Bone status of children with hemophilia A assessed with quantitative ultrasound sonography (QUS) and dual energy X-ray absorptiometry (DXA)

Analysis of the current status and characteristics of osteoporosis in adult hemophilia patients based on high-resolution peripheral quantitative computed tomography: a case control study

BACKGROUND

Current research on osteoporosis (OP) in hemophilia is insufficient. The suitability of high-resolution peripheral quantitative computed tomography (HR-pQCT) for evaluating osteoporosis in hemophilia remains unclear.

AIM

To investigate the current status of osteoporosis and the applicability of HR-pQCT in adult hemophilia patients.

METHODS

Thirty three hemophilia patients aged 23-49 years were recruited. X-ray examinations were performed on the bleeding joints. Dual energy X-ray absorptiometry (DXA) and HR-pQCT were used to assess bone mineral density (BMD). The HR-pQCT values of the distal tibia and radius were compared between hemophilia patients and healthy controls(HCs).

RESULTS

All bleeding joints showed local osteoporosis on X-ray. Only 33.3% of patients had a hip BMD lower than the expected value according to DXA. The Tb.vBMD(98.5 ± 44.2 mg/cm3), Tt.Ar(612.5 ± 163.5mm2),Tb.Ar(487.0 ± 175.6mm2), Ct.Ar(117.0 ± 25.7mm2), Tb.BV/TV(0.2 ± 0.1), Tb.N(0.9 ± 0.3 1/mm), Ct.Pm(96.3 ± 13.8 mm) of the distal tibia and Tt.Ar(248.4 ± 53.1mm2),Tb.Ar(186.0 ± 55.1mm2), Ct.Ar(66.1 ± 14.4 mm2), Ct.Pm(68.1 ± 7.1 mm) of the distal radius in the hemophilia group was significantly lower than the HCs(tibia Tb.vBMD:186.4 ± 44.3mg/cm3, Tt.Ar:906.8 ± 135.0mm2,Tb.Ar:743.7 ± 137.6mm2, Ct.Ar:169.3 ± 21.9mm2,Tb.

BV/TV

0.3 ± 0.1, Tb.N:1.5 ± 0.2 1/mm,Ct.Pm:117.8 ± 8.2 mm; radius Tt.Ar:285.7 ± 35.6 mm2, Tb.Ar:83.8 ± 7.9mm2, Ct.Ar:0.3 ± 0.1mm2, Ct.Pm:80.2 ± 4.3 mm) with statistically significant differences (p < 0.05). Correlation analysis showed a positive correlation (r = 0.768, p = 0.016) between femoral neck BMD with DXA and total volumetric BMD(Tt.vBMD) at the distal tibia.

CONCLUSION

The bone health status of adult hemophilia patients in China is worrying. The occurrence of OP may be accompanied by varying degrees of bone loss, bone destruction, and structural abnormalities observed in both trabecular and cortical bones of the upper and lower limbs. The condition of the trabecular bones in the lower limbs is particularly severe. The correlation between BMD measurements obtained from HR-pQCT and DXA is strong.

Diminished cortical bone density of long bones among children with haemophilic arthropathy

INTRODUCTION

Children with haemophilia (CwH) have lower bone mineral density in the spine (trabecular bone) than healthy children. There are few studies focusing on bone mineral density in long bones (cortical bone).

AIM

To evaluate bi-laterally the distal third of radius and midshaft tibias using quantitative ultrasound (QUS) and assess the speed of sound (SoS).

METHODS

A cross-sectional study where 91 CwH and 91 age-matched healthy boys were included. Joint evaluation was determined with the Haemophilia Joint Health Score 2.1 and SoS values. The Z scores were measured with the Sunlight Omnisense 8000 S equipment.

RESULTS

Ninety-one CwH (haemophilia A) were evaluated (26 mild form, 26 moderate, and 39 severe). Most patients were treated with on-demand factor replacement and had higher total HJHS scores according to severity (4.8, 14.8 and 14.1, respectively). Patients with moderate and severe disease showed a statistical difference in SoS values for both radius and tibias compared to controls. QUS Z-scores ≥-2 were more frequent in radius and tibias in CwH, but were statistically significant only in tibias when compared to controls (in 30% mild, 46% moderate, 28% severe, respectively).

CONCLUSIONS

There was diminished cortical bone density in radius and tibias of CwH compared to healthy controls. Changes predominated in tibias, more frequently affected according to the severity of haemophilia. Early intervention with factor replacement combined with physical activity are key aspects to promote bone health.

Comparison of quantitative ultrasonography and dual X-ray absorptiometry for bone status assessment in South African children living with HIV

Children living with HIV (CLHIV) have decreased bone mineral content (BMC) and density (BMD), increasing risk for fracture and future osteoporosis. While DXA is the gold-standard for bone assessments, it lacks availability in resource-constrained settings (RCS). Quantitative ultrasound (QUS) offers an alternative owing to its portability, low cost, ease of handling, and lack of ionizing radiation. While QUS has detected reduced bone quality in CLHIV, the relationship between QUS and DXA in this population remains unexplored. At baseline and 12 months, BMC and BMD of the whole body, lumbar spine, and radius were measured by DXA in a longitudinal cohort of CLHIV in Johannesburg, South Africa. Calcaneal speed of sound (SOS) and broadband ultrasound attenuation (BUA) and radius SOS were obtained by QUS, and calcaneal stiffness index (SI) was calculated. Spearman correlations, with and without HIV stratification, were performed between QUS and DXA measurements at each visit and for absolute difference in measurements between visits. At baseline and 12-months, calcaneal BUA and SI displayed strong positive correlations with DXA, with only modest correlations between radial QUS and DXA at baseline. Longitudinal measures of QUS did not correlate with DXA. At both baseline and 12-months, individuals with DXA whole-body BMD z-score < -1 displayed significantly lower calcaneal BUA and SI. Cross-sectionally, calcaneal QUS correlates strongly with whole body DXA and may represent a viable diagnostic alternative in RCS. Longitudinally, the two methods do not correlate well, possibly reflecting that each method assesses distinct aspects of bone architecture.

Bone health in haemophilia carriers and persons with von Willebrand disease: A large database analysis

INTRODUCTION

Persons with haemophilia(PWH) have been shown to have low bone mineral density likely the result of prolonged immobility, recurrent hemarthrosis, decreased weight bearing, lower physical activity level and obesity. Bone health has been poorly characterized in haemophilia carriers (HC) and persons with von Willebrand disease (PWvWD).

AIM

To estimate the prevalence of osteoporosis, osteoarthritis and bone fractures in HC and PWvWD and identify risk factors for poor bone health.

METHODS

This is a retrospective study using a population level, commercial database - Explorys (IBM Watson Health, Cleveland, USA). We compared prevalence rates of osteoporosis, osteoarthritis and fractures among cases (HC or PWvWD) and controls (general population without an underlying bleeding disorder) from 1999 to 2020. Prevalence of common risk factors for poor bone health were compared among cases and controls.

RESULTS

Among 72,917,850 active persons in the database, we identified 940 women with the diagnosis of HC and 19,580 PWvWD. Among HC and PWvWD, prevalence of osteoporosis, osteoarthritis and fractures were significantly higher in cases, when compared to controls. In HC, the prevalence of vitamin D deficiency, obesity, hypothyroidism, smoking, diabetes mellitus, hypocalcaemia, corticosteroid use, malignancy, renal failure and Nonsteroidal anti-inflammatory drugs (NSAID) use were significantly higher among the cases. In PWvWD, the prevalence of risk factors was significantly higher in cases when compared to controls.

CONCLUSION

The prevalence of osteoporosis, osteoarthritis and fractures is significantly higher among HC and PWvWD. This data highlights the importance of screening patients for risk factors for poor bone health and provide education to prevent these complications.

Osteoporosis management and falls prevention in patients with haemophilia: Review of haemophilia guidelines

INTRODUCTION

Patients with haemophilia (PWH) have a high prevalence of osteoporosis, falls and fractures at all ages. The role of haemophilia itself may contribute to low bone mineral density (BMD) due to coagulation factor deficiency. Guidelines for the management of osteoporosis, fracture and fall risk may help to reduce fracture and fall risk, and delay osteoporosis onset.

AIM

We aim to review current haemophilia guidelines regarding osteoporosis prevention, screening, diagnosis and management, and fall prevention.

METHOD

A database search (Ovid MEDLINE) revealed two haemophilia guidelines (World and British) published within the last ten years. Local Australian haemophilia guidelines were identified through a manual search.

RESULTS

All haemophilia guidelines were found to contain inadequate recommendations for osteoporosis management and fall prevention due to a lack of evidence in the literature.

CONCLUSION

Further studies are required to assess the trajectory of bone health in PWH, the mechanism of bone loss in PWH, and the effectiveness of weight-bearing exercises, interventions for fall prevention, screening programmes, and use of anti-osteoporosis medications in PWH across the lifecourse.

Low Bone Mineral Density in Hemophiliacs

Objective

To review the current knowledge on bone health in patients with hemophilia A and the underlying pathogenetic mechanisms.

Data Sources

Original research articles, meta-analyses, and scientific reviews.

Data Synthesis

Already in childhood, patients with hemophilia A are prone to low bone mineral density, leading to osteopenia and/or osteoporosis. Initially associated with the life style of hemophilia, today we are faced with accumulating evidence that coagulation factor VIII is involved directly or indirectly in bone physiology.

Conclusion

Understanding the role of factor VIII and the mechanisms of decreased bone mineral density in hemophilia A is critically important, especially as non-factor replacement therapies are available, and treatment decisions potentially impact bone health.

Prevalence of Bone Density Reduction and Its Related Factors in Hemophilia Patients in South Khorasan Province in 2018

Background:

The present study aimed to determine the prevalence of bone density reduction and its associated factors in hemophilia patients in South Khorasan Province in 2018.

Materials and Methods:

This case-control study was conducted on all patients with hemophilia type A with medical records in Hemophilia center in South Khorasan province. A number of 57 eligible subjects who met the criteria were selected based on census method. Thereafter, 60 non-hemophilic individuals who were similar to hemophilic patients in terms of age and body mass index were selected by convenience sampling method. DXA device was used to measure bone mineral density (BMD) in two locations of femoral neck and lumbar vertebrae. Data were analyzed in SPSS software (version 19), using Chi-square, Fisher’s exact test, and independent t-test. A P-value less than 0.05 was considered statistically significant.

Results:

The prevalence rate of bone density reduction in spine bone in hemophilia patients was measured at 31.6% and 13.3% in non-hemophilia subjects (P=0.02); moreover, this rate in hip bone was reported as 7% and 5%, respectively (P=0.65). Relative frequency of bone density reduction in the spine and hip bone was not significantly different among hemophilia patients based on age, severity of hemophilia, vitamin D, hepatitis and smoking (P>0.05). However, a significant difference was detected in terms of body mass index (P<0.05).

Conclusion:

Based on the obtained results, the prevalence of bone density reduction in hemophilic patients was significantly higher, as compared to that of non-hemophilia patients. This necessitates the implementation of drastic preventive measures, prompt diagnosis, timely treatment, and appropriate therapeutic measures.

"Which skeletal imaging modality is best for assessing bone health in children and young adults compared to DXA? A systematic review and meta-analysis"

BACKGROUND

Skeletal imaging techniques have become clinically valuable methods for measuring and assessing bone mineral density in children and young people. Dual-energy X-ray absorptiometry (DXA) is the current reference standard for evaluating bone density, as recommended by the International Society for Clinical Densitometry (ISCD). Various bone imaging modalities, such as quantitative ultrasound (QUS), peripheral quantitative computed tomography (pQCT), high-resolution peripheral quantitative computed tomography (HR-pQCT), magnetic resonance imaging (MRI), and digital X-ray radiogrammetry (DXR) have been developed to further quantify bone health in children and adults. The purpose of this review, with meta-analysis, was to systematically research the literature to compare the various imaging methods and identify the best modality for assessing bone status in healthy papulations and children and young people with chronic disease (up to 18 years).

METHODS

A systematic computerized search of Medline, PubMed, and Web of Science databases was conducted to identify English-only studies published between 1st January 1990 and 1st December 2019. In this review, clinical studies comparing imaging modalities with DXA were chosen according to the inclusion criteria. The risk of bias and quality of articles was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2). The meta-analysis to estimate the overall correlation was performed using a Fisher Z transformation of the correlation coefficient. Additionally, the diagnostic accuracy measures of different imaging methods compared with DXA were calculated.

RESULTS

The initial search strategy identified 13,412 papers, 29 of which matched the inclusion and exclusion criteria. Of these, twenty-two papers were included in the meta-analysis. DXA was compared to QUS in 17 papers, to DXR in 7 and to pQCT in 4 papers. A single paper compared DXA, DXR, and pQCT. The meta-analysis demonstrated that the strongest correlation was between DXR and DXA, with a coefficient of 0.71 [95%CI: 0.43; 1.00, p-value < 0.001], while the correlation coefficients between QUS and DXA, and pQCT and DXA were 0.57 [95%CI: 0.25; 0.90, p-value < 0.001] and 0.57 [95%CI: 0.46; 0.67, p-value < 0.001], respectively. The overall sensitivity and specificity were statistically significant 0.71 and 0.80, respectively.

CONCLUSION

No current imaging modality provides a full evaluation of bone health in children and young adults, with each method having some limitations. Compared to QUS and pQCT, DXR achieved the strongest positive relationship with DXA. DXR should be further evaluated as a reliable method for assessing bone health and as a predictor of fractures in children and young people.

FVIII at the crossroad of coagulation, bone and immune biology: Emerging evidence of biological activities beyond hemostasis

Hemophilia A is an X-linked hereditary disorder that results from deficient coagulation factor VIII (FVIII) activity, leading to spontaneous bleeding episodes, particularly in joints and muscles. FVIII deficiency has been associated with altered bone remodeling, dysregulated macrophage polarization, and inflammatory processes that are associated with the neoformation of abnormal blood vessels. Treatment based on FVIII replacement can lead to the development of inhibitors that render FVIII concentrate infusion ineffective. In this context, hemophilia has entered a new therapeutic era with the development of new drugs, such as emicizumab, that seek to restore the hemostatic balance by bypassing pathologically acquired antibodies. We discuss the potential extrahemostatic functions of FVIII that may be crucial for defining future therapies in hemophilia.

Effect of low-dose factor VIII prophylaxis therapy on bone mineral density and 25(OH) vitamin D level in children with severe haemophilia A

BACKGROUND

Decreased bone mineral density (BMD) is a significant morbidity in haemophilia. Vitamin D is important for the bone health of people with haemophilia. Regular factor VIII prophylaxis can prevent bleeding and arthropathy.

AIM

To determine the 25(OH) vitamin D level in severe haemophilia A patients and correlate it to their Hemophilia Joint Health Score (HJHS) and dual-energy X-ray absorptiometry (DEXA). We also compared the 25(OH) vitamin D and DEXA in haemophilia A and healthy children and in haemophilia A children on prophylaxis versus on-demand therapy.

METHODS

Fifty severe haemophilia A patients were compared to 50 age-matched healthy boys. Patients were recruited from the Pediatric Hematology Clinic, Ain Shams University from May 2017 to April 2018. Full medical history was taken with emphasis on frequency of bleeding episodes, duration and amplitude of pain assessed by the pain score. Weight, height, body mass index and HJHS were assessed. 25(OH) vit-D3, calcium, phosphorus and alkaline phosphatase were measured. BMD was assessed using Lunar DEXA, paediatric software.

RESULTS

People with haemophilia had significantly lower 25(OH) vit-D3 (P < .001) and DEXA z-score (P < .001) than controls. Seventy per cent of patients were on factor VIII prophylaxis twice weekly (15U/kg/dose). Significant difference was found regarding DEXA z-score (P = .012), 25(OH) vit-D3 (P = .033) and HJHS (P = .022) among patients on prophylaxis and on-demand therapy.

CONCLUSION

Severe haemophilia A patients showed significantly lower 25(OH) vit-D3 and DEXA than controls. Hence, vitamin D deficiency should be tested in all people with haemophilia for early diagnosis and treatment. Low-dose prophylaxis in severe haemophilia preserves BMD and increases vitamin D. Further studies are required to evaluate the effect of different prophylaxis protocols on BMD and haemophilic arthropathy.

Evaluation of bone mineralization in former preterm born children: Phalangeal quantitative ultrasound cannot replace dual-energy X-ray absorptiometry

Background

Preterm infants are at risk of impaired bone health in later life. Dual-energy X-ray absorptiometry-scan (DXA) is the gold standard to determine bone mineralization. Phalangeal quantitative ultrasound (pQUS) is an alternative technique that is inexpensive, easy to use and radiation-free. The aim of this study was to investigate whether both techniques reveal equivalent results.

Materials and methods

Sixty former preterm infants (31 boys; 29 girls) received a DXA and pQUS at age 9 to 10 years. DXA measured bone mineral content (BMC) and bone mineral density (BMD) for total body and lumbar spine (L1-4), while pQUS measured the amplitude dependent speed of sound (AD-SoS) and bone transit time (BTT) at metacarpals II-IV providing continuous values and Z-scores based on age and sex. Four statistical methods evaluated the association between both techniques: Pearson's correlation coefficients, partial correlation coefficients adjusted for gestational age, height and BMI, Bland-Altman analysis and cross tabulation.

Results

Both techniques showed a statistically significant weak correlation for continuous values as well as Z-scores (0.291–0.462, p < 0.05). Boys had significant and relatively high correlations (0.468–0.585, p < 0.05). In comparison, the correlations for girls were not significant. Correlation coefficients further decreased while calculating the partial correlations. The Bland-Altman plots showed poor agreement. Sensitivity ranged from 33% to 92% and specificity from 16% to 68%. Positive and negative predictive values ranged from 4% to 38% and 82% to 97%, respectively.

Conclusions

We found statistically significant weak correlations and poor agreement between DXA and pQUS measurements. DXA is not equivalent to pQUS and therefore not replaceable by this technique in former preterm born children at the age of 9 to 10 years.

•

DXA is the golden standard to determine bone mineralization, while Quantitative ultrasound is a radiation-free alternative.

•

Four statistical tests were used to investigate the equivalence of both methods.

•

Comparison of results of 60 preterm born children at age 9 to 10 years found poor agreement between both methods.

•

There was a discrepancy in differentiating the same children with normal or reduced bone mineralization.

•

Quantitative ultrasound cannot replace the DXA scan for determination of bone mineralization in preterm born children.

The role of sclerostin/dickkopf-1 and receptor activator of nuclear factor kB ligand/osteoprotegerin signalling pathways in the development of osteoporosis in patients with haemophilia A and B: A cross-sectional study

AIM

Haemophilia A and B are associated with reduced bone mineral density (BMD). The aim of this study was to assess circulating sclerostin and dickkopf-1 (Dkk-1), (inhibitors of osteoblastic differentiation), as well as the receptor activator of nuclear factor kB ligand (RANKL)/osteoprotegerin (OPG) system (the major regulator of osteoclastogenesis), in patients with haemophilia (PWH), their possible correlations with clinical risk factors and the effect of ibandronate on these markers.

METHODS

Eighty-nine male PWH (mean age 45.9 ± 15.3 years) and 30 age-matched healthy male controls participated. BMD was assessed by DXA. Sclerostin, Dkk-1, RANKL and OPG were measured in serum of patients, controls, as well as in ten patients receiving oral ibandronate (150 mg/mo), at baseline and after 12 months.

RESULTS

Patients with haemophilia had lower circulating sclerostin (median ± IQR: 47.4 ± 26.93 vs 250 ± 250 pmol/L, P < .001), Dkk-1 (21.24 ± 17.18 vs 26.16 ± 15.32pg/mL, P = .04) and higher levels of RANKL (0.23 ± 0.03 vs 0.04 ± 0.03 pmol/L, P = .001), RANKL/OPG ratio (0.063 ± 0.25 vs 0.005 ± 0.11, P = .001) compared with controls. Patients with low BMD had higher OPG concentrations compared to those with normal BMD. Sclerostin and RANKL/OPG correlated positively with BMD. Patients with severe haemophilia had lower sclerostin concentrations compared with those with mild or moderate disease. The degree of arthropathy negatively correlated with sclerostin and Dkk-1 levels. PWH who received ibandronate showed a decrease in serum Dkk-1 without any significant effect on sclerostin and RANKL/OPG.

CONCLUSIONS

Patients with haemophilia present increased osteoclastic activity coupled with compensatory increased osteoblastic activity. Ibandronate did not affect RANKL/OPG ratio, but it decreased Dkk-1.

Quantitative Ultrasound (QUS) in the Management of Osteoporosis and Assessment of Fracture Risk

The use of quantitative ultrasound (QUS) for a variety of skeletal sites, associated with the absence of technology-specific guidelines, has created uncertainty with respect to the application of QUS results to the management of individual patients in clinical practice. However, when prospectively validated (this is not the case for all QUS devices and skeletal sites), QUS is a proven, low-cost, and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurements of bone mineral density (BMD) for the assessment of fracture risk. Indeed, the clinical use of QUS to identify subjects at low or high risk of osteoporotic fracture should be considered when central DXA is unavailable. Furthermore, the use of QUS in conjunction with clinical risk factors (CRF),allows for the identification of subjects who have a low and high probability of osteoporotic fracture. Device- and parameter-specific thresholds should be developed and cross-validated to confirm the concurrent use of QUS and CRF for the institution of pharmacological therapy and monitoring therapy.

Serological biomarkers detect active joint destruction and inflammation in patients with haemophilic arthropathy

INTRODUCTION

Progressive arthropathy caused by recurrent joint bleeds is a severe complication in haemophilia.

AIM

We investigated whether biomarkers of cartilage and bone degradation, and inflammation were altered in haemophilia patients and whether these biomarkers could identify haemophilia patients with arthropathy.

METHODS

Serum from 35 haemophilia patients with varying degrees of arthropathy and 43 age- and gender-matched control subjects were analysed. Biomarkers of cartilage degradation (C2M, COMP, CTX-II, ADAMTS5), cartilage formation (PRO-C2), bone formation (PINP), bone resorption (CTX-I) and inflammation (hsCRP, CRPM) were measured by ELISA. Arthropathy was assessed by radiological evaluation (Pettersson score) and physical examination (Gilbert score).

RESULTS

In patients with haemophilia, cartilage degradation, measured by C2M, CTX-II and COMP, was increased by 25% (P < 0.05) compared with control subjects. Levels of the cartilage degradation enzyme, ADAMTS5, were 10% lower in haemophilia patients (P < 0.05). Bone formation (PINP) was reduced by 25% (P < 0.05) in haemophilia patients, whereas bone resorption (CTX-I) was increased by 30% (P < 0.001). Acute inflammation (hsCRP) was increased by 50% (P < 0.01), whereas chronic inflammation (CRPM) was decreased by 25% (P < 0.0001). The hsCRP/CRPM ratio was 60% higher (P < 0.001) in haemophilia patients relative to control subjects. A biomarker panel combining C2M, CRPM, and ADAMTS5 could distinguish haemophilia patients from control subjects with 85.3% accuracy (P < 0.0001). We found no strong correlation between biomarkers and radiological and physical examination of the joint.

CONCLUSION

Biomarkers detect increased cartilage and bone degradation, and altered inflammatory activity in haemophilia patients with arthropathy. These biomarkers could potentially be used to identify patients with progressing joint disease.

Haemophilia A and B as a cause for secondary osteoporosis and increased fracture risk

Despite the increasing evidence regarding its association with low bone mineral density (BMD) both in adults and children, haemophilia A or B has not yet been considered among the classic causes of secondary osteoporosis. Although the exact mechanisms are not fully elucidated, physical inactivity and vitamin D deficiency seem to play a fundamental role for such an association. Viral infections and arthropathy further compromise bone mass. Except for low BMD, patients with haemophilia seem to be at increased risk for fracture and falls. The FRAX tool may be of value in this population, for the estimation of fracture risk. Regular exercise, prophylactic factor replacement therapy in severe haemophilia, fall prevention strategies and optimization of calcium and vitamin D intake are recommended. In any case, individualized multidisciplinary approach and careful assessment and management of fracture risk are recommended.

Bone status measured by quantitative ultrasound: a comparison with DXA in Thai children

BACKGROUND/OBJECTIVES

Quantitative ultrasound (QUS) is used to measure bone quality and is known to be safe, radiation free and relatively inexpensive compared with dual-energy X-ray absorptiometry (DXA) that is considered the gold standard for bone status assessments. However, there is no consensus regarding the validity of QUS for measuring bone status. The aim of this study was to compare QUS and DXA in assessing bone status in Thai children.

SUBJECTS/METHODS

A total of 181 Thai children (90 boys and 91 girls) aged 6 to 12 years were recruited. Bone status was measured by two different techniques in terms of the speed of sound (SOS) using QUS and bone mineral density (BMD) using DXA. Calcium intake was assessed by 24 h diet recall. Pearson's correlation, κ-statistic and Bland and Altman analysis were used to assess the agreement between the methods.

RESULTS

There was no correlation between the two different techniques. Mean difference (s.d.) of the Z-scores of BMD and SOS was -0.61 (1.27) that was different from zero (P<0.05). Tertiles of Z-scores of BMD and QUS showed low agreement (κ 0.022, P=0.677) and the limits of agreement in Bland and Altman statistics were wide.

CONCLUSIONS

Although QUS is easy and convenient to use, the SOS measurements at the radius seem not appropriate for assessing bone quality status.

Bone mineral density in hemophilia patients

Patients with hemophilia suffer from low bone mineral density (BMD) due to several risk factors including arthropathy and resulting immobility. Recent studies have shown variable frequency of low BMD in this group of patients. This study attempts to assess the prevalence of low BMD (osteoporosis and osteopenia) and the associated risk factors in a group of Iranian hemophilia patients. Patients with moderate or severe hemophilia underwent BMD measurement by dual energy X-ray absorptiometry. The results were correlated with other variables including physical activity, calcium intake and demographic data. Forty two patients with the mean age of 31 years (range 18-72) completed the study. The prevalence of osteoporosis in the spine and the left femoral neck was 23.8 and 14.6 %, respectively, and osteopenia in the spine and femoral neck was seen in 45.2 and 31.7 % of the patients, respectively based on the WHO T-score criteria. We found only cigarette smoking to be significantly related to low BMD (P < 0.001). There were two cases of pathologic fracture at femoral neck and forearm (4.8 %). Low BMD is very common in patients with hemophilia. Appropriate assessment of BMD and control of predisposing factors such as prophylactic factor replacement (to prevent hemarthrosis) and cessation of cigarette smoking are warranted.

Measurement properties of radial and tibial speed of sound for screening bone fragility in 10- to 12-year-old boys and girls

The objective of this study was to analyze measurement properties of the radial and tibial speed of sound (SoS) evaluated by quantitative ultrasound (QUS) for screening bone fragility. Bone fragility was defined as low whole body less head bone mineral density (WBLH BMD) measured by DXA (first tertile, 95% CI -1.1 to -0.9) and as past fractures evaluated by questionnaire. The sample included 319 nonobese boys and girls, ages 10-12 yr. All bone variables were standardized. The results revealed concordance coefficient correlations between WBLH BMD and radial and tibial SoS of 0.129 and 0.038, respectively. The regression lines between DXA and QUS variables were different from the identity lines. Cross-classification analysis by Kappa statistic showed that only 34% and 36% of the 113 participants categorized in the first tertile of WBLH BMD were also categorized in the first tertile of tibial and radial SoS, correspondingly. Logistic regression with gender and maturity adjustments demonstrates that radial SoS was the single significant variable in predicting OR for identifying participants with past fractures. In conclusion, the radial QUS revealed itself to be a valuable tool for screening bone fragility in youth of 10-12 yr, despite the absence of agreement with DXA WBLH BMD.

The clinical utility of bone turnover markers in the evaluation of bone disease in patients with haemophilia A and B

Haemophilia A and B have been associated with increased prevalence of low bone mineral density (BMD). However, the utility of bone turnover markers (BTM) remains unknown. The aim of this study was to evaluate bone metabolism in men with haemophilia and to investigate associations between BTM and bone disease. Serum N- (NTX-I), C-terminal telopeptide of type I collagen (CTX-I) and tartrate-resistant acid phosphatase band-5b (TRAP-5b), as bone resorption markers, and osteocalcin (OC) and bone-specific alkaline phosphatase (b-ALP), as bone formation markers, were assessed. Seventy men with haemophilia A (n = 59) or B (n = 11) were studied. Patients with low BMD had significantly higher b-ALP concentrations compared with those with normal BMD (12.8 ± 1.60 vs. 9.72 ± 0.58 μg/L, P = 0.009), without any differences in the other BTM. NTX-I and CTX-I concentrations were negatively associated with oestradiol levels and hip BMD and positively with human immunodeficiency virus infection, number of affected joints and arthropathy scores. B-ALP and OC concentrations were negatively associated with hip BMD, severity of haemophilia and fracture history, and positively with the number of affected joints and testosterone concentrations. After multivariate analysis, NTX-I levels remained negatively associated with oestradiol levels, whereas b-ALP concentrations negatively correlated with the level of physical activity and positively with the number of affected joints. Increased bone metabolism exists in men with haemophilia and low BMD. Increased b-ALP levels may identify patients at high risk for fracture. Increased number of target joints, low physical activity and low oestradiol concentrations are independently associated with increased bone metabolism.

Clinical management of older persons with haemophilia

Life expectancy for people with haemophilia (PWH) has improved and is now approaching that of the general population. The growing population of elderly PWH will therefore increasingly face the age-related morbidities such as cardiovascular diseases, malignant disease, liver disease, and bone and joint related diseases, as well as the lifestyle and psychosocial factors that accompany many of these conditions. For many PWH, frequent contact with haemophilia specialists within the comprehensive care centres supplants the relationship that individuals in the general population have with their general practitioners. As a result, there is a risk that elderly PWH may miss the chronic disease screening opportunities offered to the general population. This review focuses on the screening tests and examinations recommended for age-related comorbidities in the general population that may be applicable to the growing population of older people with haemophilia.

Bone health in persons with haemophilia: a review

Bone density is a measure of equilibrium between bone formation and bone resorption; any imbalance in these two processes might lead to osteopenia and osteoporosis. Osteoporosis in general has been considered to be an important cause of morbidity in both men and women and more so in haemophilia and other bleeding disorders. Specific triggering factors in persons with haemophilia (PWH) are abnormal liver function because of viral infection, bleeding and inflammation, lack of physical and athletic activities, low body weight and others. Although the pathogenesis of osteoporosis is not clear, it has been considered as a severe comorbidity in PWH in both developing and developed countries. This is more evident in developing countries where there is no free access to factor concentrates, and primary prophylaxis is beyond the reach of vast majority of the patients. Only few references are available in the literature on the prevalence and management of osteoporosis in haemophilia population. This review summarises the prevalence, plausible mechanisms and management options of this important morbidity in PWH.

Peripheral quantitative computed tomography (pQCT) reveals alterations in the three-dimensional bone structure in children with haemophilia

Children with haemophilia are at risk of suboptimal bone mass accrual and low bone mineral density (BMD). We recently demonstrated that although BMD in Finnish children with haemophilia was within the normal range, their whole body BMD was significantly lower and hypercalciuria more prevalent than in controls. This study sought to determine the bone structure and strength in physically active children with haemophilia. To investigate the underlying mechanisms in this group, we conducted a case-control study to assess bone structure and strength by peripheral quantitative computed tomography (pQCT) at the radius. The study group comprised 29 patients (mean age 12.2 years) and 46 age-matched controls. Children with haemophilia had decreased total BMD Z-score at the distal radius (P ≤ 0.001), but increased cortical bone density at the proximal radius (P ≤ 0.001). Total bone area at the proximal radius was significantly lower in children with haemophilia (P = 0.002), whereas there were no differences in cortical bone area or in polar Strength-Strain Index, a parameter of bone strength, between the patients and controls. Patients with mild to moderate haemophilia and on-demand treatment had inferior bone strength compared to those with moderate to severe haemophilia and prophylaxis. Our findings suggest altered skeletal development in patients with haemophilia in the radius, resulting in smaller bone size and higher cortical bone density. Importantly, bone strength at the radius appears equal to healthy children. Prophylactic treatment seems to have a beneficial effect on bone health.

Reduced bone mineral density in patients with haemophilia A and B in Northern Greece

Haemophilia A and B has been associated with increased prevalence of low bone mass (67-86%). The aim of this study was to estimate the prevalence of bone disease in haemophiliacs and its association with potential risk factors. Adult patients with haemophilia A and B followed-up in the Haemophilia Centre of Northern Greece were included. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) in lumbar spine (LS), femoral neck (FN), total hip (TH) and great trochanter (GT). One-hundred four male patients (aged 45.8 ± 15.1 years) and 50 controls (aged 44.9 ± 12.8 years) were screened. Low BMD was diagnosed in 28 patients (26.9%) and 10 controls (20%) (p=0.0001). Patients had lower BMD in TH (p=0.007), FN (p=0.029) and GT (p=0.008) than controls, without differences in LS. BMD was positively associated with the severity of haemophilia, history of herpes virus C or human immunodeficiency virus and level of physical activity, and negatively with the level of arthropathy. In multiple-regression analysis, only the level of physical activity and 25-hydroxyvitamin D [25(OH)D] significantly predicted BMD. Half of the patients had vitamin D deficiency. In conclusion, our study showed increased prevalence of low BMD in haemophiliacs. The levels of physical activity and 25(OH)D independently predicted low BMD.