Leiden Muscular Dystrophy pages

Age-related events in DMD

(last modified February 28, 2004)

Contributed by Ton van Essen (Groningen, NL). The full manuscript was published as Chapter 3 of the PhD-thesis of Ton van Essen as The natural history of Duchenne muscular dystrophy. Analysis of data from a Dutch survey and review of age related events. Anthonie J. van Essen, Joke B.G.M. Verheij, Jennita Reefhuis, Vaclav Fidler, Jacobus H. Begeer, Marianne de Visser, Leo P. ten Kate.     (full text as .PDF copy)


We collected data on 473 Dutch Duchenne muscular dystrophy patients born and diagnosed during 1961-1982. Life-time events were analysed for birth years 1961-1974 to avoid possible effects of downward bias of age at diagnosis resulting from inclusion of birth years 1975-1982. Mean and median in certain DMD patients were calculated for, age at onset: 2.4 and 2.0 years (range 0.5-7 years), age at first walking: 1.8 and 1.7 years (range 0.8-4.5 years), age at diagnosis: 5.3 and 5.0 years (range 0-10 years), diagnostic delay: 3.1 and 2.7 years (range 0-9.5 years), chairbound age: 9.5 and 9.0 years (range 6-12 years) and age at death: 16.7 and 16.8 years (range 3.1-21.3 years). There was a significant (P<0.001) downward trend in age at diagnosis and diagnostic delay during 1961-1974. Age at diagnosis is significantly (P<0.01) lower in boys with a retarded development (4.6 years) compared to boys presenting with locomotor problems (5.8 years). Initial locomotor problems were found in 47.6% of cases. Coincidental presymptomatic diagnosis was found in 3 cases (1.1%) by elevated creatine kinase or transaminase activities. Presymptomatic diagnosis because of family history was made in 1.5% of cases. Respiratory insufficiency (25.6%), pulmonary infections (18.6%) and cardiac complications (30.2%) were the main causes of death. Median survival was 19.4 years (95%CI 19.0-19.8 years; follow-up 1961-1985) for patients who had reached an age of 10 years or more and 23.6% of patients survived at least 23.3 years. Age of loss at ambulation was correlated positively with survival. On average deceased patients died 7.9 years after becoming chairridden (range 2.6-12.4 years). In 23 unrelated sib pairs median age at diagnosis in the second affected boy was significantly (P=0.006) lower (5.0 years) than in the first affected boy (6.0 years). No significant difference was found in the distributions of life-time events between 376 patients classified as certain DMD and 97 patients classified as probable or possible DMD, exept for shorter survival in possible DMD patients.

Previous reports on life-time events in DMD did not correct their results for incomplete ascertainment of cases in recent birth years and for limited follow-up of the patients. This may have lowered the estimates of age related events. Our observation of a fall in age at diagnosis and diagnostic delay in a cohort with high ascertainment is noteworthy. Suggestions that a standing regimen, scoliosis surgery and treatment of pulmonary and cardiac complications prolong the life-span of DMD patients need further evaluation.

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