Vertebral fractures and mortality risk in hospitalised patients during the COVID-19 pandemic emergency

Progress in research on osteoporosis secondary to SARS-CoV-2 infection

The World Health Organization has declared that COVID-19 no longer constitutes a "public health emergency of international concern," yet the long-term impact of SARS-CoV-2 infection on bone health continues to pose new challenges for global public health. In recent years, numerous animal model and clinical studies have revealed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to secondary osteoporosis. The mechanisms involved are related to the virus's direct effects on bone tissue, dysregulation of the body's inflammatory response, hypoxia, noncoding RNA imbalance, and metabolic abnormalities. Although these studies have unveiled the connection between SARS-CoV-2 infection and osteoporosis, current research is not comprehensive and in depth. Future studies are needed to evaluate the long-term effects of SARS-CoV-2 on bone density and metabolism, elucidate the specific mechanisms of pathogenesis, and explore potential interventions. This review aims to collate existing research literature on SARS-CoV-2 infection-induced secondary osteoporosis, summarize the underlying mechanisms, and provide direction for future research.

Morphometric vertebral fractures at hospitalization associate with Long COVID occurrence

PURPOSE

Long COVID is a multisystemic syndrome leading to significant morbidity. To date, a comprehensive characterization of underlying risk factors is still being defined. Osteoporosis and vertebral fractures (VFs) were associated with worse acute COVID-19 and impaired respiratory recovery after hospitalization. Therefore, we aimed to assess the potential relationship between VFs and the occurrence of the Long COVID syndrome.

METHODS

Patients hospitalized for acute COVID-19 and subsequently seen in our outpatient follow-up clinic 6-months after discharge were evaluated. We retrospectively included patients with available lateral chest X-rays performed at admission suitable for VFs assessments. We excluded patients with active neoplasia, and those managed at home or those hospitalized in ICU. Long COVID was diagnosed with a multidisciplinary evaluation.

RESULTS

One-hundred sixty-two patients were included in the study. At least one VF was found in 42 patients at presentation (25.9%). Patients with VFs were significantly older and predominantly males. Long COVID was diagnosed in 25 patients (15.4%). No differences were found between patients with and without Long COVID regarding demographics and comorbidities; however, those with Long COVID were characterized by a higher prevalence of VFs at time of hospitalization for acute COVID-19 (48% vs. 22%, p = 0.01). After matching patients with and without VFs in a 1:1 ratio for demographics, comorbidities, and COVID-19 severity, a total of 84 patients were analysed and those presenting VFs were characterized by a significant higher prevalence of Long COVID (28.6% vs. 9.5%, p = 0.04) and VFs resulted as the only significant independent risk factor for Long COVID occurrence.

CONCLUSIONS

We observed that prevalent VFs detected at hospital admission were distinctive clinical features of patients presenting with Long COVID 6-months after discharge, independently from acute disease severity and other confounding factors. This highlights a potential detrimental association between skeletal fragility and the development of Long COVID.

Incidence and Outcomes of Vertebral Compression Fracture Among Patients Infected with COVID-19

Background/Objectives: Early studies have suggested that the SARS-CoV-2 virus has a deleterious effect on bone mineral density and may increase the risk of pathological fractures. This study characterized vertebral compression fractures in patients with and without a prior diagnosis of COVID-19. Methods: Using a nationwide claims database, this retrospective study used ICD-10 billing codes to identify patients with a diagnosis of vertebral compression fracture from January 2020 to April 2022. Two cohorts were created based on whether the patients had a concurrent diagnosis of COVID-19. Patient demographics, comorbidities, and outcome measures were characterized by descriptive analysis. Results: In total, 413,425 patients met the inclusion criteria. Among them, a total of 23,148 patients (5.60%) had a diagnosis of COVID-19 at the time of their compression fracture. Among the COVID-19 patients, the incidences of vertebral compression fracture were 0.42% in 2020 and 0.33% in 2021, in comparison to the historical average yearly incidence of 0.17% across all patients. The patients with COVID-19 at the time of compression fracture diagnosis had a higher rate of vitamin D deficiency (OR: 1.25) and a lower rate of routine healing (OR: 0.61). The patients without COVID-19 were more likely to be osteoporotic (OR: 0.88), experience additional compression fractures (OR: 0.38), and have kyphoplasty or vertebroplasty (OR: 0.73). Conclusions: Despite lower rates of osteoporosis, patients with a concomitant COVID-19 diagnosis exhibited a higher incidence of compression fractures. Although more research is needed, these results support increasing bone health surveillance in patients with a history of COVID-19 infection.

Acromegaly and COVID-19, lessons, and new opportunities

The COVID-19 pandemic created challenges in effective management of patients with acromegaly. Specifically, with regards to timely diagnosis, delays in surgeries, and disruption(s) to routine patient care. A transition to telemedicine did help to overcome safety restrictions that were placed on in-person care. Creation of surgical safety protocols in conjunction with widespread testing for COVID-19 has also helped with the resumption of pituitary surgery cases. However, acromegaly related comorbidities including cardiovascular disease, diabetes mellitus, sleep apnea and respiratory disease, vertebral fractures, and hypopituitarism, may increase the risk of a more severe COVID-19 infection course. Of note and to date, no negative trends in COVID-19 related outcomes have been reported in patients with acromegaly. Nevertheless, anxiety and depression rates in patients with acromegaly are higher than those in the general population. More studies are needed to assess the true impact of the COVID-19 pandemic on morbidity, mortality, and neuropsychiatric health of patients with acromegaly.

Bone Mineral Density, Bone Biomarkers, and Joints in Acute, Post, and Long COVID-19: A Systematic Review

SARS-CoV-2 is highly transmissible and affects the respiratory system. People with COVID-19 are at higher risk of physical and mental health conditions, which could impact bone health. The aim of this review was to explore the effects of COVID-19 on BMD, BTMs, and joints. An electronic search of the PubMed, Web of Science, Scopus, and Ovid Medline databases considered studies published between 1 January 2020 and 1 November 2023. The search was limited to English, original studies in adult humans. The title and abstract of the identified papers were screened, followed by a full-text review using inclusion and exclusion criteria. The data extracted included the study and participant characteristics, BTMs, BMD, and joint abnormalities. The Newcastle-Ottawa scale quality assessment tool was used to assess the risk of bias. Five studies involving 305 out of 495 infected individuals observed a reduced BMD after COVID-19, with the most significant reduction occurring a year later. Both bone resorption and bone formation markers decreased, while regulatory markers showed higher levels in infected patients. COVID-19 may harm bone health by increasing bone regulatory markers and reducing bone formation and absorption, leading to a lower BMD. Elderly, frail, and osteopenic or osteoporotic individuals are at higher risk and should be regularly monitored for bone loss if they have long COVID.

CT-derived vertebral bone mineral density is a useful biomarker to predict COVID-19 outcome

The low vertebral bone computed tomography (CT) Hounsfield unit values measured on CT scans reflect low bone mineral density (BMD) and are known as diagnostic indicators for osteoporosis. The potential prognostic significance of low BMD defined by vertebral bone CT values for the coronavirus disease 2019 (COVID-19) remains unclear. This study aimed to assess the impact of BMD on the clinical outcome in Japanese patients with COVID-19 and evaluate the association between BMD and critical outcomes, such as high-flow nasal cannula, non-invasive and invasive positive pressure ventilation, extracorporeal membrane oxygenation, or death. We examined the effects of COVID-19 severity on the change of BMD over time. This multicenter retrospective cohort study enrolled 1132 inpatients with COVID-19 from the Japan COVID-19 Task Force database between February 2020 and September 2022. The bone CT values of the 4th, 7th, and 10th thoracic vertebrae were measured from chest CT images. The average of these values was defined as BMD. Furthermore, a comparative analysis was conducted between the BMD on admission and its value 3 months later. The low BMD group had a higher proportion of critical outcomes than did the high BMD group. In a subanalysis stratifying patients by epidemic wave according to onset time, critical outcomes were higher in the low BMD group in the 1st-4th waves. Multivariable logistic analysis of previously reported factors associated with COVID-19 severity revealed that low BMD, chronic kidney disease, and diabetes were independently associated with critical outcomes. At 3 months post-infection, patients with oxygen demand during hospitalization showed markedly decreased BMD than did those on admission. Low BMD in patients with COVID-19 may help predict severe disease after the disease onset. BMD may decrease over time in patients with severe COVID-19, and the impact on sequelae symptoms should be investigated in the future.

The abortive SARS-CoV-2 infection of osteoclast precursors promotes their differentiation into osteoclasts

The Coronavirus Disease 2019 (COVID-19) pandemic has resulted in the loss of millions of lives, although a majority of those infected have managed to survive. Consequently, a set of outcomes, identified as long COVID, is now emerging. While the primary target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the respiratory system, the impact of COVID-19 extends to various body parts, including the bone. This study aims to investigate the effects of acute SARS-CoV-2 infection on osteoclastogenesis, utilizing both ancestral and Omicron viral strains. Monocyte-derived macrophages, which serve as precursors to osteoclasts, were exposed to both viral variants. However, the infection proved abortive, even though ACE2 receptor expression increased postinfection, with no significant impact on cellular viability and redox balance. Both SARS-CoV-2 strains heightened osteoclast formation in a dose-dependent manner, as well as CD51/61 expression and bone resorptive ability. Notably, SARS-CoV-2 induced early pro-inflammatory M1 macrophage polarization, shifting toward an M2-like profile. Osteoclastogenesis-related genes (RANK, NFATc1, DC-STAMP, MMP9) were upregulated, and surprisingly, SARS-CoV-2 variants promoted RANKL-independent osteoclast formation. This thorough investigation illuminates the intricate interplay between SARS-CoV-2 and osteoclast precursors, suggesting potential implications for bone homeostasis and opening new avenues for therapeutic exploration in COVID-19.

The impact of the COVID-19 virus and pandemic on healthcare utilization, access, delivery, experiences, and outcomes in the spinal cord injuries/dysfunction population: A scoping review study

BACKGROUND

Individuals with spinal cord injuries or disease (SCI/D) require frequent healthcare services. The COVID-19 pandemic may have impacted healthcare. Furthermore, due to secondary health conditions and comorbidities persons with SCI/D are at increased risk of experiencing severe symptoms or outcomes if infected with the COVID-19 virus. It is unclear to what extent research has investigated the pandemic and virus impacts on the SCI/D population.

OBJECTIVE

To identify and summarize what is reported in the literature on the impact the COVID-19 virus and pandemic had on healthcare, health outcomes, and experiences in the adult SCI/D population.

METHODS

Electronic databases and grey literature were searched for articles that included an adult population with a SCI/D and investigated the impact the COVID-19 virus and pandemic had on healthcare-related outcomes and experiences. Articles were double screened, and data were extracted, and synthesized to provide a descriptive summary of the findings.

RESULTS

Twenty-four studies were included in this review with eight qualitative, fifteen quantitative, and one mixed methods study. Sixteen studies investigated healthcare utilization/access; nine investigated care delivery, nine investigated patient outcomes, and eight investigated patient experiences, with multiple studies spanning different categories of investigation. The pandemic was detrimental to healthcare utilization, access, and outcomes, but no studies quantified these changes. Virtual care was well-received by the SCI/D population to maintain continuity of care. The SCI/D population had issues with maintaining caregiving support. It was unclear if the COVID-19 virus infection impacted individuals with SCI/D differently than the general population.

CONCLUSIONS

This scoping review found the pandemic negatively impacted multiple aspects of healthcare in individuals with SCI/D, however further investigation on health outcomes is required. More research, particularly large-scale quantitative studies, investigating healthcare access, utilization, and delivery, as well as patient outcomes and experiences is needed to improve care in the SCI/D population post-pandemic onset.

SARS-CoV-2 and its Multifaceted Impact on Bone Health: Mechanisms and Clinical Evidence

PURPOSE OF REVIEW

SARS-CoV-2 infection, the culprit of the COVID-19 pandemic, has been associated with significant long-term effects on various organ systems, including bone health. This review explores the current understanding of the impacts of SARS-CoV-2 infection on bone health and its potential long-term consequences.

RECENT FINDINGS

As part of the post-acute sequelae of SARS-CoV-2 infection, bone health changes are affected by COVID-19 both directly and indirectly, with multiple potential mechanisms and risk factors involved. In vitro and preclinical studies suggest that SARS-CoV-2 may directly infect bone marrow cells, leading to alterations in bone structure and osteoclast numbers. The virus can also trigger a robust inflammatory response, often referred to as a "cytokine storm", which can stimulate osteoclast activity and contribute to bone loss. Clinical evidence suggests that SARS-CoV-2 may lead to hypocalcemia, altered bone turnover markers, and a high prevalence of vertebral fractures. Furthermore, disease severity has been correlated with a decrease in bone mineral density. Indirect effects of SARS-CoV-2 on bone health, mediated through muscle weakness, mechanical unloading, nutritional deficiencies, and corticosteroid use, also contribute to the long-term consequences. The interplay of concurrent conditions such as diabetes, obesity, and kidney dysfunction with SARS-CoV-2 infection further complicates the disease's impact on bone health. SARS-CoV-2 infection directly and indirectly affects bone health, leading to potential long-term consequences. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

COVID-19 and Bone Loss: A Review of Risk Factors, Mechanisms, and Future Directions

PURPOSE OF REVIEW

SARS-CoV-2 drove the catastrophic global phenomenon of the COVID-19 pandemic resulting in a multitude of systemic health issues, including bone loss. The purpose of this review is to summarize recent findings related to bone loss and potential mechanisms.

RECENT FINDINGS

The early clinical evidence indicates an increase in vertebral fractures, hypocalcemia, vitamin D deficiencies, and a loss in BMD among COVID-19 patients. Additionally, lower BMD is associated with more severe SARS-CoV-2 infection. Preclinical models have shown bone loss and increased osteoclastogenesis. The bone loss associated with SARS-CoV-2 infection could be the result of many factors that directly affect the bone such as higher inflammation, activation of the NLRP3 inflammasome, recruitment of Th17 cells, the hypoxic environment, and changes in RANKL/OPG signaling. Additionally, SARS-CoV-2 infection can exert indirect effects on the skeleton, as mechanical unloading may occur with severe disease (e.g., bed rest) or with BMI loss and muscle wasting that has also been shown to occur with SARS-CoV-2 infection. Muscle wasting can also cause systemic issues that may influence the bone. Medications used to treat SARS-CoV-2 infection also have a negative effect on the bone. Lastly, SARS-CoV-2 infection may also worsen conditions such as diabetes and negatively affect kidney function, all of which could contribute to bone loss and increased fracture risk. SARS-CoV-2 can negatively affect the bone through multiple direct and indirect mechanisms. Future work will be needed to determine what patient populations are at risk of COVID-19-related increases in fracture risk, the mechanisms behind bone loss, and therapeutic options. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

New Insights in the Pathophysiology, Epidemiology, and Response to Treatment of Osteoporotic Vertebral Fractures

CONTEXT

Vertebral fractures (VFs) make up an important but challenging group of fractures often caused by osteoporosis. Osteoporotic fractures pose unique diagnostic challenges in generally requiring imaging for diagnosis. The objective of this narrative mini-review is to provide an overview of these recent advances in our knowledge of VF pathophysiology and epidemiology with particular focus on endocrine diseases, prevention, and treatment.

EVIDENCE ACQUISITION

We searched PubMed on May 23, 2022, for studies of VFs in humans. Results were limited to papers available as full-text publications in English, published from 2020 and onward. This yielded 3457 citations. This was supplemented by earlier publications selected to add context to the recent findings.

EVIDENCE SYNTHESIS

Studies addressed VF risk in hyperthyreosis, hyperparathyroidism, acromegaly, Cushing syndrome, primary aldosteronism, and diabetes. For pharmaceutical treatment, new studies or analyses were identified for romosozumab and for weekly teriparatide. Several studies, including studies in the immediate pipeline, were intervention studies with vertebroplasty or kyphoplasty, including combination with stem cells or pharmaceuticals.

CONCLUSIONS

Endocrinologists should be aware of the high likelihood of osteoporotic VFs in patients with endocrine diseases. Though licensed treatments are able to substantially reduce the occurrence of VFs in patients with osteoporosis, the vast majority of recent or ongoing randomized controlled trials in the VF area focus on advanced invasive therapy of the fracture itself.

Prognostic Value of Diaphragm Diameter, Muscle Volume, and Bone Mineral Density in Critically Ill COVID-19 Patients

Objective: We aimed to analyze the prognostic value of muscle volume (MV), bone mineral density (BMD), and diaphragm diameter (DD) in COVID-19. Method: The study included 498 patients admitted to the intensive care unit (ICU) with a positive polymerase chain reaction test for COVID-19 from March 11, 2020, through August 31, 2022. The patients' laboratory and demographic data of the patients at the time of ICU admission were recorded. MV, DD, and BMD measurements were performed using computed tomography examinations. Muscle index (MI) was calculated as MV/height2. Quartiles were determined for all 4 measurements. Patients in the lowest quartile were recorded as having low MV, MI, DD, and BMD values. The parameters were evaluated for the whole group and compared according to gender and mortality. The multiple regression analysis was performed for the prediction of mortality. Results: In the mortality group, the male and female patients had significantly statistically lower values in MV (P < .001 and P = .002, respectively), MI (P < .001 and P = .005, respectively), DD (P < .001 and P < .001, respectively), and BMD (P = .002 and P < .001, respectively). In the multiple regression analysis, low MI (OR: 2.03, 95% CI: 1.14-3.61, P = .016) and DD (OR: 10.47, 95% CI: 5.59-19.59, P < .001) values remained significant for the prediction of mortality. Conclusion: BMD is a risk factor for mortality in patients with severe COVID-19, but cannot be used as an independent predictor. However, MI and DD can be used as independent predictors of mortality even in severe cases.

Potential impacts of SARS-CoV-2 on parathyroid: current advances and trends

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection affects several important organs including endocrine glands. Experimental studies demonstrated that the virus exploits the ACE2, a transmembrane glycoprotein on the cell surface as a receptor for cellular entry. This entry process is exclusively facilitated by other intracellular protein molecules such as TMPRSS2, furin, NRP1, and NRP2. Recent findings documented the involvement of the SARS-CoV-2 in inducing various parathyroid disorders including hypoparathyroidism and hypocalcemia, which received significant attention. This review extensively describes rapidly evolving knowledge on the potential part of SARS-CoV-2 in emerging various parathyroid disorders due to SARS-CoV-2 infection particularly parathyroid malfunction in COVID-19 cases, and post-COVID-19 conditions. Further, it presents the expression level of various molecules such as ACE2, TMPRSS2, furin, NRP1, and NRP2 in the parathyroid cells that facilitate the SARS-CoV-2 entry into the cell, and discusses the possible mechanism of parathyroid gland infection. Besides, it explores parathyroid malfunction in COVID-19 vaccine-administered cases. It also explains the possible long-COVID-19 effect on parathyroid and post-COVID-19 management of parathyroid. A complete understanding of the mechanisms of SARS-CoV-2-triggered pathogenesis in parathyroid dysfunctions may curtail treatment options and aid in the management of SARS-CoV-2-infected cases.

Correlation of bone density measured on CT chest with the severity of COVID-19 infection: A retrospective study

PURPOSE

This retrospective study investigated the correlation between bone mineral density (BMD) and COVID-19 severity among COVID-19 patients who underwent chest computed tomography (CT) scans.

METHODS

This study was carried out at the King Abdullah Medical Complex in Jeddah, Saudi Arabia, one of the largest COVID-19 centers in the western province. All adult COVID-19 patients who had a chest CT between January 2020 and April 2022 were included in the study. The pulmonary severity scores (PSS) and vertebral BMD measurements were obtained from the patient's CT chest. Data from the patients' electronic records were collected.

RESULTS

The average patient age was 56.4 years, and most (73.5%) patients were men. Diabetes (n = 66, 48.5%), hypertension (n = 56, 41.2%), and coronary artery disease (n = 17, 12.5%) were the most prevalent comorbidities. Approximately two-thirds of hospitalized patients required ICU admission (64%), and one-third died (30%). The average length of stay in the hospital was 28.4 days. The mean CT pneumonia severity score (PSS) was 10.6 at the time of admission. Patients with lower vertebral BMD (< = 100) numbered 12 (8.8%), while those with higher vertebral BMD (>100) numbered 124 (91.2%). Only 46 out of the total survived patients (n = 95) were admitted to the ICU versus all deceased (P<0.01). The logistic regression analysis revealed that an elevated PSS upon admission resulted in a reduced chance of survival. Age, gender, and BMD did not predict survival chances.

CONCLUSION

The BMD had no prognostic advantage, and the PSS was the significant factor that could have predicted the outcome.

Endocrine Disorders and COVID-19

The multifaceted interaction between coronavirus disease 2019 (COVID-19) and the endocrine system has been a major area of scientific research over the past two years. While common endocrine/metabolic disorders such as obesity and diabetes have been recognized among significant risk factors for COVID-19 severity, several endocrine organs were identified to be targeted by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). New-onset endocrine disorders related to COVID-19 were reported while long-term effects, if any, are yet to be determined. Meanwhile, the "stay home" measures during the pandemic caused interruption in the care of patients with pre-existing endocrine disorders and may have impeded the diagnosis and treatment of new ones. This review aims to outline this complex interaction between COVID-19 and endocrine disorders by synthesizing the current scientific knowledge obtained from clinical and pathophysiological studies, and to emphasize considerations for future research.

The osteo-metabolic phenotype of COVID-19: an update

CONTEXT

In the multifaceted COVID-19 clinical scenario characterized by a multi-system disorder with negative implications not only on respiratory function but also on cardiac, hematological, neurological and endocrine-metabolic systems, a distinctive osteo-metabolic phenotype with an independent influence on disease severity and recovery of patients affected was early reported.

AIM

To summarize and update the main evidences regarding the distinct components of this phenotype in acute and Long COVID-19, reinforcing its clinical relevance and discussing the main pathophysiological and clinical-therapeutic implications of the most recent reported findings.

RESULTS

This emerging phenotype is characterized by a widespread acute hypocalcemia and hypovitaminosis D with an impaired compensatory parathyroid hormone response, and a high prevalence of skeletal complications such as vertebral fractures. The clinical relevance of this osteo-metabolic phenotype on acute COVID-19 is well characterized, and novel seminal evidences are progressively highlighting its importance also in predicting patient's long-term outcomes and Long COVID-19 occurrence.

CONCLUSIONS

These findings reinforced the central role of a multidisciplinary team, including endocrinologists, in evaluating these patients for a proactive search of each aspect of the osteo-metabolic phenotype components since they may represent suitable therapeutic targets to prevent SARS-CoV-2 infection, poor COVID-19 outcomes, Long COVID-19 occurrence and even possibly better responses to COVID-19 vaccination.

Vertebral fractures at hospitalization predict impaired respiratory function during follow-up of COVID-19 survivors

PURPOSE

Morphometric vertebral fractures (VFs) have been recently reported as an important component of the endocrine phenotype of COVID-19 and emerging data show negative respiratory sequelae at long-term follow-up in COVID-19 survivors. The aim of this study was to evaluate the impact of VFs on respiratory function in COVID-19 survivors.

METHODS

We included patients referred to our Hospital Emergency Department and re-evaluated during follow-up. VFs were detected on lateral chest X-rays on admission using a qualitative and semiquantitative assessment and pulmonary function tests were obtained by Jaeger-MasterScreen-Analyzer Unit 6 months after discharge.

RESULTS

Fifty patients were included. Median age was 66 years and 66% were males. No respiratory function data were available at COVID-19 diagnosis. VFs were detected in 16 (32%) patients. No differences between fractured and non-fractured patients regarding age and sex were observed. Although no difference was observed between VF and non-VF patient groups in the severity of pneumonia as assessed by Radiological-Assessment-of-Lung-Edema score at admission, (5 vs. 6, p = 0.69), patients with VFs were characterized as compared to those without VFs by lower Forced Vital Capacity (FVC, 2.9 vs. 3.6 L, p = 0.006; 85% vs. 110% of predicted, respectively, p = 0.001), Forced Expiratory Volume 1st s (FEV1, 2.2 vs. 2.8 L, p = 0.005; 92% vs. 110% of predicted, respectively, p = 0.001) and Diffusing Capacity of the Lungs for Carbon Monoxide (DLCO 5.83 vs. 6.98 mmol/min/kPa, p = 0.036, 59% vs. 86.3% of predicted, respectively, p = 0.043) at 6-month follow up.

CONCLUSIONS

VFs, expression of the endocrine phenotype of the disease, appear to influence medium-term impaired respiratory function of COVID-19 survivors which may significantly influence their recovery. Therefore, our findings suggest that a VFs assessment at baseline may help in identifying patients needing a more intensive respiratory follow-up and patients showing persistent respiratory impairment without evidence of pulmonary disease may benefit from VFs assessment to preventing the vicious circle of further fractures and respiratory deterioration.

Osteoporosis in Patients With Respiratory Diseases

Climate change, environmental pollution, and virus epidemics have sharply increased the number of patients suffering from respiratory diseases in recent years. Prolonged periods of illness and drug use increase the occurrence of complications in these patients. Osteoporosis is the common bone metabolism disease with respiratory disturbance, which affects prognosis and increases mortality of patients. The problem of osteoporosis in patients with respiratory diseases needs more attention. In this review, we concluded the characteristics of osteoporosis in some respiratory diseases including COPD, asthma, COVID-19, tuberculosis, and lung cancer. We revealed that hypoxia was the common pathogenesis of osteoporosis secondary to respiratory diseases, with malnutrition and corticosteroid abuse driving the progression of osteoporosis. Hypoxia-induced ROS accumulation and activated HIF-1α lead to attenuated osteogenesis and enhanced osteoclastogenesis in patients with respiratory diseases. Tuberculosis and cancer also invaded bone tissue and reduced bone strength by direct infiltration. For the treatment of osteoporosis in respiratory patients, oral-optimized bisphosphonates were the best treatment modality. Vitamin D was a necessary supplement, both for calcium absorption in osteogenesis and for improvement of respiratory lesions. Reasonable adjustment of the dose and course of corticosteroids according to the etiology and condition of patients is beneficial to prevent the occurrence and development of osteoporosis. Additionally, HIF-1α was a potential target for the treatment of osteoporosis in respiratory patients, which could be activated under hypoxia condition and involved in the process of bone remodeling.