Approach to the Patient: Pharmacological Therapies for Fracture Risk Reduction in Adults With Osteogenesis Imperfecta

Unraveling the genetic collagen connection: clinical and therapeutic insights on genetic connective tissue disorders

Hereditary connective tissue disorders include more than 200 conditions affecting different organs and tissues, compromising the biological role of the extracellular matrix through interference in the synthesis, development, or secretion of collagen and/or its associated proteins. The clinical phenotype includes multiple signs and symptoms, usually nonspecific but of interest to rheumatologists because of musculoskeletal involvement. The patient´s journey to diagnosis is long, and physicians should include these disorders in their differential diagnoses of diseases with systemic involvement. In this review, insights for the diagnosis and treatment of osteogenesis imperfecta, hypermobility spectrum disorder/Ehlers-Danlos syndrome, Marfan, Loeys-Dietz, and Stickler syndromes are presented.

Demographics and medical burden of osteogenesis imperfecta: a nationwide database analysis

The epidemiological data on osteogenesis imperfecta (OI) in Asia is limited. This study, representing the first comprehensive epidemiological investigation on OI in Taiwan, reveals high medical resource utilization and underscores the importance of early diagnosis to enhance care quality.

INTRODUCTION

This study examines osteogenesis imperfecta, a hereditary connective tissue disorder causing pediatric fractures and limb deformities, using a nationwide database from Taiwan to analyze clinical features and medical burden.

METHODS

The study identified validated OI patients from the Catastrophic Illness Registry in the National Health Insurance Research Database from 2008 to 2019. Demographic data and medical resource utilization were analyzed. A multivariate Cox model assessed the influence of sex, validation age, and comorbidities.

RESULTS

319 OI patients (M/F = 153/166) were identified, with 58% validated before age 20. Prevalence and incidence were 0.8-1.3/100,000 and 0.02-0.09/100,000, respectively, with higher rates in the pediatric demographic. In the study period, 69.6% of the patients had admission history, primarily to pediatric and orthopedic wards. The median admission number was 3, with a median length of stay of 12 days and a median inpatient cost of approximately 3,163 USD during the period. Lower limb fractures were the main reason for hospitalization. 57% of OI patients received bisphosphonate treatment. The leading causes of mortality were OI-related deaths, neurovascular disease, and cardiovascular disease. The median age of validation in the non-survival group was significantly higher compared to the survival group (33 vs. 14 years), and patients validated during childhood required more inpatient fracture surgeries than those validated during adulthood.

CONCLUSION

This study provides comprehensive real-world evidence on the clinical characteristics and high medical resource utilization of OI patients in a low prevalence region like Taiwan. Early diagnosis is crucial for improving care quality and enhancing health outcomes.

Health-related quality of life and fatigue in adult rare bone disease patients: A cross-sectional study from Austria

OBJECTIVES

To assess physical and mental health domains of health related quality of life (HRQoL) as well as fatigue in rare bone disease (RBD) patients and to compare to patients with osteoporosis (OPO) and healthy controls (CTRL) without known bone diseases and to study associations of Fatique Severity Scale (FSS) with eight domains of HRQoL.

METHODS

Monocentric, cross-sectional study carried out between 2020 and 2022 in a hospital affiliated with the Vienna Bone and Growth Center (European Reference Network Center for Rare Bone Disease) in Vienna, Austria. The study comprised three types of RBD: Osteogenesis imperfecta, Hypophosphatasia and X-linked Hypophosphatemia. Fatigue was assessed by FSS. The higher score indicates more fatigue severity. HRQoL was assessed by Short-Form Health Survey (SF-36 v2). Physical component (PCS) and mental component summary scores (MCS) were calculated and normalised to a general population. A higher score indicates better HRQoL. Age-adjusted ANCOVA was used to assess differences in PCS and MCS between groups. Spearman correlation was used for associations of FSS with eight domains of HRQoL.

RESULTS

Study comprised 50 RBD patients [Mean age (SD) 48.8 (±15.9), 26 % male], 51 OPO patients [66.6 (±10.0), 9.8 % male] and 52 controls [50.8 (±16.3), 26.9 % male]. RBD patients had significantly higher mean age-adjusted FSS (3.5, 95 % CI 3.1-4.0) than controls (2.6, 95 % CI 2.2-3.0, p = 0.008), but not in comparison to osteoporotic patients 2.6 (95 % CI 2.2-3.0, p = 0.69). Diminished age-adjusted PCS of HRQoL was observed in RBD patients with a mean score of 37.1 (95 % CI 33.4-40.8), whereas their MCS of 50.1 (95 % CI 46.6-53.7) was comparable to controls (52.9, 95 % CI 49.8-56.0) and osteoporotic patients (50.2, 95 % CI 45.4-54.9). FSS score was negatively correlated with physical and mental component in RBD (ρ = -0.37, p < 0.05 and ρ = -0.54, p < 0.01, respectively) and OPO patients (ρ = -0.37, p < 0.05 and ρ = -0.35, p < 0.01, respectively).

CONCLUSIONS

The HRQoL in adult patients with rare bone diseases is lower than compared to osteoporotic and control group in this Austrian population. Fatigue has significant negative impact on HRQoL and it is important to address it when meeting with RBD patients in clinical practice.

Current and Developing Pharmacologic Agents for Improving Skeletal Health in Adults with Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility largely caused by defects in structure, synthesis, or post-translational processing of type I collagen. Drugs currently used to improve skeletal health in OI were initially developed to treat osteoporosis and clinical trials are ongoing to study their effectiveness in OI adults. Additionally, novel bone-protective agents are in preclinical studies and various phases of OI clinical trials. This review summarizes current knowledge on available pharmacologic agents and current drug trials involving OI participants. A PubMed online database search of all study types published in the English language using the terms "osteogenesis imperfecta," "OI," and "brittle bone disease" was performed in August 2022. Articles screened were restricted to adults. A ClinicalTrials.gov database search of all studies involving "osteogenesis imperfecta" was performed in August 2023. Although clinical trial data are limited, bisphosphonates and teriparatide may be useful in improving bone mineral density. As of yet, no clinical trials are available that adequately evaluate the usefulness of current therapies in reducing fracture risk. Several therapeutics, including teriparatide, setrusumab, anti-TGF-β antibodies, and allogeneic stem cells, are being studied in clinical trials. Preclinical studies involving Dickkopf-1 antagonists present promising data in non-OI bone disease, and could be useful in OI. Research is ongoing to improve therapeutic options for adults with OI and clinical trials involving gene-editing may be possible in the coming decade.

Osteoporosis Improved by Romosozumab Therapy in a Patient With Type I Osteogenesis Imperfecta

Background/Objective

Osteogenesis imperfecta (OI) is a genetic disorder that affects type 1 collagen synthesis causing increased bone fragility, low bone mass, and skeletal deformity. Bisphosphonates are recommended for treatment of OI patients; however, the efficacy of sclerostin inhibitors such as romosozumab has not been determined in OI patients with osteoporosis.

Case Report

A 52-year-old G2P2 clinically diagnosed with OI, with a history of multiple fractures beginning in childhood presented with low bone mass. On physical examination, blue sclera was observed. She was previously treated with alendronate therapy from April 2014 to June 2015 without significant improvement in bone mineral density (BMD). After the onset of menopause, she began romosozumab 210 mg subcutaneous therapy once a month for 12 months. Repeat dual-energy X-ray absorptiometry showed an increase of 10.3% in BMD of the spine and a 5.4% increase in BMD of the right hip. The trabecular bone score increased by 5.2%.

Discussion

Current literature is limited regarding the use of sclerostin inhibitors in OI patients. Our patient's improvement in BMD of the spine and right hip after romosozumab therapy was significant at a 95% confidence level, compared to treatment initiation. Her trabecular bone score also improved significantly. Six months into our patient's treatment course, a case in Japan of a male with severe osteoporotic OI and recurrent fractures showed improvement in BMD after romosozumab therapy.

Conclusion

This case highlights our patient's significant response to romosozumab and warrants further investigation of romosozumab as a potential treatment option for OI patients with osteoporosis.