Respiratory muscle strength and quality of life in myotonic dystrophy patients [Força muscular respiratória e qualidade de vida em pacientes com distrofia miotonica]

Introduction: studies on quality of life in myotonic dystrophy (md) are scarce and the relationship between respiratory muscle strength and health-related quality of life (hrqol) has yet to be determined. the present study aims to investigate respiratory muscle strength and hrqol and their relationship in md patients. methods: twenty-three patients (13 men,aged 40 ± 16 years) with md were evaluated for pulmonary function,maximal inspiratory and expiratory pressure (mip and mep,respectively),sniffnasal inspiratory pressure (snip) and hrqol using the short form (sf-36) quality of life questionnaire. results: respiratory muscle strength values were 71 ± 20 cmh2o (64 % predicted),76 ± 32 cmh2o (70 % predicted),and 79 ± 28 cmh2o (80 % predicted) for mep,mip,and snip respectively. significant differences were found in the sf-36 domains of physical functioning 58.7 ± 31.4 vs 84.5 ± 23 (p < 0.01,95 % ci = 1.6-39.9) and physical problems 43.4 ± 35.2 vs 81.2 ± 34 (p < 0.001,95 % ci = 19.4-6.1) when compared with the reference values. according to single linear regression analysis,mip explains 29 % of the variance in physical functioning,18 % of physical problems and 20 % of vitality. conclusions: individuals with md have reduced expiratory muscle strength. hrqol may be more impaired in some physical domains,which might be influenced by variations in inspiratory muscle strength. © 2010 published by elsevier españa,s.l. on behalf of sociedade portuguesa de pneumologia. all rights reserved.