Kim M.j.a. Claessen

Progression of Vertebral Fractures Despite Long-Term Biochemical Control of Acromegaly: A Prospective Follow-up Study

BACKGROUND In active acromegaly, pathologically elevated GH and IGF-1 levels are associated with increased bone turnover and a high bone mass, the latter being sustained after normalization of GH values. In a cross-sectional study design, we have previously reported a high prevalence of vertebral fractures (VFs) of about 60% in patients with controlled acromegaly, despite normal mean bone mineral density (BMD) values. Whether these fractures occur during the active acromegaly phase or after remission is achieved is not known. OBJECTIVE Our objective was to study the natural progression of VFs and contributing risk factors in patients with controlled acromegaly over a 2.5-year follow-up period. METHODS Forty-nine patients (mean age 61.3 ± 11.1 years, 37% female) with controlled acromegaly for ≥ 2 years after surgery, irradiation, and/or medical therapy and not using bisphosphonates were included in the study. Conventional spine radiographs including vertebrae Th4-L4 were assessed for VFs according to the Genant method. VF progression was defined as development of new/incident fractures and/or a minimum 1-point increase in the Genant scoring of preexisting VFs. BMD was assessed by dual-energy x-ray absorptiometry (Hologic 4500). RESULTS Prevalence of baseline VFs was 63%, being highest in men, and fractures were unrelated to baseline BMD. VF progression was documented in 20% of patients, especially in men and in case of ≥ 2 VFs at baseline. VF progression was not related to BMD values or BMD changes over time. CONCLUSION Findings from this longitudinal study show that VFs progress in the long term in 20% of patients with biochemically controlled acromegaly in the absence of osteoporosis or osteopenia. These data suggest that an abnormal bone quality persists in these patients after remission, possibly related to pretreatment long-term exposure to high circulating levels of GH.

Long-term effects of recombinant human GH replacement in adults with GH deficiency: a systematic review

BACKGROUND The beneficial effects of recombinant human GH (rhGH) therapy in GH deficient (GHD) adults are well-established in the short term. However, data documenting the effects during prolonged follow-up are relatively scarce. OBJECTIVE To evaluate the reported effects of rhGH replacement (≥5 years) in GHD adults on biochemical and anthropometric parameters, quality of life (QoL), bone metabolism, muscle strength, serious adverse events and mortality. METHODS We conducted a systematic literature search. Quality assessment of retrieved papers was performed using a quality assessment based on the modified STROBE statement. RESULTS We included 23 prospective studies with a rhGH treatment duration ranging from 5 to 15 years. Overall, beneficial effects were reported on QoL, body composition, lipid profile, carotid intima media thickness and bone mineral density. In contrast, the prevalence of the metabolic syndrome, glucose levels, BMI and muscle strength were not, or negatively, influenced. Most of the studies were uncontrolled, lacked the presence of a control group (of non-treated GHD patients), and reported no data on lipid-lowering and anti-diabetic medication. Overall mortality was not increased. CONCLUSION rhGH treatment in adult GHD patients is well-tolerated and positively affects QoL in the long term. However, the metabolic and cardiovascular effects during long-term treatment are variable. The low numbers of long-term studies and studied patients and lack of control data hamper definite statements on the efficacy of prolonged treatment. Therefore continuous monitoring of the effects of rhGH replacement to enable an adequate risk-benefit analysis that may justify prolonged, potentially life-long, treatment is advisable.

Metabolic Profile in Growth Hormone-Deficient (GHD) Adults after Long-Term Recombinant Human Growth Hormone (rhGH) Therapy

BACKGROUND The metabolic effects of recombinant human GH (rhGH) therapy in adults are well-documented in the short term. The effects of long-term rhGH therapy beyond 5 yr on metabolic parameters are presently unknown. OBJECTIVE The aim of the study was to evaluate the long-term effects of rhGH treatment on biochemical and anthropometric parameters in a large cohort of GH-deficient adults. METHODS Ninety-eight GH-deficient adult patients treated with rhGH for at least 10 yr were included (mean age, 59.4 yr; 50% female). Total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, anthropometric parameters, IGF-I, and glucose were evaluated at baseline and after 5, 10, and 15 yr of treatment. In addition, the prevalence of the metabolic syndrome (MS) and the incidence of cardiovascular events were assessed. RESULTS Total cholesterol and low-density lipoprotein cholesterol concentrations were lower, and high-density lipoprotein cholesterol levels were significantly higher during long-term rhGH replacement when compared to baseline (all P < 0.001). Both waist circumference (P < 0.001) and body mass index (P = 0.018) were significantly higher after 10 yr, as were fasting plasma glucose levels (P < 0.001). No significant changes were observed in triglycerides, waist-to-hip ratio, and blood pressure during follow-up. In the subset of patients with 15-yr rhGH treatment (n = 43), generally similar metabolic effects were found. MS prevalence was increased after 10 yr of rhGH treatment (57.1 vs. 32.7%; P < 0.001), especially in males (69.4 vs. 32.7%; P < 0.001). CONCLUSION Despite improvement of several cardiovascular risk factors, MS prevalence increased significantly during rhGH treatment. The effect of long-term rhGH treatment on overall cardiovascular risk profile needs to be established in a larger cohort.

Bone and Joint Disorders in Acromegaly

Acromegaly is a chronic, progressive disease caused by a growth hormone (GH)-producing pituitary adenoma, resulting in elevated GH and insulin-like growth factor 1 concentrations. Following appropriate therapy (surgery, radiotherapy and/or medical treatment), many systemic GH-induced comorbid conditions improve considerably. Unfortunately, despite biochemical control, acromegaly patients suffer from a high prevalence of late manifestations of transient GH excess, significantly impairing their quality of life. In this overview article, we summarize the pathophysiology, diagnosis, clinical picture, disease course and management of skeletal complications of acromegaly, focusing on vertebral fractures and arthropathy.

Progression of acromegalic arthropathy despite long-term biochemical control: a prospective, radiological study

OBJECTIVE Arthropathy is an invalidating complication of acromegaly, of which the prognosis and determinants are currently unknown in treated acromegaly. Therefore, the objective of the present study was to investigate the radiographic progression of arthropathy over a mean follow-up period of 2.6 years and determinants of outcome in patients with long-term, well-controlled acromegaly. DESIGN Prospective follow-up study. METHODS In a prospective cohort study we studied 58 patients (mean age 62, women 41%) with controlled acromegaly for a mean of 17.6 years. Radiographic progression of joint disease was defined by the Osteoarthritis Research Society International classification as a 1-point increase in joint space narrowing (JSN) or osteophyte scores on radiographs of the hands, knees, and hips obtained at the first study visit and after 2.6 years. Potential risk factors for progression were assessed. RESULTS Progression of osteophytes and JSN was observed in 72 and 74% of patients respectively. Higher age predisposed for osteophyte progression. Patients with biochemical control by somatostatin (SMS) analogs had more progression of osteophytosis than surgically cured patients (odds ratio=18.9, P=0.025), independent of age, sex, BMI, baseline IGF1 SDS and exon 3 deletion of the GHR. This was also evident for JSN progression, as were higher age and higher baseline IGF1 SDS. CONCLUSIONS Acromegalic patients have progressive JSN and osteophytosis, despite long-term biochemical control. Parameters reflecting GH/IGF1 activity were associated with progressive joint disease. Remarkably, biochemical control by SMS analogs was associated with more progression than surgical cure. Although the present study is not a randomized controlled trial, this may indicate insufficient GH control according to current criteria and the need for more aggressive therapy.

Effects of up to 15 years of recombinant human GH (rhGH) replacement on bone metabolism in adults with growth hormone deficiency (GHD): the Leiden Cohort Study.

Growth hormone deficiency (GHD) in adulthood may be associated with a decreased bone mineral density (BMD), a decreased bone mineral content (BMC) and an increased fracture risk. Recombinant human GH (rhGH) replacement induces a progressive increase in BMD for up to 5–7 years of treatment. Data on longer follow‐up are, however, scarce.

Therapy of Endocrine disease: Long-term effects of recombinant human GH replacement in adults with GH deficiency: a systematic review

BACKGROUND The beneficial effects of recombinant human GH (rhGH) therapy in GH deficient (GHD) adults are well-established in the short term. However, data documenting the effects during prolonged follow-up are relatively scarce. OBJECTIVE To evaluate the reported effects of rhGH replacement (≥5 years) in GHD adults on biochemical and anthropometric parameters, quality of life (QoL), bone metabolism, muscle strength, serious adverse events and mortality. METHODS We conducted a systematic literature search. Quality assessment of retrieved papers was performed using a quality assessment based on the modified STROBE statement. RESULTS We included 23 prospective studies with a rhGH treatment duration ranging from 5 to 15 years. Overall, beneficial effects were reported on QoL, body composition, lipid profile, carotid intima media thickness and bone mineral density. In contrast, the prevalence of the metabolic syndrome, glucose levels, BMI and muscle strength were not, or negatively, influenced. Most of the studies were uncontrolled, lacked the presence of a control group (of non-treated GHD patients), and reported no data on lipid-lowering and anti-diabetic medication. Overall mortality was not increased. CONCLUSION rhGH treatment in adult GHD patients is well-tolerated and positively affects QoL in the long term. However, the metabolic and cardiovascular effects during long-term treatment are variable. The low numbers of long-term studies and studied patients and lack of control data hamper definite statements on the efficacy of prolonged treatment. Therefore continuous monitoring of the effects of rhGH replacement to enable an adequate risk-benefit analysis that may justify prolonged, potentially life-long, treatment is advisable.

Relationship between insulin-like growth factor-1 and radiographic disease in patients with primary osteoarthritis: a systematic review

OBJECTIVE To evaluate the association between radiographic osteoarthritis (OA) and either serum insulin-like growth factor-1 (IGF-1) levels or IGF-1 gene polymorphisms in patients with primary OA. METHODS We conducted a systematic review of reported associations between circulating IGF-1 and/or IGF-1 gene polymorphisms and radiographic OA. Studies were eligible when: (1) investigating serum IGF-1 and/or IGF-1 gene polymorphisms in relation to prevalent or incident radiographic OA; (2) written in English; (3) full-text article or abstract; (4) patients had primary OA in knee, hip, hand or spine; (5) longitudinal, case-control or cross-sectional design. Quality assessment was done using a standardized criteria set. Best-evidence synthesis was performed based on guidelines on systematic review from the Cochrane Collaboration Back Review Group, using five evidence levels: strong, moderate, limited, conflicting and no evidence. RESULTS We included 11 studies with more than 3000 primary OA cases. Data on the relationship between serum IGF-1 and radiographic OA were inconsistent. Adjustment for body mass index (BMI) was often omitted. Of four high-quality studies, three studies reported no association, one study found significantly higher IGF-1 levels in OA patients compared to controls. Patients with IGF-1 gene promoter polymorphisms and a genetic variation at the IGF-1R locus had an increased OA prevalence compared to controls. CONCLUSIONS Observational data showed no association between serum IGF-1 and occurrence of radiographic OA (moderate level of evidence), and a positive relationship between IGF-1 gene polymorphisms and radiographic OA (moderate level of evidence); however the confounding effect of BMI was insufficiently addressed. Future well-designed prospective studies should further elaborate the role of the complex GH/IGF-1 system in primary OA.

Bone material strength index as measured by impact microindentation is altered in patients with acromegaly

OBJECTIVE Acromegaly is a rare disease caused by excess growth hormone (GH) production by the pituitary adenoma. The skeletal complications of GH and IGF-1 excess include increased bone turnover, increased cortical bone mass and deteriorated microarchitecture of trabecular bone, associated with a high risk of vertebral fractures in the presence of relatively normal bone mineral density (BMD). We aimed to evaluate tissue-level properties of bone using impact microindentation (IMI) in well-controlled patients with acromegaly aged ≥18 years compared to 44 controls from the outpatient clinic of the Centre for Bone Quality. DESIGN AND METHODS In this cross-sectional study, bone material strength index (BMSi) was measured in 48 acromegaly patients and 44 controls with impact microindentation using the osteoprobe. RESULTS Mean age of acromegaly patients (54% male) was 60.2 years (range 37.9-76.5), and 60.5 years (range 39.8-78.6) in controls (50% male). Patients with acromegaly and control patients had comparable BMI (28.2 kg/m2 ± 4.7 vs 26.6 kg/m2 ± 4.3, P = 0.087) and comparable BMD at the lumbar spine (1.04 g/cm2 ± 0.21 vs 1.03 g/cm2 ± 0.13, P = 0.850) and at the femoral neck (0.84 g/cm2 ± 0.16 vs 0.80 g/cm2 ± 0.09, P = 0.246). BMSi was significantly lower in acromegaly patients than that in controls (79.4 ± 0.7 vs 83.2 ± 0.7; P < 0.001). CONCLUSION Our data indicates that tissue-level properties of cortical bone are significantly altered in patients with controlled acromegaly after reversal of long-term exposure to pathologically high GH and IGF-1 levels. Our findings also suggest that methods other than DXA should be considered to evaluate bone fragility in patients with acromegaly.

High prevalence of metabolic syndrome features in patients previously treated for nonfunctioning pituitary macroadenoma.

Objective Patients treated for nonfunctioning pituitary macroadenoma (NFMA) with suprasellar extension show disturbed sleep characteristics, possibly related to hypothalamic dysfunction. In addition to hypopituitarism, both structural hypothalamic damage and sleep restriction per se are associated with the metabolic syndrome. However, the prevalence of the metabolic syndrome in patients with NFMA is not well established. Our objective was to study the prevalence and risk factors for (components of) the metabolic syndrome in patients treated for NFMA. Design The metabolic syndrome (NCEP-ATP III criteria) was studied in an unselected cohort of 145 NFMA patients (aged 26–88yr, 44% female) in long-term remission after treatment, receiving adequate stable hormone replacement for any pituitary deficiencies. The results were compared to population data of 63,995 Dutch inhabitants by standardization (LifeLines cohort study). Results NFMA patients showed increased risk for reduced HDL-cholesterol (SMR 1.59, 95% CI 1.13–2.11), increased triglyceride levels (SMR 2.31, 95% CI 1.78–2.90) and the metabolic syndrome (SMR 1.60, 95% CI 1.22–2.02), but not for increased blood pressure, waist circumference or hyperglycemia. Preoperative visual field defects independently affected the risk for increased blood pressure (OR 6.5, 95% CI 1.9–22.2), and hypopituitarism was associated with a body mass index - dependent risk for increased waist circumference (OR 1.6, 95% CI 1.2–2.2) and the metabolic syndrome (OR 1.4, 95% CI 1.0–1.9). Conclusions Patients treated for NFMA are increased at risk for developing the metabolic syndrome, mainly due to decreased HDL-cholesterol and increased triglycerides. Risk factors included hypopituitarism and preoperative visual field defects. Hypothalamic dysfunction may explain the metabolic abnormalities, in addition to intrinsic imperfections of hormone replacement therapy. Additional research is required to explore the relation between derangements in circadian rhythmicity and metabolic syndrome in these patients.