title: Short-form Zarit Caregiver Burden Interviews were valid in advanced conditions.
abstract: OBJECTIVE
  To assess six short-form versions of Zarit Burden Interview (ZBI-12, ZBI-8, ZBI-7, ZBI-6, ZBI-4, and ZBI-1) among three caregiving populations.
  
  
  METHODS
  Secondary analysis of carers' surveys in advanced cancer (n=105), dementia (n=131), and acquired brain injury (n=215). All completed demographic information and the ZBI-22 were used. Validity was assessed by Spearman correlations and internal consistency using Cronbach's alpha. Overall discrimination ability was evaluated using the area under the receiver operating characteristic curve (AUC).
  
  
  RESULTS
  All short-form versions, except the ZBI-1 in advanced cancer (rho=0.63), displayed good correlations (rho=0.74-0.97) with the ZBI-22. Cronbach's alphas suggested high internal consistency (range: 0.69-0.89) even for the ZBI-4. Discriminative ability was good for all short forms (AUC range: 0.90-0.99); the best AUC was for ZBI-12 (0.99; 95% confidence interval [CI]: 0.98-0.99) and the second best for ZBI-7 (0.98; 95% CI: 0.96-0.98) and ZBI-6 (0.98; 95% CI: 0.97-0.99).
  
  
  CONCLUSIONS
  All six short-form ZBI have very good validity, internal consistency, and discriminative ability. ZBI-12 is endorsed as the best short-form version; ZBI-7 and ZBI-6 show almost equal properties and are suitable when a fewer-question version is needed. ZBI-4 and ZBI-1 are suitable for screening, but ZBI-1 may be less valid in cancer.
authors.affiliation: King's College London, Department of Palliative Care, Policy and Rehabilitation, School of Medicine at Guy's, King's College and St Thomas' Hospitals, London, United Kingdom. irene.higginson@kcl.ac.uk <irene.higginson@kcl.ac.uk>
authors.forename: Irene J
authors.initials: IJ
authors.lastname: Higginson
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.forename: Diana
authors.initials: D
authors.lastname: Jackson
authors.forename: Joanna
authors.initials: J
authors.lastname: Murray
authors.forename: Richard
authors.initials: R
authors.lastname: Harding
mesh_terms: D000368:Aged; D020208:Brain Injury, Chronic / Q000451:nursing; D017028:Caregivers / Q000523:psychology*; D002908:Chronic Disease / Q000451:nursing*; D017281:Cost of Illness; D003704:Dementia / Q000451:nursing; D005260:Female; D006801:Humans; D007407:Interviews as Topic / Q000379:methods; D008297:Male; D009369:Neoplasms / Q000451:nursing; D010166:Palliative Care; D011594:Psychometrics; D015203:Reproducibility of Results