title: PROFSS: a screening tool for early identification of functional somatic symptoms.
abstract: OBJECTIVE
  To develop and validate a brief screening tool for predicting functional somatic symptoms (FSS) based on clinical and non-clinical information from the general practitioner referral letter, and to assess its inter-rater reliability.
  
  
  METHODS
  The derivation sample consisted of 357 consecutive patients referred to an internal outpatient clinic by their general practitioner. Referral letters were scored for candidate predictors for the main outcome measure, which was a final diagnosis of FSS made by the internist. Logistic regression identified the following independent predictors: type of symptoms, somatic and psychiatric comorbidity, absence of abnormal physical findings by the general practitioner, previous specialist consultation, and the use of illness terminology. Temporal validation was performed in a cohort of 94 consecutive patients in whom predictors were scored by two independent raters.
  
  
  RESULTS
  In both the derivation and validation sample, the discriminatory power of the model was good with areas under the receiver operating characteristic curves of 0.84 (95%confidence interval: 0.80-0.88) after bootstrapping and 0.82 (95%confidence interval: 0.73-0.91), respectively. Calibration of the models was excellent in both samples and the interobserver agreement in the validation sample was very good (intraclass coefficient: 0.82 (95%confidence interval: 0.75-0.88)). Based on this model, we constructed the brief screening tool PROFSS (Predicted Risk Of Functional Somatic Symptoms). PROFSS identified patient groups with risks of FSS ranging from 17% (95%CI: 10-26%) to 92% (95%CI:86-96%).
  
  
  CONCLUSIONS
  The presence of FSS can be predicted with the brief screening tool PROFSS, based on a limited set of items present in the general practitioner referral letter.
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Psychiatry, P.O. Box 30.011, 9700 RB Groningen, The Netherlands; University of Groningen, University Medical Centre Groningen, Department of Internal Medicine, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: J.M.Gol@umcg.nl.
authors.forename: Janna M
authors.initials: JM
authors.lastname: Gol
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of General Practice, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: H.Burger@umcg.nl.
authors.forename: Huibert
authors.initials: H
authors.lastname: Burger
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Psychiatry, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: K.A.M.Janssens@umcg.nl.
authors.forename: Karin A M
authors.initials: KA
authors.lastname: Janssens
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Internal Medicine, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: J.P.J.Slaets@umcg.nl.
authors.forename: Joris P J
authors.initials: JP
authors.lastname: Slaets
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Internal Medicine, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: R.O.B.Gans@umcg.nl.
authors.forename: Rijk O B
authors.initials: RO
authors.lastname: Gans
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Psychiatry, P.O. Box 30.011, 9700 RB Groningen, The Netherlands; University of Groningen, University Medical Centre Groningen, Department of Internal Medicine, P.O. Box 30.011, 9700 RB Groningen, The Netherlands. Electronic address: J.G.M.Rosmalen@umcg.nl.
authors.forename: Judith G M
authors.initials: JG
authors.lastname: Rosmalen
mesh_terms: D000328:Adult; D000554:Ambulatory Care Facilities; D015897:Comorbidity; D005260:Female; D058006:General Practice; D006801:Humans; D016015:Logistic Models; D008297:Male; D008403:Mass Screening / Q000379:methods; D011237:Predictive Value of Tests; D012017:Referral and Consultation; D015203:Reproducibility of Results; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control; D011795:Surveys and Questionnaires / Q000592:standards
keywords: Functional somatic symptoms; General practitioner; Medically unexplained symptoms; PROFSS; Prediction model; Referral letter