Scoliosis and Cardiopulmonary Outcomes in Osteogenesis Imperfecta Patients

Is Osteogenesis Imperfecta Associated with Cardiovascular Abnormalities? A Systematic Review of the Literature

Osteogenesis imperfecta (OI) is a rare genetic disorder caused by abnormal collagen type I production. While OI is primarily characterized by bone fragility and deformities, patients also have extraskeletal manifestations, including an increased risk of cardiovascular disease. This review provides a comprehensive overview of the literature on cardiovascular diseases in OI patients in order to raise awareness of this understudied clinical aspect of OI and support clinical guidelines. In accordance with the PRISMA guidelines, a systematic literature search in PubMed, Embase, Web of Science and Scopus was conducted that included articles from the inception of these databases to April 2023. Valvular disease, heart failure, atrial fibrillation, and hypertension appear to be more prevalent in OI than in control individuals. Moreover, a larger aortic root was observed in OI compared to controls. Various cardiovascular diseases appear to be more prevalent in OI than in controls. These cardiovascular abnormalities are observed in all types of OI and at all ages, including young children. As there are insufficient longitudinal studies, it is unknown whether these abnormalities are progressive in nature in OI patients. Based on these findings, we would recommend referring individuals with OI to a cardiologist with a low-threshold.

A case-control study of early-stage radiological markers of endothelial dysfunction and cardiovascular findings in patients with osteogenesis imperfecta: genotype-phenotype correlations

OBJECTIVES

Osteogenesis imperfecta (OI) is a disease caused by defective collagen synthesis. Collagen type 1 is found in many structures in the cardiovascular system. Endothelial dysfunction, which develops prior to the emergence of structural and clinical signs of atherosclerosis, is believed to play a key role in atherogenesis. Endothelial dysfunction may be detected presymptomatically by non-invasive radiologic methods, such as flow-mediated dilatation (FMD) and carotid intima-media thickness (CIMT). These modalities may provide early indicators of endothelial dysfunction. This cross-sectional comparative study aimed to investigate early-stage radiological markers of endothelial dysfunction and cardiovascular diseases in OI patients and healthy controls and to investigate the correlation of findings with OI genotype.

METHODS

Thirty patients diagnosed with OI were paired with thirty healthy age- and gender-matched controls and echocardiogram findings were compared.

RESULTS

None of the patients had known underlying cardiovascular disease. The mean age was 13.18 ± 2.91 years. According to Sillence classification, 15 patients had type 1 OI, 10 had type III, and 5 had type IV. Mean CIMT in the OI group was higher in the control group (OI group: 0.42 ± 0.06 vs. healthy controls: 0.34 ± 0.04 mm, p<0.01), and mean FMD percent was lower in the patient group (p<0.01). Left ventricular ejection fraction was 78.97 ± 10.32 vs. 77.56 ± 8.50 %, (OI group: 7.00 ± 3.06 vs. healthy controls: 12.14 ± 1.99, p=0.56), and fractional shortening was 42.68 ± 11.94 vs. 40.23 ± 7.99 %, (p=0.35), in OI patients and controls, respectively.

CONCLUSIONS

Pediatric patients with OI without clinical signs of cardiovascular abnormality had significantly worse CIMT and FMD findings than healthy controls. However, no difference was determined when comparing left ventricular ejection fraction or fractional shortening. OI patients may need to be screened for cardiovascular system complications starting from an early age.

Scoliosis in osteogenesis imperfecta: identifying the genetic and non-genetic factors affecting severity and progression from longitudinal data of 290 patients

BACKGROUND

Scoliosis is widely prevalent among osteogenesis imperfecta (OI) patients, and is progressive with age. However, factors affecting scoliosis in OI are not well known.

METHODS

We retrospectively retrieved longitudinal radiographic and clinical records of consecutive OI patients seeking treatments at our hospital from 2014 to 2022, graded their pre-operative spinal conditions into four outcome groups, estimated their progression rates, and descriptively and inferentially analyzed the genetic and non-genetic factors that may affect the outcomes and progression rates.

RESULTS

In all, 290 OI patients met the inclusion criteria, where 221 had genetic records. Of these 221, about 2/3 had mutations in COL1A1 or COL1A2, followed by mutations in WNT1 (9.0%), IFITM5 (9.0%) and other OI risk genes. With an average age of 12.0 years (interquartile range [IQR] 6.9-16.1), 70.7% of the cohort had scoliosis (Cobb angle > 10°), including 106 (36.5%) mild (10°-25°), 40 (13.8%) moderate (25°-50°), and 59 (20.3%) severe (> 50°) scoliosis patients. Patients with either COL1A1 and COL1A2 were strongly biased toward having mild or no scoliosis, whereas patients with mutations in IFITM5, WNT1 and other recessive genes were more evenly distributed among the four outcome grades. Lower-limb discrepancy, bone mineral density (BMD) and age of first drug used were all significantly correlated with severity outcomes. Using multivariate logistic regression, we estimated that each year older adds an odds ratio of 1.13 (95% confidence interval [CI] 1.07-1.2) in progression into advanced stages of scoliosis. We estimated a cohort-wide progression rate of 2.7 degrees per year (95% CI 2.4-3.0). Early-onset patients experienced fast progressions during both infantile and adolescent stages. Twenty-five of the 59 (42.8%) patients with severe scoliosis underwent spinal surgeries, enjoying an average Cobb angle reduction of 33° (IQR 23-40) postoperatively.

CONCLUSION

The severity and progression of scoliosis in osteogenesis imperfecta were affected by genetic factors including genotypes and mutation types, and non-genetic factors including age and BMD. As compared with COL1A1, mutations in COL1A2 were less damaging while those on IFITM5 and other recessive genes conferred damaging effects. Progression rates were the fastest in the adolescent adult age-group.

Medical Care Use Among Patients with Monogenic Osteoporosis Due to Rare Variants in LRP5, PLS3, or WNT1

Pathogenic variants in the LRP5, PLS3, or WNT1 genes can significantly affect bone mineral density, causing monogenic osteoporosis. Much remains to be discovered about the phenotype and medical care needs of these patients. The purpose of this study was to examine the use of medical care among Dutch individuals identified between 2014 and 2021 with a pathogenic or suspicious rare variant in LRP5, PLS3, or WNT1. In addition, the aim was to compare their medical care utilization to both the overall Dutch population and the Dutch Osteogenesis Imperfecta (OI) population. The Amsterdam UMC Genome Database was used to match 92 patients with the Statistics Netherlands (CBS) cohort. Patients were categorized based on their harbored variants: LRP5, PLS3, or WNT1. Hospital admissions, outpatient visits, medication data, and diagnosis treatment combinations (DTCs) were compared between the variant groups and, when possible, to the total population and OI population. Compared to the total population, patients with an LRP5, PLS3, or WNT1 variant had 1.63 times more hospital admissions, 2.0 times more opened DTCs, and a greater proportion using medication. Compared to OI patients, they had 0.62 times fewer admissions. Dutch patients with an LRP5, PLS3, or WNT1 variant appear to require on average more medical care than the total population. As expected, they made higher use of care at the surgical and orthopedic departments. Additionally, they used more care at the audiological centers and the otorhinolaryngology (ENT) department, suggesting a higher risk of hearing-related problems.

Key4OI Recommendations for Lung Function Guidance in Osteogenesis Imperfecta: Based on an Internationally Performed Comprehensive International Consortium for Health Outcomes Measurement Procedure

INTRODUCTION

Pulmonary involvement in Osteogenesis Imperfecta (OI) can be severe but may be overlooked in milder cases. The Care4BrittleBones Foundation initiated this project to develop a set of global outcome measures focusing on respiratory-related issues in patients with OI. The objective was to reach an international consensus for a standardized set of outcomes and associated measuring instruments for the pulmonary care of individuals with OI. Based on the initial tests and questionnaires, we suggest parameters for when pulmonologists should seek guidance from the growing literature on OI pulmonary care and/or recognized experts in the field.

STUDY DESIGN AND METHODS

The project team consisted of a multidisciplinary mix of 12 people from six countries, including an OI patient representative, and facilitated by the Care4BrittleBones Foundation director. The International Consortium for Health Outcomes Measurement (ICHOM) process was followed, which includes the Delphi method, used to collect the opinions of the expert team. Patient input was present in each meeting due to the inclusion of a patient representative. In addition, online focus groups were held. They consisted of adults with OI from different countries, and they determined which questions matter the most to the OI community worldwide.

RESULTS

After three Delphi rounds, the expert team reached a consensus on the final set of measuring instruments, which included pulmonary function testing and patient self-reporting of symptoms related to breathing and sleep. Two questionnaires were decided upon: St. George's Respiratory Questionnaire (shortened version) and four questions regarding sleep. Patients should be screened for a history of pneumonia. Advanced testing for select patients by a pulmonologist would include further pulmonary function tests and a chest radiograph.

CONCLUSIONS

A standardized set of outcome measures related to pulmonary care of individuals with OI was determined based on what is important to both experts and patients. This included patient-reported outcome measures and basic pulmonary function testing. Using these outcome measures, it can be determined which patients are at high risk for pulmonary complications.

The patient clinical journey and socioeconomic impact of osteogenesis imperfecta: a systematic scoping review

BACKGROUND

Osteogenesis imperfecta (OI) is a rare heritable connective tissue disorder primarily characterised by skeletal deformity and fragility, and an array of secondary features. The purpose of this review was to capture and quantify the published evidence relating specifically to the clinical, humanistic, and economic impact of OI on individuals, their families, and wider society.

METHODS

A systematic scoping review of 11 databases (MEDLINE, MEDLINE in-progress, EMBASE, CENTRAL, PsycINFO, NHS EED, CEA Registry, PEDE, ScHARRHUd, Orphanet and Google Scholar), supplemented by hand searches of grey literature, was conducted to identify OI literature published 1st January 1995-18th December 2021. Searches were restricted to English language but without geographical limitations. The quality of included records was assessed using the AGREE II checklist and an adapted version of the JBI cross-sectional study checklist.

RESULTS

Of the identified 7,850 records, 271 records of 245 unique studies met the inclusion criteria; overall, 168 included records examined clinical aspects of OI, 67 provided humanistic data, 6 reported on the economic impact of OI, and 30 provided data on mixed outcomes. Bone conditions, anthropometric measurements, oral conditions, diagnostic techniques, use of pharmacotherapy, and physical functioning of adults and children with OI were well described. However, few records included current care practice, diagnosis and monitoring, interactions with the healthcare system, or transition of care across life stages. Limited data on wider health concerns beyond bone health, how these concerns may impact health-related quality of life, in particular that of adult men and other family members, were identified. Few records described fatigue in children or adults. Markedly few records provided data on the socioeconomic impact of OI on patients and their caregivers, and associated costs to healthcare systems, and wider society. Most included records had qualitative limitations.

CONCLUSION

Despite the rarity of OI, the volume of recently published literature highlights the breadth of interest in the OI field from the research community. However, significant data gaps describing the experience of OI for individuals, their families, and wider society warrant further research to capture and quantify the full impact of OI.

Distinct type I collagen alterations cause intrinsic lung and respiratory defects of variable severity in mouse models of osteogenesis imperfecta

Type I collagen alterations cause osteogenesis imperfecta (OI), a connective tissue disorder characterized by severe bone fragility. Patients with OI can suffer from significant pulmonary manifestations including severe respiratory distress in the neonatal period and a progressive decline in respiratory function in adulthood. We and others have shown intrinsic lung defects in some mouse models of OI. In this large study, we performed histological, histomorphometric, microcomputed tomography and invasive studies on oim/+, Col1a2+/G610C , CrtapKO and oim/oim mice, mimicking mild to moderate to severe OI, with the overall goal of determining the extent of their pulmonary and respiratory mechanics defects and whether these defects correlate with the skeletal disease severity and affect each sex equally. Although with variable severity, OI lung histology consistently showed alveolar simplification with enlarged acinar airspace and reduced alveolar surface. Numerous respiratory mechanics parameters, including respiratory system resistance and elastance, tissue damping, inspiratory capacity, total lung capacity, and others, were significantly and similarly impacted in CrtapKO and oim/oim but not in oim/+ or Col1a2+/G610C compared to control mice. Our data indicate that the impact of type I collagen alterations and OI on lung morphology and function positively correlate with the severity of the extracellular matrix deficiency. Moreover, the respiratory defects were more pronounced in male compared to female mice. It will be important to determine whether our observations in mice translate to OI patients and to dissect the respective contribution of intrinsic lung defects vs. extrinsic skeletal defects to impaired lung function in OI. KEY POINTS: Different type I collagen alterations in mouse models of osteogenesis imperfecta (OI) cause similar abnormal lung histology, with alveolar simplification and reduced alveolar surface, reminiscent of emphysema. Several respiratory mechanics parameters are altered in mouse models of OI. The impact of type I collagen alterations and OI on lung morphology and function positively correlate with the severity of the extracellular matrix deficiency. Respiratory defects were more pronounced in male compared to female mice. It will be important to determine whether our observations in mice translate to OI patients and to dissect the respective contribution of intrinsic lung defects vs. extrinsic skeletal defects to impaired lung function in OI.

Lung and chest wall volume during vital capacity manoeuvre in Osteogenesis Imperfecta

Background

Although Osteogenesis Imperfecta (OI) affects the connective tissue, pulmonary function might be compromised because of thoracic deformities. OI is known to be a restrictive lung disease, but spirometry provides global measurement without localizing the site of the restriction. Opto-electronic plethysmography (OEP), is a non-invasive method able to underline altered respiratory function as well as ventilatory thoraco-abdominal paradoxes during spontaneous breathing. We aimed to reconstruct the thoraco-abdominal surface, to perform local analyses of trunk motion and to make quantitative comparison of trunk shape and respiratory kinematics according to OI severity, particularly during maximal inspiratory and expiratory expansions. This is a cross-sectional study where we have studied the thoraco-abdominal compartmental analysis in 26 adult OI patients (14 Type III) at rest and during vital capacity manoeuvre using OEP. We have also applied a new method that created realistic and accurate 3D models to perform local analyses of trunk motion and to make quantitative comparison of trunk shape and respiratory kinematics.

Results

Type III patients were characterized by lower spirometric lung volume, by lower sleep quality, by a more compressed thoracic configuration aggravated by severe scoliosis, by reduced global expansion at rest and during maximal maneuvers because of the reduced expansion of the pulmonary ribcage at rest (12% vs. 65% in healthy subjects), during maximal inspiration (37% vs. 69%) and expiration (16% vs. 68%) with local paradoxical movement occurring on the side of the ribcage region.

Conclusion

The kinematics of the trunk changed to compensate for the severe structural deformities by shifting the expansion in the abdomen both at rest and during maximal manoeuvre because of a restricted thorax. For the first time, we have quantified and localized the site of the restriction in OI patients in the lateral part of the thorax. The 3D analysis proposed seemed a promising graphical immediate new method for pathophysiology study of chest wall restriction.

Prevalence of scoliosis and impaired pulmonary function in patients with type III osteogenesis imperfecta

PURPOSE

Osteogenesis Imperfecta (OI) is a rare group of congenital genetic disorders that consists of a collagen synthesis defect. The most severe phenotype is type III OI. Characterized by progressive bone deformity, fragility and pulmonary impairment, causing significant morbidity and mortality. Also, multilevel spine deformities are observed, such as scoliosis. The literature on the pathophysiology of pulmonary impairment in relation to scoliosis in these patients is scarce and conflicting. This study aims to determine the prevalence of scoliosis and its relation to pulmonary function in type III OI patients.

METHODS

This retrospective cohort study took place between April 2020 and November 2021. Forty-two patients with type III OI were included. Anterior-posterior spine radiographs were evaluated for scoliosis. Pulmonary function was assessed using spirometry and partial pressure of carbon dioxide.

RESULTS

All 42 patients had scoliosis, with a mean curve of 66° (95% CI of range). Vital lung capacity was decreased, compared to a non-OI population (mean 1.57 L). This was correlated to the degree of scoliosis (st. β - 0.40, P = 0.03), especially in increasing thoracic curves. Restrictive lung pathophysiology was shown in our study population with a mean FEV1/FVC ratio of 0.85.

CONCLUSIONS

Increasing thoracic scoliosis was correlated with decreased vital lung capacity in our study population of type III OI patients. High FEV1/FVC ratios found in this study population show restrictive lung pathophysiology. Therefore, it is plausible that the pulmonary impairment found in type III OI patients is a combined issue, partly associated to scoliosis and partly intrinsic to OI.

Management of Severe Scoliosis with Pulmonary Arterial Hypertension: A Single-Center Retrospective Case Series Study

Aims

To determine the impact of anesthesia encountered and to optimize the treatment of perioperative pulmonary arterial hypertension (PAH) in an effort to improve perioperative management and reduce complications.

Methods

We conducted a retrospective analysis of scoliosis patients with PAH who underwent scoliosis surgery.

Results

During this period, we identified a total of 22 patients. Their mean age was 22.18 ± 2.11 years. 16 PAH patients (72.72%) received PAH-specific treatment. Only Propofol-based TIVA was used intraoperatively. During the procedure, pulmonary artery catheters and PICCO catheters were placed in all patients to monitor intraoperative and postoperative mPAP, MAP, PRVI and SRVI. During tracheal intubation and intraoperative awake testing, mPAP generally tended to increase in all patients. 6 patients (27.27%) received intraoperative PAH-Specific therapy. All patients received oral sildenafil (75-100 mg/d orally), and 9 patients received postoperative oral sildenafil combined with nebulized iloprost (20 μg/d); intravenous treprostinil (2 ng/kg/min started and titrated to 10-17.5 ng/kg/min); or bosentan (250 mg/d) postoperatively. 7 patients (31.82%) reported postoperative complications, including 2 cases of respiratory failure requiring reintubation, 1 case of right heart failure, 2 cases of superficial surgical site infection, 1 case of fluid and electrolyte and acid-base imbalances, 2 cases of pneumonia and 1 case of pulmonary oedema with fluid overload. Two patients developed more than 1 postoperative complication. No in-hospital death occurred.

Conclusions

The anesthetic management of scoliosis patients with PAH is important task that, like its own surgery, relies on the input of the multidisciplinary team for its success. Close monitoring, optimization of systemic blood pressure, pain control, oxygenation and ventilation, avoidance of exacerbating factors, and the use of vasopressors and pulmonary vasodilators when necessary are essential elements of management.

Pathophysiology of respiratory failure in patients with osteogenesis imperfecta: a systematic review

INTRODUCTION

Respiratory failure is a major cause of death in patients with Osteogenesis Imperfecta. Moreover, respiratory symptoms seem to have a dramatic impact on their quality of life. It has long been thought that lung function disorders in OI are mainly due to changes in the thoracic wall, caused by bone deformities. However, recent studies indicate that alterations in the lung itself can also undermine respiratory health.

OBJECTIVES

Is there any intrapulmonary alteration in Osteogenesis Imperfecta that can explain decreased pulmonary function? The aim of this systematic literature review is to investigate to what extent intrapulmonary or extrapulmonary thoracic changes contribute to respiratory dysfunction in Osteogenesis Imperfecta.

METHODS

A literature search (in PubMed, Embase, Web of Science, and Cochrane), which included articles from inception to December 2020, was performed in accordance with the PRISMA guidelines.

RESULTS

Pulmonary function disorders have been described in many studies as secondary to scoliosis or to thoracic skeletal deformities. The findings of this systematic review suggest that reduced pulmonary function can also be caused by a primary pulmonary problem due to intrinsic collagen alterations.

CONCLUSIONS

Based on the most recent studies, the review indicates that pulmonary defects may be a consequence of abnormal collagen type I distorting the intrapulmonary structure of the lung. Lung function deteriorates further when intrapulmonary defects are combined with severe thoracic abnormalities. This systematic review reveals novel findings of the underlying pathological mechanism which have clinical and diagnostic implications for the assessment and treatment of pulmonary function disorders in Osteogenesis Imperfecta.KEY MESSAGESDecreased pulmonary function in Osteogenesis Imperfecta can be attributed to primary pulmonary defects due to intrapulmonary collagen alterations and not solely to secondary problems arising from thoracic skeletal dysplasia.Type I collagen defects play a crucial role in the development of the lung parenchyma and defects, therefore, affect pulmonary function. More awareness is needed among physicians about pulmonary complications in Osteogenesis Imperfecta to develop novel concepts on clinical and diagnostic assessment of pulmonary functional disorders.

A roadmap to surgery in osteogenesis imperfecta: results of an international collaboration of patient organizations and interdisciplinary care teams

Background and purpose - Involvement of patient organizations is steadily increasing in guidelines for treatment of various diseases and conditions for better care from the patient's viewpoint and better comparability of outcomes. For this reason, the Osteogenesis Imperfecta Federation Europe and the Care4BrittleBones Foundation convened an interdisciplinary task force of 3 members from patient organizations and 12 healthcare professionals from recognized centers for interdisciplinary care for children and adults with osteogenesis imperfecta (OI) to develop guidelines for a basic roadmap to surgery in OI.Methods - All information from 9 telephone conferences, expert consultations, and face-to-face meetings during the International Conference for Quality of Life for Osteogenesis Imperfecta 2019 was used by the task force to define themes and associated recommendations.Results - Consensus on recommendations was reached within 4 themes: the interdisciplinary approach, the surgical decision-making conversation, surgical technique guidelines for OI, and the feedback loop after surgery.Interpretation - The basic guidelines of this roadmap for the interdisciplinary approach to surgical care in children and adults with OI is expected to improve standardization of clinical practice and comparability of outcomes across treatment centers.

Osteogenesis imperfecta in children

Osteogenesis imperfecta (OI) is a disease characterised by altered bone tissue material properties together with abnormal micro and macro-architecture and thus bone fragility, increased bone turnover and hyperosteocytosis. Increasingly appreciated are the soft tissue changes, sarcopenia in particular. Approaches to treatment are now multidisciplinary, with bisphosphonates having been the primary pharmacological intervention over the last 20 years. Whilst meta-analyses suggest that anti-fracture efficacy across the life course is equivocal, there is good evidence that for children bisphosphonates reduce fracture risk, increase vertebral size and improve vertebral shape, as well as improving motor function and mobility. The genetics of OI continues to provide insights into the molecular pathogenesis of the disease, although the pathophysiology is less clear. The complexity of the multi-scale interactions of bone tissue with cellular function are gradually being disentangled, but the fundamental question of why increased tissue brittleness should be associated with so many other changes is unclear; ER stress, pro-inflammatory cytokines, accelerated senesence and altered matrix component release might all contribute, but a unifying hypothesis remains elusive. New approaches to therapy are focussed on increasing bone mass, following the paradigm established by the treatment of postmenopausal osteoporosis. For adults, this brings the prospect of restoring previously lost bone - for children, particularly at the severe end of the spectrum, the possibility of further reducing fracture frequency and possibly altering growth and long term function are attractive. The alternatives that might affect tissue brittleness are autophagy enhancement (through the removal of abnormal type I collagen aggregates) and stem cell transplantation - both still at the preclinical stage of assessment. Preclinical assessment is not supportive of targeting inflammatory pathways, although understanding why TGFb signalling is increased, and whether that presents a treatment target in OI, remains to be established.

Cardiopulmonary Status in Adults with Osteogenesis Imperfecta: Intrinsic Lung Disease May Contribute More Than Scoliosis

BACKGROUND

Osteogenesis imperfecta (OI) is a heterogeneous group of collagen-related disorders characterized by osteopenia, bone fractures, spine deformities, and nonskeletal complications. Cardiopulmonary complications are the major cause of morbidity and mortality in adults with OI. The cause of such problems was often attributed solely to the presence of large scoliosis curves affecting pulmonary function and, indirectly, cardiovascular health. However, recent studies suggest this may not be the case. Therefore, determining the relationships and causative agents of cardiopulmonary problems in patients with OI, specifically pulmonary impairment, is important to improving the overall wellbeing, quality of life, and survival of these patients.

QUESTIONS/PURPOSES

(1) Is cardiopulmonary fitness in OI solely related to the presence of scoliosis? (2) What is the prevalence of heart and lung complications in this adult population? (3) Does the presence of pulmonary impairment impact quality of life in adults with OI?

METHODS

This is a prospective observational cross-sectional study. Within 1 year, each participant (n = 30) completed pulmonary function testing, echocardiogram, ECG, chest CT, AP spine radiography, and quality-of-life assessments (SF-36, St. George's Respiratory Questionnaire, Functional Outcomes of Sleep Questionnaire, and Pittsburgh Sleep Quality Index). In terms of pulmonary function, we differentiated restrictive and obstructive physiology using the ratio of forced expiratory volume over one second to forced vital capacity (FEV1/FVC), with restrictive lung physiology defined as FEV1/FVC > 0.8 and obstructive lung physiology as FEV1/FVC < 0.7. Spine radiographs were evaluated for scoliosis. Chest CT images were reviewed to qualitatively assess the lungs. The statistical analysis involved a Kruskall-Wallis test with Bonferroni's correction and a bivariate correlation analysis using Spearman's rho correlation coefficient (p < 0.05).

RESULTS

Sixteen of 23 participants with restrictive lung physiology had scoliosis; their ages ranged from 19 years to 67 years. There was no correlation between the magnitude of the scoliosis curve and deficient pulmonary function (R = 0.08; p = 0.68). Seven participants had normal pulmonary function. The average scoliosis curve was 44 ± 29°. Thirteen participants had abnormal ECG findings while 10 had abnormal echocardiogram results. All but two individuals with abnormal chest CT results were found to have bronchial wall thickening. There were no differences in pulmonary or cardiac findings between OI types, except for FVC and total lung capacity, which were lower in individuals with Type III OI than in those with other types of OI. FEV1/FVC correlated with St. George's Respiratory Questionnaire (R = 0.429; p = 0.02) but not with Functional Outcomes of Sleep Questionnaire (R = -0.26; p = 0.19) or SF-36 scores (physical component summary: R = -0.037, p = 0.85; mental component summary: R = -0.204, p = 0.29).

CONCLUSIONS

The lack of a relationship between decreased pulmonary function and the severity of scoliosis suggests that restrictive lung physiology in this population is likely because of factors intrinsic to OI and not entirely because of thoracic cage deformities. The fact that pulmonary impairment influences self-perceived quality of life exemplifies how detrimental such complications may be to everyday functioning. This also reinforces the importance of determining the underlying cause of cardiopulmonary impairment in this population to set clear clinical guidelines of care.

LEVEL OF EVIDENCE

Level II, prognostic study.

Respiratory impairment impacts QOL in osteogenesis imperfecta independent of skeletal abnormalities

Respiratory insufficiency is the leading cause death in people with osteogenesis imperfecta (OI). Adults with OI reported that respiratory symptoms negatively impacted psychosocial wellbeing and limited daily physical activities, irrespective of OI type, age, stature, or scoliosis. The impact of respiratory status on quality of life in this population warrants further investigation.

PURPOSE

Respiratory insufficiency is the leading cause of mortality in osteogenesis imperfecta (OI), a heterogeneous group of heritable connective tissue disorders characterized by fractures, bone fragility, and scoliosis. There is little research on how respiratory health influences daily life in this population. This study explores the relationship between respiratory function and quality of life in adults with OI.

METHODS

One hundred fifty-seven adults with OI completed the St. George's Respiratory Questionnaire (SGRQ) and provided demographic and health information through REDCap. SGRQ scores were compared to reference scores for the general population, and comparisons were made between OI type, presence of scoliosis, stature, and other factors such as age or comorbidities.

RESULTS

Average age was 45.87 years (range 19-81). Respondents scored worse on average (32 ± 23) than the normative data (6 ± 1). Those with type I OI scored better than those with type IV (p = 0.002) or type III (p = 0.024). Total scores correlated with age, activity level, assistive device use, and presence of pulmonary or cardiac comorbidities but did not correlate with stature or degree of scoliosis.

CONCLUSION

Respiratory symptoms negatively impact both psychosocial wellbeing in the OI population and limit daily physical activity. These limitations occur irrespective of their OI type, age, stature, or scoliosis and reflect the dramatic impact of respiratory status on quality of life for people with OI. Future studies should examine the etiology of respiratory insufficiency in this population so guidelines for management can be established.

Osteogenesis imperfecta: an update on clinical features and therapies

Osteogenesis imperfecta (OI) is an inherited skeletal dysplasia characterized by bone fragility and skeletal deformities. While the majority of cases are associated with pathogenic variants in COL1A1 and COL1A2, the genes encoding type I collagen, up to 25% of cases are associated with other genes that function within the collagen biosynthesis pathway or are involved in osteoblast differentiation and bone mineralization. Clinically, OI is heterogeneous in features and variable in severity. In addition to the skeletal findings, it can affect multiple systems including dental and craniofacial abnormalities, muscle weakness, hearing loss, respiratory and cardiovascular complications. A multi-disciplinary approach to care is recommended to address not only the fractures, reduced mobility, growth and bone pain but also other extra-skeletal manifestations. While bisphosphonates remain the mainstay of treatment in OI, new strategies are being explored, such as sclerostin inhibitory antibodies and TGF beta inhibition, to address not only the low bone mineral density but also the inherent bone fragility. Studies in animal models have expanded the understanding of pathomechanisms of OI and, along with ongoing clinical trials, will allow to develop better therapeutic approaches for these patients.