Impact of prophylaxis on health-related quality of life of boys with hemophilia: An analysis of pooled data from 9 countries.

BACKGROUND: Prophylaxis reduces the frequency of bleeds in boys with severe hemophilia and is the standard care for their management in resource-abundant countries. The effect of prophylaxis on Health-Related Quality of Life (HRQoL) has not been established, because the sample sizes of most studies are too small to explore the relationship of multiple factors that influence HRQoL. METHODS: The aim of this study was to assess the impact of hemophilia severity and treatment regimen on HRQoL and to establish the minimum important difference (MID) using the international level of score distributions. HRQoL data were pooled from 7 studies across 9 countries. HRQoL was measured using the Canadian Hemophilia Outcomes-Kids' Life Assessment Tool (CHO-KLAT). A mixed-effect linear regression analysis was employed to assess the impact of prophylaxis on the CHO-KLAT score. RESULTS: Data from 401 boys with hemophilia were analyzed (57.6% severe hemophilia and 57.6% receiving prophylaxis). The model revealed that receiving prophylaxis was significantly associated with higher HRQoL (regression coefficient 8.5, 95% confidence interval [CI] 3.9-13.1). Boys with severe hemophilia had a significantly lower HRQoL as compared to boys with moderate and mild hemophilia whose CHO-KLAT scores were 7.0 and 6.6 points higher, respectively. There was a significant interaction between treatment and disease severity (P = 0.023), indicating prophylaxis has the most significant impact in boys with severe hemophilia. Based on these pooled data, the MID of the CHO-KLAT was established at 6.5. CONCLUSIONS: This study confirms the positive effect of prophylaxis on HRQoL in boys with hemophilia in a real-world setting and provides initial benchmarks for interpreting HRQoL scores based on use of the CHO-KLAT instrument.