title: Clinical applications for change-point analysis of herpes zoster pain.
abstract: Pain is the most frequent and disabling complication of herpes zoster. The analysis of pain severity data is complicated by the nonlinear rate of resolution. Further, three distinct phases characterize pain resolution--acute, subacute, and chronic. Using two clinical trial datasets as the bases for analyses, the rates of baseline pain resolution were computed across each of three phases and compared for age, severity of pain at onset, and number of lesions at baseline. The results defined transition points of 24.4 +/- 3.34 for the subacute phase and 110.3 +/- 11.9 days for the chronic phase. The model demonstrated a treatment effect of valiciclovir (VACV) during the subacute phase as compared to acyclovir (ACV) (P = 0.006) and supports effects of age, baseline pain and number lesions on pain cessation rates in the acute phase. This model verifies three phases of zoster pain and delineates the impact of treatment and other factors on the phase-specific rates of pain cessation.
authors.affiliation: Medical Statistics Section, Department of Medicine, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294-3300, USA.
authors.forename: Renee A
authors.initials: RA
authors.lastname: Desmond
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Weiss
authors.forename: Ramin B
authors.initials: RB
authors.lastname: Arani
authors.forename: Seng-jaw
authors.initials: SJ
authors.lastname: Soong
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Wood
authors.forename: Paul A
authors.initials: PA
authors.lastname: Fiddian
authors.forename: John W
authors.initials: JW
authors.lastname: Gnann
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Whitley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006562:Herpes Zoster / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010146:Pain / Q000175:diagnosis / Q000453:epidemiology*; D010147:Pain Measurement / Q000379:methods*; D016016:Proportional Hazards Models