Duchenne型肌营养不良患儿四肢肌力随年龄变化特征及其与6min步行距离的相关性

关键词：Duchenne型肌营养不良  6min步行距离  肌力  相关性

Keywords:Duchenne muscular dystrophy  6 minutes walking distance  muscle strength  correlation

摘要：

      摘要 目的：观察Duchenne型肌营养不良（DMD）患儿四肢肌力随年龄变化的特征，分析四肢肌力与6min步行距离的关系。 方法：纳入在2019年8月至2020年10月期间，就诊于北京大学第一医院康复医学科门诊的Duchenne型肌营养不良患儿。采用手持式肌力测试仪（HHD）对上、下肢主要肌群进行等长肌力测定，采用6min步行试验（6MWT）评定步行功能，同时收集受试者年龄、身高、体重等一般资料。采用二次曲线拟合分析患儿四肢肌力随年龄变化特征，采用Pearson检验分析四肢各组肌群肌力与6min步行距离（6MWD）间的相关性，将6MWD作为应变量，10组肌群肌力、年龄、BMI作为自变量，进行多重线性回归分析。 结果：本研究共纳入54例，年龄为5—10岁的DMD男性患儿，膝伸展肌群肌力随着年龄增长呈下降趋势；6MWD为（369.6±72.1）m，（7.00—7.99）岁患儿的6MWD均值最大，7岁以上患儿6MWD均值逐渐下降。6MWD与肘伸展（r=0.448，P＜0.01）、膝屈曲（r=0.460，P＜0.01）、膝伸展（r=0.418，P＜0.01）肌群肌力呈中度正相关，与肩外展（r=0.273，P＜0.05）、踝背屈（r=0.273，P＜0.05）、踝跖屈（r=0.313，P＜0.05）肌群肌力呈低度正相关。多重线性回归分析结果显示，影响6MWD的主要因素为膝伸展肌群肌力（P<0.05），校正决定系数为0.47。年龄、BMI以及其他肌群肌力对6MWD的影响无显著性意义（P>0.05）。 结论：5—10岁的DMD患儿的膝伸展肌群肌力随年龄增长而下降。大于7岁的患儿6MWD有逐年下降的趋势。膝周肌群、上肢近端肌群和踝周肌群肌力与患儿的步行功能相关。其中膝伸展肌群肌力是影响6MWD的主要因素，因此为维持DMD患儿步行功能，需更加关注膝周肌群肌力。

Abstract:

      Abstract Objective： To observe the changes of limb muscle strength with age in children with Duchene muscular dystrophy (DMD) and to analyze the correlation between the limb muscle strength and the 6-minute walking distance (6MWD). Method： Children with DMD who visited the Department of Rehabilitation Medicine in the Peking University 1st Hospital from August 2019 to October 2020 were recruited as participants. The Hand-held dynamometer (HHD) was used to measure the isometric muscle strength of upper and lower limb muscle groups and the 6-minute walking test (6MWT) was used to measure walking function. Basic information such as age， height， and body weight was gathered. The changes in limb muscle strength with age were analyzed using the quadratic curve fitting. Correlation between the limb muscle strength and 6-minute walking distance was analyzed using the Pearson test. 6MWD was taken as the dependent variable and 10 groups of muscle strength， age， and BMI were taken as independent variables， then the dependent variable and independent variables were analyzed using the multiple linear regression. Result： A total of 54 boys with DMD aged 5—10 years were included. The muscle strength of the knee extensor muscle group showed a decreasing trend. The average of 6MWD was （369.6±72.1）m and the mean 6MWD was the largest in the participants aged 7.00—7.99 years， and decreased successively in the children with DMD aged over 7 years. There were moderately positive correlations between the 6MWD and muscle strength of elbow extensors (r=0.448， P<0.01)， knee flexors (r=0.460， P<0.01)， knee extensors (r=0.418， P<0.01)， and low positive correlations between 6MWD and shoulder abductors (r=0.273， P<0.05)， ankle dorsiflexors (r=0.273， P<0.05)， and ankle plantar flexors (r=0.313， P<0.05). The results of multiple linear regression analysis showed that the main factor affecting 6MWD was muscle strength of knee extensors (P<0.05) and the correction coefficient of determination was 0.47. Age， BMI and strength of other muscle groups had no significant effect on 6MWD (P>0.05). Conclusion： The muscle strength of the knee extensor group decreases with age in children with DMD aged 5-10 years. A decreasing trend of 6MWD with age is shown in children older than 7 years. The walking function of children with DMD is related to the muscle strength around the knee， the proximal upper limb， and the ankle. The muscle strength of the knee extensor group is the main factor affecting 6MWD. Therefore， increased attention should be paid to the muscle strength around the knee to maintain the walking function of children with DMD.