Longitudinal data of serum creatine kinase levels and motor, pulmonary, and cardiac functions in 337 patients with Duchenne muscular dystrophy.

INTRODUCTION/AIMS: Duchenne muscular dystrophy (DMD) presents with skeletal muscle weakness, followed by cardiorespiratory involvement. The need for longitudinal data regarding DMD that could serve as a control for determining treatment efficacy in clinical trials has increased notably. The present study examined the longitudinal data of Japanese DMD patients collectively and assessed individual patients with pathogenic variants eligible for exon-skipping therapy. METHODS: Patients with DMD who visited Kobe University Hospital between March 1991 and March 2019 were enrolled. Data between the patients' first visit until age 20 years were examined. RESULTS: Three hundred thirty-seven patients were included. Serum creatine kinase levels showed extremely high values until the age of 6 years and a rapid decline from ages 7-12 years. Both the median 10-m run/walk velocity and rise-from-floor velocity peaked at the age of 4 years and declined with age. The values for respiratory function declined from the age of 11 years. The median left ventricular ejection fraction was >60% until the age of 12 years and rapidly declined from ages 13-15 years. Examination of the relationship between pathogenic variants eligible for exon-skipping therapy and longitudinal data revealed no characteristic findings. DISCUSSION: We found that creatine kinase levels and motor, respiratory, and cardiac functions each exhibited various changes over time. These findings provide useful information about the longitudinal data of several outcome measures for patients with DMD not receiving corticosteroids. These data may serve as historical controls in comparing the natural history of DMD patients not on regular steroid use in appropriate clinical trials.

Ambulatory capacity in Japanese patients with Duchenne muscular dystrophy.

INTRODUCTION: Few long-term cohort studies have addressed changes in the ambulatory capacity of patients with Duchenne muscular dystrophy (DMD), and no reports have evaluated the factors associated with ambulatory capacity in Japanese. METHODS: The longitudinal changes in 10-meter run/walk ability and associated factors were retrospectively investigated using general practice data. The factors associated with loss of this ability before the age of 10 years were explored by logistic regression analysis using parameters of genetic mutations, corticosteroid use, the manual muscle test (MMT), and the joint range of motion (ROM). Explanatory variables of MMT grade included hip flexors, knee flexors, and knee extensors; ROM included hip extension, knee extension, and ankle dorsiflexion. RESULTS: Among 418 patients diagnosed with DMD, 145 patients underwent the 10-meter run/walk test between March 1999 and July 2015. The median age at loss of 10-meter walking ability was 10.4 (interquartile range: 9.2-11.3) years. The 10-meter run/walk speed began to decline 3 years before the loss of 10-meter walking ability, and the median was <1 m/s 1 year before the loss of 10-meter walking ability. MMT grade for knee flexors and ROM for hip and knee extension were identified as independent predictors. Based on the change over time of these three items, limitation of the hip extension ROM preceded knee flexor weakness and limitation of the knee extension ROM. CONCLUSIONS: This knowledge can be used in optimizing rehabilitation programs and evaluating effect of treatment for DMD patients.