title: The Longitudinal Examination of Arthritis Pain (LEAP) study: relationships between weekly fluctuations in patient-rated joint pain and other health outcomes.
abstract: OBJECTIVE
  To examine relationships between weekly fluctuations in self-rated joint pain and other health outcomes among adults with osteoarthritis (OA).
  
  
  METHODS
  In this observational study, 287 adults (aged > or = 50 yrs) with hip or knee OA were recruited from 16 medical practices across the United States. Patients were telephoned weekly for 12 weeks to assess pain/stiffness, daily activities/function, productivity, emotional well-being, quality of life, and healthcare utilization. Associations between changes in joint pain levels and other health outcomes were evaluated using a generalized estimating equation model.
  
  
  RESULTS
  The mean (SD) pain score at Week 1 was 4.2 (2.1) on the Western Ontario and McMaster Universities OA index (WOMAC) pain subscale (0 = no pain, 10 = extreme pain); during the study, 49% of patients reported a between-week fluctuation of > or = 2 points. A 2-point decrease in WOMAC pain subscale score was associated with a 22% decrease in number of days of limited activity/week (beta = -0.107; 95% confidence interval -0.163, -0.051); a 48% decrease in number of days of missed work/week (beta = -0.217; 95% CI -0.395, -0.039); a 14% decrease in number of nights with pain-related sleep interference/week (beta = -0.068; 95% CI -0.109, -0.027). Patients were 1.6 times more likely to contact a healthcare provider when their pain changed from "acceptable" to "unacceptable."
  
  
  CONCLUSIONS
  Weekly fluctuations in pain levels and other health outcomes were identified among adults with OA. Decreases in patient-reported pain were associated with improvements in daily activities/functioning and decreases in work absenteeism, sleep interference, and healthcare resource use.
authors.affiliation: Global Health Outcomes, GlaxoSmithKline, 5 Moore Drive, Research Triangle Park, NC 27709, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Hutchings
authors.forename: Michael
authors.initials: M
authors.lastname: Calloway
authors.forename: Ernest
authors.initials: E
authors.lastname: Choy
authors.forename: Michele
authors.initials: M
authors.lastname: Hooper
authors.forename: David J
authors.initials: DJ
authors.lastname: Hunter
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Jordan
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Onur
authors.initials: O
authors.lastname: Baser
authors.forename: Stacey
authors.initials: S
authors.lastname: Long
authors.forename: Liisa
authors.initials: L
authors.lastname: Palmer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D018771:Arthralgia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000503:physiopathology*; D010147:Pain Measurement / Q000706:statistics & numerical data; D011379:Prognosis; D011795:Surveys and Questionnaires; D013997:Time Factors; D014481:United States