Researchers have identified potential baseline and ceiling effects with use of the Unified Multiple System Atrophy Rating Scale (UMSARS), which could have important implications for clinical trial planning.
Dr Miguel Pérez from the NYU School of Medicine, in New York, USA, said previous studies have shown a wide variability in disease progression as measured by UMSARS: reported 1-year rates have ranged from 3.9-6.5 with UMSARS-I and from 3.6-8.2 with UMSARS-II.
Dr Pérez and colleagues hypothesized that this variability could be due to differences in severity at enrollment and a potential ceiling effect in the rating scale: patients in more advanced stages may appear to worsen less.