title: Power law relationships between health care utilization and symptom assessment among people with panic attacks.
abstract: BACKGROUND
  Although people with panic attacks are high utilizers of health care, the role of symptom assessment in care-seeking is unclear. Previous studies suggest that symptom perceptions are linearly related to utilization but panic appraisal is not. The purpose of this study was to determine whether the relationships between symptom assessment and utilization are non-linear, displaying power law distributions.
  
  
  METHODS
  This community-based study of 97 subjects with panic attacks assessed utilization of family doctor offices, total ambulatory utilization, and hospitalizations as well as symptom perceptions and panic appraisals. Matrices of symptom assessment versus utilization were created, and log-log plots were constructed. To minimize the risk of overestimation of power law distributions, linear, quadratic and cubic regression models were computed.
  
  
  RESULTS
  None of the utilization versus symptom perceptions displayed power law distributions. However, all three measures of utilization showed power law relationships with panic appraisals, but in unique patterns.
  
  
  CONCLUSIONS
  Although power law relationships were not found between symptom perceptions and utilization, unique patterns of power laws were identified between panic appraisals and all three measures of utilization.
authors.affiliation: Department of Family and Community Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA. katerndahl@uthscsa.edu
authors.forename: David
authors.initials: D
authors.lastname: Katerndahl
mesh_terms: D000328:Adult; D005260:Female; D006296:Health Services / Q000706:statistics & numerical data*; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000175:diagnosis / Q000503:physiopathology*; D013781:Texas