title: The somatic symptom scale-8 (SSS-8): a brief measure of somatic symptom burden.
abstract: OBJECTIVE
  Somatic symptoms are the core features of many medical diseases, and they are used to evaluate the severity and course of illness. The 8-item Somatic Symptom Scale (SSS-8) was recently developed as a brief, patient-reported outcome measure of somatic symptom burden, but its reliability, validity, and usefulness have not yet been tested.
  
  
  OBJECTIVE
  To investigate the reliability, validity, and severity categories as well as the reference scores of the SSS-8.
  
  
  METHODS
  A national, representative general-population survey was performed between June 15, 2012, and July 15, 2012, in Germany, including 2510 individuals older than 13 years.
  
  
  METHODS
  The SSS-8 mean (SD), item-total correlations, Cronbach α, factor structure, associations with measures of construct validity (Patient Health Questionnaire-2 depression scale, Generalized Anxiety Disorder-2 scale, visual analog scale for general health status, 12-month health care use), severity categories, and percentile rank reference scores.
  
  
  RESULTS
  The SSS-8 had excellent item characteristics and good reliability (Cronbach α = 0.81). The factor structure reflects gastrointestinal, pain, fatigue, and cardiopulmonary aspects of the general somatic symptom burden. Somatic symptom burden as measured by the SSS-8 was significantly associated with depression (r = 0.57 [95% CI, 0.54 to 0.60]), anxiety (r = 0.55 [95% CI, 0.52 to 0.58]), general health status (r = -0.24 [95% CI, -0.28 to -0.20]), and health care use (incidence rate ratio, 1.12 [95% CI, 1.10 to 1.14]). The SSS-8 severity categories were calculated in accordance with percentile ranks: no to minimal (0-3 points), low (4-7 points), medium (8-11 points), high (12-15 points), and very high (16-32 points) somatic symptom burden. For every SSS-8 severity category increase, there was a 53% (95% CI, 44% to 63%) increase in health care visits.
  
  
  CONCLUSIONS
  The SSS-8 is a reliable and valid self-report measure of somatic symptom burden. Cutoff scores identify individuals with low, medium, high, and very high somatic symptom burden.
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany2Schön Clinic Hamburg Eilbek, Hamburg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gierk
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany2Schön Clinic Hamburg Eilbek, Hamburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kohlmann
authors.affiliation: Department of Medicine, Indiana University, Indianapolis4Veterans Affairs Health Services Research and Development Service, Center for Health Information and Communication, Indianapolis, Indiana5Regenstrief Institute, Inc, Indianapolis, Indiana.
authors.forename: Kurt
authors.initials: K
authors.lastname: Kroenke
authors.affiliation: Department of Medical Psychology and Medical Sociology, University of Leipzig, Leipzig, Germany.
authors.forename: Lena
authors.initials: L
authors.lastname: Spangenberg
authors.affiliation: Department of Medical Psychology and Medical Sociology, University of Leipzig, Leipzig, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Zenger
authors.affiliation: Department of Medical Psychology and Medical Sociology, University of Leipzig, Leipzig, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Brähler
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany2Schön Clinic Hamburg Eilbek, Hamburg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Löwe
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005221:Fatigue / Q000175:diagnosis*; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis*; D010147:Pain Measurement; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D063189:Symptom Assessment / Q000379:methods*