PB0504 - Exploratory study for characterization of joint condition and bleeding phenotype of hemophilia carriers

Background: Bleeding phenotype (BPh) and joint condition in hemophilia carriers (HC) is poorly known because, in general, HC reject medical follow-up.

Aims: To carry out a local registry of HC and determine their joint condition, BPh and their correlation with the basal factor (F) VIII/FIX levels and global clotting capacity (GCC).

Methods: Center databases, support from the Malaga Hemophilia Association and hemophilia patients were the sources of information. After family identification, HC were invited randomly to participate. Joint condition and BPh were evaluated by the HEAD-US and the ISTH-BAT scores, respectively. GCC was evaluated by rotational thromboelastography (ROTEM®, naTEM® test) using 20 subjects as healthy controls. Data are reported using the median [25-75 percentiles]. P-value < 0.05 was considered significant.

Results: Seventy families were identified and 19 patients were evaluated. Six patients were excluded: 3 due to presence of von Willebrand disease and 3 due to mild hemophilia. In the remained 13 patients (true HC without other known coagulopathy) the median age was 48.1 [38.1-61.3] years old and basal FVIII/FIX= 63.1 [54.3-82.1] IU/dL. Slight joint damage (JD) (HEAD-US= 0.0 [0.0-3.0]) (minimum-maximum values= 0-5) and mild BPh (ISTH-BAT= 3.0 [3.0-5.0] were observed except for one HC with a severe BPh (ISTH-BAT= 14, FVIII= 82.1% and ROTEM parameters within the normal ranges). Overall, HC values of the ROTEM parameters were similar to the healthy controls (p < 0.05). No relationship between JD or BPh and basal FVIII/FIX levels or ROTEM parameters were found.

Conclusion(s): HC may present mild JD accompanied by a mild to severe BPh. None of these clinical variables showed correspondence with the basal levels of FVIII/FIX or ROTEM parameters. Larger studies are needed to expand knowledge on the JD and BPh of HC to elucidate the veracity of our preliminary findings and the causes that could be involved in these alterations.