title: Children with chronic cough: when is watchful waiting appropriate? development of likelihood ratios for assessing children with chronic cough.
abstract: BACKGROUND
  Chronic cough is associated with poor quality of life and may signify a serious underlying disease. Differentiating nonspecific cough (when watchful waiting can be safely undertaken) from specific cough (treatment and further investigations are beneficial) would be clinically useful. In 326 children, we aimed to (1) determine how well cough pointers (used in guidelines) differentiate specific from nonspecific cough and (2) describe the clinical profile of children whose cough resolved without medications (spontaneous resolution).
  
  
  METHODS
  A dataset from a multicenter study involving children newly referred for chronic cough (median duration, 3-4 months) was used to determine the sensitivity, specificity, predictive values, and likelihood ratios (LRs) of cough pointers (symptoms, signs, and simple investigations [chest radiography, spirometry]) recommended in guidelines.
  
  
  RESULTS
  The pretest probability of specific cough was 88%. The absence of false-positive results meant that most pointers had strongly positive LRs. The most sensitive pointer (wet cough) had a positive LR of 26.2 (95% CI, 3.8-181.5). Although the absence of other individual pointers did not change the pretest probability much (negative LR close to 1), the absence of all pointers had a strongly negative LR of 0 (95% CI, 0-0.03). Children in the resolved spontaneously group were significantly more likely to be older, to be non-Indigenous, and to have a dry cough and a normal chest radiograph.
  
  
  CONCLUSIONS
  Children with chronic dry cough without any cough pointers can be safely managed using the watchful waiting approach. The high pretest probability and high positive LRs of cough pointers support the use of individual cough pointers to identify high risk of specific cough in pediatric chronic cough guidelines.
  
  
  BACKGROUND
  Australian New Zealand Clinical Trials Registry; No.: 12607000526471; URL: www.anzctr.org.au.
authors.affiliation: Child Health Division, Queensland Children's Respiratory Centre, Queensland Children's Medical Research Institute, Royal Children's Hospital, Brisbane, QLD. Electronic address: annechang@ausdoctors.net.
authors.forename: Anne B
authors.initials: AB
authors.lastname: Chang
authors.affiliation: Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW.
authors.forename: Peter P
authors.initials: PP
authors.lastname: Van Asperen
authors.affiliation: Medical School, Australian National University, Canberra, ACT.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Glasgow
authors.affiliation: Department of Respiratory Medicine, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC.
authors.forename: Colin F
authors.initials: CF
authors.lastname: Robertson
authors.affiliation: Sydney Medical School, Central Clinical School, University of Sydney, Sydney, NSW.
authors.forename: Craig M
authors.initials: CM
authors.lastname: Mellis
authors.affiliation: Queensland Children's Respiratory Centre, Queensland Children's Medical Research Institute, Royal Children's Hospital, Brisbane, QLD.
authors.forename: I Brent
authors.initials: IB
authors.lastname: Masters
authors.affiliation: Medical Workforce, Health Department of Western Australia and The University of Western Australia, Perth, WA.
authors.forename: Louis I
authors.initials: LI
authors.lastname: Landau
authors.affiliation: Child Health Division, The Canberra Hospital, Canberra, ACT.
authors.forename: Laurel
authors.initials: L
authors.lastname: Teoh
authors.affiliation: Child Health Division, Thursday Island Primary Health Care Centre, Thursday Island, QLD, Australia.
authors.forename: Irene
authors.initials: I
authors.lastname: Tjhung
authors.affiliation: Queensland Children's Respiratory Centre, Queensland Children's Medical Research Institute, Royal Children's Hospital, Brisbane, QLD.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Petsky
authors.affiliation: Child Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Morris
mesh_terms: D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003371:Cough / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D016013:Likelihood Functions; D008297:Male; D017410:Practice Guidelines as Topic; D013902:Radiography, Thoracic; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013147:Spirometry; D057832:Watchful Waiting / Q000706:statistics & numerical data*