The natural history of idiopathic autonomic failure: The IAF-BO cohort study

Neurology. 2018 Sep 25;91(13):e1245-e1254. doi: 10.1212/WNL.0000000000006243. Epub 2018 Aug 22.

Abstract

Objective: To retrospectively describe clinical and instrumental features of a cohort of patients with at least a 5-year history of idiopathic autonomic failure (IAF) longitudinally evaluated at the Autonomic Unit of the University of Bologna (IAF-Bo cohort).

Methods: We identified patients with at least a 5-year history of IAF who were referred to our department from 1989 to 2016 and evaluated at least once a year during the disease course. Clinical and instrumental data were collected from medical records. Clinical variables were categorized as early if presenting within 3 years from disease onset. Predictors associated with conversion to other synucleinopathies were identified in a Cox regression analysis.

Results: The IAF-Bo cohort included 50 patients (39 male, 19 deceased at the last follow-up). At the last follow-up visit, 34 patients retained IAF phenotype (ncIAF group), while 16 developed a CNS synucleinopathy (converters group). Specific clinical and instrumental features were represented differently in the converters and ncIAF groups. The converters group showed a higher risk of death than the ncIAF group. Early onset of urinary dysfunction, early onset of REM sleep behavior disorder, and a Valsalva ratio ≥1.25 were identified as variables associated with phenoconversion.

Conclusions: This is one of the largest studies on the natural history of a cohort of patients with at least a 5-year history of IAF, showing a percentage of phenoconversion of 32%. We demonstrated that specific clinical and instrumental features entail an increased probability of phenoconversion. These findings could contribute to a better definition of the nature of IAF and to the identification of early markers of phenoconversion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autonomic Nervous System Diseases / epidemiology*
  • Autonomic Nervous System Diseases / physiopathology*
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Neurodegenerative Diseases / epidemiology
  • Neurodegenerative Diseases / physiopathology
  • Proteostasis Deficiencies / epidemiology
  • Proteostasis Deficiencies / physiopathology
  • Retrospective Studies
  • Survival Analysis