[Prognostic factors for inability to walk independently in patients with multiple system atrophy]

Objective: To explore the prognostic factors for inability to walk independently in patients with multiple system atrophy (MSA). Methods: A total of 123 patients with clinically confirmed MSA admitted to Navy General Hospital and Dongfang Hospital affiliated to the Second Clinical Medical College of Beijing University of Chinese Medicine, from February 2013 to February 2016, were retrospectively reviewed. Clinical data and all records were collected and all subjects were followed up by a telephone call in February 2016. The second milestone of activities of daily living scale (ADL), defined as inability to walk independently, was taken as the primary outcome. Eight possible prognostic factors were investigated and the survival analysis was performed with Cox proportional hazards model regression. Results: Of all the MSA patients, 74 subjects were men and 49 were women with a sex radio of 1.51∶1(M∶F). Seventy cases were diagnosed with MSA-cerebellar type (MSA-C) and 53 with MSA-Parkinson type (MSA-P) (C∶P=1.32∶1). Mean age at the onset of first symptom was (53±8) years old. All patients had severe autonomic nervous dysfunction. At the last follow-up, 56 cases (45.5%) were unable to walk independently. The median survival time from the onset of MSA to inability to walk independently was 73 months. The age of onset ≥ 55 years (HR=1.969, 95%CI 1.095-3.542, P=0.024) and the interval time from disease onset to combined motor and autonomic involvement≤3 years (HR=2.308, 95%CI 1.158-4.600, P=0.017) were independent prognostic factors for inability to walk independently, while gender, MSA clinical subtypes, initial symptoms, alcohol intake, smoking and toxic exposure were not indicators for independent walking (P>0.05). Conclusions: The prognostic factors for inability to walk independently in patients with MSA are the age of onset ≥55 years and the interval time from disease onset to combined motor and autonomic involvement≤3 years. Although factors including gender, MSA clinical subtypes, initial symptoms, alcohol intake, smoking and toxic exposure are not the predictive factors for inability to walk independently in our MSA patients, their roles in the prognosis of MSA still need further investigation.