Endocrine Abstracts

Introduction: Emerging research in 3D-bone shape has provided new insights into the pathogenesis of osteoarthritis (OA). OA patients have increased subchondral bone area, associated with higher prevalence of cartilage loss. Higher B-score, a novel, machine learning-derived OA bone biomarker, is associated with increased OA symptom severity and structural progression. Arthropathy, despite being the commonest cause of morbidity amongst acromegaly patients, remains one of the under-investigated areas in acromegaly and currently, data based on modern imaging modalities are limited.

Design/Methods: Cross-sectional study, in which bilateral knee MRI scans were obtained from 60 patients with acromegaly. Knee bone shape, 3D-joint space width (3DJSW), cartilage thickness, B-score and bone area were measured based on automated segmentation of MR images using active appearance models.

Results: Thirty-nine acromegaly patients (65%) had B-score <2 (Group 1), indicating absence of significant arthropathy on knee MRI, with the remaining 21 patients (Group 2) having B-score ≥2. There was no difference in age, male:female ratio, height and weight between the two groups. Following adjustment for these variables, Group 2 patients had increased mean femoral, tibia and patella bone areas compared with Group 1. Both mean medial and lateral femorotibial cartilage thickness were increased in Group 2 [Medial cartilage thickness, Group 1: 5.35mm (95% CI 5.0-5.7) vs Group 2: 6.12 mm (95% CI 5.66-6.59), P=0.01; Lateral cartilage thickness, Group 1: 6.48 mm (95% CI 6.17-6.79) vs Group 2: 7.78 mm (95% CI 7.36-8.2), P<0.001], leading to increased 3DJSW medially. Patients with B-score ≥2 had higher median pre-treatment GH levels [Group 1: 6.6 (4.1-17) mg/l vs Group 2: 39 (5.4-57.8) mg/l, P=0.015] and required significantly higher number of pituitary surgeries than patients with B-score <2. Multiple linear regression analysis showed that higher number of pituitary surgeries, radiotherapy and use of GH-lowering medications were independently correlated with higher B-scores. 3DJSW was positively associated with higher pre-treatment GH levels, height, weight and male gender. Regarding clinical outcomes, Group 2 patients had significantly longer median duration of knee pain [4 years (1.75-10)] than Group 1 [1.5 years (0-5)], P=0.01. Additionally, 47.6% of Group 2 patients had undergone previous joint replacement surgery compared with 12.8% in Group 1 (P=0.009).

Conclusions: Patients with B-score ≥2 had higher pre-treatment GH values and required higher number of therapeutic interventions for the management of acromegaly, suggesting that the risks of more profound changes to the bone shape and increased severity of arthropathy are dependent on the degree of overall GH excess.