title: The effect of study design and analysis methods on recovery rates in Bell's palsy.
abstract: OBJECTIVE
  We investigated how study design affects the rate of recovery in Bell's palsy.
  
  
  METHODS
  Prospective, randomized, double-blind, placebo-controlled, multicenter trial.
  
  
  METHODS
  Data were extracted from the Scandinavian Bell's palsy study, which included 829 patients. The study design was factorial; 416 patients given prednisolone, 413 not given prednisolone, 413 patients given valacyclovir, 416 not given valacyclovir. Data were analyzed with intention-to-treat principle and complete-case analysis methods and recovery was defined as Sunnybrook score 100, House-Brackmann grade I or < or =grade II at 12 months.
  
  
  RESULTS
  With the intention-to-treat principle and last-observation-carried-forward method (n = 829) and recovery defined as Sunnybrook 100, 300 of the 416 patients (72%) receiving prednisolone had recovered compared with 237 of the 413 (57%) who did not receive prednisolone (P < .0001). With recovery defined as House-Brackmann grade I, the corresponding recovery rates were 324 of 416 (78%) and 266 of 413 (64%) (P < .0001). With complete-case analysis and recovery defined House-Brackmann grade I (n = 782), 335 of 389 patients (86%) given prednisolone recovered compared with 277 of 393 (70%) in the group not given prednisolone (P < .0001). With recovery defined as House-Brackmann < or =grade II (n = 797), the corresponding recovery rates were 380 of 396 (96%) and 353 of 401 (88%) (P < .0001). The analysis method affected the recovery rates in the valacyclovir and no-valacyclovir groups in a similar way as in the prednisolone and no-prednisolone groups.
  
  
  CONCLUSIONS
  Recovery rates in a Bell's palsy study are substantially affected by the choice of analysis method and definition of recovery.
authors: Department of Plastic and Reconstructive Surgery, Uppsala University Hospital, Uppsala, Sweden. thomas.moe.berg@akademiska.se
authors: Thomas
authors: T
authors: Berg
authors: Elin
authors: E
authors: Marsk
authors: Mats
authors: M
authors: Engström
authors: Malou
authors: M
authors: Hultcrantz
authors: Nermin
authors: N
authors: Hadziosmanovic
authors: Lars
authors: L
authors: Jonsson
mesh_terms: D000212:Acyclovir / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D000998:Antiviral Agents / Q000627:therapeutic use*; D020330:Bell Palsy / Q000188:drug therapy*; D003627:Data Interpretation, Statistical; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000627:therapeutic use*; D011446:Prospective Studies; D020127:Recovery of Function; D012107:Research Design; D016896:Treatment Outcome; D000077483:Valacyclovir; D014633:Valine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000893:Anti-Inflammatory Agents; D000998:Antiviral Agents; D011239:Prednisolone; D014633:Valine; D000077483:Valacyclovir; D000212:Acyclovir