title: In non-severe hemophilia A the risk of inhibitor after intensive factor treatment is greater in older patients: a case-control study.
abstract: BACKGROUND
  Twenty-five percent of new anti-factor VIII (FVIII) antibodies (inhibitors) that complicate hemophilia A occur in those with mild and moderate disease. Although intensive FVIII treatment has long been considered a risk factor for inhibitor development in those with non-severe disease, its strength of association and the influence of other factors have remained undefined.
  
  
  OBJECTIVE
  To evaluate risk factors for inhibitor development in patients with non-severe hemophilia A.
  
  
  METHODS
  Information on clinical and demographic variables and FVIII genotype was collected on 36 subjects with mild or moderate hemophilia A and an inhibitor and 62 controls also with mild or moderate hemophilia A but without an inhibitor.
  
  
  RESULTS
  Treatment with FVIII for six or more consecutive days during the prior year was more strongly associated with inhibitor development in those ≥30years of age compared with those <30years of age [adjusted odds ratio (OR) 12.62; 95% confidence interval (CI), 2.76-57.81 vs. OR 2.54; 95% CI, 0.61-10.68]. Having previously received <50days of FVIII was also not statistically associated with inhibitor development on univariate or multivariate analysis.
  
  
  CONCLUSIONS
  These findings suggest that inhibitor development in mild and moderate hemophilia A varies with age, but does not vary significantly with lifetime FVIII exposure days: two features distinct from severe hemophilia A.
authors: Aflac Cancer Center and Blood Disorders Service and Department of Hematology and Medical Oncology, Emory University, Atlanta, GA, USA. christine.kempton@emory.edu
authors: C L
authors: CL
authors: Kempton
authors: J M
authors: JM
authors: Soucie
authors: C H
authors: CH
authors: Miller
authors: C
authors: C
authors: Hooper
authors: M A
authors: MA
authors: Escobar
authors: A J
authors: AJ
authors: Cohen
authors: N S
authors: NS
authors: Key
authors: A R
authors: AR
authors: Thompson
authors: T C
authors: TC
authors: Abshire
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D005169:Factor VIII / Q000276:immunology* / Q000627:therapeutic use; D005838:Genotype; D006467:Hemophilia A / Q000097:blood* / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020125:Mutation, Missense; D012307:Risk Factors
chemical_list: D005169:Factor VIII