Impact of cystic fibrosis on bone health

Bisphosphonates for osteoporosis in people with cystic fibrosis

BACKGROUND

Osteoporosis is a disorder of bone mineralisation occurring in about one third of adults with cystic fibrosis. Bisphosphonates can increase bone mineral density and decrease the risk of new fractures in post-menopausal women and people receiving long-term oral corticosteroids. This is an updated version of a previous review.

OBJECTIVES

To assess the effects of bisphosphonates on the frequency of fractures, bone mineral density, quality of life, adverse events, trial withdrawals, and survival in people with cystic fibrosis.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register of references (identified from electronic database searches and hand searches of journals and abstract books) on 5 May 2022. We performed additional searches of PubMed, clinicaltrials.gov and the WHO ICTRP (International Clinical Trials Registry Platform) on 5 May 2022.

SELECTION CRITERIA

Randomised controlled trials of at least six months duration studying bisphosphonates in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Authors independently selected trials, extracted data and assessed risk of bias in included studies. Trial investigators were contacted to obtain missing data. We judged the certainty of the evidence using GRADE.

MAIN RESULTS

We included nine trials with a total of 385 participants (272 adults and 113 children (aged five to 18 years)). Trial durations ranged from six months to two years. Only two of the studies were considered to have a low risk of bias for all the domains.  Bisphosphonates compared to control in people with cystic fibrosis who have not had a lung transplant Seven trials included only adult participants without lung transplants, one trial included both adults and children without lung transplantation (total of 238 adults and 113 children). We analysed adults (n = 238) and children (n = 113) separately. Adults Three trials assessed intravenous bisphosphonates (one assessed pamidronate and two assessed zoledronate) and five trials assessed oral bisphosphonates (one assessed risedronate and four assessed alendronate). Bisphosphonates were compared to either placebo or calcium (with or without additional vitamin D). Data showed no difference between treatment or control groups in new vertebral fractures at 12 months (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.02 to 2.09; 5 trials, 142 participants; very low-certainty evidence) and two trials (44 participants) reported no vertebral fractures at 24 months. There was no difference in non-vertebral fractures at 12 months (OR 2.11, 95% CI 0.18 to 25.35; 4 trials, 95 participants; very low-certainty evidence) and again two trials (44 participants) reported no non-vertebral fractures at 24 months. There was no difference in total fractures between groups at 12 months (OR 0.57, 95% CI 0.13 to 2.50; 5 trials, 142 participants) and no fractures were reported in two trials (44 participants) at 24 months. At 12 months, bisphosphonates may increase bone mineral density at the lumbar spine (mean difference (MD) 6.31, 95% CI 5.39 to 7.22; 6 trials, 171 participants; low-certainty evidence) and at the hip or femur (MD 4.41, 95% 3.44 to 5.37; 5 trials, 155 participants; low-certainty evidence). There was no clear difference in quality of life scores at 12 months (1 trial, 47 participants; low-certainty evidence), but bisphosphonates probably led to more adverse events (bone pain) at 12 months (OR 8.49, 95% CI 3.20 to 22.56; 7 trials, 206 participants; moderate-certainty evidence). Children The single trial in 113 children compared oral alendronate to placebo. We graded all evidence as low certainty. At 12 months we found no difference between treatment and placebo in new vertebral fractures (OR 0.32, 95% CI 0.03 to 3.13; 1 trial, 113 participants) and non-vertebral fractures (OR 0.19, 95% CI 0.01 to 4.04; 1 trial, 113 participants). There was also no difference in total fractures (OR 0.18, 95% CI 0.02 to 1.61; 1 trial, 113 participants). Bisphosphonates may increase bone mineral density at the lumbar spine at 12 months (MD 14.50, 95% CI 12.91 to 16.09). There was no difference in bone or muscle pain (MD 3.00, 95% CI 0.12 to 75.22), fever (MD 3.00, 95% CI 0.12 to 75.22) or gastrointestinal adverse events (OR 0.67, 95% CI 0.20 to 2.26). The trial did not measure bone mineral density at the hip/femur or report on quality of life.  Bisphosphonates compared to control in people with cystic fibrosis who have had a lung transplant One trial of 34 adults who had undergone lung transplantation compared intravenous pamidronate to no bisphosphonate treatment. It did not report at 12 months and we report the 24-month data (not assessed by GRADE). There was no difference in the number of fractures, either vertebral or non-vertebral. However, bone mineral density increased with treatment at the lumbar spine (MD 6.20, 95% CI 4.28 to 8.12) and femur (MD 7.90, 95% CI 5.78 to 10.02). No participants in either group reported either bone pain or fever. The trial did not measure quality of life.

AUTHORS' CONCLUSIONS

Oral and intravenous bisphosphonates may increase bone mineral density in people with cystic fibrosis, but there are insufficient data to determine whether treatment reduces fractures. Severe bone pain and flu-like symptoms may occur with intravenous bisphosphonates. Before any firm conclusions can be drawn, trials in larger populations, including children, and of longer duration are needed to determine effects on fracture rate and survival. Additional trials are needed to determine if bone pain is more common or severe (or both) with the more potent zoledronate and if corticosteroids can ameliorate or prevent these adverse events. Future trials should also assess gastrointestinal adverse effects associated with oral bisphosphonates.

Secondary Osteoporosis and Metabolic Bone Diseases

Fragility fracture is a worldwide problem and a main cause of disability and impaired quality of life. It is primarily caused by osteoporosis, characterized by impaired bone quantity and or quality. Proper diagnosis of osteoporosis is essential for prevention of fragility fractures. Osteoporosis can be primary in postmenopausal women because of estrogen deficiency. Secondary forms of osteoporosis are not uncommon in both men and women. Most systemic illnesses and organ dysfunction can lead to osteoporosis. The kidney plays a crucial role in maintaining physiological bone homeostasis by controlling minerals, electrolytes, acid-base, vitamin D and parathyroid function. Chronic kidney disease with its uremic milieu disturbs this balance, leading to renal osteodystrophy. Diabetes mellitus represents the most common secondary cause of osteoporosis. Thyroid and parathyroid disorders can dysregulate the osteoblast/osteoclast functions. Gastrointestinal disorders, malnutrition and malabsorption can result in mineral and vitamin D deficiencies and bone loss. Patients with chronic liver disease have a higher risk of fracture due to hepatic osteodystrophy. Proinflammatory cytokines in infectious, autoimmune, and hematological disorders can stimulate osteoclastogenesis, leading to osteoporosis. Moreover, drug-induced osteoporosis is not uncommon. In this review, we focus on causes, pathogenesis, and management of secondary osteoporosis.

Brazilian Guidelines for Nutrition in Cystic Fibrosis

OBJECTIVE

To develop a scientific consensus on nutrition in cystic fibrosis.

METHODS

Sixteen coordinators elaborated relevant questions on nutritional therapy in cystic fibrosis, which were divided into six sections: nutritional assessment, nutritional recommendations, nutritional intervention, dietary counseling, special situations and enzyme replacement, and gastrointestinal manifestations. Two to three specialists in the field were responsible for each section and obtaining answers formulated based on standardized bibliographic searches. The available literature was searched in the PubMed®/MEDLINE database, after training and standardization of search strategies, to write the best level of evidence for the questions elaborated. Issues related to disagreement were discussed until a consensus was reached among specialists, based on the current scientific literature.

RESULTS

Forty-two questions were prepared and objectively answered, resulting in a consensus of nutritional therapy in cystic fibrosis.

CONCLUSION

This work enabled establishing a scientific consensus for nutritional treatment of cystic fibrosis patients.

Re-imagining cystic fibrosis care: next generation thinking

Cystic fibrosis (CF) is a common multi-system genetically inherited condition, predominately found in individuals of Caucasian decent. Since the identification of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene in 1989, and the subsequent improvement in understanding of CF pathophysiology, significant increases in life-expectancy have followed. Initially this was related to improvements in the management and systems of care for treating the various affected organ systems. These cornerstone treatments are still essential for CF patients born today. However, over the last decade, the major advance has been in therapies that target the resultant genetic defect: the dysfunctional CFTR protein. Small molecule agents that target this dysfunctional protein via a variety of mechanisms have led to lung function improvements, reductions in pulmonary exacerbation rates and increases in weight and quality-of-life indices. As more patients receive these agents earlier and earlier in life, it is likely that general CF care will increasingly pivot around these specific therapies, although it is also likely that effects other than those identified in the initial trials will be discovered and need to be managed. Despite great excitement for modulator therapies, they are unlikely to be suitable or available for all; whether this is due to a lack of availability for specific CFTR mutations, drug-reactions or the health economic set-up in certain countries. Nevertheless, the CF community must be applauded for its ongoing focus on research and development for this life-limiting disease. With time, personalised individualised therapy would ideally be the mainstay of CF care.

ClC-3 chloride channels are involved in estradiol regulation of bone formation by MC3T3-E1 osteoblasts

Evidence has been reported by us and others supporting the important roles of chloride channels in a number of osteoblast cell functions. The ClC-3 chloride channel is activated by estradiol binding to estrogen receptor alpha on the cell membranes of osteoblasts. However, the functions of these chloride channels in estrogen regulation of osteoblast metabolism remain unclear. In the present study, the roles of chloride channels in estrogen regulation of osteoblasts were investigated in the osteoblastic cell line MC3T3-E1. Estrogen 17β-estradiol enhanced collagen I protein expression, alkaline phosphatase activity, and mineralization were inhibited, by chloride channel blockers. Estradiol promoted ClC-3 chloride channel protein expression. Silencing of ClC-3 chloride channel expression prevented the elevation of osteodifferentiation in osteoblasts, which were regulated by estrogen. These data suggest that estrogen can regulate bone formation by activating ClC-3 chloride channels and the activation of ClC-3 chloride channels can enhance the osteodifferentiation in osteoblasts.

Vitamin D status correlates with the markers of cystic fibrosis-related pulmonary disease

BACKGROUND

The prevalence of Vitamin D deficiency remains high in cystic fibrosis despite daily supplementation. Vitamin D as an immunomodulator has been related to lower respiratory tract infections in children. The present study was undertaken to examine the association between vitamin D status and markers of cystic fibrosis-related pulmonary disease including exacerbations, bacterial colonization and pulmonary function.

METHODS

The study includes review of records of 51 cystic fibrosis patients. Baseline patient variables and serum vitamin D levels were recorded. Based on vitamin D levels study patients were divided into three groups: vitamin-D sufficient (≥20 ng/mL), vitamin-D insufficient (12 to 20 ng/mL), and vitamin D-deficient (≤12 ng/ml).

RESULTS

The proportion of children with deficient, insufficient and sufficient vitamin D levels were 47.1%, 15.7%, and 37.2%, respectively. Female sex, bacterial colonization and a greater number of exacerbations were associated with highest odds of developing vitamin D deficiency in patients with CF with 1.77 (0.22-4.61) (p = 0.002), 2.9(0.57-14.82) (p = 0.011), and 5.12 (1.28-20.50) (p = 0.021) respectively. The comparison of vitamin-D levels taken during exacerbations, colonization and during routine follow-up were significant [16.04 (7.42-27.91), 24.3 (15.5-32.4) and 48.54 (18.37-78.7) ng/ml, p < 0.001]. The FEV1 was determined in 24 patients; the comparison was significant between vitamin D-deficient and -sufficient groups [0.75 (0.717-0.777) vs. 0.82 (0.74-0.92) p < 0.05].

CONCLUSION

We concluded that vitamin D deficiency was highly prevalent in children with CF, despite daily supplementation of the vitamin in diet. Further, vitamin D deficiency was associated with a higher rate of pulmonary exacerbations and higher incidence of pulmonary bacterial colonization. In addition, in younger patients, low vitamin D levels were associated with reduced pulmonary function.

Overexpression of RANKL in osteoblasts: a possible mechanism of susceptibility to bone disease in cystic fibrosis

Bone fragility and loss are a significant cause of morbidity in patients with cystic fibrosis (CF), and the lack of effective therapeutic options means that treatment is more often palliative rather than curative. A deeper understanding of the pathogenesis of CF-related bone disease (CFBD) is necessary to develop new therapies. Defective CF transmembrane conductance regulator (CFTR) protein and chronic inflammation in bone are important components of the CFBD development. The receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG) drive the regulation of bone turnover. To investigate their roles in CFBD, we evaluated the involvement of defective CFTR in their production level in CF primary human osteoblasts with and without inflammatory stimulation, in the presence or not of pharmacological correctors of the CFTR. No major difference in cell ultrastructure was noted between cultured CF and non-CF osteoblasts, but a delayed bone matrix mineralization was observed in CF osteoblasts. Strikingly, resting CF osteoblasts exhibited strong production of RANKL protein, which was highly localized at the cell membrane and was enhanced in TNF (TNF-α) or IL-17-stimulated conditions. Under TNF stimulation, a defective response in OPG production was observed in CF osteoblasts in contrast to the elevated OPG production of non-CF osteoblasts, leading to an elevated RANKL-to-OPG protein ratio in CF osteoblasts. Pharmacological inhibition of CFTR chloride channel conductance in non-CF osteoblasts replicated both the decreased OPG production and the enhanced RANKL-to-OPG ratio. Interestingly, using CFTR correctors such as C18, we significantly reduced the production of RANKL by CF osteoblasts, in both resting and TNF-stimulated conditions. In conclusion, the overexpression of RANKL and high membranous RANKL localization in osteoblasts are related to defective CFTR, and may worsen bone resorption, leading to bone loss in patients with CF. Targeting osteoblasts with CFTR correctors may represent an effective strategy to treat CFBD. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Physiotherapy for cystic fibrosis in Australia and New Zealand: A clinical practice guideline

Physiotherapy management is a key element of care for people with cystic fibrosis (CF) throughout the lifespan. Although considerable evidence exists to support physiotherapy management of CF, there is documented variation in practice. The aim of this guideline is to optimize the physiotherapy management of people with CF in Australia and New Zealand. A systematic review of the literature in key areas of physiotherapy practice for CF was undertaken. Recommendations were formulated based on National Health and Medical Research Council (Australia) guidelines and considered the quality, quantity and level of the evidence; the consistency of the body of evidence; the likely clinical impact; and applicability to physiotherapy practice in Australia and New Zealand. A total of 30 recommendations were made for airway clearance therapy, inhalation therapy, exercise assessment and training, musculoskeletal management, management of urinary incontinence, managing the newly diagnosed patient with CF, delivery of non-invasive ventilation, and physiotherapy management before and after lung transplantation. These recommendations can be used to underpin the provision of evidence-based physiotherapy care to people with CF in Australia and New Zealand.

Bone disease in cystic fibrosis: new pathogenic insights opening novel therapies

Mutations within the gene encoding for the chloride ion channel cystic fibrosis transmembrane conductance regulator (CFTR) results in cystic fibrosis (CF), the most common lethal autosomal recessive genetic disease that causes a number of long-term health problems, as the bone disease. Osteoporosis and increased vertebral fracture risk associated with CF disease are becoming more important as the life expectancy of patients continues to improve. The etiology of low bone density is multifactorial, most probably a combination of inadequate peak bone mass during puberty and increased bone losses in adults. Body mass index, male sex, advanced pulmonary disease, malnutrition and chronic therapies are established additional risk factors for CF-related bone disease (CFBD). Consistently, recent evidence has confirmed that CFTR plays a major role in the osteoprotegerin (OPG) and COX-2 metabolite prostaglandin E2 (PGE2) production, two key regulators in the bone formation and regeneration. Several others mechanisms were also recognized from animal and cell models contributing to malfunctions of osteoblast (cell that form bone) and indirectly of bone-resorpting osteoclasts. Understanding such mechanisms is crucial for the development of therapies in CFBD. Innovative therapeutic approaches using CFTR modulators such as C18 have recently shown in vitro capacity to enhance PGE2 production and normalized the RANKL-to-OPG ratio in human osteoblasts bearing the mutation F508del-CFTR and therefore potential clinical utility in CFBD. This review focuses on the recently identified pathogenic mechanisms leading to CFBD and potential future therapies for treating CFBD.

ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with cystic fibrosis

BACKGROUND

Malnutrition is both a frequent feature and a comorbidity of cystic fibrosis (CF), with nutritional status strongly associated with pulmonary function and survival. Nutritional management is therefore standard of care in CF patients. ESPEN, ESPGHAN and ECFS recommended guidelines to cover nutritional management of patients with CF.

METHODS

The guidelines were developed by an international multidisciplinary working group in accordance with officially accepted standards. The GRADE system was used for determining grades of evidence and strength of recommendation. Statements were discussed, submitted to Delphi rounds, reviewed by ESPGHAN and ECFS and accepted in an online survey among ESPEN members.

RESULTS

The Working Group recommends that initiation of nutritional management should begin as early as possible after diagnosis, with subsequent regular follow up and patient/family education. Exclusive breast feeding is recommended but if not possible a regular formula is to be used. Energy intake should be adapted to achieve normal weight and height for age. When indicated, pancreatic enzyme and fat soluble vitamin treatment should be introduced early and monitored regularly. Pancreatic sufficient patients should have an annual assessment including fecal pancreatic elastase measurement. Sodium supplementation is recommended and a urinary sodium:creatinine ratio should be measured, corresponding to the fractional excretion of sodium. If iron deficiency is suspected, the underlying inflammation should be addressed. Glucose tolerance testing should be introduced at 10 years of age. Bone mineral density examination should be performed from age 8-10 years. Oral nutritional supplements followed by polymeric enteral tube feeding are recommended when growth or nutritional status is impaired. Zinc supplementation may be considered according to the clinical situation. Further studies are required before essential fatty acids, anti-osteoporotic agents, growth hormone, appetite stimulants and probiotics can be recommended.

CONCLUSION

Nutritional care and support should be an integral part of management of CF. Obtaining a normal growth pattern in children and maintaining an adequate nutritional status in adults are major goals of multidisciplinary cystic fibrosis centers.

Evaluation of factors related to bone disease in Polish children and adolescents with cystic fibrosis

PURPOSE

The aim of the study was to evaluate factors related to bone formation and resorption in Polish children and adolescents with cystic fibrosis and to examine the effect of nutritional status, biochemical parameters and clinical status on bone mineral density.

MATERIALS AND METHODS

The study group consisted of 100 children and adolescents with cystic fibrosis with a mean age 13.4 years old. Anthropometric measurements, included body height, body mass and body mass index (BMI); bone mineral densitometry and biochemical testing were performed. Bone mineral density was measured using a dual-energy X-ray absorption densitometer. Biochemical tests included serum calcium, phosphorus, parathyroid hormone and vitamin D concentrations, as well as 24-h urine calcium and phosphorus excretion. Pulmonary function was evaluated using FEV1%, and clinical status was estimated using the Shwachman-Kulczycki score.

RESULTS

Standardized body height, body mass and BMI were significantly lower than in the reference population. Mean serum vitamin D concentration was decreased. Pulmonary disease was generally mild, with a mean FEV1% of 81%. Multivariate linear regression revealed that the only factors that had a significant effect on bone marrow density were BMI and FEV1%. There were no significant correlations between bone mineral density and the results of any of the biochemical tests performed.

CONCLUSIONS

Nutritional status and bone mineral density were significantly decreased in children and adolescents with cystic fibrosis. In spite of abnormalities in biochemical testing, the factors that were found to have the strongest effect on bone mineral density were standardized BMI and clinical status.

A randomized controlled trial of vitamin D replacement strategies in pediatric CF patients

BACKGROUND

Vitamin D insufficiency is common in children with cystic fibrosis (CF), yet data are sparse regarding the most effective form of vitamin D supplementation. The aim of this study was to compare two different vitamin D replacement regimens.

METHODS

We conducted a randomized controlled trial comparing 50,000 IU of ergocalciferol (vitamin D2) twice weekly for 8 weeks versus 50,000 IU of cholecalciferol (vitamin D3) weekly in patients with CF, pancreatic insufficiency, age 6-21 years and a 25(OH)D<30 ng/mL. The primary outcome was change in serum 25(OH)D concentration. For secondary analyses, we examined changes in IgG, IgE and CRP in patients who normalized their vitamin D levels.

RESULTS

A total of 47 patients completed the trial. The mean pre-treatment 25(OH)D concentration was 23.1 (SD 4.7) ng/mL. The overall mean increase in 25(OH)D was 11.1 (11.9) ng/mL and 31/47 (66%) achieved a 25(OH)D concentration ≥ 30 ng/mL; of the 26 participants who received D2, 18 (69%) achieved sufficiency while 13/21 (62%) participants treated with D3 achieved sufficiency. There was no difference between groups in change of 25(OH)D (p=0.65). Similarly, there was no difference in the number of patients to achieve vitamin D sufficiency between treatments (p=0.6).

CONCLUSIONS

Ergocalciferol administered as 50,000 IU twice weekly is as effective as cholecalciferol 50,000 IU weekly for 8 weeks in pediatric patients with CF and vitamin D insufficiency. Only 66% of the patients studied achieved the desired 25(OH)D concentration.

Quantitative bone ultrasound at the distal radius in adults with cystic fibrosis

It is of clinical importance to identify bone disease related to cystic fibrosis (CF) early in its course to allow therapeutic interventions that optimize bone health. To test the technical (precision) and clinical (percentage of abnormal results, correlation with clinical parameters) performance of a commercial quantitative ultrasound apparatus for radial measurements, speed of sound (SOS) was measured at the distal third of the left radius with the Omnisense 7000p apparatus (Sunlight Medical, Tel-Aviv, Israel) in a group of young adult CF patients with regular follow-up at the Brussels and Ghent University Hospital. Sixty-three (37 males) CF patients at a median (range) age of 23.5 y (18.1-39.9) were included. SOS, SOS z-score and SOS t-score were respectively 4017 ± 97 m/s, -0.31 ± 0.74 and -0.60 ± 0.78 in males and 4086 ± 97 m/s, -0.19 ± 0.75 and -0.51 ± 0.95 in females. Mean SOS t-score was significantly lower compared with the manufacturer's reference data for males (p < 0.0001) and females (p = 0.01). SOS z- and t-scores correlated with weight z-score and body mass index z-score in females. No significant correlation was found between SOS and forced expiratory volume in 1 s (%). Neither diabetes mellitus nor liver disease was found to influence SOS. Radial quantitative ultrasound has a precision of 0.55%. The SOS is in the low normal range in 14% of CF patients and is influenced by weight in female patients, but not by the severity of the lung disease.

Vitamin D status in children with cystic fibrosis. Associations with inflammation and bacterial colonization

RATIONALE

Patients with cystic fibrosis (CF) have high rates of vitamin D insufficiency. The relation between vitamin D status and inflammation in patients with CF is poorly understood.

OBJECTIVES

To determine the prevalence of vitamin D deficiency and insufficiency in a young CF population and to examine correlations between vitamin D status, disease severity, and inflammatory markers.

METHODS

This was a retrospective chart review of patients with CF under the age of 12 years. Serum laboratory parameters, growth indices, pancreatic status, CFTR genetics, medications, microbiology, and presence of CF-related comorbidities were collected for patients who had fat-soluble vitamin levels measured between January 1, 2009 and December 31, 2011. Vitamin D deficiency was defined as a serum 25(OH)D less than 20 ng/ml and insufficiency as serum 25(OH)D 20 to 29.9 ng/ml. Associations between serum vitamin D concentration and clinical/inflammatory markers were assessed using Chi-square and t tests.

MEASUREMENTS AND MAIN RESULTS

Data were collected for 148 children. The mean serum 25(OH)D concentration was 32.4 ng/ml (SD, 8.9). Seven percent (10 of 148) were vitamin D deficient, and 36% (53 of 148) were vitamin D insufficient. Among the pancreatic-sufficient patients, 50% (14 of 28) were vitamin D insufficient/deficient, whereas among pancreatic-insufficient patients, 41% (49 of 120) were vitamin D insufficient/deficient. Pseudomonas aeruginosa was a more common pathogen in the patients who were vitamin D insufficient/deficient (18 of 63 vs. 11 of 85, P = 0.018). There was no difference between vitamin D-sufficient versus -insufficient groups in terms of other bacterial colonization or inflammatory markers.

CONCLUSIONS

Overall, vitamin D insufficiency is common among young children with CF. Vitamin D insufficiency is prevalent even in children who are pancreatic sufficient. In this population, vitamin D insufficiency is associated with a history of Pseudomonas colonization but not with classic markers of systemic inflammation.

Bisphosphonates for osteoporosis in people with cystic fibrosis

BACKGROUND

Osteoporosis is a bone mineralisation disorder occurring in about one third of adults with cystic fibrosis. Bisphosphonates can increase bone mineral density and decrease the risk of new fractures in post-menopausal women and people receiving long-term oral corticosteroids.

OBJECTIVES

To assess the effects of bisphosphonates on the frequency of fractures, bone mineral density, quality of life, adverse events, trial withdrawals, and survival in people with cystic fibrosis.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group Trials Register of references (identified from electronic database searches and handsearches of journals and abstract books) on 13 January 2014.Additional searches of PubMed were performed on 13 January 2014.

SELECTION CRITERIA

Randomised controlled trials of at least six months duration studying bisphosphonates in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials and extracted data. Trial investigators were contacted to obtain missing data.

MAIN RESULTS

Nine trials were identified and seven (with a total of 237 adult participants) were included.Data were combined (when available) from six included studies in participants without a lung transplant. Data showed that there was no significant reduction in fractures between treatment and control groups at 12 months, odds ratio 0.72 (95% confidence interval 0.13 to 3.80). No fractures were reported in studies with follow-up at 24 months. However, in patients taking bisphosphonates after six months the percentage change in bone mineral density increased at the lumbar spine, mean difference 4.61 (95% confidence interval 3.90 to 5.32) and at the hip or femur, mean difference 3.35 (95% confidence interval 1.63 to 5.07); but did not significantly change at the distal forearm, mean difference -0.49 (95% confidence interval -2.42 to 1.45). In patients taking bisphosphonates, at 12 months the percentage change in bone mineral density increased at the lumbar spine, mean difference 6.10 (95% confidence interval 5.10 to 7.10) and at the hip or femur, mean difference 4.35 (95% confidence interval 2.99 to 5.70). At 24 months, in patients treated with bisphosphonates the percentage change in bone mineral density also increased at the lumbar spine, mean difference 5.49 (95% confidence interval 4.38 to 6.60) and at the hip or femur, mean difference 6.05 (95% confidence interval 3.74 to 8.36). There was clinical heterogeneity between studies and not all studies reported all outcomes. Bone pain was the most common adverse event with intravenous agents. Flu-like symptoms were also increased in those taking bisphosphonates.In participants with a lung transplant (one study), intravenous pamidronate did not change the number of new fractures. At axial sites, bone mineral density increased with treatment compared to controls: percentage change in bone mineral density at lumbar spine, mean difference 6.20 (95% confidence interval 4.28 to 8.12); and femur mean difference 7.90 (95% confidence interval 5.78 to 10.02).

AUTHORS' CONCLUSIONS

Oral and intravenous bisphosphonates increase bone mineral density in people with cystic fibrosis. Severe bone pain and flu-like symptoms may occur with intravenous agents. Additional trials are needed to determine if bone pain is more common or severe (or both) with the more potent zoledronate and if corticosteroids ameliorate or prevent these adverse events. Additional trials are also required to further assess gastrointestinal adverse effects associated with oral bisphosphonates. Trials in larger populations are needed to determine effects on fracture rate and survival.

Bone turnover markers, osteoprotegerin and RANKL cytokines in children with cystic fibrosis

PURPOSE

Some scientific studies show decreased bone mineral density and increased fracture frequency in adult patients with cystic fibrosis (CF). The mechanism for early bone loss in CF patients are multifactorial: chronic pulmonary inflammation, malnutrition, reduced physical activity, delayed pubertal maturation. The aim of this study was to assess bone metabolism markers with special attention paid to osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) balance in CF children.

MATERIAL AND METHODS

The study included 35 children with diagnosed CF and 35 healthy controls aged 5-9 years (median 7.0 years). Serum levels of fat soluble vitamins were measured by chemiluminescence (vitamin D) and HPLC (vitamins A, E) methods. Concentrations of bone metabolism markers were determined by immunoenzymatic assay.

RESULTS

Mean levels of fat soluble vitamins (A, D, E) were lower in patients with CF compared to controls. In CF children we observed a significant (p<0.01) decrease in concentration of bone formation marker (osteocalcin) and similar bone resorption markers (CTX, TRACP5b) in comparison with healthy children. The serum level of OPG was significantly lower (p<0.05) and RANKL nearly 2-fold higher in patients with CF than in the healthy ones. The ratio of OPG to RANKL was about 2-fold lower in children with CF compared to healthy peers (p<0.01).

CONCLUSION

In CF children, an imbalance between bone formation and resorption processes occurs. An increase serum RANKL concentration coexisting with lower levels of OPG may be associated with intensification of bone resorption.

Quantitative Ultrasound in Spanish Children and Young Adults With Cystic Fibrosis

We studied the relationship between bone density and cystic fibrosis in Spanish children and young adults. We measured the phalangeal bone amplitude-dependent speed of sound (Ad-SoS) in 35 patients with cystic fibrosis and in 30 healthy controls matched for gender, age, and body mass index (BMI). Participants were subjects with normal levels of 25(OH) Vitamin D. We found no difference in Ad-SoS between patients and controls. The only difference between the groups was that the patients had a significantly higher daily caloric intake than the controls ( p < .05) as a result of the patient group's greater intake of fats ( p < .05). There was a positive correlation between Ad-SoS and weight ( p < .0001), but after adjusting for potential confounding factors such as age, the correlation was lost. The percentage of ideal weight did not differ between the two groups. We conclude that well-nourished CF patients had similar Ad-SoS to controls.

Bisphosphonates for osteoporosis in people with cystic fibrosis

BACKGROUND

Osteoporosis is a bone mineralisation disorder occurring in about one third of adults with cystic fibrosis. Bisphosphonates can increase bone mineral density and decrease the risk of new fractures in post-menopausal women and people receiving long-term oral corticosteroids.

OBJECTIVES

To assess the effects of bisphosphonates on the frequency of fractures, bone mineral density, quality of life, adverse events, trial withdrawals, and survival in people with cystic fibrosis.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group Trials Register of references (identified from electronic database searches and handsearches of journals and abstract books) on 15 February 2012.Additional searches of PubMed were performed on 14 May 2011.

SELECTION CRITERIA

Randomised controlled trials of at least six months duration studying bisphosphonates in people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials and extracted data. Trial investigators were contacted to obtain missing data.

MAIN RESULTS

Nine trials were identified and seven (with a total of 237 adult participants) were included.Data were combined (when available) from six included studies in participants without a lung transplant. Data showed that there was no significant reduction in fractures between treatment and control groups at 12 months, odds ratio 0.72 (95% confidence interval 0.13 to 3.80). No fractures were reported in studies with follow-up at 24 months. However, in patients taking bisphosphonates after six months the percentage change in bone mineral density increased at the lumbar spine, mean difference 4.61 (95% confidence interval 3.90 to 5.32) and at the hip or femur, mean difference 3.35 (95% confidence interval 1.63 to 5.07); but did not significantly change at the distal forearm, mean difference -0.49 (95% confidence interval -2.42 to 1.45). In patients taking bisphosphonates, at 12 months the percentage change in bone mineral density increased at the lumbar spine, mean difference 6.10 (95% confidence interval 5.10 to 7.10) and at the hip or femur, mean difference 4.35 (95% confidence interval 2.99 to 5.70). At 24 months, in patients treated with bisphosphonates the percentage change in bone mineral density also increased at the lumbar spine, mean difference 5.49 (95% confidence interval 4.38 to 6.60) and at the hip or femur, mean difference 6.05 (95% confidence interval 3.74 to 8.36). There was clinical heterogeneity between studies and not all studies reported all outcomes. Bone pain was the most common adverse event with intravenous agents. Flu-like symptoms were also increased in those taking bisphosphonates.In participants with a lung transplant (one study), intravenous pamidronate did not change the number of new fractures. At axial sites, bone mineral density increased with treatment compared to controls: percentage change in bone mineral density at lumbar spine, mean difference 6.20 (95% confidence interval 4.28 to 8.12); and femur mean difference 7.90 (95% confidence interval 5.78 to 10.02).

AUTHORS' CONCLUSIONS

Oral and intravenous bisphosphonates increase bone mineral density in people with cystic fibrosis. Severe bone pain and flu-like symptoms may occur with intravenous agents. Additional trials are needed to determine if bone pain is more common or severe (or both) with the more potent zoledronate and if corticosteroids ameliorate or prevent these adverse events. Additional trials are also required to further assess gastrointestinal adverse effects associated with oral bisphosphonates. Trials in larger populations are needed to determine effects on fracture rate and survival.