Intensity of factor VIII treatment and the development of inhibitors in non-severe hemophilia A patients: results of the INSIGHT case-control study

Essentials Research suggests that intensive treatment episodes may increase the risk to develop inhibitors. We performed an international nested case-control study with 298 non-severe hemophilia A patients. Surgery and a high dose of factor VIII concentrate were associated with increased inhibitor risk. Physicians need to review arguments for factor VIII dose and elective surgery extra critically.

SUMMARY

Background Inhibitor development is a major complication of treatment with factor VIII concentrates in hemophilia. Findings from studies among severe hemophilia A patients suggest that intensive treatment episodes increase the risk of developing inhibitors. Objectives We set out to assess whether intensive treatment is also associated with an increased risk of inhibitor development among non-severe hemophilia A patients. Patients/Methods We performed a nested case-control study. A total of 75 inhibitor patients (cases) and 223 control patients were selected from 2709 non-severe hemophilia A patients (FVIII:C, 2-40%) of the INSIGHT cohort study. Cases and controls were matched for date of birth and cumulative number of exposure days (EDs) to FVIII concentrates. Conditional logistic regression was used to calculate both unadjusted and adjusted odds ratios (aOR); the latter were adjusted for a priori specified confounders. Results Peak treatment of 5 or 10 consecutive EDs did not increase inhibitor risk (aOR, 1.0; 95% confidence interval (CI), 0.4-2.5; and aOR, 1.8; CI, 0.6-5.5, respectively). Both surgical intervention (aOR, 4.2; CI, 1.7-10.3) and a high mean dose (> 45 IU kg-1 /ED) of FVIII concentrate (aOR, 7.5; CI, 1.6-35.6) were associated with an increased inhibitor risk. Conclusions Our findings suggest that high-dose FVIII treatment and surgery increase the risk of inhibitor development in non-severe hemophilia A. Together with the notion that non-severe hemophilia A patients are at a lifelong risk of inhibitor development, we suggest that in the future physicians will review the arguments for the FVIII dose and elective surgery extra critically.

Mortality caused by intracranial bleeding in non-severe hemophilia A patients

Essentials Data on bleeding-related causes of death in non-severe hemophilia A (HA) patients are scarce. Such data may provide new insights into areas of care that can be improved. Non-severe HA patients have an increased risk of dying from intracranial bleeding. This demonstrates the need for specialized care for non-severe HA patients.

SUMMARY

Background Non-severe hemophilia (factor VIII concentration [FVIII:C] of 2-40 IU dL-1 ) is characterized by a milder bleeding phenotype than severe hemophilia A. However, some patients with non-severe hemophilia A suffer from severe bleeding complications that may result in death. Data on bleeding-related causes of death, such as fatal intracranial bleeding, in non-severe patients are scarce. Such data may provide new insights into areas of care that can be improved. Aims To describe mortality rates, risk factors and comorbidities associated with fatal intracranial bleeding in non-severe hemophilia A patients. Methods We analyzed data from the INSIGHT study, an international cohort study of all non-severe hemophilia A patients treated with FVIII concentrates during the observation period between 1980 and 2010 in 34 participating centers across Europe and Australia. Clinical data and vital status were collected from 2709 patients. We report the standardized mortality rate for patients who suffered from fatal intracranial bleeding, using a general European male population as a control population. Results Twelve per cent of the 148 deceased patients in our cohort of 2709 patients died from intracranial bleeding. The mortality rate between 1996 and 2010 for all ages was 3.5-fold higher than that in the general population (95% confidence interval [CI] 2.0-5.8). Patients who died from intracranial bleeding mostly presented with mild hemophilia without clear comorbidities. Conclusion Non-severe hemophilia A patients have an increased risk of dying from intracranial bleeding in comparison with the general population. This demonstrates the need for specialized care for non-severe hemophilia A patients.

Variation in baseline factor VIII concentration in a retrospective cohort of mild/moderate hemophilia A patients carrying identical F8 mutations

Essentials Factor VIII levels vary in mild and moderate hemophilia A (MHA) patients with the same mutation. We aimed to estimate the variation and determinants of factor VIII levels among MHA patients. Age and genotype explain 59% of the observed inter-individual variation in factor VIII levels. Intra-individual variation accounted for 45% of the variation in the three largest mutation groups.

SUMMARY

Background The bleeding phenotype in patients with mild/moderate hemophilia A (MHA) is inversely associated with the residual plasma concentration of factor VIII (FVIII:C). Within a group of patients with the same F8 missense mutation, baseline FVIII:C may vary, because, in healthy individuals, von Willebrand factor (VWF) levels, ABO blood group and age are also known to influence baseline FVIII:C. Our understanding of the pathophysiologic process of the causative genetic event leading to reduced baseline FVIII:C in MHA patients is still limited. Objectives To estimate the variation and determinants of baseline FVIII:C among MHA patients with the same F8 missense mutation. Methods Three hundred and forty-six patients carrying mutations that were present in at least 10 patients in the cohort were selected from the INSIGHT and the RISE studies, which are cohort studies including data of 3534 MHA patients from Europe, Canada, and Australia. Baseline FVIII:C was measured with a one-stage clotting assay. We used Levene's test, univariate and multivariate linear regression, and mixed-model analyses. Results For 59% of patients, the observed variation in baseline FVIII:C was explained by age and genotype. Compared to FVIII:C in patients with Arg612Cys, FVIII:C was significantly different in patients with eight other F8 missense mutations. Intra-individual variation explained 45% of the observed variance in baseline FVIII:C among patients with the same mutation. Conclusion Our results indicate that baseline FVIII:C levels are not exclusively determined by F8 genotype in MHA patients. Insights into other factors may provide potential novel targets for the treatment of MHA.

Gestational weight gain and the risk of offspring obesity at 10 and 16 years: a prospective cohort study in low-income women

OBJECTIVE

To study the association between gestational weight gain (GWG) and offspring obesity risk at ages chosen to approximate prepuberty (10 years) and postpuberty (16 years).

DESIGN

Prospective pregnancy cohort.

SETTING

Pittsburgh, PA, USA.

SAMPLE

Low-income pregnant women (n = 514) receiving prenatal care at an obstetric residency clinic and their singleton offspring.

METHODS

Gestational weight gain was classified based on maternal GWG-for-gestational-age Z-score charts and was modelled using flexible spline terms in modified multivariable Poisson regression models.

MAIN OUTCOME MEASURES

Obesity at 10 or 16 years, defined as body mass index (BMI) Z-scores ≥95th centile of the 2000 CDC references, based on measured height and weight.

RESULTS

The prevalence of offspring obesity was 20% at 10 years and 22% at 16 years. In the overall sample, the risk of offspring obesity at 10 and 16 years increased when GWG exceeded a GWG Z-score of 0 SD (equivalent to 30 kg at 40 weeks); but for gains below a Z-score of 0 SD there was no relationship with child obesity risk. The association between GWG and offspring obesity varied by prepregnancy BMI. Among mothers with a pregravid BMI <25 kg/m(2) , the risk of offspring obesity increased when GWG Z-score exceeded 0 SD, yet among overweight women (BMI ≥25 kg/m(2) ), there was no association between GWG Z-scores and offspring obesity risk.

CONCLUSIONS

Among lean women, higher GWG may have lasting effects on offspring obesity risk.

Inhibitor development and mortality in non-severe hemophilia A

BACKGROUND

The life expectancy of non-severe hemophilia A (HA) patients equals the life expectancy of the non-hemophilic population. However, data on the effect of inhibitor development on mortality and on hemophilia-related causes of death are scarce. The development of neutralizing factor VIII antibodies in non-severe HA patients may dramatically change their clinical outcome due to severe bleeding complications.

OBJECTIVES

We assessed the association between the occurrence of inhibitors and mortality in patients with non-severe HA.

METHODS

In this retrospective cohort study, clinical data and vital status were collected for 2709 non-severe HA patients (107 with inhibitors) who were treated between 1980 and 2011 in 34 European and Australian centers. Mortality rates for patients with and without inhibitors were compared.

RESULTS

During 64,200 patient-years of follow-up, 148 patients died (mortality rate, 2.30 per 1000 person-years; 95% confidence interval (CI), 1.96-2.70) at a median age of 64 years (interquartile range [IQR], 49-76). In 62 patients (42%) the cause of death was hemophilia related. Sixteen inhibitor patients died at a median age of 71 years (IQR, 60-81). In ten patients the inhibitor was present at time of death; seven of them died of severe bleeding complications. The all-cause mortality rate in inhibitor patients was > 5 times increased compared with that for those without inhibitors (age-adjusted mortality rate ratio, 5.6).

CONCLUSION

Inhibitor development in non-severe hemophilia is associated with increased mortality. High rates of hemophilia-related mortality in this study indicate that non-severe hemophilia is not mild at all and stress the importance of close follow-up for these patients.

The Fc gamma receptor IIa R131H polymorphism is associated with inhibitor development in severe hemophilia A

BACKGROUND

The development of factor (F) VIII neutralizing alloantibodies (inhibitors) is a major complication of treatment with FVIII concentrates in hemophilia A and the etiology is still poorly understood. The low-affinity Fc gamma receptors (FcγR), which are expressed on immune cells, provide an important link between cellular and humoral immunity by interacting with IgG subtypes. Genetic variations of the genes encoding FcγRs (FCGR genes) have been associated with susceptibility to infectious and autoimmune diseases.

OBJECTIVES

The aim of this study was to investigate the association between genetic variation of FCGR and inhibitor development in severe hemophilia A.

PATIENTS/METHODS

In this case-control study samples of 85 severe hemophilia A patients (siblings from 44 families) were included. Single nucleotide polymorphisms and copy number variation of the FCGR2 and FCGR3 gene cluster were studied in an FCGR-specific multiplex ligation-dependent probe amplification assay. Frequencies were compared in a generalized estimating equation regression model.

RESULTS

Thirty-six patients (42%) had a positive history of inhibitor development. The polymorphism 131R > H in the FCGR2A gene was associated with an increased risk of inhibitor development (odds ratio [OR] per H-allele, 1.8; 95% confidence interval [CI], 1.1-2.9). This association persisted in 29 patients with high titer inhibitors (OR per H-allele, 1.9; 95% CI, 1.2-3.2) and in 44 patients with the F8 intron 22 inversion (OR per H-allele, 2.6; 95% CI, 1.1-6.6).

CONCLUSIONS

Hemophilia A patients with the HH genotype of the FCGR2A polymorphism 131R > H have a more than 3-fold increased risk of inhibitor development compared with patients with the RR genotype.

Surgery and inhibitor development in hemophilia A: a systematic review

BACKGROUND

Although the association between intensive treatment and the formation of inhibiting antibodies towards factor VIII (FVIII) in hemophilia A has been demonstrated, the contributing effect of surgery is presently unclear. The release of immunological danger signals resulting from tissue damage during surgery in the presence of a high FVIII antigen load may elicit the formation of FVIII antibodies. The aim of this systematic review was to investigate the role of surgery in the inhibitor risk associated with intensive treatment as compared with treatment for bleeding and prophylactic administration of FVIII.

METHODS

A comprehensive literature search was performed that identified four cohort studies and three case control studies, comprising 342 inhibitor patients among a total of 957 hemophilia A patients.

RESULTS

Intensive treatment increased the inhibitor risk, most pronounced with intensive treatment of ≥ 5 exposure days (EDs) compared with < 3 EDs (OR, 4.1; 95% confidence interval, 2.6-6.5). Pooled odds ratio for inhibitor development in severe hemophilia patients that received intensive treatment for surgery at first exposure was 4.1 (95% confidence interval, 2.0-8.4) compared with treatment for bleeding or prophylaxis. Information on continuous infusion, previously treated patients and non-severe hemophilia A was insufficient for valid meta-analyses.

CONCLUSIONS

Intensive FVIII treatment for surgery at first exposure leads to a higher inhibitor risk in hemophilia A patients compared with intensive treatment for bleeding.

Intensive peri-operative use of factor VIII and the Arg593-->Cys mutation are risk factors for inhibitor development in mild/moderate hemophilia A

BACKGROUND

A severe and challenging complication in the treatment of hemophilia A is the development of inhibiting antibodies (inhibitors) directed towards factor VIII (FVIII). Inhibitors aggravate bleeding complications, disabilities and costs. The etiology of inhibitor development is incompletely understood.

OBJECTIVES

In a large cohort study in patients with mild/moderate hemophilia A we evaluated the role of genotype and intensive FVIII exposure in inhibitor development.

PATIENTS/METHODS

Longitudinal clinical data from 138 mild/moderate hemophilia A patients were retrospectively collected from 1 January 1980 to 1 January 2008 and analyzed by multivariate analysis using Poisson regression.

RESULTS

Genotyping demonstrated the Arg593Cys missense mutation in 52 (38%) patients; the remaining 86 patients had 26 other missense mutations. Sixty-three (46%) patients received intensive FVIII concentrate administration, 41 of them for surgery. Ten patients (7%) developed inhibitors, eight of them carrying the Arg593Cys mutation. Compared with the other patients, those with the Arg593Cys mutation had a 10-fold increased risk of developing inhibitors (RR 10; 95% CI, 0.9-119).The other two inhibitor patients had the newly detected mutations Pro1761Gln and Glu2228Asp. In both these patients and in five patients with genotype Arg593Cys, inhibitors developed after intensive peri-operative use of FVIII concentrate (RR 186; 95% CI, 25-1403). In five of the 10 inhibitor patients FVIII was administered by continuous infusion during surgery (RR 13; 95% CI, 1.9-86).

CONCLUSION

The Arg593Cys genotype and intensive peri-operative use of FVIII, especially when administered by continuous infusion, are associated with an increased risk for inhibitor development in mild/moderate hemophilia A.

The overlap of overweight and anaemia among women in three countries undergoing the nutrition transition

OBJECTIVE

To compare the odds of anaemia in overweight and obese (OVWT) (body mass index (BMI) > or =25) versus non-overweight (non-OVWT) (BMI<25) women in three countries at different stages of the nutrition transition.

DESIGN

Analysis of cross-sectional data.

SETTING

Nationally representative data from Mexico (1998 National Nutrition Survey), Peru and Egypt (2000 Demographic and Health Surveys) were analyzed.

SUBJECTS

Data from non-pregnant women ages 18-49 years were used.

ANALYSIS

Logistic regression was used to test whether the odds of anaemia differed by BMI category, controlling for sociodemographic factors.

RESULTS

More than half of the women were OVWT in all three countries and the prevalence of OVWT reached 77% in Egypt. Anaemia prevalence was similar across countries (28, 31 and 23% in Egypt, Peru and Mexico respectively). In Egypt, OVWT women had significantly lower odds of anaemia than non-OVWT women (OR=0.78, 95% CI: 0.68, 0.90). Similar results were found in Peru, but the difference was smaller in magnitude (OR=0.83, 95% CI: 0.71, 0.96). In Mexico, there were no differences in the odds of anaemia by BMI group.

CONCLUSIONS

These findings show that the iron needs of OVWT women in developing countries are not necessarily being met. The intakes of other micronutrients might also be insufficient. Diet quality remains an important issue even among women with sufficient energy intakes.

Differences in stunting prevalences calculated from two similar growth references may be large and inconsistent in undernourished children

BACKGROUND

In 2000, the US Centers for Disease Control and Prevention (CDC) released a set of growth references that address limitations of the internationally recommended 1977 National Center for Health Statistics (NCHS) references.

AIM

This study compares length-for-age Z-scores (LA Z-scores), height-for-age Z-scores (HA Z-scores), and age-specific stunting prevalences of undernourished children using the 1977 NCHS versus the 2000 CDC references.

SUBJECTS AND METHODS

Data come from > 2000 children from the Cebu Longitudinal Health and Nutrition Study in the Philippines. Anthropometric data were collected bimonthly from birth to 2 years, at 8.5 and 11.5 years, and at 15 years in girls and 16 years in boys. Z-scores and stunting prevalences are compared between references.

RESULTS

LA Z-scores were generally lower using the 1977 references, and stunting prevalences were higher from 0 to 2 years, with some crossover. Differences in HA Z-scores after 8.5 years of age were inconsistent in both direction and magnitude by reference and sex, with additional crossover.

CONCLUSIONS

When applied to an undernourished population, the two references in question perform differently, with inconsistencies in direction and magnitude of Z-scores and stunting prevalences. The 2000 CDC growth references are clearly an improved tool. However, there are challenges inherent in switching to a new reference that will require the attention of researchers and field workers.

Full breast-feeding for at least four months has differential effects on growth before and after six months of age among children in a Mexican community

This study examines the relationship between breast-feeding and growth from 0 to 6 and 6 to 20 mo among 185 children in a Mexican community. Infants from a previous 6-mo longitudinal study were followed up for additional anthropometric measurements at a mean age of 19.9 mo. Size at 6 mo and at follow-up were modeled as outcomes of whether infants were fully breast-fed (exclusively or predominantly breast-fed) for at least 4 mo, controlling for size at birth and 6 mo, respectively, and potential confounders. From birth to 6 mo, fully breast-fed infants had ponderal index increments of 0.07 units larger (P = 0.04) than comparison infants. There were no differences in weight. For length, an interaction between full breast-feeding and socioeconomic status (SES) was found, with fully breast-fed infants of low SES growing more than comparison infants, whereas the opposite was seen at upper SES levels. From 6 to 20 mo, fully breast-fed infants had weight and length increments of 0.53 cm (P < 0.001) and 0.72 kg (P = 0.01) smaller than those of comparison infants. For ponderal index, an interaction between mother's education and breast-feeding revealed an inverted U-shaped response across levels of education. Additionally, logistic regressions of monthly breast-feeding on lagged measurements revealed that relatively heavier infants had higher odds of being fully breast-fed at 2 and 3 mo. Our findings indicate that the benefits of full breast-feeding on growth may be most pronounced early in life. Further research of unmeasured confounders may explain the association of full breast-feeding with slower growth beyond 6 mo.