Limited evidence to strong evidence was found for reliability in various chronic conditions .
Little evidence was available for responsiveness and measurement error .
Studies showed large variability in test procedures despite existing guidelines for the performance of the 6MWT .
Evidence for measurement properties of the 6MWT  varies largely among chronic pediatric conditions .
BACKGROUND The Six-Minute Walk Test ( 6MWT ) is increasingly being used as a functional outcome measure for chronic pediatric conditions .
Knowledge about its measurement properties is needed to determine whether it is an appropriate test to use .
PURPOSE The purpose of this study was to systematic ally review all published clinimetric studies on the 6MWT in chronic pediatric conditions .
Systemic administration of PRO051 in Duchenne's muscular dystrophy.
BACKGROUND Local intramuscular administration of the antisense oligonucleotide PRO051 in patients with Duchenne 's muscular dystrophy with relevant mutations was previously reported to induce the skipping of exon 51 during pre-messenger RNA splicing of the dystrophin gene and to facilitate new dystrophin expression in muscle-fiber membranes . The present phase 1 - 2a study aim ed to assess the safety , pharmacokinetics , and molecular and clinical effects of systemically administered PRO051 . METHODS We administered weekly abdominal subcutaneous injections of PRO051 for 5 weeks in 12 patients , with each of four possible doses ( 0.5 , 2.0 , 4.0 , and 6.0 mg per kilogram of body weight ) given to 3 patients . Changes in RNA splicing and protein levels in the tibialis anterior muscle were assessed at two time points . All patients subsequently entered a 12-week open-label extension phase , during which they all received PRO051 at a dose of 6.0 mg per kilogram per week . Safety , pharmacokinetics , serum creatine kinase levels , and muscle strength and function were assessed . RESULTS The most common adverse events were irritation at the administration site and , during the extension phase , mild and variable proteinuria and increased urinary α(1)-microglobulin levels ; there were no serious adverse events . The mean terminal half-life of PRO051 in the circulation was 29 days . PRO051 induced detectable , specific exon-51 skipping at doses of 2.0 mg or more per kilogram . New dystrophin expression was observed between approximately 60 % and 100 % of muscle fibers in 10 of the 12 patients , as measured on post-treatment biopsy , which increased in a dose-dependent manner to up to 15.6 % of the expression in healthy muscle . After the 12-week extension phase , there was a mean ( ±SD ) improvement of 35.2±28.7 m ( from the baseline of 384±121 m ) on the 6-minute walk test . CONCLUSIONS Systemically administered PRO051 showed dose-dependent molecular efficacy in patients with Duchenne 's muscular dystrophy , with a modest improvement in the 6-minute walk test after 12 weeks of extended treatment . ( Funded by Prosensa Therapeutics ; Netherl and s National Trial Register number , NTR1241 . )
Limited evidence to strong evidence was found for reliability in various chronic conditions .
Little evidence was available for responsiveness and measurement error .
Studies showed large variability in test procedures despite existing guidelines for the performance of the 6MWT .
Evidence for measurement properties of the 6MWT  varies largely among chronic pediatric conditions .
BACKGROUND The Six-Minute Walk Test ( 6MWT ) is increasingly being used as a functional outcome measure for chronic pediatric conditions .
Knowledge about its measurement properties is needed to determine whether it is an appropriate test to use .
PURPOSE The purpose of this study was to systematic ally review all published clinimetric studies on the 6MWT in chronic pediatric conditions .