title: Risk factors for peak dose dyskinesia in 100 levodopa-treated parkinsonian patients.
abstract: BACKGROUND
  No clinical parameter other than "sufficient" dopamine denervation and exposure to exogenous levodopa has been unquestionably linked to dyskinesia in levodopa-treated Parkinson's disease patients.
  
  
  METHODS
  We retrospectively analyzed data on 100 consecutive patients treated with levodopa for 1 to 18 years to identify clinical risk factors for dyskinesia. The cumulative dyskinesia-free survival probability in relation to levodopa therapy was assessed using the Kaplan-Meier method.
  
  
  RESULTS
  Overall, 56% of patients developed dyskinesia after a mean of 2.9 years, a figure similar to the average duration of levodopa treatment in the non-dyskinetic group. Dyskinetic patients were significantly younger at disease onset, but their mean latency to dyskinesia induction after levodopa initiation was not different from older dyskinetic individuals and the overall dyskinesia-free survival of younger subjects was not worse either. Dyskinetic patients were on a higher daily levodopa dose than non-dyskinetic subjects when dyskinesia emerged, but the cumulative levodopa dose used prior to dyskinesia did not discriminate dyskinetic from non-dyskinetic patients. A delay in initiating levodopa therapy of more than three years after disease onset and levodopa treatment initiation in Hoehn-Yahr stage II compared to stage I patients did not increase the probability of developing dyskinesia over time.
  
  
  CONCLUSIONS
  Since withholding levodopa therapy did not increase the risk for dyskinesia in our patients and can delay the emergence of dyskinesia after onset of parkinsonian symptom, a trial with a dopaminomimetic agonist as initial treatment appears logical.
authors.affiliation: Neurobiology Research Centre, Hôpital de l'Enfant-Jésus, Québéc City (Québec), Canada.
authors.forename: P J
authors.initials: PJ
authors.lastname: Blanchet
authors.forename: P
authors.initials: P
authors.lastname: Allard
authors.forename: L
authors.initials: L
authors.lastname: Grégoire
authors.forename: F
authors.initials: F
authors.lastname: Tardif
authors.forename: P J
authors.initials: PJ
authors.lastname: Bédard
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000188:drug therapy*; D010300:Parkinson Disease / Q000188:drug therapy*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors
chemical_list: D007980:Levodopa