Clinical Course of Factor VIII Inhibitors Developed after Exposure to a Pasteurised Dutch Concentrate Compared to Classic Inhibitors in Hemophilia A

After the introduction of a new pasteurised factor VIII concentrate (Factor VIII CPS-P) in The Netherlands in June 1990, an increase in the occurrence of inhibitors in hemophilia A patients was reported. The clinical course of this group of inhibitors (n = 12) was compared with hemophilia patients in whom an inhibitor developed before June 1990 (classic inhibitors) (n = 32). Striking differences were found between both groups not only in patient age (median 22 years versus 8 years) and number of exposure days (<50 − >1000 versus <50), as described in previous reports, but also in clinical course and response to treatment. In the recent group of inhibitors antibody titers showed a rapid decline when product was changed which was not the case in the group with classic inhibitors. In the group of classic inhibitors immune tolerance therapy with low dose factor VIII succeeded in 83%. Success was to a high degree dependent on the inhibitor level. In the group of recent inhibitors immune tolerance with the same concentrate was only successful in a single patient. However, once the patients were switched to another concentrate, antibody levels dropped to less than 2 BU/ml within 8 months in all patients.

It seems likely that in this group of product associated inhibitors, treatment success was due to elimination of antigen stimulation rather than induction of immune tolerance.

Risk of Hepatitis A in Dutch Hemophilia Patients

Recently, clotting factor preparations transmitted hepatitis A virus (HAV) to hemophilia patients. To study the risk of HAV infection in Dutch hemophilia patients, serum samples of 341 patients with hemophilia were tested for HAV antibodies (anti-HAV).

197/341 patients (group 1) were treated with clotting factor concentrates produced from large plasma pools, 144/341 patients (group 2) were treated with small pool cryoprecipitate. The test results were compared to those of healthy blood donors (n = 19,746) of the same age. In addition stored serum samples (1983-1994) from hemophilia patients were tested for HAV antibodies.

No increased risk of HAV infection was found in Dutch hemophilia patients. The anti-HAV prevalence in group 1 was 20%, in group 213% and in blood donors 41%. A significantly (p <0.002) lower percentage of HAV antibodies was found in hemophilia patients born in the 1950s using cryoprecipitate (11%) as compared to blood donors of the same age (40%), probably caused by passive administration of anti-HAV through clotting product. Passive immunization in the past was significantly (p <0.02) more often found in group 2 (41.7%) than in group 1 (28%).

In the period 1983 till 1988 five seroconversions were seen in group 1 (2%) and one in group 2 (0.7%). Anti-HAV seroconversions were not observed after 1988.

In a risk analysis we estimated that 2 plasma pools of 10,000 Dutch blood donors per year may contain HAV. The absence of HAV among Dutch hemophilia patients suggests that this contamination is successfully inactivated.

Clinical trials and registries in haemophilia: Opponents or collaborators? Comparison of PUP data derived from different data sources

INTRODUCTION

The "Guideline on the clinical investigation of recombinant and human plasma-derived factor VIII products" (ClinGL) provides the requirements for the performing of clinical trials (CTs) for marketing authorization in Europe. The number of eligible previously untreated patients (PUPs) for CTs might be difficult to meet because of the concurrent development of FVIII concentrates, and additional data sources must be explored.

AIM

The extent to which CTs and the PedNet registry met relevant parameters, identified in the ClinGL, as well as inhibitor incidences were investigated in patients from both sources.

METHODS

Anonymized data of eight CTs in 369 PUPs performed from 1987 to 2009 were compared with each other and with 632 PUPs (born 2000-2009) from PedNet.

RESULTS

Clinical trials in PUPs performed for marketing authorization were too heterogeneous in their investigated parameters; therefore, a comparison of single factor concentrates was not possible. Data collection in PedNet met relevant parameters required for PUPs in accordance with the ClinGL. The overall inhibitor incidences were comparable (CT = 30.9% vs PedNet = 30.6%) when only severe haemophilia A (HA) patients from both data sources were considered.

CONCLUSIONS

Previously performed CTs in PUPs were divergent, which prevented a direct comparison of outcomes. However, this study demonstrated that data from CTs and carefully designed registries may complement each other in the establishing of sufficient safety information for single products to improve clinical insights and support regulatory decisions.

Endogenous Clotting Factor Activity and Long-term Outcome in Patients with Moderate Haemophilia

In order to address the question of the optimum target level for prophylactic treatment of severe haemophilia patients, the association between endogenous clotting factor activity and outcome was studied in a cohort of 46 patients with moderate haemophilia. Data on treatment and outcome were collected annually.

Median follow-up was 8.0 years (range 1-26). Median joint bleed frequency was 1 per year and median radiological score according to Pettersson was 1 point (max. 78) at the age of 25 years. One percent increase in clotting factor level was associated with a 4 months later onset of joint bleeds (95% Confidence Interval (CI): 2-6 months) and a 16% lower Pettersson score (95% CI: 3-27%). No statistically significant effect of clotting factor activity on joint bleed frequency could be demonstrated.

These findings confirm that patients with moderate haemophilia experience only mild arthropathy, and provide evidence for a protective effect of higher clotting factor levels on joint damage.

Association between joint bleeds and pettersson scores in severe haemophilia

Purpose: To assess and quantify the association of haemophilic arthropathy, measured by the radiological Pettersson score, with the number of joint bleeds suffered by the patient.

Material and Methods: In order to quantify the effect of the cumulative number of joint bleeds on the Pettersson score, a study was performed using 295 Pettersson scores obtained in 117 patients with severe haemophilia. The patients were born between 1965 and 1994, and had no history of inhibitors. The number of joint bleeds was determined annually from the entry in the clinic and onwards. The localization of bleeds was not assessed. The patients entered the clinic at a median age of 3.6 years, and received intermediate dose prophylaxis, starting at a median age of 5.3 years. Evaluation of 1643 treatment years showed a mean of 6.8 joint bleeds/year. Pettersson scores were obtained at a mean age of 15.9 years (range 1.7–32.9) and had a median value of 4 points (range 0–50).

Results and Conclusion: The Pettersson scores began to rise after the age of 5 years and increased with one point for every 13 joint bleeds (95% confidence interval 11–15). No evidence was found of ‘autonomous’ progression of Pettersson scores, independent of bleeds.

Assessments of outcome in haemophilia - what is the added value of QoL tools?

INTRODUCTION

Access to treatment and especially to long-term regular replacement treatment with clotting factor concentrates (prophylaxis) have caused dramatic contrasts in the clinical picture between haemophilia populations. An individual patient with severe haemophilia age 20 years can have normal joints or can be severely crippled and unable to work. Assessment of outcome in a standardized way has therefore become essential.

AIM

Discuss the relevance and utility of the different outcome assessment tools in patient groups with different access to treatment.

METHODS

In the last decade new outcome assessment tools specific for haemophilia have been developed that measure all aspects of health according to the International Classification of Functioning, Disability and Health (ICF) model. These tools are directed at assessing the clinical and radiological status of joints as well as overall functioning, such as participation and psychosocial aspects, evaluating overall health-related quality of life (HRQOL). For deciding which tools to use in clinical practice or research, one needs to consider the specific context with regard to disease burden, healthcare environment and socioeconomic background of the patients being evaluated.

CONCLUSION

Prospective systematic assessment of outcome in haemophilia and related bleeding disorders is important. Based upon recent literature a critical appraisal of outcome tools is described.

The growing number of hemophilia registries: Quantity vs. quality

Registries for rare diseases provide a tool for obtaining an overview of the clinical situation and can be used to discover points of improvement and to monitor long-term safety. Registries could also become a powerful tool to provide supporting information for marketing authorization. There is an urgent need for a pan-European or global strategy that supports consistent data. Therefore, transparency in data collection, harmonization of the database structures, and the convergence of scientific approaches are required.

Improved prediction of inhibitor development in previously untreated patients with severe haemophilia A

Treatment of previously untreated patients (PUPs) with severe haemophilia A is complicated by the formation of inhibitors. Prediction of PUPs with high risk is important to allow altering treatment with the intention to reduce the occurrence of inhibitors. An unselected multicentre cohort of 825 PUPs with severe haemophilia A (FVIII<0.01 IU mL(-1) ) was used. Patients were followed until 50 exposure days (EDs) or inhibitor development. All predictors of the existing prediction model including three new potential predictors were studied using multivariable logistic regression. Model performance was quantified [area under the curve (AUC), calibration plot] and internal validation (bootstrapping) was performed. A nomogram for clinical application was developed. Of the 825 patients, 225 (28%) developed inhibitors. The predictors family history of inhibitors, F8 gene mutation and an interaction variable of dose and number of EDs of intensive treatment were independently associated with inhibitor development. Age and reason for first treatment were not associated with inhibitor development. The AUC was 0.69 (95% CI 0.65-0.72) and calibration was good. An improved prediction model for inhibitor development and a nomogram for clinical use were developed in a cohort of 825 PUPs with severe haemophilia A. Clinical applicability was improved by combining dose and duration of intensive treatment, allowing the assessment of the effects of treatment decisions on inhibitor risk and potentially modify treatment.

Clinical prediction models for inhibitor development in severe hemophilia A

Clinical prediction models for factor VIII inhibitor development may potentially facilitate the identification of patients at high risk of this complication. In particular, recognition of early intensive FVIII replacement therapy as a significant risk factor for inhibitor development has defined a clear clinical decision point that influences patient care. To assess the effect and potential acceptance of a prediction tool for FVIII inhibitor development in clinical practice, a 15-item survey was developed to assess whether these included items were accepted as potential risk factors by the health care providers taking care of these patients. The rating of these items was on a 5-point linear scale, with '1' representing it to be very unlikely and '5' very likely. Responses from 42 centers were available for analysis. These centers were responsible for taking care of 2642 children <18 years with severe hemophilia A. In addition to genetic factors (mean score approximately 4.5), early intensive treatment was considered important for inhibitor development (mean score 4.07). Other factors likely to reduce inhibitor development were early onset of prophylaxis (mean score 3.68) and avoidance of early surgery (mean score 4.05). Physicians also agreed that institution of early prophylaxis and avoidance of elective surgery are important management strategies to reduce inhibitor development (mean scores 3.54 and 4.32, respectively).

Risk stratification for inhibitor development at first treatment for severe hemophilia A: a tool for clinical practice

BACKGROUND

Replacement therapy in severe hemophilia A patients is complicated by formation of inhibitory antibodies against factor VIII (inhibitors) in around 25% of children. Management of bleeds and eradicating inhibitors is complicated, costly and not always successful.

OBJECTIVE

To develop a simple score that stratifies untreated patients with severe hemophilia according to their risk of developing inhibitory antibodies.

METHODS

The study population consisted of 332 children, with severe hemophilia A, selected from a retrospective multicentre cohort (the CANAL study). The score was based on risk factors available at the first treatment episode. The score was validated in an external population.

RESULTS

A total of 87 patients (25%) developed inhibitory antibodies. The selected risk score comprised positive family history (two points), high risk factor VIII gene mutations (two points), and intensive treatment at initial treatment (three points). Inhibitor incidence was 6% (six of 95) in patients without risk factor, 23% (38 of 170) in those with two points, and 57% (38 of 67) in patients with three points or more. The discriminative ability of the score was good (area under the receiver operating curve 0.74). The score performed equally well in the external validation population.

CONCLUSION

These findings suggest that the development of inhibitory antibodies in untreated patients with severe hemophilia A can validly be predicted with the presented risk stratification score.

Safety and efficacy of a plasma-derived monoclonal purified factor VIII concentrate during 10 years of follow-up

In 1995, AAFACT, a new monoclonal purified factor VIII concentrate (FVIII), derived from human plasma, was introduced in the Netherlands. The monoclonal purification based production process includes a viral inactivation step by solvent/detergent treatment. Products manufactured according to this procedure, for example Hemofil M are used worldwide. The aim of the present study was to assess inhibitor development in a large cohort of previously treated patients (PTPs) who were followed up for 10 years. In addition, efficacy, HIV and hepatitis C virus (HCV) transmission, and allergic reactions were monitored. All 165 patients with severe haemophilia A (FVIII<1%) known at the van Creveldkliniek who ever used AAFACT during the period from October 1995 to September 2005 were included. Two of them were previously untreated patients (PUPs) and two others had <50 exposure days. Data on FVIII consumption, number of exposures, bleedings and hospitalization days were collected from start of AAFACT until last clinical and laboratory evaluation while on this product. At the end of follow-up, 91 patients were still using this plasma-derived FVIII. Median age at start of follow-up was 26 years (range 1-52). None of the patients reported lack of efficacy. Median FVIII consumption per patient during follow-up was 2058 IU kg(-1) bodyweight per year, and median number of exposures was 148 per year. During 1029 patient-years of follow-up, one inhibitor was diagnosed in a previously treated patient PTP. This patient developed high titre inhibitor following surgery for which he, during 1 week, had been treated with continuous infusion with recombinant FVIII. No inhibitor occurred during 68 cases of surgery using continuous infusion with AAFACT. No viral transmissions or other adverse events occurred during 10 years of follow-up; AAFACT appeared to be an effective and safe FVIII product.

Phenotypic heterogeneity in severe hemophilia

Large heterogeneity in bleeding pattern and arthropathy is observed among patients with severe hemophilia. Studies have reported a large variability in bleeding pattern among patients with severe hemophilia. Of special interest are some 10% of the patients with severe hemophilia who only rarely bleed and don't need prophylactic therapy. Prothrombotic risk factors seem to influence phenotype but they can account for only a small part of the heterogeneity. Half-lives for factor VIII (FVIII) range between 7 and 20 h; a significantly shorter half-life has been reported in patients with blood group O and a low von Willebrand antigen level. In addition, thrombin generation tests have been used to differentiate between mild and more severe phenotypes. As the advanced forms of these tests also measure the effects of platelets, it has been argued that they are more sensitive to differentiate phenotypes. We conclude that the origin of the large heterogeneity of phenotypes in severe hemophilia is multifactorial. As they produce no FVIII, patients with severe hemophilia and an intron 22 inversion are ideal candidates to study further bleeding variability. Until other parameters have been identified, the heterogeneity of the clinical phenotype may best be predicted by the first onset of the clinical features. At the moment, age at first joint bleed seems to be the most reliable factor to differentiate between phenotypes.

Treatment characteristics and the risk of inhibitor development: a multicenter cohort study among previously untreated patients with severe hemophilia A

CONTEXT

The development of inhibitory antibodies against infused factor (F) VIII is a major complication of treatment of patients with severe hemophilia A.

OBJECTIVE

This study was set up to examine the effects of treatment-related factors on inhibitor development among previously untreated patients with severe hemophilia A.

DESIGN, SETTING AND PATIENTS

In this multicenter cohort study, we combined individual patient data obtained from four recombinant FVIII product registration studies (Kogenate, Kogenate Bayer, Recombinate, ReFacto) that were performed between 1989 and 2001. From the databases we selected all 236 previously untreated patients with severe hemophilia A who were subsequently treated with FVIII on at least 50 days.

MAIN OUTCOME MEASURES

Clinically relevant inhibitor development, defined as the occurrence of at least two positive inhibitor titers and a decreased recovery.

RESULTS

67 patients (28%) developed clinically relevant inhibitors (44 high-titer) at a median of ten exposure days. Age at first exposure was not associated with inhibitor development. Peak treatment moments and surgical procedures were related to an increased inhibitor risk [adjusted relative risk 1.6 (95% confidence interval 1.0-2.6) and 2.7 (95% confidence interval 1.3-5.7), respectively]. A shorter duration between exposure days was associated with an increased risk of inhibitor development. There was a possible association between dosing of FVIII and inhibitor development, which largely disappeared after adjustment for confounding factors.

INTERPRETATION

These findings show that intensive treatment periods are associated with an increased risk of inhibitor development in previously untreated patients with severe hemophilia A. Our results do not support the notion that age at first exposure is associated with the risk of developing inhibitors.

RCTs and observational studies to determine the effect of prophylaxis in severe haemophilia

It has been suggested that more RCTs should be conducted in the evaluation of haemophilia treatment, including prophylaxis. To draw valid conclusions from experimental or observational studies, internal validity should be ensured. In particular, similarity of prognosis between treatment groups compared in a particular study is needed. Because the use of prophylaxis in observational studies is nonrandomized by definition, special efforts should be made to achieve comparability of prognosis, that is, to avoid 'confounding by indication'; in RCTs this is ensured by randomized allocation of treatment. However, the high costs of an RCT results in a limitation of both patient numbers and length of follow up. Observational studies tend to be more generalizable and cheaper, as they may include a wider spectrum of morbidities, use treatment protocols in agreement with routine care, and use available data. Therefore, observational studies can be much larger and of longer duration than RCTs; and are the preferred design for the evaluation of long term treatment effects. Several valid observational studies comparing prophylaxis and on demand treatment have reported both a short term reduction of 75-90% in bleeding frequency, and significant improvement in arthropathy, quality of life, and socioeconomic parameters after more than 20 years of prophylactic treatment. RCTs provide the most powerful tool for the evaluation of short term effects of any treatment, but are infeasible for the evaluation of long term effects. The definitive assessment of the long-term benefits of prophylaxis requires observational studies that should be performed according to rigorous standards.

The use of a disability model in haemophilia research

Most haemophilia research is medically orientated. However, assessment of the impact of disease on the individual is different when viewed from a rehabilitation perspective. Several models are available to explore functioning and health from this perspective. The disablement process (DP) is such a model, and the aim of this study was to introduce this process in haemophilia research to see whether this type of research could lead to meaningful data. Forty-three adult patients with severe haemophilia participated in this study in which the three 'main pathway' domains of the DP (impairments, functional limitations and disability) and two additional factors (intra-individual and risk factors) were addressed. Three questionnaires (HAL, Dutch-AIMS2 and IPA) were incorporated, and Pettersson scores for 21 patients were retrieved. Step-wise and hierarchical regression analysis was used to assess relationship between the various domains. Arthropathy explained 48% of the variance in functional limitations and nearly 25% of the variance in disability. Functional limitations explained 54% of the variance in disability. Patients identified pain as an important aspect of health which addressed 22% and 13% of the variance in functional limitations and disability respectively. Age was correlated with arthropathy (r = 0.85; P < 0.001), whereas psychological health correlated with pain (r = 0.67; P < 0.001). Both variables were also correlated with functional limitations and disability. Analyses adjusting for the effects of age and psychological health were subsequently performed resulting in more insight in the associations within the DP. The use of the DP in haemophilia research proved to be useful.

Measuring patients' perceptions on their functional abilities: validation of the Haemophilia Activities List

Recently, the Haemophilia Activities List (HAL), a haemophilia-specific self-assessment questionnaire to assess a patient's self-perceived functional ability, was introduced and a limited pilot study warranted its further development. The present study finalizes the HAL and assesses the convergent and construct validity, as well as the internal consistency of its definitive version. Three questionnaires (HAL, Dutch-Arthritis Impact Measurement Scales 2 and the Impact on Participation and Autonomy questionnaire) were completed by 127 patients with severe haemophilia (<1% clotting activity), as well as four performance tests (button test, 50 metre walking test, timed-up-and-go test and figure-8 walking test). After removal of 15 non-informative items from the provisional HAL, three components within the questionnaire were identified (upper extremity activities, basic lower extremity activities and complex lower extremity activities). The internal consistency of these components was high (Cronbach's alpha = 0.93-0.95), as was internal consistency for the seven domains of the HAL (alpha = 0.61-0.96). The convergent validity of the HAL when compared to the other two questionnaires was good (r = 0.47-0.84). The construct validity of the HAL when compared to the four performance tests was generally lower (r = 0.23-0.77). The final version of the HAL has good internal consistency and convergent validity and gives the clinician insight into a patient's self-perceived ability to perform activities of daily life. It is likely that self-assessment instruments (questionnaires) and performance tests consider different concepts of functional health status and it is therefore recommended that both types are included when clinicians assess a patient's functional abilities.

Current European practice in immune tolerance induction therapy in patients with haemophilia and inhibitors

The management of patients with inhibitors is an important challenge in haemophilia care. The lack of randomized controlled trials means that clinical decisions are generally based on subjective opinions, and purchasers' attention is likely to focus on the costs of treatment. In order to assess the current management of inhibitor patients and use of immune tolerance induction therapy (ITI) in Europe, we performed a survey within a European network of 21 comprehensive care centres from 14 countries (the European Haemophilia Therapy Standardisation Board). The survey identified a total of 381 patients with inhibitors attending the centres, 211 (55.4%) of whom had never been exposed to ITI. Between 1998 and 2003, the centres performed 233 procedures and 114 (48.9%) were successful. The survey demonstrated that dosing, which is the time to start and stop the ITI, the type of concentrate to use and the definition of success varied among the centres. Well-designed trials are warranted to guide decision-making, but in the absence of these studies we have developed consensus guidance for the management of inhibitor patients based on current clinical practice, as identified by the survey, and review of the literature.

Pain and functional limitations in patients with severe haemophilia

Patients with severe haemophilia often experience pain caused by haemophilic arthropathy, and it is known that pain acts as a predictor of disability. The role of pain in functional limitations in these patients, however, has not been systematically investigated. The aim of this study was to describe pain as experienced by patients with haemophilia and to address the role of pain in subsequent functional limitations. Seventy-eight adult patients (18-70 years) with severe haemophilia completed one questionnaire on pain and one on self-perceived functional abilities. Two-thirds of the patients suffered from more than one painful joint, the ankle being mentioned most frequently (n=43). Analgesics were used by 36% of the patients indicating having pain. Six of 10 most frequently mentioned pain descriptors were of evaluative nature. Evaluative qualities of pain were associated with pain intensity, which in turn was associated with the impact of pain on daily life. Pain outcomes, after adjusting for age and treatment modality, explained 3-22% of the variance in self-perceived functional abilities. Data on radiological joint damage (Pettersson scores) were retrieved for a subgroup of 28 younger patients on prophylaxis and no significant correlations with pain parameters were found. Over two-thirds of the patients with severe haemophilia had one or more painful joints. Pain plays a small, but significant role in functional limitations. In the identified subgroup, arthropathy, as measured by the Pettersson score, seemed to have no role in pain experience. Promoting analgesic use might decrease the impact of pain on functional limitations.

Variability in clinical phenotype of severe haemophilia: the role of the first joint bleed

To quantify variation in clinical phenotype of severe haemophilia we performed a single centre cohort study among 171 severe haemophilia patients. Age at first joint bleed, treatment requirement (i.e. annual clotting factor use), annual bleeding frequency and arthropathy were documented. Because treatment strategies intensified during follow-up, patients were stratified in two age groups: patients born 1968-1985 (n = 91), or 1985-2002 (n = 80). A total of 2166 patient-years of follow-up were available (median 12.0 years per patient). Age at first joint bleed ranged from 0.2 to 5.8 years. Patients who had their first joint bleed later needed less treatment and developed less arthropathy. In patients born 1968-1985 during both on-demand and prophylactic treatment, the 75th percentile of annual joint bleed frequency was consistently four times as high as the 25th percentile. In both age groups variation in annual clotting factor use between 25th and 75th percentiles was 1.4-1.5 times for prophylaxis and 3.8 times for on-demand treatment. To conclude, the onset of joint bleeding is inversely related with treatment requirement and arthropathy and may serve as an indicator of clinical phenotype. Thus, providing a starting point for aetiological research and individualization of treatment.

Can long-term prophylaxis for severe haemophilia be stopped in adulthood? Results from Denmark and the Netherlands

Prophylaxis is the treatment of choice for children with severe haemophilia. As prophylaxis is especially important during the period of growth, the need for continued prophylaxis in adulthood should be considered. The aim of this study was to describe the incidence and outcome of stopping prophylaxis in patients with severe haemophilia who were offered prophylaxis during childhood. All patients with severe haemophilia (factor VIII/IX <0.01 IU/ml), born 1970-80, treated in two Danish and one Dutch treatment centre were studied. Data on discontinuation of prophylaxis, treatment, joint bleed frequency, clinical scores and radiological scores were collected. Eighty patients were studied. Median follow-up was 19 years (range 7-29). A total of 35% of patients discontinued prophylaxis at a median age of 21.5 years [interquartile range (IQR) 18.4-24.4], experiencing only three joint bleeds per year (IQR 1.4-8.7). Median clinical scores were similar in patients who discontinued prophylaxis [4 points (IQR 0-6)] and those who continued [3 points (IQR 1-6)], as were median Pettersson scores at 13 (IQR 1-24) vs. 13 points (IQR 5-23) respectively. In conclusion one-third of young adults with severe haemophilia on a prophylactic regimen discontinued prophylaxis in early adulthood, while maintaining a low joint bleed frequency and similar arthropathy after 4 years.

Functional consequences of haemophilia in adults: the development of the Haemophilia Activities List

Several instruments can be used to evaluate the functional status of patients with haemophilia, but none of these instruments is specific for haemophilia. We developed a haemophilia-specific self-assessment questionnaire to evaluate and monitor a patient's perceived functional health status: the Haemophilia Activities List (HAL). In three separate but interlinked substudies, the questionnaire was constructed and tested for face, expert, and convergent validity, as well as internal consistency and patient-evaluated relevance. Items for the questionnaire were collected by interviewing 162 patients, using the McMaster-Toronto Arthritis Patient Preference Disability Questionnaire (MACTAR). The items were combined to generate the first version of the questionnaire [HAL(1)]. This version was evaluated and commented on by two focus groups (patients and caregivers), and then the questionnaire was adapted on the basis of these comments, forming the final version, HAL(2). This version was then validated in a pilot study with 50 consecutive patients using the Dutch Arthritis Impact Measurements Scales 2 (Dutch-AIMS2) and the Impact on Participation and Autonomy (IPA) questionnaires. The HAL(2) showed good convergent validity (Pearson correlation 0.80-0.91; P < 0.01), and the internal consistency was good for six of the eight domains (Cronbach's alpha 0.83-0.95). Patients considered the content of the HAL to be more relevant to their situation than the content of the other questionnaires (P < 0.01). Three major factors (upper extremity function, lower extremity function, key activities/major problem activities) were identified by factor analysis. The questionnaire seems to be a useful tool to identify problematic activities as part of the functional health status of patients with haemophilia. The construct validity, test-retest reliability, and responsiveness of the HAL will be established in the future.

Hepatitis C infection in children with haemophilia: a pilot study

Many haemophilia patients were infected with hepatitis C virus (HCV) in childhood after transfusion with inadequately or non-virus inactivated clotting factor products. Limited information is available on the clinical course of HCV infection in children. To assess the clinical consequences of hepatitis C in these young patients we performed a pilot study of 31 patients with haemophilia, infected with HCV before the age of 13. Current median age was 20 years. Nineteen (61%) patients had chronic hepatitis C, whereas the remaining 12 patients spontaneously cleared HCV. The median duration of infection was 17 years. Among patients chronically infected with HCV, an enlarged liver and/or spleen on ultrasound was present in 59%, whereas 63% had abnormal aminotransferases and/or gamma-GT values. In conclusion, 39% of the patients infected in childhood cleared HCV spontaneously. The majority of the patients with chronic hepatitis C had ultrasound and/or laboratory abnormalities and these findings may be associated with the presence of chronic liver disease.

Haemoglobin-derived iron-dependent hydroxyl radical formation in blood-induced joint damage: an in vitro study

OBJECTIVE

It has been reported that joint bleeds cause cartilage damage and that the combination of red blood cells (RBC) plus mononuclear cells (MNC) causes the adverse effects. The present study is to elucidate the mechanism by which blood, as present in whole blood, may cause this cartilage damage.

METHODS

Human cartilage samples were cultured for 4 days in the presence of 50% whole blood, isolated MNC plus RBC, CD14+ cells (monocytes/macrophages) plus RBC, or lysed RBC with interleukin 1beta (IL-1beta; a major catabolic product of activated monocytes/macrophages). Antioxidants were used to investigate the involvement of oxidative stress. A subsequent 12-day culture period in the absence of additions is referred to as the recovery period. Changes in cartilage proteoglycan synthesis were determined at days 4 and 16.

RESULTS

Cartilage cultured in the presence of whole blood, MNC plus RBC, or monocytes/macrophages plus RBC resulted in a prolonged inhibition of proteoglycan synthesis (>90% inhibition at day 16; all three P<0.05). Lysed RBC together with IL-1beta also induced prolonged inhibition of proteoglycan synthesis (>56% of controls, P<0.05). Dimethylsulphoxide (DMSO), scavenging hydroxyl radicals, could reverse the inhibition of cartilage proteoglycan synthesis.

CONCLUSIONS

Based on these results we hypothesize that IL-1beta produced by activated monocytes/macrophages increases the production of hydrogen peroxide by chondrocytes. This in combination with haemoglobin-derived iron from the RBC will result in the formation of hydroxyl radicals in the vicinity of chondrocytes. This mechanism may result in chondrocyte damage and as such be involved in blood-induced cartilage damage.

Consensus perspectives on prophylactic therapy for haemophilia: summary statement

Participants in an international conference on prophylactic therapy for severe haemophilia developed a consensus summary of the findings and conclusions of the conference. In the consensus, participants agreed upon revised definitions for primary and secondary prophylaxis and also made recommendations concerning the need for an international system of pharmacovigilance. Considerations on starting prophylaxis, monitoring outcomes, and individualizing treatment regimens were discussed. Several research questions were identified as needing further investigation, including when to start and when to stop prophylaxis, optimal dosing and dose interval, and methods for assessment of long-term treatment effects. Such studies should include carefully defined cohorts, validated orthopaedic and quality-of-life assessment instruments, and cost-benefit analyses.

Comparing outcomes of different treatment regimens for severe haemophilia

Published retrospective reports from France, the Netherlands and Sweden were analysed for data relating to the long-term outcomes (primarily the development of arthropathy) of three regimens for the management of severe haemophilia: on-demand treatment, intermediate-dose prophylaxis and high-dose prophylaxis. The mean annual consumption of factor concentrate was also compared. These data indicate that both prophylaxis regimens resulted in significantly improved long-term outcomes, as assessed by pain, clinical and radiological assessment scores. At the same time, the most recently reported annual factor consumption levels of these young adult patients are comparable in the on-demand and intermediate-dose prophylaxis cohorts, suggesting that the improvement in long-term clinical outcomes and reduced risk of arthropathy may lead to reduced factor consumption in adult patients who received early prophylactic therapy.

Health-related quality of life as outcome parameter in haemophilia treatment

Health-related quality of life (HRQoL) is increasingly used as an outcome parameter in haemophilia treatment. Currently, only generic HRQoL instruments are used, as disease-specific instruments for haemophilia are not available. The most widely used generic instruments are the descriptive SF-36 questionnaire and the EQ-5D questionnaire for assessment of utilities, ie preference-based HRQoL. Results of both instruments show significant correlation. All haemophilia prophylaxis studies using HRQoL as an outcome report a decreased HRQoL compared with the general population, a positive effect of prophylactic treatment and a negative effect of age. Generic instruments for measuring HRQoL are able to pick up differences between groups of patients with haemophilia and enable us to make comparisons across diseases. However, in order to establish the optimal treatment strategy for severe haemophilia, further information is needed on the long-term effects of different strategies on HRQoL. In addition, haemophilia-specific HRQoL instruments should be developed in order to provide detailed information for adjustment and evaluation of treatment in individual patients.

[Oral surgery in hemophilia patients]

Oral surgery in hemophilia patients requires special arrangements in close collaboration with a hemotologist. Minor oral surgeries in not complicated cases can be done by a dentist or an oral surgeon with aid and assistance of a hemotologist. All major oral surgeries in hemophilia patients with antibodies counteracting coagulation agents should occur in a hemophilia treatment centre.

Prophylactic versus on-demand treatment strategies for severe haemophilia: a comparison of costs and long-term outcome

A multicentre study was performed to compare clotting factor use and outcome between on-demand and prophylactic treatment strategies for patients with severe haemophilia. Data on treatment and outcome of 49 Dutch patients with severe haemophilia, born 1970-80, primarily treated with prophylaxis, were compared with those of 106 French patients, who were primarily treated on demand. Dutch patients received intermediate dose prophylaxis, for a median duration of 12.7 years. Patients primarily treated with prophylaxis had fewer joint bleeds per year (median 2.8 vs. 11.5), a higher proportion of patients without joint bleeds (29% vs. 9%), lower clinical scores (median 2.0 vs. 8.0), and less arthropathy as measured by the Pettersson score (median 7 points vs. 16 points). Mean annual clotting factor use was equal at 1,488 +/- 783 IU kg-1 year-1 (mean +/- standard deviation) for patients primarily treated with prophylaxis and 1,612 +/- 1,442 IU kg-1 year-1 for patients primarily treated on demand. These findings suggest that, compared with a primarily on-demand treatment strategy, a primarily prophylactic treatment strategy leads to better outcome at equal treatment costs in young adults with severe haemophilia.

Prophylactic treatment for severe haemophilia: comparison of an intermediate-dose to a high-dose regimen

A multicentre study was performed in Sweden and the Netherlands, comparing effects of two prophylactic regimens in 128 patients with severe haemophilia, born 1970-90. 42 Swedish patients (high-dose prophylaxis), were compared with 86 Dutch patients (intermediate-dose prophylaxis). Patients were evaluated at the date of their last radiological score according to Pettersson. Annual clotting factor consumption and bleeding frequency were registered for a period of three years before evaluation. Patients in the high-dose group were younger at evaluation (median 15.2 vs. 17.9 years), started prophylaxis earlier (median 2 vs. 5 years), and used 2.19 times more clotting factor kg-1 year-1. Patients treated with high-dose prophylaxis had fewer joint bleeds (median 0.3 year-1 vs. 3.3 year-1) and the proportion of patients without arthropathy as measured by the Pettersson score was higher (69% vs. 32%), however, the age-adjusted difference in scores (median 0 points vs. 4 points) was small and at present not statistically significant. Clinical scores and quality of life were similar. These findings suggest that, compared with intermediate-dose prophylaxis, high-dose prophylaxis significantly increases treatment costs and reduces joint bleeds over a period of 3 years, but only slightly reduces arthropathy after 17 years of follow-up.