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Factor structure, internal consistency and construct validity of the Sheehan Disability Scale in a Spanish primary care sample
Author(s) -
Luciano Juan V.,
Bertsch Jordan,
SalvadorCarulla Luis,
Tomás José M.,
Fernández Ana,
PintoMeza Alejandra,
Haro Josep M.,
Palao Diego J.,
SerranoBlanco Antoni
Publication year - 2010
Publication title -
journal of evaluation in clinical practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.737
H-Index - 73
eISSN - 1365-2753
pISSN - 1356-1294
DOI - 10.1111/j.1365-2753.2009.01211.x
Subject(s) - confirmatory factor analysis , construct validity , psychology , clinical psychology , anxiety , mental health , psychiatry , psychometrics , medicine , gerontology , structural equation modeling , statistics , mathematics
Rationale, aims and objectives The Sheehan Disability Scale (SDS) is a three‐item instrument that measures disability in three inter‐related domains: work, family life/home responsibilities and social/leisure activities. The main objective of the present study was to examine the factor structure, reliability and construct validity of the SDS in a wide Spanish sample of primary care (PC) patients. Methods One phase cross‐sectional survey. A total of 3815 patients, aged 18 years or older attending PC for a medical visit, were interviewed between October 2005 and March 2006. The interviews included the Structured Clinical Interview for DSM‐IV Axis I Disorders for depressive and anxiety disorders, the Mini‐International Neuropsychiatric Interview for the rest of mental disorders, a medical conditions checklist, the 2.0 version of the 12‐item Short‐Form Health Survey (SF‐12) for measuring quality of life and the SDS. Results The principal component analysis and the subsequent confirmatory factor analysis indicated that the SDS is one‐dimensional (normed fit index = 0.990, non‐normed fit index = 0.987, comparative fit index = 0.991, goodness‐of‐fit index = 0.993, standardized root mean‐square residual = 0.037, root mean‐square error of approximation = 0.053). The internal consistency of the scale was good (α = 0.83) and it was significantly associated with the physical and mental component of the SF‐12. Concerning discriminative validity, patients with major depression or panic disorder scored higher on the SDS than patients with chronic medical conditions or with no chronic pathology. We also found that a cut‐off point of 8 in the SDS adequately discriminated between patients with and without depression (area under the curve = 0.814, sensitivity = 81.60%, specificity = 70.60%). Conclusions The SDS seems a reliable, valid and useful clinical tool for measuring disability in Spanish PC patients.