title: The association between hydroxyurea treatment and pain intensity, analgesic use, and utilization in ambulatory sickle cell anemia patients.
abstract: BACKGROUND
  We compared daily pain, home analgesic use, and utilization among ambulatory adults in the randomized multicenter study of hydroxyurea in sickle cell anemia (MSH). We related the fetal hemoglobin (HbF) hydroxyurea response to these response variables.
  
  
  METHODS
  Patients rated their sickle cell pain intensity (0-9), use of analgesics, and visits for pain daily. Diaries were collected biweekly, and intensity was collapsed into single interval ratings. The interval proportions of days of analgesic use and medical visits for pain were also calculated. Group comparisons were made by intention to treat as well as by HbF change levels from baseline to 2 years of treatment (placebo and low, medium, high, or very high response).
  
  
  RESULTS
  A total of 134 (44.8%) enrollees completed 2 years of follow-up. Pain intensity correlated with analgesic use (r = 0.83, P > 0.0001) and utilization (r = 0.50, P < 0.0001). Pain intensity was lower for patients on hydroxyurea (2.51 ± 0.062 vs 2.82 ± 0.063 placebo, F(1270) = 11.65, P = 0.0007). The difference, though small, appeared early and was sustained. Analgesic use and utilization were also slightly lower (analgesic use: F (1270) = 11.97, P = 0.0006; utilization: F(1270) = 32.0, P < 0.0001). Each was statistically significantly lower among hydroxyurea patients with higher HbF treatment responses to hydroxyurea.
  
  
  CONCLUSIONS
  Hydroxyurea usage led to a small, statistically significant reduction in daily pain, analgesic use, and utilization in adults in MSH, corroborating previously shown larger reductions in crises and mortality. The degree of daily symptomatic reduction was related to the size of the HbF treatment response, further confirming HbF response as a useful laboratory correlate.
authors.affiliation: Division of Quality Health Care, Virginia Commonwealth University, Richmond, Virginia 23060, USA. wrsmith@vcu.edu
authors.forename: Wally R
authors.initials: WR
authors.lastname: Smith
authors.forename: Samir K
authors.initials: SK
authors.lastname: Ballas
authors.forename: William F
authors.initials: WF
authors.lastname: McCarthy
authors.forename: Robert L
authors.initials: RL
authors.lastname: Bauserman
authors.forename: Paul S
authors.initials: PS
authors.lastname: Swerdlow
authors.forename: Martin H
authors.initials: MH
authors.lastname: Steinberg
authors.forename: Myron A
authors.initials: MA
authors.lastname: Waclawiw
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000700:Analgesics / Q000627:therapeutic use*; D000755:Anemia, Sickle Cell / Q000188:drug therapy* / Q000503:physiopathology; D002908:Chronic Disease; D005260:Female; D005319:Fetal Hemoglobin / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006918:Hydroxyurea / Q000009:adverse effects* / Q000737:chemistry / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced* / Q000188:drug therapy*; D010919:Placebos; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000700:Analgesics; D010919:Placebos; D005319:Fetal Hemoglobin; D006918:Hydroxyurea