Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
JAMA. 2012 Oct 10;308(14):1452-9. doi: 10.1001/jama.2012.12727.
Vigorous physical activity is thought to increase risk of bleeds in children with hemophilia, but the magnitude of the risk is unknown.
To quantify the transient increase in risk of bleeds associated with physical activity in children with hemophilia.
DESIGN, SETTING, AND PARTICIPANTS: A case-crossover study nested within a prospective cohort study was conducted at 3 pediatric hemophilia centers in Australia between July 2008 and October 2010. A total of 104 children and adolescent boys aged 4 through 18 years with moderate or severe hemophilia A or B were monitored for bleeds for up to 1 year. Following each bleed, the child or parent was interviewed to ascertain exposures to physical activity preceding the bleed. Physical activity was categorized according to expected frequency and severity of collisions. The risk of bleeds associated with physical activity was estimated by contrasting exposure to physical activity in the 8 hours before the bleed with exposures in two 8-hour control windows, controlling for levels of clotting factor in the blood.
Association of physical activity and factor level with risk of bleeding.
The participants were observed for 4839 person-weeks during which time 436 bleeds occurred. Of these, 336 bleeds occurred more than 2 weeks after the preceding bleed and were used in the primary analysis of risk. Compared with inactivity and category 1 activities (eg, swimming), category 2 activities (eg, basketball) were associated with a transient increase in the risk of bleeding (30.6% of bleed windows vs 24.8% of first control windows; odds ratio, 2.7; 95% CI, 1.7-4.8, P < .001). Category 3 activities (eg, wrestling) were associated with a greater transient increase in risk (7.0% of bleed windows vs 3.4% of first control windows; odds ratio, 3.7; 95% CI, 2.3-7.3, P < .001). To illustrate absolute risk increase, for a child who bleeds 5 times annually and is exposed on average to category 2 activities twice weekly and to category 3 activities once weekly, exposure to these activities was associated with only 1 of the 5 annual bleeds. For every 1% increase in clotting factor level, bleeding incidence was lower by 2% (95% CI, 1%-3%; P = .004).
In children and adolescents with hemophilia, vigorous physical activity was transiently associated with a moderate relative increase in risk of bleeding. Because the increased relative risk is transient, the absolute increase in risk of bleeds associated with physical activity is likely to be small.
剧烈的身体活动被认为会增加儿童血友病患者出血的风险，但风险的程度尚不清楚。
量化与血友病儿童身体活动相关的出血风险的短暂增加。
设计、地点和参与者：这是一项嵌套在前瞻性队列研究中的病例交叉研究，于 2008 年 7 月至 2010 年 10 月在澳大利亚的 3 个儿科血友病中心进行。共有 104 名年龄在 4 至 18 岁之间的男孩接受了监测，以观察他们在 1 年内是否有出血。在每次出血后，通过访谈孩子或家长来确定出血前身体活动的暴露情况。根据预期的碰撞频率和严重程度对身体活动进行分类。通过对比出血前 8 小时的身体活动暴露与两个 8 小时对照窗口的暴露，控制血液中凝血因子的水平，估计身体活动与出血风险之间的关联。
身体活动和因子水平与出血风险的关系。
在 4839 人周的观察期间，共有 436 例出血发生。其中，336 例出血发生在之前出血后 2 周以上，用于主要的出血风险分析。与不活动和第 1 类活动（如游泳）相比，第 2 类活动（如篮球）与出血风险的短暂增加相关（30.6%的出血窗口比第 1 个对照窗口的 24.8%；比值比，2.7；95%置信区间，1.7-4.8，P <.001）。第 3 类活动（如摔跤）与风险的增加更为显著（7.0%的出血窗口比第 1 个对照窗口的 3.4%；比值比，3.7；95%置信区间，2.3-7.3，P <.001）。为了说明绝对风险增加，对于每年出血 5 次、平均每周接触第 2 类活动 2 次和第 3 类活动 1 次的儿童，如果接触这些活动，与每年 5 次出血中的 1 次相关。凝血因子水平每增加 1%，出血发生率就会降低 2%（95%置信区间，1%-3%；P =.004）。
在患有血友病的儿童和青少年中，剧烈的身体活动与出血风险的适度相对增加短暂相关。由于相对风险的增加是短暂的，因此与身体活动相关的出血风险的绝对增加可能很小。
