Timed rise from floor as a predictor of disease progression in Duchenne muscular dystrophy: An observational study

Background Theroleoftimeditems,andmorespecifically,ofthetimetorisefromthefloor,hasbeen reportedasanearlyprognosticfactorfordiseaseprogressionandlossofambulation.The aimofourstudywastoinvestigatethepossibleeffectofthetimetorisefromthefloorteston thechangesobservedonthe6MWTover12monthsinacohortofambulantDuchenneboys. Subjectsandmethods Atotalof48712-monthdatapointswerecollectedfrom 215ambulantDuchenneboys.The agerangedbetween5.0and20.0years(mean8.48 ±2.48DS). Results Theresultsofthetimetorisefrom theflooratbaselineranged from1.2to29.4secondsin theboyswhocouldperformthetest.49patientswereunabletoperform thetestatbaseline and87at12monthThe6MWTvaluesrangedfrom82to567metersatbaseline.3patients losttheabilitytoperformthe6mwtat12months. Thecorrelationbetweentimetorisefrom thefloorand6MWTatbaselinewashigh(r=0.6,p<0.01). Conclusions Bothtimetorisefrom thefloorandbaseline6MWTwererelevantforpredicting6MWT changesinthegroupabovetheageof7years,withnointeractionbetweenthetwomeasures,astheimpactoftimetorisefromtheflooron6MWTchangewassimilarinthe patientsbelowandabove350m.Our resultssuggestthat,timetorisefrom thefloorcanbe consideredanadditionalimportantprognosticfactorof12monthchangesonthe6MWT and,moregenerally, ofdiseaseprogression.