Longitudinal data analysis: an application to construction of a natural history profile of Duchenne muscular dystrophy

A 30-month prospective study of 27 Scandinavian boys with confirmed diagnos is of Duchenne muscular dystrophy was carried out to construct profiles of the natural history of the disease. Assessments which included measures of voluntary muscle strength and function were done at 3 monthly intervals exc ept for the first and second which were separated by 1 month. Recently deve loped statistical methods for analysis of longitudinal data with repeated o bservations on the same individual were used avoiding the problem of induce d serial correlations. This allowed for the construction of both reference and prediction profiles for the variables %MRC, motor ability, walking time for 10 In and the sum of myometry of seven muscle groups. (C) 2001 Elsevie r Science B.V. All rights reserved.