Outcome measures in haemophilia: more than just factor levels

The impact of inhibitors on the quality of life in patients with hemophilia

Objective

To investigate the association of health-related quality of life in hemophilia patients with inhibitor and clinical and demographic characteristics.

Methods

In this multi-center cross-sectional study, 41 male patients with hemophilia A were investigated from May to October 2021. All patients were registered at the Hemophilia Clinic affiliated with Shiraz and Zahedan Universities of Medical Sciences in Iran. Health-related quality of life of the patients was evaluated by the Short Form-36 questionnaire.

Results

The patients' mean ± SD of age was 36.9 ± 13.2 (range: 18-76) years. Eleven patients (26.8%) were inhibitor positive. In univariate analysis, physical function, mental health dimension, and total Short Form-36 scores were significantly lower in the inhibitor-positive patients (p < 0.001, p = 0.045, and p = 0.035, respectively). Moreover, patients with severe disease showed significantly lower scores in physical function (p < 0.001), physical health dimension (p = 0.018), and total Short Form-36 (p = 0.031) than those with mild and moderate hemophilia. Also, blood-borne infections showed a significant association with lower score in physical health dimension (p = 0.038). In addition, annual bleeding rate showed significant negative correlations with physical health dimension (r_s = -0.609, p < 0.001), mental health dimension (r = -0.317, p = 0.044), and total Short Form-36 (r = -0.455, p = 0.003) scores. In multiple linear regression analysis, disease severity revealed a significant negative relationship with scores in physical function (p = 0.001), role physical (RP) (p = 0.015), general health (GH) (p = 0.006), physical health dimension (p = 0.006), and marginally in total Short Form-36 score (p = 0.054). Also, age of the patients showed a significant negative association with physical function and GH scores (p < 0.001 and p = 0.015, respectively).

Conclusion

Disease severity and age were shown as independent factors affecting health-related quality of life, but inhibitor alone was not an independent influencing factor. Reduced health-related quality of life was also observed in hemophilia patients with higher annual bleeding rate and blood-borne infections. Therefore, it is necessary to pay more attention to these subgroups. Further studies with larger sample size are needed for more accurate results.

Developments in the treatment of hemophilia B: focus on emerging gene therapy

Hemophilia B is a genetic disorder that is characterized by a deficiency of clotting factor IX (FIX) and excessive bleeding. Advanced understanding of the pathophysiology of the disease has led to the development of improved treatment strategies that aim to minimize the acute and long-term complications of the disease. Patients with hemophilia B are ideal candidates for gene therapy, mostly because a small increase in protein production can lead to significantly decreased bleeding diathesis. Although human clotting FIX was cloned and sequenced over 30 years ago, progress toward achieving real success in human clinical trials has been slow, with long-term, therapeutically relevant gene expression only achieved in one trial published in 2011. The history of this extensive research effort has revealed the importance of the interactions between gene therapy vectors and multiple arms of the host immune system at multiple stages of the transduction process. Different viral vector systems each have unique properties that influence their ability to deliver genes to different tissues, and the data generated in several clinical trials testing different vectors for hemophilia have guided our understanding toward development of optimal configurations for treating hemophilia B. The recent clinical success implementing a novel adeno-associated virus vector demonstrated sufficient FIX expression in patients to convert a severe hemophilia phenotype to mild, an achievement which has the potential to profoundly alter the impact of this disease on human society. Continued research should lead to vector designs that result in higher FIX activity at lower vector doses and with reduced host immune responses to the vector and the transgene product.

Treatment of hemophilia: a review of current advances and ongoing issues

Replacement of the congenitally deficient factor VIII or IX through plasma-derived or recombinant concentrates is the mainstay of treatment for hemophilia. Concentrate infusions when hemorrhages occur typically in joint and muscles (on-demand treatment) is able to resolve bleeding, but does not prevent the progressive joint deterioration leading to crippling hemophilic arthropathy. Therefore, primary prophylaxis, ie, regular infusion of concentrates started after the first joint bleed and/or before the age of two years, is now recognized as first-line treatment in children with severe hemophilia. Secondary prophylaxis, whenever started, aims to avoid (or delay) the progression of arthropathy and improve patient quality of life. Interestingly, recent data suggest a role for early prophylaxis also in preventing development of inhibitors, the most serious complication of treatment in hemophilia, in which multiple genetic and environmental factors may be involved. Treatment of bleeds in patients with inhibitors requires bypassing agents (activated prothrombin complex concentrates, recombinant factor VIIa). However, eradication of inhibitors by induction of immune tolerance should be the first choice for patients with recent onset inhibitors. The wide availability of safe factor concentrates and programs for comprehensive care has now resulted in highly satisfactory treatment of hemophilia patients in developed countries. Unfortunately, this is not true for more than two-thirds of persons with hemophilia, who live in developing countries.

Enabling normal psychophysical development in children with hemophilia: the choice for prophylaxis

Hemophilia A and B, the congenital deficiencies of coagulation factors VIII and IX, are characterized by recurrent joint and muscle bleeding episodes and progressive musculoskeletal damage (hemophilic arthropathy). Primary prophylaxis – that is, the regular infusion of factor concentrates after the first hemarthrosis and/or before 2 years of age – is now recognized as the first-choice treatment for children with severe hemophilia. Preventing bleeding from an early age enables avoidance of the clinical impact of hemophilic arthropathy and the consequences regarding psychosocial development and quality of life for these children. Interestingly, recent data suggest a role for early prophylaxis in also preventing inhibitor development, the most serious complication of treatment in hemophilia. Secondary prophylaxis, initiated after 2 years of age or after two or more joint bleeds, aims to avoid (or delay) the progression of arthropathy. In addition, better outcomes and better quality of life have been reported with earlier treatment. This review summarizes the evidence, current clinical strategies and open issues regarding prophylxis in children with hemophilia.

A study of reported factor VIII use around the world

The effect of replacement therapy has significantly improved the morbidity and mortality of people with haemophilia A in high income countries, a recent socio-economic development as the availability of safe concentrates has been matched by a willingness for their provision through reimbursement. In the developing world, however, this state has not been achieved, primarily because of the low visibility of haemophilia coupled with its expense, leading to inadequate treatment with its sequelae of severe pain, joint deformities, arthropathy, disabilities, and even death in childhood or early adult life. The objective of this paper was to study the reported factor VIII (FVIII) use on a country-by-country basis. Data on the reported FVIII use for 104 countries were obtained from the Marketing Research Bureau, Inc. and the World Federation of Hemophilia. The results show that FVIII use varies considerably among countries, even among the wealthiest of countries. The use of FVIII concentrate increases as economic capacity increases; in addition, consumption of FVIII has been increasing at a greater rate in high income countries. Given these trends, there probably will be a global increase in FVIII concentrates usage. Such information is critical for national healthcare agencies to determine realistic budget priorities in planning for an increased allocation of resources required to improve the treatment of patients with haemophilia A. This information is also important for pharmaceutical manufacturers to adequately plan for increased production of FVIII concentrates.

Need for Prophylactic Treatment in Adult Haemophilia A Patients

BACKGROUND AND METHODS: A single centre study including 52 German patients aged ≥16 years with severe haemophilia A was performed to compare the amount of clotting factor and outcome between on-demand therapy (26 patients) and continuous prophylaxis (26 patients) over 1 year. RESULTS: Prophylaxis reduced the number of bleeds significantly. Compared to on-demand treatment (20.5 ± 3.0 bleeds/year/patient), under prophylaxis 7.8 ± 1.3 bleeds/year/patient were observed. Joint bleeds were reduced from 12.2 ± 1.5 to 4.7 ± 1.0/year/ patient. In the on-demand group 38% of the patients suffered from more than 2 bleeds/month, whereas in the prophylaxis group no patient was found with more than 2 bleeds/month. Mean annual factor VIII (FVIII) consumption increased from 767 ± 110 IU/kg body weight under on-demand treatment to 2,841 ± 341 IU/kg body weight under continuous prophylaxis, displaying a nearly fourfold increase in FVIII consumption. Furthermore, prophylaxis implies a more than four-fold increase in treatment days which escalated from a mean weekly injection rate of 0.56 ± 0.08 FVIII injections/week when bleeds were treated on demand to 2.52 ± 0.30 FVIII injections/week during prophylaxis. CONCLUSION: Even though the results reflect a benefit also for prophylactically treated patients regarding their bleeding frequency, one has to take into account a substantial increase of the costs for coagulation concentrates when all patients with severe haemophilia A switch to continuous prophylaxis.

Primary prophylaxis in children with haemophilia

Starting from the clinical observations that moderate haemophiliacs experienced only few bleeding episodes and rarely developed significant joint deterioration (haemophilic arthropathy), and the pioneer experience in Sweden, prophylaxis (i.e. the regular and long-term administration of clotting factor concentrate in order to prevent bleeding) has been practiced for more than forty years in severe haemophilia and is currently recommended as the first choice of treatment by the World Health Organisation and World Federation of Hemophilia and by many national medical/scientific organizations. Observational studies clearly established the superiority of prophylaxis over on-demand treatment in reducing the risk of arthropathy, also showing that starting prophylaxis earlier in life and after very few joint bleeds was associated with better joint outcomes, and led to the current definitions of primary (started before the age of 2 yrs and after no more than one joint bleed) and secondary prophylaxis. More recently, evidences from randomized trials, which were previously lacking in this setting, were also provided. This review summarizes available data from which current clinical practice of primary (and early secondary) prophylaxis in children with severe haemophilia was drawn. Open issues concerning optimal regimens and barriers to the implementation of prophylaxis are also discussed.

Health-related quality of life in a cohort of adult patients with mild hemophilia A

OBJECTIVES

To compare the health-related quality of life among adult males affected with mild hemophilia A due to the same mutation (Val2016ala) to that of unaffected age and sex matched controls from the same general population.

METHODS

The Short-Form 36 (SF-36) and Health Assessment Questionnaire (HAQ) were used to measure health-related quality of life and physical function. Other measures included bleeding history, a measure of joint damage, body mass index, age, and viral infection status. Cross-sectional data were collected through research clinics and a retrospective chart audit over a two-year period.

RESULTS AND CONCLUSIONS

The study included 47 affected males and 33 controls. The affected males had a higher level of co-morbidity, prior bleeding, and existing joint damage than controls. With the exception of the social function and health transition scales, mean scores for each of the SF-36 domains were worse among affected males. Mean differences were more than a clinically important five points in five of eight domains, with the general health scale showing more than a 10-point difference. Despite the degree of difference noted, only two of the differences were statistically significant (general health and role emotional scales) because of the small sample size and considerable individual variation in SF-36 scale scores. Multiple regression analyses suggested existing joint damage and presence of heart disease as the strongest associates of lower physical health-related quality of life. Joint damage in turn was partly related to prior hemarthroses. Compared to the Canadian population, affected males had lower scores in six out of eight SF-36 domains as well as the physical component summary score. There were no significant differences found in the HAQ scores between the two groups. So-called mild hemophilia A was associated with a negative effect on physical health-related quality of life, contributed to by joint damage as a result of prior bleeding.

Recommendations for reporting economic evaluations of haemophilia prophylaxis: a nominal groups consensus statement on behalf of the Economics Expert Working Group of The International Prophylaxis Study Group

BACKGROUND

The need for clearly reported studies evaluating the cost of prophylaxis and its overall outcomes has been recommended from previous literature.

OBJECTIVES

To establish minimal ''core standards'' that can be followed when conducting and reporting economic evaluations of hemophilia prophylaxis.

METHODS

Ten members of the IPSG Economic Analysis Working Group participated in a consensus process using the Nominal Groups Technique (NGT). The following topics relating to the economic analysis of prophylaxis studies were addressed; Whose perspective should be taken? Which is the best methodological approach? Is micro- or macro-costing the best costing strategy? What information must be presented about costs and outcomes in order to facilitate local and international interpretation?

RESULTS

The group suggests studies on the economic impact of prophylaxis should be viewed from a societal perspective and be reported using a Cost Utility Analysis (CUA) (with consideration of also reporting Cost Benefit Analysis [CBA]). All costs that exceed $500 should be used to measure the costs of prophylaxis (macro strategy) including items such as clotting factor costs, hospitalizations, surgical procedures, productivity loss and number of days lost from school or work. Generic and disease specific quality of lífe and utility measures should be used to report the outcomes of the study.

CONCLUSIONS

The IPSG has suggested minimal core standards to be applied to the reporting of economic evaluations of hemophilia prophylaxis. Standardized reporting will facilitate the comparison of studies and will allow for more rational policy decisions and treatment choices.

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.

Hemophilia management: optimizing treatment based on patient needs

PURPOSE OF REVIEW

Progress in hemophilia management over the past year has focused on improving understanding of the most common complications of genetic bleeding disorders and building upon available therapeutic strategies.

RECENT FINDINGS

Research continued to link factor VIII structure with immune recognition and inhibitor formation. Clinical regimens of immune tolerance induction confirmed and expanded basic understanding. Barriers to optimal prevention using prophylaxis were explored allowing future refinements to address unmet needs. Outcome tools to assess joint health and overall quality of life were developed and validated. The inclusion of standardized instruments in assessment of outcome will allow meaningful comparison of available therapies. Use and complications of central venous access devices (CVAD), needed to deliver aggressive infusion regimens, were exhaustively reviewed. Finally, continued progress was achieved in development of improved vectors for future gene therapy of the hemophilias.

SUMMARY

A general theme of recent progress in hemophilia management is harmonization in definitions and assessments of complications and outcomes, facilitating more rigorous and ultimately more useful interpretation of laboratory and clinical research.