title: Early Response in Cellulitis: A Prospective Study of Dynamics and Predictors.
abstract: Skin and soft tissue infections are common reasons for medical care. Use of broad-spectrum therapy and costs have increased. Assessment of early treatment response has been given a central role both in clinical trials and everyday practice. However, there is a paucity of data on the dynamics of response, causes of early nonresponse, and how early nonresponse affects resource use and predicts outcome.
  
  
  
  We prospectively enrolled 216 patients hospitalized with cellulitis. Clinical and biochemical response data during the first 3 days of treatment were analyzed in relation to baseline factors, antibiotic use, surgery, and outcome. Multivariable analysis included logistic lasso regression.
  
  
  
  Clinical or biochemical response was observed in the majority of patients the day after treatment initiation. Concordance between clinical and biochemical response was strongest at days 2 and 3. Female sex, cardiovascular disease, higher body mass index, shorter duration of symptoms, and cellulitis other than typical erysipelas were predictors of nonresponse at day 3. In contrast, baseline factors were not predictive of clinical failure assessed posttreatment. Among cases with antibiotic treatment escalation by day 2, 90% (37/41) had nonresponse at day 1, but only 5% (2/40) had inappropriate initial therapy. Nonresponse at day 3 was a predictor of treatment duration >14 days, but not of clinical failure.
  
  
  
  Nonpharmacological factors had a major impact on early response dynamics. Delayed response was rarely related to inappropriate therapy but strongly predictive of early treatment escalation, suggesting that broadening antibiotic treatment may often be premature.
authors.affiliation: Department of Clinical Science, University of Bergen.|Department of Medicine.
authors.forename: Trond
authors.initials: T
authors.lastname: Bruun
authors.affiliation: Department of Clinical Science, University of Bergen.|Department of Medicine.
authors.forename: Oddvar
authors.initials: O
authors.lastname: Oppegaard
authors.affiliation: Centre for Clinical Research.
authors.forename: Karl Ove
authors.initials: KO
authors.lastname: Hufthammer
authors.affiliation: Department of Clinical Science, University of Bergen.|National Centre for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway.
authors.forename: Nina
authors.initials: N
authors.lastname: Langeland
authors.affiliation: Department of Clinical Science, University of Bergen.|Department of Medicine.
authors.forename: Steinar
authors.initials: S
authors.lastname: Skrede
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D015415:Biomarkers; D002481:Cellulitis / Q000175:diagnosis / Q000382:microbiology / Q000601:surgery / Q000628:therapy*; D003131:Combined Modality Therapy; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D063189:Symptom Assessment; D013997:Time Factors; D017211:Treatment Failure; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers
keywords: cellulitis; early response; outcome; skin infections; treatment failure