Disease course and prognostic factors of progressive muscular atrophy.
OBJECTIVE
To investigate the natural history and prognostic factors in patients with nonhereditary, adult-onset progressive muscular atrophy.


METHODS
Inception cohort conducted for 18 months. Settings Three university hospitals in the Netherlands (referral centers for neuromuscular diseases). Patients Thirty-seven consecutive patients newly diagnosed (onset of weakness <4 years) with progressive muscular atrophy enrolled between 1998 and 2001.


METHODS
Disease progression was measured at 0, 3, 6, 9, 12, 15, and 18 months by the Medical Research Council sum score, number of affected limb regions, and the Amyotrophic Lateral Sclerosis Functional Rating Scale score. Multivariate linear regression analysis was used to identify predictors of poor outcome. Clinical features and classification of phenotype during follow-up were evaluated. Survival analysis was planned after data collection, performed 5 years after the end of the study.


RESULTS
Significant decline of muscle strength (mean, 6.01 Medical Research Council sum score points [95% confidence interval [CI], 3.84-8.18]; P value <.001) and significant increase in the number of affected regions (mean, 0.53 affected region [95% CI, 0.42-0.65]; P value <.001) and functional impairment (mean, 1.85 Amyotrophic Lateral Sclerosis Functional Rating Scale score points [95% CI, 1.38-2.33]; P value <.001) were found. Vital capacity (VC) at baseline and decrease of VC during the first 6 months were significantly associated with outcome. Median survival duration after initial weakness was 56 months.


CONCLUSIONS
This study shows that patients with progressive muscular atrophy have a relentlessly progressive disease course. Patients with a low VC at baseline and a sharp decline of VC during the first 6 months have an especially poor prognosis.
Visser
Jeldican
J
Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands. j.visser@amc.uva.nl
van den Berg-Vos
Renske M
RM
Franssen
Hessel
H
van den Berg
Leonard H
LH
Wokke
John H
JH
de Jong
J M Vianney
JM
Holman
Rebecca
R
de Haan
Rob J
RJ
de Visser
Marianne
M
D000328:Adult; D000368:Aged; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006785:Hospitals, University; D006801:Humans; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053580:Muscle Strength / Q000502:physiology; D018908:Muscle Weakness / Q000503:physiopathology; D009133:Muscular Atrophy / Q000473:pathology* / Q000503:physiopathology*; D009426:Netherlands; D011379:Prognosis; D013997:Time Factors