Bone disease after liver transplantation

A systematic review and meta-analysis on the incidence of osteoporosis and fractures after liver transplant

Following liver transplant (LT), osteoporosis is a severe complication that causes morbidity. However, the incidence and risk factors of osteoporosis and fractures have not been well described. Single-arm meta-analysis of studies reporting osteopenia, osteoporosis, and fractures post-LT was performed with meta-regression for study period. Dichotomous variables, continuous variables and time-to-event variables were pooled in odds ratio, weighted mean difference and hazard ratio, respectively. For risk factors with limited data, a systematic review of literature was conducted. There was a significant increase in both osteoporosis and fractures compared to non-LT patients. Osteopenia, osteoporosis and incident fractures were newly diagnosed in 34.53% (CI: 0.17-0.56, n = 301), 11.68% (CI: 0.05-0.24, n = 1251) and 20.40% (CI: 0.13-0.30, n = 4322) of LT patients, respectively. Female gender (P = 0.017) increased risks of osteoporosis but not older age and BMI. Older age, lower pre-LT bone mineral density (BMD), presence of bone disease pre-LT were significant risk factors for fractures but not female gender, post-menopausal state, BMI, smoking and alcohol. There is a high incidence of skeletal complications post-LT. Older age, lower pre-LT BMD and presence of bone disease pre-LT are significant risk factors that are associated with incident fractures physicians should be cognisant of in liver transplant recipients.

Management of Autoimmune Liver Diseases after Liver Transplantation

Autoimmune liver diseases are characterized by immune-mediated inflammation and eventual destruction of the hepatocytes and the biliary epithelial cells. They can progress to irreversible liver damage requiring liver transplantation. The post-liver transplant goals of treatment include improving the recipient’s survival, preventing liver graft-failure, and decreasing the recurrence of the disease. The keystone in post-liver transplant management for autoimmune liver diseases relies on identifying which would be the most appropriate immunosuppressive maintenance therapy. The combination of a steroid and a calcineurin inhibitor is the current immunosuppressive regimen of choice for autoimmune hepatitis. A gradual withdrawal of glucocorticoids is also recommended. On the other hand, ursodeoxycholic acid should be initiated soon after liver transplant to prevent recurrence and improve graft and patient survival in primary biliary cholangitis recipients. Unlike the previously mentioned autoimmune diseases, there are not immunosuppressive or disease-modifying agents available for patients with primary sclerosing cholangitis. However, colectomy and annual colonoscopy are key components during the post-liver transplant period.

Risk Factors and Management of Osteoporosis Post-Transplant

Bone and mineral disorders are common after organ transplantation. Osteoporosis post transplantation is associated with increased morbidity and mortality. Pathogenesis of bone disorders in this particular sub set of the population is complicated by multiple co-existing factors like preexisting bone disease, Vitamin D deficiency and parathyroid dysfunction. Risk factors include post-transplant immobilization, steroid usage, diabetes mellitus, low body mass index, older age, female sex, smoking, alcohol consumption and a sedentary lifestyle. Immunosuppressive medications post-transplant have a negative impact on outcomes, and further aggravate osteoporotic risk. Management is complex and challenging due to the sub-optimal sensitivity and specificity of non-invasive diagnostic tests, and the underutilization of bone biopsy. In this review, we summarize the prevalence, pathophysiology, diagnostic tests and management of osteoporosis in solid organ and hematopoietic stem cell transplant recipients.

Body composition, muscle strength, functional capacity, and physical disability risk in liver transplanted familial amyloidotic polyneuropathy patients

BACKGROUND

Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disease leading to sensory and motor polyneuropathies, and functional limitations. Liver transplantation is the only treatment for FAP, requiring medication that negatively affects bone and muscle metabolism. The aim of this study was to compare body composition, levels of specific strength, level of physical disability risk, and functional capacity of transplanted FAP patients (FAPTx) with a group of healthy individuals (CON).

METHODS

A group of patients with 48 FAPTx (28 men, 20 women) was compared with 24 CON individuals (14 men, 10 women). Body composition was assessed by dual-energy X-ray absorptiometry, and total skeletal muscle mass (TBSMM) and skeletal muscle index (SMI) were calculated. Handgrip strength was measured for both hands as was isometric strength of quadriceps. Muscle quality (MQ) was ascertained by the ratio of strength to muscle mass. Functional capacity was assessed by the six-minute walk test.

RESULTS

Patients with FAPTx had significantly lower functional capacity, weight, body mass index, total fat mass, TBSMM, SMI, lean mass, muscle strength, MQ, and bone mineral density.

CONCLUSION

Patients with FAPTx appear to be at particularly high risk of functional disability, suggesting an important role for an early and appropriately designed rehabilitation program.

Elevation of intact parathyroid hormone level is a risk factor for low bone mineral density in pretransplant patients with liver diseases

The purpose of this study was to investigate the frequency and risk factors for low bone mineral density (BMD) among patients awaiting liver transplantation. BMD of the lumbar spine (LS) and femoral neck (FN), measured by dual-energy X-ray absorptiometery (DEXA), were obtained in 64 pretransplant patients. We measured markers of bone metabolism including serum calcium, phosphorus, serum 25-hydroxyvitamin D (25-OH D), intact parathyroid hormone (iPTH), bone alkaline phosphatase (BAP), osteocalcin (OC), and urinary deoxypyridinoline/creatinine (DPD/Cr) ratio. Osteoporosis and osteopenia (low BMD) were observed in 36 patients (36/64, 56.2%), including 6 cases of osteoporosis (6/64, 9.3%) and 30 cases of osteopenia (30/64, 46.9%). Of all variables, cholestatic liver disease and elevated levels of iPTH were significantly associated with low BMD. Moreover, elevated iPTH level was identified as an independent risk factor for low BMD (P<.05, OR=1.017, 95% CI=1.001-1.032) by multivariate analysis. The median level of iPTH was increased to 55.6 pg/mL (range, 7.8-337 pg/mL) in the low BMD group, while the median level was 33 pg/mL (range, 3-162 pg/mL) in the normal BMD group (P<.05). This study revealed a high incidence of low BMD in the pretransplant patients with liver diseases. The elevated iPTH level was the predominant risk factor for low BMD. We suggest that both BMD and iPTH examinations be considered routine tests to identify the status of bone mass and bone metabolism among recipients prior to liver transplantation.

The Prevention of Bone Fractures After Liver Transplantation: Experience With Alendronate Treatment

OBJECTIVE

The aim of this study was to prevent fractures in the first postoperative year.

METHODS AND PATIENTS

We studied 59 patients (48 men, 11 women) aged 42.6+/-11.4 years, who underwent liver transplantation. All patients received oral alendronate 70 mg weekly and calcium 1 g and calcitriol 0.5 mug daily. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at the lumbar spine and proximal femur at baseline as well as at 6 and 12 months after transplantation for comparison with an historical control group (n=31). Spinal radiographs were obtained to assess vertebral fractures at the same time. Additionally, serum osteocalcin, serum parathyroid hormone (PTH), urinary deoxypyridinoline (DPD), and biochemical parameters were determined every 3 months.

RESULTS

At baseline, femoral total BMD of men was significantly greater than that of women (P<.05, .85+/-.1 vs .74+/-.1). A significant increase in BMD was observed at 12 months (P<.05), no patient developed a bone fracture. Comparison analysis of genders showed that there was a significant difference in favor of men (P<.05). The lumbar BMD, neck T-, and Z-scores were significantly higher among patients treated with alendronate than historical controls (P<.05). After 3 months, serum PTH was increased and serum osteocalcin and urinary DPD were reduced. No severe side effects from alendronate treatment were observed during the study.

CONCLUSION

A direct sign of the success of our study was no fracture observed during the first postoperative year. Alendronate should be considered for patients with low bone mass after liver transplantation.

Effects of alendronate on bone mineral density and bone metabolic markers in patients with liver transplantation

INTRODUCTION

The purpose of this study was to evaluate the effects of alendronate (ALN) on bone mineral density (BMD) and bone turnover markers in patients with orthotopic liver transplantation (OLT).

METHODS

In the prospective, controlled, open study with 24 months of follow-up, 98 patients with OLT were randomised to receive ALN 70 mg weekly or no ALN; calcium (Ca) 1,000 mg daily and 0.5 mcg calcitriol daily were provided to all patients. Lumbar spine (LS) and hip BMDs were measured at 6-month intervals by dual-energy X-ray absorptiometry (DEXA). Spinal radiographs were obtained to assess vertebral fractures. Additionally, bone turnover markers, serum parathyroid hormone (PTH) and biochemical parameters were determined every 3 months.

RESULTS

Compared with the control group, the ALN group showed significant increases in BMD of the LS (5.1+/-3.9% vs 0.4+/-4.2%, p<0.05 at 12 months, 8.9+/-5.7% vs 1.4+/-4.9%, p<0.05 at 24 months), femoral neck (4.3+/-3.8% vs -1.1+/-3.1%, p<0.05 at 12 months, 8.7+/-4.8% vs 0.6+/-4.5%, p<0.05 at 24 months) and total femur (3.6+/-3.8% vs -0.6+/-4.0%, p<0.05 at 12 months, 6.2+/-3.8% vs 0.3+/-4.6%, p<0.05 at 24 months). In the ALN group, osteocalcin and urinary deoxypyridinoline (DPD) decreased significantly at the sixth month, with no further change, by -35.6% and -63.0%, on average, respectively (p<0.05). In the control group, a significant increase in biochemical markers of bone turnover was observed in comparison to baseline values (p<0.05). PTH increased within reference levels without a difference between groups. Two nonvertebral fractures (4.2%) and nine vertebral fractures (18.8%) in the control group and three vertebral fractures (6.8%) in the ALN group occurred during the follow-up. The weekly ALN was well tolerated, and no severe side effects occurred.

CONCLUSION

This is the first randomised study including a control group to demonstrate that weekly ALN was able to significantly increase BMD in patients with OLT when compared with Ca and calcitriol alone. However, ALN did not appear to offer protection against fractures.

The safety and outcome of joint replacement surgery in liver transplant recipients

A small group of patients may require total hip arthroplasty, total knee arthroplasty, or other joint replacement surgery after OLT for osteoporotic fractures, osteonecrosis, and osteoarthritis. Although arthroplasty is safe in the general population, its safety in liver transplant recipients is unclear. The aim of the study was to determine the safety and outcome of joint replacement surgery in our liver transplant recipients. A retrospective analysis was performed on all liver transplant recipients who had total joint arthroplasty at a single teaching institution between 1986 and 2002. Data regarding major intraoperative and postoperative complications was obtained from the medical charts and a hospital-based computer system. Of over 1,200 liver transplant recipients, we identified 7 patients who underwent 12 total arthroplasties (8 knee, 3 hip, 1 ankle). Joint replacements were performed electively for osteonecrosis (5 of 12) and osteoarthritis (5 of 12), whereas two hip arthroplasties were performed emergently for fractures. All patients with osteonecrosis or hip fracture had been treated with prolonged corticosteroids. There were no deaths or major complications in the intraoperative and postoperative periods. On long-term follow-up, no patients have had pain, dislocation, or infection in the postsurgical joint. No joint revision surgery has been required. In conclusion, a small number of stable liver transplant recipients at our institution underwent joint replacement surgery without major short-term or long-term complications. Our study suggests that joint replacement surgery may be safely and successfully performed in this population, although larger, randomized, prospective trials are needed to confirm our findings.

Predominant factors associated with bone loss in liver transplant patients - after prolonged post-transplantation period

INTRODUCTION

Osteoporosis is a major cause of morbidity in liver transplant recipients and is associated with multiple factors.

OBJECTIVES

To evaluate bone mineral density (BMD), bone turnover and calcium-regulating hormones in 29 patients (17 men, 12 women) 2-12 yrs following liver transplantation for non-alcoholic liver diseases.

RESULTS

Fifteen patients (52%) were on immunosuppressive treatment with tacrolimus and 14 (48%) with cyclosporine. Eleven patients (38%) were currently on prednisone, 18 patients (62%) had stopped glucocorticoid treatment 6 months to 11 yrs prior to the study. Nineteen patients (65.5%) had decreased BMD according to WHO criteria, 17 (58.2%) at the femoral neck, 13 (44.8%) at the lumbar spine. Nineteen patients (65.5%) had a subnormal (<15 ng/mL) serum level of 25 (OH) D3. These patients had significantly lower BMD at the femoral neck (p = 0.02). Femoral neck BMD negatively correlated with serum parathyroid hormone level (p = 0.06, r = -0.35), length of the post-transplantation period (p = 0.025, r = -0.416) and duration of glucocorticoid treatment (p = 0.029, r = -0.406), regardless of its cumulative dose. Symptomatic fractures were less frequent in tacrolimus treated patients than in cyclosporine users (p = 0.03).

CONCLUSIONS

Decreased BMD is frequent following liver transplantation and is affected by vitamin D deficiency, cyclosporine use, and the duration of glucocorticoid therapy, but not by its cumulative dose. Achievement and maintenance of optimal vitamin D status and shortening of glucocorticoid treatment period may have a favorable effect on bone preservation.