromegaly and the age at diagnosis significantly increased during the study period, whereas growth hormone and insulin-like growth factor I decreased. Incidentalomas constituted 32% of all cases diagnosed with acromegaly in the last decade. Primary surgery was used in 93% of all cases, and repeated surgery decreased from 24% to 10% during the three decades. The use of first-generation somatostatin analogues (21%-48%) and second-line medical treatment (4%-20%) increased with a concomitant improvement of biochemical disease control (58%-91%).

CONCLUSION

The prevalence of acromegaly is higher than previously reported and the clinical presentation has shifted towards a milder phenotype. Modern treatment of acromegaly enables individualized treatment and disease control in the majority of patients.

Acromegaly: pathogenesis, diagnosis, and management

Growth hormone-secreting pituitary adenomas that cause acromegaly arise as monoclonal expansions of differentiated somatotroph cells and are usually sporadic. They are almost invariably benign, yet they can be locally invasive and show progressive growth despite treatment. Persistent excess of both growth hormone and its target hormone insulin-like growth factor 1 (IGF-1) results in a wide array of cardiovascular, respiratory, metabolic, musculoskeletal, neurological, and neoplastic comorbidities that might not be reversible with disease control. Normalisation of IGF-1 and growth hormone are the primary therapeutic aims; additional treatment goals include tumour shrinkage, relieving symptoms, managing complications, reducing excess morbidity, and improving quality of life. A multimodal approach with surgery, medical therapy, and (more rarely) radiation therapy is required to achieve these goals. In this Review, we examine the epidemiology, pathogenesis, diagnosis, complications, and treatment of acromegaly, with an emphasis on the importance of tailoring management strategies to each patient to optimise outcomes.

Characteristics and treatment outcomes of micromegaly - acromegaly with apparently normal basal GH: A retrospective study and literature review

Objective. Micromegaly describes a subgroup of patients with clinically evident acromegaly and elevated insulin-like growth factor I (IGF-I) with apparently normal basal growth hormone (bGH) and often a glucose-suppressed growth hormone (GH) of <1 ng/mL at diagnosis. It is controversial whether this condition is a distinct clinical entity or a classic acromegaly in early stages. The aim of the present article was to characterize the prevalence, clinical and biochemical characteristics, and therapeutic outcomes of micromegaly. Methods. A retrospective study of patients with an acromegaly followed ≥1 year at a tertiary center from 1995 to 2019. Patients without IGF-I or GH measurements at diagnosis were excluded. At diagnosis, bGH was considered normal if <2 ng/mL. Results. From 74 patients with acromegaly, 6 (8.1%) had normal bGH levels. There was no difference in the gender distribution, median diagnostic delay, and follow-up time between patients with normal bGH and elevated bGH. Patients with normal bGH were significantly older at time of the first acromegalic manifestation and diagnosis they had significantly lower nadir post-glucose GH and IGF-I levels, and tended to have a higher prevalence of obesity than patients with the elevated bGH. The frequency of acromegalic symptoms, signs, and other comorbidities than obesity was similar between groups. Five patients (83.3%) with normal bGH presented microadenomas. Post-operative remission and outcomes at last visit were comparable between patients with or without normal bGH. Conclusions. Normal bGH acromegaly is relatively uncommon in our patients. These patients showed differentiating characteristics from the classical acromegaly with elevated bGH. Further studies are needed to extend the knowledge about its clinical behavior, therapeutic outcomes, morbidity, and mortality.

Discordant GH and IGF-1 Results in Treated Acromegaly: Impact of GH Cutoffs and Mean Values Assessment

CONTEXT

Discordant growth hormone (GH) and insulin-like growth factor-1 (IGF-1) values are frequent in acromegaly.

OBJECTIVE

To evaluate the impact of different GH cutoffs on discordance rate. To investigate whether the mean of consecutive GH measurements impacts discordance rate when matched to the last available IGF-1 value.

DESIGN

Retrospective study.

SETTING

Referral center for pituitary diseases.

PATIENTS

Ninety acromegaly patients with at least 3 consecutive evaluations for GH and IGF-1 using the same assay in the same laboratory (median follow-up 13 years).

INTERVENTIONS

Multimodal treatment of acromegaly.

MAIN OUTCOME MEASURES

Single fasting GH (GHf) and IGF-1 (IGF-1f). Mean of 3 GH measurements (GHm), collected during consecutive routine patients' evaluations.

RESULTS

At last evaluation GHf values were 1.99 ± 2.79 µg/L and age-adjusted IGF-1f was 0.86 ± 0.44 × upper limit of normality (mean ± SD). The discordance rate using GHf was 52.2% (cutoff 1 µg/L) and 35.6% (cutoff 2.5 µg/L) (P = 0.025). "High GH" discordance was more common for GHf <1.0 µg/L, while "high IGF-1" was predominant for GHf <2.5 µg/L (P < 0.0001). Using GHm mitigated the impact of GH cutoffs on discordance (GHm <1.0 µg/L: 43.3%; GHm <2.5 µg/L: 38.9%; P = 0.265). At receiver-operator characteristic curve (ROC) analysis, both GHf and GHm were poor predictors of IGF-1f normalization (area under the curve [AUC] = 0.611 and AUC = 0.645, respectively). The prevalence of disease-related comorbidities did not significantly differ between controlled, discordant, and active disease patients.

DISCUSSION

GH/IGF-1 discordance strongly depends on GH cutoffs. The use of GHm lessen the impact of GH cutoffs. Measurement of fasting GH levels (both GHf and GHm) is a poor predictor of IGF-1f normalization in our cohort.