title: Risk and course of motor complications in a population-based incident Parkinson's disease cohort.
abstract: BACKGROUND
  Motor complications may become major challenges in the management of patients with Parkinson's disease. In this study, we sought to determine the incidence, risk factors, evolution, and treatment of motor fluctuations and dyskinesias in a population-representative, incident Parkinson's disease cohort.
  
  
  METHODS
  In this prospective population-based 5-year longitudinal study, we followed 189 incident and initially drug-naïve Parkinson's disease patients biannually for detailed examination of dyskinesias and motor fluctuations as defined by the Unified Parkinson's disease Rating Scale. We performed Kaplan-Meier survival and Cox regression analyses to assess cumulative incidence and risk factors of these motor complications.
  
  
  RESULTS
  The 5-year cumulative incidence of motor complications was 52.4%. Motor fluctuations occurred in 42.9% and dyskinesias in 24.3%. Besides higher motor severity predicting both motor fluctuations (p = 0.016) and dyskinesias (p < 0.001), lower age at diagnosis predicted motor fluctuations (p = 0.001), whereas female gender predicted dyskinesias (p = 0.001). Actual levodopa dose at onset of motor fluctuations (p = 0.037) or dyskinesias (p < 0.001) rather than initial treatment with levodopa (p > 0.1) independently predicted development of motor complications. Motor fluctuations reversed in 37% and dyskinesias in 49% of patients on oral treatment and remained generally mild in those with persistent complications. No patients received device-aided therapies during the study.
  
  
  CONCLUSIONS
  More than 50% in the general Parkinson's disease population develop motor complications within 5 years of diagnosis. However, they remain mild in the vast majority and are reversible in a substantial proportion of patients.
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, PO Box 8100, N-4068 Stavanger, Norway; Department of Neurology, Stavanger University Hospital, Stavanger, Norway. Electronic address: anders.bjornestad@outlook.com.
authors.forename: Anders
authors.initials: A
authors.lastname: Bjornestad
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, PO Box 8100, N-4068 Stavanger, Norway; Department of Neurology, Stavanger University Hospital, Stavanger, Norway. Electronic address: elin.bjelland.forsaa@sus.no.
authors.forename: Elin B
authors.initials: EB
authors.lastname: Forsaa
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, PO Box 8100, N-4068 Stavanger, Norway; Department of Neurology, Stavanger University Hospital, Stavanger, Norway. Electronic address: kenn.freddy.pedersen@sus.no.
authors.forename: Kenn Freddy
authors.initials: KF
authors.lastname: Pedersen
authors.affiliation: Department of Neurology, Haukeland University Hospital, PO Box 1400, N-5021 Bergen, Norway; Institute of Clinical Medicine, University of Bergen, Norway. Electronic address: ole-bjorn.tysnes@helse-bergen.no.
authors.forename: Ole-Bjorn
authors.initials: OB
authors.lastname: Tysnes
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, PO Box 8100, N-4068 Stavanger, Norway. Electronic address: jpl@sus.no.
authors.forename: Jan Petter
authors.initials: JP
authors.lastname: Larsen
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, PO Box 8100, N-4068 Stavanger, Norway; Department of Neurology, Stavanger University Hospital, Stavanger, Norway. Electronic address: algu@sus.no.
authors.forename: Guido
authors.initials: G
authors.lastname: Alves
mesh_terms: D000367:Age Factors; D000368:Aged; D000978:Antiparkinson Agents / Q000009:adverse effects; D015331:Cohort Studies; D018450:Disease Progression; D004409:Dyskinesia, Drug-Induced / Q000453:epidemiology / Q000209:etiology; D020820:Dyskinesias / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D007980:Levodopa / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D009664:Norway / Q000453:epidemiology; D010300:Parkinson Disease / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology* / Q000503:physiopathology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D054063:Superior Sagittal Sinus
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Dyskinesias; Motor complications; Motor fluctuations; Parkinson's disease; Risk factors