Enfermedad pulmonar obstructiva crónica y osteoporosis

Osteoporosis is one of the systemic effects associated with chronic obstructive pulmonary disease (COPD). Risk factors for bone loss include smoking, skeletal muscle weakness, low bone mass index (BMI), vitamin D deficiency, glucocorticoid use, hypogonadism and systemic inflammation. The most important clinical feature is vertebral fracture, due to its significant morbidity and mortality. The treatment of osteoporosis includes calcium and vitamin D, bisphosphonates, anabolic agents and pulmonary rehabilitation. Prospective studies are required to determine the prevalence of osteoporosis in COPD and to identify which patients are at high risk for osteoporotic fracture. The development of new drugs to control systemic inflammation may contribute to specific treatments for osteoporosis in COPD.     

Recognizing and treating glucocorticoid-induced osteoporosis in patients with pulmonary diseases

Glucocorticoids are frequently used to treat patients with pulmonary diseases, but continuous long-term use of glucocorticoids may lead to significant bone loss and an increased risk of fragility fractures. Patients with certain lung diseases, regardless of pharmacotherapy-particularly COPD and cystic fibrosis-and patients waiting for lung transplantation are also at increased risk of osteoporosis. Fragility fractures, especially of the hip, will have substantial effects on the health and well-being of older patients. Vertebral collapse and kyphosis secondary to glucocorticoid-induced osteoporosis (GIO) may affect lung function. Identification of patients with osteopenia, osteoporosis, or fragility fractures related to osteoporosis is strongly recommended and should lead to appropriate treatment. Prevention of GIO in patients receiving continuous oral glucocorticoids is also recommended. In patients receiving either high-dose inhaled glucocorticoids or low- to medium-dose inhaled glucocorticoids with frequent courses of oral glucocorticoids, bone mineral density measurements should be performed to screen for osteopenia and osteoporosis. A bisphosphonate (risedronate or alendronate), calcium and vitamin D supplementation, and lifestyle modifications are recommended for the prevention and treatment of GIO.     

Glucocorticoid-induced osteoporosis

Glucocorticoid-induced osteoporosis is the most frequent cause of secondary osteoporosis. Glucocorticoids cause a rapid bone loss in the first few months of use, but the most important effect of the drug is suppression of bone formation. The administration of oral glucocorticoid is associated with an increased risk of fractures at the spine and hip. The risk is related to the dose, but even small doses can increase the risk. Patients on glucocorticoid therapy lose more trabecular than cortical bone and the fractures are more frequent at the spine than at the hip. Calcium, vitamin D and activated forms of vitamin D can prevent bone loss and antiresorptive agents are effective for prevention and treatment of bone loss and to decrease fracture risk. Despite the known effects of glucocorticoids on bone, only a few patients are advised to take preventive measures and treat glucocorticoid-induced osteoporosis.     

Chronic glucocorticoid therapy-induced osteoporosis in patients with obstructive lung disease

Long-term glucocorticoid (GC) therapy has been instrumental in decreasing morbidity and mortality in a variety of chronic inflammatory diseases, including persistent asthma. Long-term GC therapy is also widely prescribed for COPD. One of the important and often unrecognized side effects of chronic GC therapy is secondary osteoporosis. The risk of GC-induced bone loss is roughly correlated with daily dose, duration, and total cumulative lifetime dose of GC treatment. Oral prednisone increases the risk of bone loss and fracture. High doses of inhaled GCs may also increase the risk of osteopenia/osteoporosis, but the risk appears to be less than that associated with oral GCs. Hormone replacement therapy, oral and parenteral bisphosphonates, supplemental calcium and vitamin D, calcitonin, and fluoride compounds have been used, experimentally, in the management of GC-induced bone loss. Asthma and COPD specialists are key prescribers of oral and inhaled steroids and are likely to encounter patients with significant bone loss. Despite known risk factors and the availability of reliable diagnostic tools to recognize bone loss, the opportunity to slow, reverse, and treat bone loss is often missed. We present a review of the current literature regarding the incidence, treatment, and prevention of osteopenia/osteoporosis secondary to chronic GC therapy in adult asthma and COPD patients. Guidelines are presented regarding the identification of patients at risk for developing GC-induced secondary bone loss, and therapeutic alternatives are discussed.     

COPD and bone metabolism: a clinical update

Increasing evidence indicates that COPD and osteoporosis are strongly linked. Both diseases share common risk factors like age, smoking and inactivity but the typical presence in COPD of systemic inflammation, vitamin D deficiency and the frequent use of corticosteroids catalyse ongoing bone resorption. Osteoporosis in its turn may lead to vertebral compression fractures with a consequent further decline of forced vital capacity and forced expiratory volume in one second. In addition, fragility fractures in disabled COPD patients may cause further immobility and increased morbidity. Prevention and treatment of osteoporosis in COPD should therefore be based on population specific risk assessments which combine measures of bone mineral density and clinical factors. Unfortunately, intervention studies specifically designed for patients with COPD are currently lacking and no specific guidelines have yet been established. Hence, a rigorous application of the current treatment guidelines with respect to osteoporosis in general would already be a major step forward in the treatment of COPD.     

The prevalence of osteoporosis in patients with chronic obstructive pulmonary disease: a cross sectional study

Chronic obstructive pulmonary disease (COPD) is a complex disease, where the initial symptoms are often cough as a result of excessive mucus production and dyspnea. With disease progression several other symptoms may develop, and patients with moderate to severe COPD have often multiorganic disease with severely impaired respiratory dysfunction, decreased physical activity, right ventricular failure of the heart, and a decreased quality of life. In addition osteoporosis might develop possibly due to a number of factors related to the disease. We wanted to investigate the prevalence of osteoporosis in a population of patients with severe COPD as well as to correlate the use of glucocorticoid treatment to the occurrence of osteoporosis in this population. Outpatients from the respiratory unit with COPD, a history of forced expiratory volume in 1s (FEV1) less than 1.3 L, with FEV1% pred. ranging from 17.3% to 45.3% (mean 31.4%, standard deviation (sd) 7.3%). Patients between 50 and 70 years were included. Other causes of osteoporosis were excluded before inclusion. At study entry spirometry, X-ray of the spine (to evaluate presence of vertebral fractures), and bone mineral density of lumbar spine and hip were performed. Of 181 patients invited by mail, 62 patients were included (46 females and 16 males). All had symptoms of COPD such as exertional dyspnea, productive cough, limitations in physical activity etc. The mean FEV1 was 0.90 L (sd: 0.43 L) and the mean FEV1% pred. of 32.6% (sd: 14.1%). All had sufficient daily intake of calcium and vitamin D. In 15 patients, X-ray revealed compression fractures previously not diagnosed. Bone density measurements showed osteoporosis in 22 patients and osteopenia in 16. In total, 26 of the COPD patients were osteoporotic as evaluated from both X-ray and bone density determinations. Thus 68% of the participants had osteoporosis or osteopenia, but glucocorticoid use alone could not explain the increased prevalence of osteoporosis. A large fraction of these needed treatment for severe osteoporosis in order to prevent further bone loss and to reduce future risk of osteoporotic fractures. Thus, there is a significant need to screen patients with COPD to select the individuals in risk of fracture and to initiate prophylaxis or treatment for the disease.     

COPD继发骨质疏松症机制的研究进展

骨质疏松症是COPD的一个重要合并症.COPD患者中骨质疏松症的发病率、病死率增加,这一相关性可能与体质量指数下降和游离脂肪减少、全身炎症反应、激素使用、维生素D的缺乏及患者病理类型等因素有关.本文将对二者相关性及其可能机制的研究进展进行综述.     

炎症性肠病与骨质疏松研究进展

骨质疏松是炎症性肠病(IBD)患者常见但易被忽视的并发症之一.炎症性肠病患者骨质疏松的发病机制尚未完全明了,皮质类固醇激素的应用、炎性细胞因子的增加、维生素D的缺乏及遗传等众多因素均可能参与骨质疏松的发生.对于炎症性肠病患者并发骨质疏松者应及早诊断及治疗,早期干预可减轻IBD患者骨质疏松的发生与发展.     

COPD, bone metabolism, and osteoporosis

COPD and osteoporosis are strongly associated because of common risk factors such as age, smoking, and inactivity. In addition, COPD-related systemic inflammation, vitamin D deficiency, and the use of systemic corticosteroids enhance ongoing bone destruction. Osteoporosis, in turn, may cause fragility fractures, which further impair mobility and increase morbidity and mortality. Vertebral compression fractures and rib cage fractures in patients with COPD may also reduce pulmonary function or enhance exacerbations. Early prevention and treatment of osteoporosis in COPD is, therefore, important and should be based on integrated risk assessment tools such as FRAX, which take bone mineral density, history of fragility fractures, and population-specific clinical factors into account. As long as intervention studies focusing on the bone in COPD are lacking, a more rigorous application of existing treatment guidelines of osteoporosis in general is mandatory.     

Progression of osteoporosis in patients with COPD: a 3-year follow up study

Currently, our knowledge on the progression of osteoporosis and its determinants is limited in patients with chronic obstructive pulmonary disease (COPD). Bone mineral density generally remains stable in patients with COPD over a period of 3 years. Nevertheless, the progression of vertebral fractures was not assessed, while an increase of vertebral fractures over time may be reasonable. Aims of the current study were to determine the percentage of newly diagnosed osteoporotic patients after a follow up of 3 years and to identify baseline risk factors for the progression of osteoporosis in COPD. Clinically stable COPD outpatients were included. Lung function parameters, body composition measures, six minute walk distance, DXA-scan and X-spine were assessed at baseline and repeated after 3 years. Prevalence of osteoporosis in COPD patients increased from 47% to 61% in 3 years mostly due to an increase of vertebral fractures. Lower baseline T-score at the trochanter independently increased the risk for the development of osteoporosis. Additionally, baseline vitamin D deficiency increased this risk 7.5-fold. In conclusion, the prevalence of osteoporosis increased over a 3-year period in patients with COPD. Baseline risk factors for the development of osteoporosis are osteopenia at the trochanter and vitamin D deficiency.     

Osteoporosis in chronic obstructive pulmonary disease

Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of osteoporosis because of their age, limited physical activity, low body mass index, smoking, hypogonadism, malnutrition, and use of corticosteroids. Systemic inflammation represents an additional pathomechanism contributing to the development of osteoporosis in COPD patients. Males in their mid to late 60s with a smoking history of greater than 60 pack-years have a prevalence rate of vertebral fractures similar to, and possibly greater than, postmenopausal women greater than or equal to 65 years old: in patients with severe COPD, up to 50-70% have osteoporosis or osteopenia, and up to 24-30% have compression vertebral fractures. Correlates of osteoporosis in COPD are mainly measures of body composition, disease severity and the use of corticosteroids, although causality has not been proven. Systemic corticosteroids remain the most common cause of drug-related osteoporosis, and a meta-analysis concluded that the use of more than 6.25 mg prednisone daily led to decreased bone mineral density (BMD) and increased fracture risk. In contrast, the effects of the long-term use of inhaled corticosteroids on BMD remain debatable. Effects of treatment of osteoporosis have not been investigated in samples consisting of COPD patients only but the recommendations follow the general recommendations for the diagnosis and treatment of osteoporosis. Early recognition of BMD loss is essential, and assumes close interdisciplinary cooperation between respirologists and reumatologists. Longitudinal follow-up to assess determinants of osteoporosis in COPD and randomised placebo-controlled trials on the effects of treatment of osteoporosis in patients with COPD only are warranted. In the future, novel therapeutical strategies such as monoclonal antibodies against osteoclasts activators may prove their beneficial effects in the treatment of COPD-related osteoporosis.     

维生素D缺乏与骨质疏松

维生素D对骨骼最主要的作用之一是为骨质矿化提供合适的微环境。尽管部分食物中强化维生素D,或额外补充维生素D,但人群中维生素D缺乏仍很普遍。维生素D缺乏可导致甲状旁腺功能亢进、骨转换增加和骨丢失,引起骨折风险增加。维生素D和钙剂补充是防治骨质疏松症的基本措施。研究表明补充足量维生素D能增加骨量、肌肉容量,和肌肉协调功能,有助于预防骨质疏松及其骨折。     

Prostate cancer, osteoporosis and fracture risk

Prostate cancer is often treated with androgen deprivation therapy (ADT). Although this treatment is effective the associated hypogonadism causes accelerated bone loss, osteoporosis and increased fracture risk in men with prostate cancer, even in the absence of bone metastases. In addition to the negative effects of ADT on bone metabolism, men with prostate cancer are at increased risk of osteoporosis due to advanced age, poor nutrition and vitamin D deficiency. Some treatments for prostate cancer avoid this side effect and these are discussed, together with treatment strategies to minimise the impact of ADT on bone health.     

Relative value of plain vitamin D and of biologically active vitamin D in the prevention and treatment of osteoporosis

Vitamin D metabolism has an important role in the pathogenesis of osteoporosis. Vitamin D deficiency is very common in elderly people in central Europe. This leads to secondary hyperparathyroidism and to increased bone resorption, resulting in osteoporosis. Combined with the elevated risk of falling that results from vitamin D deficiency, this increases the frequency of bone fractures. Severe vitamin D deficiency also causes impaired bone mineralization (osteomalacia). Controlled intervention trials with native vitamin D (and calcium) yielded no consistent results in terms of the prevention of extravertebral fractures. It appears likely that treatment with plain vitamin D is effective only in populations with vitamin D deficiency. Treatment with active vitamin D (1-alpha-hydroxylated metabolites such as alfacalcidol) has to be considered a pharmacological intervention that exerts pleiotropic effects on the gut (calcium absorption), bone (stimulation of formation), muscle (decreasing of the risk of falling), and immune system. Target groups are patients with disturbed vitamin D metabolism (renal insufficiency, glucocorticoid therapy, inflammatory disease such as rheumatoid arthritis). Alfacalcidol can prevent glucocorticoid-induced bone loss (high-grade evidence). In comparative studies alfacalcidol was superior to plain vitamin D.     

Corticosteroid-Induced Osteoporosis

Corticosteroid-induced osteoporosis is the leading cause of secondary osteoporosis and a significant cause of morbidity in both men and women. Long-term use of even low-dose corticosteroids has been associated with increased risk of bone loss. Recent large randomized controlled trials have generated new knowledge on treatment strategies for patients with corticosteroid-induced osteoporosis. However, the majority of individuals receiving corticosteroids are not receiving prophylaxis for osteoporosis. Calcium and vitamin D should be recommended to patients initiating therapy with corticosteroids (and should be adequate for those receiving corticosteroids for less than 3 months). For those receiving corticosteroids for greater than 3 months, bisphosphonates are the therapy of choice, with both alendronate (alendronic acid) and risedronate (risedronic acid) approved by the US FDA for use in this indication. Calcitonin can be considered a second-line agent and should be reserved for patients who are intolerant of bisphosphonates or who are experiencing pain from a vertebral fracture. Hormone replacement therapy or testosterone therapy may be offered to those individuals on long-term corticosteroid treatment who are hypogonadal. Teriparatide (recombinant human parathyroid hormone 1-34) shows promise as a future anabolic agent for the prevention and treatment of patients with corticosteroid-induced osteoporosis.     

Glucocorticoid-induced osteoporosis: mechanisms for bone loss; evaluation of strategies for prevention

Osteoporosis is a common complication of chronic glucocorticoid therapy, especially in older patients who already are at risk of having a reduced bone mass. Glucocorticoids cause bone loss by altering the bone remodeling sequence: bone resorption by osteoclasts is increased, and bone formation by osteoblasts is decreased. Serum levels of osteocalcin, a protein made by osteoblasts, are decreased with glucocorticoid therapy, further evidence of decreased osteoblast function. Glucocorticoids decrease calcium absorption by the gastrointestinal tract and increase renal calcium excretion. Several recent studies suggest that low-dose glucocorticoid therapy is not associated with bone loss. Calcium supplementation with vitamin D is recommended. Several short-term studies have shown prevention of glucocorticoid-induced bone loss with bisphosphonates, calcitonin, and progesterone. Long-term clinical trials should be undertaken to determine strategies to prevent this type of osteoporosis.     

Risk factors for osteoporosis in inflammatory bowel disease patients

Inflammatory bowel disease (IBD) patients exhibit higher risk for bone loss than the general population. The chronic inflammation causes a reduction in bone mineral density (BMD), which leads to osteopenia and osteoporosis. This article reviewed each risk factor for osteoporosis in IBD patients. Inflammation is one of the factors that contribute to osteoporosis in IBD patients, and the main system that is involved in bone loss is likely RANK/RANKL/osteoprotegerin. Smoking is a risk factor for bone loss and fractures, and many mechanisms have been proposed to explain this loss. Body composition also interferes in bone metabolism and increasing muscle mass may positively affect BMD. IBD patients frequently use corticosteroids, which stimulates osteoclastogenesis. IBD patients are also associated with vitamin D deficiency, which contributes to bone loss. However, infliximab therapy is associated with improvements in bone metabolism, but it is not clear whether the effects are because of inflammation improvement or infliximab use. Ulcerative colitis patients with proctocolectomy and ileal pouches and Crohn’s disease patients with ostomy are also at risk for bone loss, and these patients should be closely monitored.     

华法林引发骨质疏松症的发病机制及治疗策略

骨质疏松症是一种以骨矿物质含量低下、骨微结构损坏、骨强度降低、骨脆性增加、易发生骨折为主要特征的全身性骨代谢障碍性疾病。华法林可拮抗维生素K,使骨钙素的羧化受抑制,减少骨钙沉积,抑制骨矿化,从而干扰骨代谢,导致骨质疏松症或骨折,对于老年患者的影响尤其明显。长期服用华法林导致骨质疏松症的风险可能与用药剂量和时间相关。目前预防和治疗华法林引起的骨质疏松症主要依据原发性骨质疏松症的治疗原则,对于长期服用华法林的患者应补充钙剂和维生素D以预防骨质疏松症,对于已出现骨质疏松症的患者根据具体病情选择用双膦酸盐、降钙素、雌激素和甲状旁腺类似物治疗。本文对华法林引发骨质疏松症的发病机制、研究进展和治疗策略进行综述。     

The effect of vitamin D on bone and osteoporosis

The main effect of the active vitamin D metabolite 1,25(OH)2D is to stimulate the absorption of calcium from the gut. The consequences of vitamin D deficiency are secondary hyperparathyroidism and bone loss, leading to osteoporosis and fractures, mineralization defects, which may lead to osteomalacia in the long term, and muscle weakness, causing falls and fractures. Vitamin D status is related to bone mineral density and bone turnover. Vitamin D supplementation may decrease bone turnover and increase bone mineral density. Several randomized placebo-controlled trials with vitamin D and calcium showed a significant decrease in fracture incidence. However, very high doses of vitamin D once per year may have adverse effects. When patients with osteoporosis are treated with a bisphosphonate, they should receive a vitamin D and calcium supplement unless the patient is vitamin D replete. These subjects are discussed in detail in this review. Finally, the knowledge gaps and research agenda are discussed.     

Bone health and vitamin D status in alcoholic liver disease

Alcohol consumption is harmful to many organs and tissues, including bones, and it leads to osteoporosis. Hepatic osteodystrophy is abnormal bone metabolism that has been defined in patients with chronic liver disease (CLD), including osteopenia, osteoporosis, and osteomalacia. Decreased bone density in patients with CLD results from decreased bone formation or increased bone resorption. The prevalence of osteopenia in alcoholic liver disease (ALD) patients is between 34 % and 48 %, and the prevalence of osteoporosis is between 11 % and 36 %. Cirrhosis is also a risk factor for osteoporosis. The liver has an important role in vitamin D metabolism. Ninety percent of patients with alcoholic liver cirrhosis have vitamin D inadequacy (<80 nmol/L). The lowest serum vitamin D levels were observed in patients with Child–Pugh class C. Bone densitometry is used for the definitive diagnosis of osteoporosis in ALD. There are no specific controlled clinical studies on the treatment of osteoporosis in patients with ALD. Alcohol cessation and abstinence are principal for the prevention and treatment of osteoporosis in ALD patients, and the progression of osteopenia can be stopped in this way. Calcium and vitamin D supplementation is recommended, and associated nutritional deficiencies should also be corrected. The treatment recommendations of osteoporosis in CLD tend to be extended to ALD. Bisphosphonates have been proven to be effective in increasing bone mineral density (BMD) in chronic cholestatic disease and post-transplant patients, and they can be used in ALD patients. Randomized studies assessing the management of CLD-associated osteoporosis and the development of new drugs for osteoporosis may change the future. Here, we will discuss bone quality, vitamin D status, mechanism of bone effects, and diagnosis and treatment of osteoporosis in ALD.