Risk of secondary osteoporosis due to lobular cholestasis in non-cirrhotic primary biliary cholangitis

Grip strength is a strong indicator of osteoporosis in both women and men with chronic liver disease

AIM

Osteoporosis (Op) and sarcopenia are common complications of chronic liver disease. We sought to identify clinical screening indicators for Op, and evaluated their relationship with bone and muscle.

METHOD

We retrospectively evaluated 495 patients (264 women) with chronic liver disease who underwent a bone mineral density evaluation at their first outpatient visit. Bone mineral density was measured in the lumbar spine (mean of L2-L4) and femoral neck using dual-energy X-ray absorptiometry. The relationship between Op and various clinical factors was examined.

RESULTS

Op was diagnosed in 156 patients (31.5%). Sex, age, steatotic liver disease, fibrosis-4 index, body mass index, and grip strength (GS) were associated with Op. In logistic multivariate analysis, Op was associated with older age (>68 years in women and >69 years in men), low body mass index (<20), and low GS (<18 kg in women and <28 kg in men). Factors associated with Op were analyzed in 254 patients whose body composition was evaluated. Op was associated with older age, low GS, and low skeletal muscle (<86 cm2) in women, and only low skeletal muscle (<116 cm2) in men. Combined Op and sarcopenia was observed in 19.6% of patients. Sarcopenia was associated with Op in both sexes. The number of patients with a low GS increased with age in both sexes. However, the number of patients with low bone mineral density increased with age in women, but not in men.

CONCLUSION

Low GS is an indicator of Op in both sexes. Overlooked Op in chronic liver disease should be screened using GS.

Association of chronic liver disease with bone diseases and muscle weakness

The liver is a vital organ involved in nutrient metabolism, hormone regulation, immunity, cytokine production, and gut homeostasis. Impairment in liver function can result in malnutrition, chronic inflammation, decreased anabolic hormone levels, and dysbiosis. These conditions eventually cause an imbalance in osteoblast and osteoclast activities, resulting in bone loss. Osteoporosis is a frequent complication of chronic liver disease (CLD) that adversely affects quality of life and increases early mortality. Sarcopenia is another common complication of CLD characterized by progressive loss of skeletal muscle mass and function. Assessment criteria for sarcopenia specific to liver disease have been established, and sarcopenia has been reported to be associated with an increase in the risk of liver disease-related events and mortality in patients with CLD. Owing to their similar risk factors and underlying pathophysiological mechanisms, osteoporosis and sarcopenia often coexist (termed osteosarcopenia), progress in parallel, and further exacerbate the conditions mentioned above. Therefore, comprehensive management of these musculoskeletal disorders is imperative. This review summarizes the clinical implications and characteristics of osteoporosis, extending to sarcopenia and osteosarcopenia, in patients with CLD caused by different etiologies.

Increased risk of fragility fractures in patients with primary biliary cholangitis

Large-scale studies on the risk of fragility fractures in patients with primary biliary cholangitis (PBC) are limited due to low incidence. We aimed to investigate whether PBC is associated with fragility fractures using real-world nationwide data. The Korean National Health Insurance Service claims data from 2007 to 2020 were analyzed in this population-based cohort study. Patients with PBC (n = 4951) were matched with controls (n = 19 793) using a 1:4 ratio based on age, sex, and follow-up duration. The primary outcome was fragility fracture, which comprised fractures of the vertebra, hip, distal radius, and proximal humerus. The incidence rates (IRs) and hazard ratios (HRs) were determined to assess the impact of PBC on fragility fractures. During the median follow-up period of 5.37 years, 524 patients in the PBC group had fragility fractures (IR, 18.59/1000 person-years [PYs]). After adjusting for covariates, PBC increased the risk of fragility fractures by 1.63-fold (95% confidence interval, 1.20-2.22; P = .002). The vertebra and hip were particularly susceptible to fracture in patients with PBC, with adjusted HRs of 1.77 and 2.23, respectively. In the subgroup analysis, the risk of fragility fracture was 2.53-fold higher in men and 1.59-fold higher in women with PBC than that in the respective matched control groups. Considering the morbidity and mortality related to fragility fractures, increasing awareness of fragility fracture risk and implementing appropriate preventive measures in patients with PBC are imperative.

Genetic association and causal relationship between multiple modifiable risk factors and autoimmune liver disease: a two-sample mendelian randomization study

BACKGROUND

The intricate etiology of autoimmune liver disease (AILD) involves genetic, environmental, and other factors that yet to be completely elucidated. This study comprehensively assessed the causal association between genetically predicted modifiable risk factors and AILD by employing Mendelian randomization.

METHODS

Genetic variants associated with 29 exposure factors were obtained from genome-wide association studies (GWAS). Genetic association data with autoimmune hepatitis (AIH), primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) were also obtained from publicly available GWAS. Univariate and multivariate Mendelian randomization analyses were performed to identify potential risk factors for AILD.

RESULTS

Genetically predicted rheumatoid arthritis (RA) (OR = 1.620, 95%CI 1.423-1.843, P = 2.506 × 10- 13) was significantly associated with an increased risk of AIH. Genetically predicted smoking initiation (OR = 1.637, 95%CI 1.055-2.540, P = 0.028), lower coffee intake (OR = 0.359, 95%CI 0.131-0.985, P = 0.047), cholelithiasis (OR = 1.134, 95%CI 1.023-1.257, P = 0.017) and higher C-reactive protein (CRP) (OR = 1.397, 95%CI 1.094-1.784, P = 0.007) were suggestively associated with an increased risk of AIH. Genetically predicted inflammatory bowel disease (IBD) (OR = 1.212, 95%CI 1.127-1.303, P = 2.015 × 10- 7) and RA (OR = 1.417, 95%CI 1.193-1.683, P = 7.193 × 10- 5) were significantly associated with increased risk of PBC. Genetically predicted smoking initiation (OR = 1.167, 95%CI 1.005-1.355, P = 0.043), systemic lupus erythematosus (SLE) (OR = 1.086, 95%CI 1.017-1.160, P = 0.014) and higher CRP (OR = 1.199, 95%CI 1.019-1.410, P = 0.028) were suggestively associated with an increased risk of PBC. Higher vitamin D3 (OR = 0.741, 95%CI 0.560-0.980, P = 0.036) and calcium (OR = 0.834, 95%CI 0.699-0.995, P = 0.044) levels were suggestive protective factors for PBC. Genetically predicted smoking initiation (OR = 0.630, 95%CI 0.462-0.860, P = 0.004) was suggestively associated with a decreased risk of PSC. Genetically predicted IBD (OR = 1.252, 95%CI 1.164-1.346, P = 1.394 × 10- 9), RA (OR = 1.543, 95%CI 1.279-1.861, P = 5.728 × 10- 6) and lower glycosylated hemoglobin (HbA1c) (OR = 0.268, 95%CI 0.141-0.510, P = 6.172 × 10- 5) were positively associated with an increased risk of PSC.

CONCLUSIONS

Evidence on the causal relationship between 29 genetically predicted modifiable risk factors and the risk of AIH, PBC, and PSC is provided by this study. These findings provide fresh perspectives on the management and prevention strategies for AILD.

Guidelines on the Diagnosis and Management of Primary Biliary Cholangitis (2021)

In 2015, the Chinese Society of Hepatology and the Chinese Society of Gastroenterology published a consensus on primary biliary cholangitis (PBC). In the past years, numerous clinical studies have been published in the field of PBC. To guide the clinical diagnosis and management of PBC patients, the Chinese Society of Hepatology invited a panel of experts to assess the new clinical evidence and formulate the current guidelines.

Serum Insulin-Like Growth Factor 1 Levels, Facture Risk Assessment Tool Scores and Bone Disorders in Patients with Primary Biliary Cholangitis

Insulin-like growth factor 1 (IGF-1) plays an important role in bone growth and maintenance, and its decreased levels are associated with bone disorders. This study aimed to evaluate the association of serum IGF-1 levels with osteoporosis, prevalent fractures and fracture risk based on the Fracture Risk Assessment Tool (FRAX) in patients with primary biliary cholangitis (PBC). This study included 127 consecutive patients with PBC. Based on the baseline serum IGF-1 levels, the participants were classified into the low (L)-, intermediate (I)- and high (H)-IGF-1 groups. According to the FRAX score, high fracture risk was defined as a 10-year major osteoporotic fracture probability (FRAX-MOF) ≥ 20% or a 10-year hip fracture probability (FRAX-HF) ≥ 3%. The serum IGF-1 levels were positively correlated with bone mineral density, and were negatively correlated with the FRAX-MOF/FRAX-HF. The L-IGF-1 group had the highest prevalence of osteoporosis (58.1%), prevalent fracture (48.4%) and high fracture risk (71.0%). Meanwhile, the H-IGF-1 group had the lowest prevalence of osteoporosis (9.7%), prevalent fracture (12.9%) and high fracture risk (9.7%). The prevalence of these events increased stepwise with decreasing serum IGF-1 levels. The cutoff values of IGF-1 for predicting osteoporosis, prevalent fracture and high fracture risk were 61.5 ng/mL (sensitivity/specificity, 0.545/0.894), 69.5 ng/mL (0.633/0.784) and 61.5 ng/mL (0.512/0.929), respectively. Serum IGF-1 levels were associated with bone disorders and the FRAX-derived fracture risk, and may be a useful indicator for initiating therapeutic intervention to prevent the incidence of fracture in patients with PBC.

A Systematic Review and Meta-Analysis on Metabolic Bone Disease in Patients with Primary Sclerosing Cholangitis

Data about the association between primary sclerosing cholangitis (PSC) and metabolic bone disease are still unclear. PSC is a chronic cholestatic liver disease (CCLD) which affects the biliary tract, and it has a highly variable natural history. We systematically searched until 28 February 2022 MEDLINE, Cochrane Central Register of Controlled Trials, the ISI Web of Science, and SCOPUS, for studies in patients with PSC. We identified 343 references to potential studies. After screening them, we included eight studies (893 PSC patients, 398 primary biliary cirrhosis (PBC) patients, and 673 healthy controls) for the present meta-analysis. Pooled analyses found no difference in BMD-LS (Z = 0.02, p-value = 0.98) between PSC patients and healthy controls. BMD-LS was statistically lower in PBC patients than in PSC patients (Mean Difference, MD, 0.06, 95% CI 0.03 to 0.09, p-value = 0.0007). The lumbar spine T-score was higher in the PSC patients compared with PBC patients (MD 0.23, 95% CI 0.04 to 0.42, p-value = 0.02). Given the limited literature available, better designed, and larger scale primary studies will be required to confirm our conclusion.

Mechanism for development of malnutrition in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that is associated with impaired biliary excretion processes. Along with the development of cholestasis, there is a deficient flow of bile acids into the intestinal lumen causing malnutrition (MN) that is manifested in deficiencies of both macro- and micronutrients. The mechanism for development of trophological insufficiency is multifactorial. However, the trigger of MN in PBC is impaired enterohepatic circulation of bile acids. The ingress of bile acids with a detergent effect into the general bloodstream, followed by elimination via the kidneys and skin, triggers a cascade of metabolic disturbances, which leads to the gradual development and progression of calorie MN. The latter gradually transforms into protein-calorie MN (PСM) (as marasmus) due to the insufficient entry of bile acids into the duodenum, which is accompanied by a decrease in the emulsification, hydrolysis, and absorption of fats and fat-soluble vitamins, as well as disturbance of intestinal motility and bacterial overgrowth. Fat-soluble vitamin deficiencies complement PСM with vitamin and mineral MN. The development of hepatocellular failure enhances the progression of PСM due to the impaired protein synthetic function of hepatocytes in the advanced stage of PBC, which results in deficiency of not only the somatic but also the visceral pool of proteins. A mixed PСM form of marasmus and kwashiorkor develops. Early recognition of energy, protein, micronutrient, and macronutrient deficiencies is of great importance because timely nutritional support can improve liver function and quality of life in patients with PBC. In this case, it is important to know what type (energy, protein-calorie, vitamin, and vitamin-mineral) and form (marasmus, marasmus-kwashiorkor) of MN is present in the patient and how it is associated with the stage of the disease. Therefore, it is recommended to screen all patients with PBC for MN, from the early asymptomatic stage of the disease in order to identify and avoid preventable complications, such as fatigue, malaise, performance decrement, sarcopenia, osteoporosis, and hepatic encephalopathy, which will be able to provide appropriate nutritional support for correction of the trophological status.

Osteosarcopenia in autoimmune cholestatic liver diseases: Causes, management, and challenges

Primary biliary cholangitis and primary sclerosing cholangitis (PSC) are the most common cholestatic liver diseases (CLD) in adults and are both characterized by an immune pathogenesis. While primary biliary cholangitis is a model autoimmune disease, with over 90% of patients presenting very specific autoantibodies against mitochondrial antigens, PSC is considered an immune mediated disease. Osteoporosis is the most common bone disease in CLD, resulting in frequent fractures and leading to significant morbidity. Further, sarcopenia is emerging as a frequent complication of chronic liver diseases with a significant prognostic impact and severe implications on the quality of life of patients. The mechanisms underlying osteoporosis and sarcopenia in CLD are still largely unknown and the association between these clinical conditions remains to be dissected. Although timely diagnosis, prevention, and management of osteosarcopenia are crucial to limit the consequences, there are no specific guidelines for management of osteoporosis and sarcopenia in patients with CLD. International guidelines recommend screening for bone disease at the time of diagnosis of CLD. However, the optimal monitoring strategies and treatments have not been defined yet and vary among centers. We herein aim to comprehensively outline the pathogenic mechanisms and clinical implications of osteosarcopenia in CLD, and to summarize expert recommendations for appropriate diagnostic and therapeutic approaches.

Clinical Management of Primary Biliary Cholangitis-Strategies and Evolving Trends

PBC is a chronic progressive autoimmune disorder involving the destruction of intrahepatic small bile ducts, cholestasis, fibrosis, and ultimately cirrhosis if left untreated. It is largely driven by the autoimmune response, but bile acids and the intestinal microbiota are implicated in disease progression as well. The only drugs licensed for PBC are UDCA and OCA. UDCA as a first-line and OCA as a second-line therapy are safe and effective, but the lack of response in a significant portion of patients and inadequate control of symptoms such as fatigue and pruritus remain as concerns. Liver transplantation is an end-stage therapy for many patients refractory to UDCA, which gives excellent survival rates but also moderate to high recurrence rates. The limited options for FDA-approved PBC therapies necessitate the development of alternative approaches. Currently, a wide variety of experimental drugs exist targeting immunological and physiological aspects of PBC to suppress inflammation. Immunological therapies include drugs targeting immune molecules in the B cell and T cell response, and specific cytokines and chemokines implicated in inflammation. Drugs targeting bile acids are also noteworthy as bile acids can perpetuate hepatic inflammation and lead to fibrosis over time. These include FXR agonists, ASBT inhibitors, and PPAR agonists such as bezafibrate and fenofibrate. Nonetheless, many of these drugs can only delay disease progression and fail to enhance patients' quality of life. Nanomedicine shows great potential for treatment of autoimmune diseases, as it provides a new approach that focuses on tolerance induction rather than immunosuppression. Tolerogenic nanoparticles carrying immune-modifying agents can be engineered to safely and effectively target the antigen-specific immune response in autoimmune diseases. These may work well with PBC especially, given the anatomical features and immunological specificity of the disease. Nanobiological therapy is thus an area of highly promising research for future treatment of PBC.

Relationship between osteoporosis, sarcopenia, vertebral fracture, and osteosarcopenia in patients with primary biliary cholangitis

AIM

Bone disorders are serious complications in patients with primary biliary cholangitis (PBC), especially in postmenopausal female patients. Given that osteoporosis interrelates closely with sarcopenia, the concept of osteosarcopenia (coexistence of the two complications) has been established. This study aimed to investigate the relationship between osteoporosis, sarcopenia, vertebral fracture, and osteosarcopenia in PBC patients.

METHODS

This study involved 117 consecutive PBC patients (21 males and 96 females). Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry. Sarcopenia was diagnosed according to the Japan Society of Hepatology assessment criteria.

RESULTS

Of the 117 patients, 33 (28.2%), 27 (23.1%), 21 (17.9%), and 18 (15.4%) had osteoporosis, sarcopenia, vertebral fracture, and osteosarcopenia, respectively. Multivariate analysis identified sarcopenia as a significant, independent risk factor associated with osteoporosis in all and female patients [odds ratio (OR) = 4.126, P = 0.018; OR = 6.510, P = 0.001, respectively], and vice versa (OR = 3.420, P = 0.040; OR = 4.012, P = 0.026, respectively). The skeletal muscle mass index and handgrip strength were significantly correlated with the BMD of the lumbar spine, femoral neck, and total hip (r = 0.46-0.59, P < 0.001). Patients with osteosarcopenia had significantly higher prevalence of vertebral fracture (10/18; 55.6%) than those without both osteoporosis and sarcopenia (5/75; 6.7%).

CONCLUSION

We demonstrated the prevalence of osteoporosis, sarcopenia, vertebral fracture, and osteosarcopenia in PBC, and noted that these complications interrelated closely with each other. Comprehensive assessment and treatment strategies for bone and muscle disorders are essential for PBC patients.

Bone Health in Patients With Liver Diseases

Osteoporosis is the most common bone disease in chronic liver disease (CLD) resulting in frequent fractures and leading to significant morbidity in this population. In addition to patients with cirrhosis and chronic cholestasis, patients with CLD from other etiologies may be affected in the absence of cirrhosis. The mechanism of osteoporosis in CLD varies according to etiology, but in cirrhosis and cholestatic liver disease it is driven primarily by decreased bone formation, which differs from the increased bone resorption seen in postmenopausal osteoporosis. Direct toxic effects from iron and alcohol play a role in hemochromatosis and alcoholic liver disease, respectively. Chronic inflammation also has been proposed to mediate bone disease in viral hepatitis and nonalcoholic fatty liver disease. Treatment trials specific to osteoporosis in CLD are small, confined to primary biliary cholangitis and post-transplant patients, and have not consistently demonstrated a benefit in this population. As it stands, prevention of osteoporosis in CLD relies on the mitigation of risk factors such as smoking and alcohol use, treatment of underlying hypogonadism, and encouraging a healthy diet and weight-bearing exercise. The primary medical intervention for the treatment of osteoporosis in CLD remains bisphosphonates though a benefit in terms of fracture reduction has never been shown. This review outlines what is known regarding the pathogenesis of bone disease in CLD and summarizes current and emerging therapies.

Osteoporosis in Primary Biliary Cholangitis: Prevalence, Impact and Management Challenges

Primary biliary cholangitis (PBC) is a chronic, cholestatic condition associated with symptoms that directly impact the quality of life in those afflicted with the disease. In addition to pruritus and fatigue, patients with PBC may develop metabolic bone disease from reduced bone density, such as osteopenia and osteoporosis. Osteoporosis increases the risk of fractures, as well as morbidity and mortality. The prevalence of osteoporosis in PBC is expected to increase in conjunction with the rising prevalence of PBC as a whole. Timely diagnosis, prevention and management of osteoporosis are crucial in order to optimize the quality of life. There is a paucity of data evaluating the management of osteoporosis in PBC. The optimal timing for diagnosis and monitoring is not yet established and is guided by expert opinion. National guidelines recommend screening for osteoporosis at the time of diagnosis of PBC. Monitoring strategies are based on results of initial screening and individual risk factors for bone disease. Identifying reduced bone density is imperative to institute timely preventive and treatment strategies. However, treatment remains challenging as efficacious therapies are currently lacking. The data on treatment of osteoporosis in PBC are mostly extrapolated from postmenopausal osteoporosis literature. However, this data has not directly translated to useful treatment strategies for PBC-related osteoporosis, partly because of the different pathophysiological mechanisms of the two diseases. The lack of useful preventive measures and efficacious treatment strategies remains the largest pitfall that challenges the management of patients with PBC. In this review, we comprehensively outline the epidemiology, clinical implications and challenges, as well as management strategies of PBC-related osteoporosis.

Th17 cell frequency is associated with low bone mass in primary sclerosing cholangitis

BACKGROUND & AIMS

Osteoporotic fractures are a major cause of morbidity and reduced quality of life in patients with primary sclerosing cholangitis (PSC), a progressive bile duct disease of unknown origin. Although it is generally assumed that this pathology is a consequence of impaired calcium homeostasis and malabsorption, the cellular and molecular causes of PSC-associated osteoporosis are unknown.

METHODS

We determined bone mineral density by dual-X-ray absorptiometry and assessed bone microstructure by high-resolution peripheral quantitative computed tomography in patients with PSC. Laboratory markers of liver and bone metabolism were measured, and liver stiffness was assessed by FibroScan. We determined the frequency of Th17 cells by the ex vivo stimulation of peripheral blood mononuclear cells in a subgroup of 40 patients with PSC. To investigate the potential involvement of IL-17 in PSC-associated bone loss, we analyzed the skeletal phenotype of mice lacking Abcb4 and/or Il-17.

RESULTS

Unlike in patients with primary biliary cholangitis, bone loss in patients with PSC was not associated with disease duration or liver fibrosis. However, we observed a significant negative correlation between the bone resorption biomarker deoxypyridinoline and bone mineral density in the PSC cohort, indicating increased bone resorption. Importantly, the frequency of Th17 cells in peripheral blood was positively correlated with the urinary deoxypyridinoline level and negatively correlated with bone mass. We observed that Abcb4-deficient mice displayed a low-bone-mass phenotype, which was corrected by an additional Il-17 deficiency or anti-IL-17 treatment, whereas the liver pathology was unaffected.

CONCLUSIONS

Our findings demonstrate that an increased frequency of Th17 cells is associated with bone resorption in PSC. Whether antibody-based IL-17 blockade is beneficial against bone loss in patients with PSC should be addressed in future studies.

LAY SUMMARY

Primary sclerosing cholangitis (PSC) is a cholestatic liver disease characterized by progressive bile duct destruction. One serious complication of PSC is reduced bone mass resulting in increased fracture risk. Herein, we demonstrate that Th17 cells mediate bone loss in PSC by inducing bone resorption, which suggests that antibody-based IL-17 blockade might be beneficial for the treatment of bone loss in affected patients.

Primary biliary cholangitis and bone disease

Osteoporosis, characterized by compromised bone strength leading to fragility fractures, is a common event in patients with primary biliary cholangitis (PBC). Osteomalacia, defined by poor bone mineralization is very uncommon. The pathogenesis of osteoporosis is not well clarified, but it mainly results from low bone formation. Few reports have revealed increased bone resorption, particularly in end-stage disease. The prevalence of osteoporosis is about 35% in the most significant studies, and it depends on the diagnostic criteria and severity of liver damage. Osteoporosis is associated with age, postmenopausal status, duration of PBC and advanced histological stage. Bone densitometry is the common method for the diagnosis of osteoporosis and should be performed in all patients with PBC. Lateral X-rays of the dorsal and lumbar spine should also be carried out to disclose vertebral fractures. There is no specific treatment but bisphosphonates, especially alendronate and ibandronate, efficiently increases bone mass and prevents bone loss. Despite these positive effects on bone mass no clear results on decreasing the fracture rate have been demonstrated, probably because the low number of patients included in the trials. The potential value of new agents requires further evaluation.

Disease Duration and Stage Influence Bone Microstructure in Patients With Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is known to be a major risk factor for osteoporosis reflected by a reduction of bone mineral density (BMD). However, both the extent of the macro- and microstructural alterations of bone as well as the causative factors are unknown. We have retrospectively analyzed a total of 96 patients with PBC and 53 healthy controls matched for age, sex, and body mass index. In addition to dual-energy X-ray absorptiometry (DXA) measurements at the lumbar spine and hip, high-resolution peripheral quantitative computed tomography (HR-pQCT) was used to assess the geometric, volumetric, and microstructural changes of bone at the distal radius and tibia. Furthermore, serum analyses and measures of disease duration and stage including transient elastography were performed. Total, cortical, and trabecular volumetric BMD as well as geometric parameters were significantly reduced in PBC patients. Microstructural analysis revealed a significantly lower cortical thickness (p < 0.001) and bone volume per tissue volume (p < 0.001) in the radius and tibia but unchanged trabecular number in patients with PBC (radius: p = 0.42; tibia: p = 0.12). Multivariate regression models pointed out that disease duration and stage are the primary factors that are independently associated with bone loss in PBC. A subgroup analysis of patients with additional autoimmune hepatitis (AIH) revealed no significant changes in bone structure compared with PBC only. Taken together, PBC patients demonstrate severe alterations in bone microstructure that are positively associated with disease duration and stage. By applying HR-pQCT in the distal radius and tibia, a combined bone loss syndrome expressed by a predominant decrease in BMD and cortical thickness could be detected. © 2018 American Society for Bone and Mineral Research.

Osteoporosis in chronic liver disease

Osteoporosis is a frequent complication in patients with chronic liver disease, especially in end-stages and in chronic cholestasis, in addition to non-alcoholic fatty liver disease, haemochromatosis and alcoholism. Mechanisms underlying osteoporosis are poorly understood, but osteoporosis mainly results from low bone formation. In this setting, sclerostin, a key regulator of the Wnt/β-catenin signalling pathway which regulates bone formation, in addition to the effects of the retained substances of cholestasis such as bilirubin and bile acids on osteoblastic cells, may influence the decreased bone formation in chronic cholestasis. Similarly, the damaging effects of iron and alcohol on osteoblastic cells may partially explain bone disease in haemochromatosis and alcoholism. A role for proinflammatory cytokines has been proposed in different conditions. Increased bone resorption may occur in cholestatic women with advanced disease. Low vitamin D, poor nutrition and hypogonadism, may be contributing factors to the full picture of bone disorders in chronic liver disease.

Increased risk of osteoporosis in patients with primary biliary cirrhosis

BACKGROUND

We evaluated the risk of osteoporosis in patients with primary biliary cirrhosis (PBC) using a nationwide population-based dataset.

METHODS

In a cohort study of 986,713 individuals, we selected 2,493 PBC patients who were aged 18 years or older and had been diagnosed with PBC, based on the International Classification of Disease (ICD-9-CM) codes 571.6, during 20002010. The control cohort comprised 9,972 randomly selected, propensity matched patients (by age, gender, and index date), without PBC. Using this adjusted data, a possible association between PBC and the risk of developing osteoporosis was estimated using a Cox proportional hazard regression model.

RESULTS

During the follow-up period, osteoporosis was diagnosed in 150 (6.02%) patients in the PBC cohort and in 539 (5.41%) patients in the non-PBC cohort. After adjusting for covariates, osteoporosis risk was found to be 3.333 times greater in the PBC cohort than in the non-PBC cohort when measured over 6 years after PBC diagnosis. Stratification revealed that the use of ursodeoxycholic acid (UDCA) had no significance in decreasing the risk of osteoporosis when comparing the PBC cohorts with the non-PBC cohorts (P = 0.124). Additionally, osteoporosis risk was significantly higher in PBC patients with steroid use (aHR: 6.899 vs 3.333). Moreover, when comparing the PBC cohorts to the non-PBC cohorts, the non-cirrhotic patients were prone to osteoporosis at a younger age compared to those in the cirrhotic cohorts. We also found that the associated risk of fractures is only prominent for vertebral and wrist fractures in the PBC cohort compared to that in the non-PBC cohort.

CONCLUSION

A significant association exists between PBC and subsequent risk for osteoporosis. Therefore, PBC patients, particularly those treated with steroids, should be evaluated for subsequent risk of osteoporosis.