TY - JOUR
T1 - Harmonization of delirium severity instruments
T2 - a comparison of the DRS-R-98, MDAS, and CAM-S using item response theory
AU - BASIL Study Group
AU - Gross, Alden L.
AU - Tommet, Doug
AU - D'Aquila, Madeline
AU - Schmitt, Eva
AU - Marcantonio, Edward R.
AU - Helfand, Benjamin
AU - Inouye, Sharon K.
AU - Jones, Richard N.
N1 - Funding Information:
This work was supported by grants from the National Institutes of Health [K01-AG050699 (ALG), R01AG044518 (SKI/RNJ), R24AG054259 (SKI), K07AG041835 (SKI), P01AG031720 (SKI), R01AG030618 (ERM), K24AG035075 (ERM). Dr. Inouye holds the Milton and Shirley F. Levy Family Chair.
PY - 2018/9/10
Y1 - 2018/9/10
N2 - BACKGROUND: This study aimed to describe the level of agreement of three commonly used delirium instruments: the Delirium Rating Scale-Revised-98 (DRS-R-98), Memorial Delirium Assessment Scale (MDAS), and Confusion Assessment Method-Severity (CAM-S). METHODS: We used data from a prospective clinical research study, in which a team of trained lay interviewers administered each instrument along with supporting interview and cognitive assessments in the same group of patients daily while in the hospital (N = 352). We used item response theory methods to co-calibrate the instruments. RESULTS: The latent traits underlying the three measures, capturing the severity of a delirium assessment, had a high degree of correlation (r's > .82). Unidimensional factor models fit well, facilitating co-calibration of the instruments. Across instruments, the less intense symptoms were generally items reflecting cognitive impairment. Although the intensity of delirium severity for most in the sample was relatively low, many of the item thresholds for the delirium severity scales are high (i.e., in the more severe range of the latent ability distribution). This indicates that even people with severe delirium may have a low probability of endorsing the highest severity categories for many items. Co-calibration enabled us to derive crosswalks to map delirium severity scores among the delirium instruments. CONCLUSION: These delirium instruments measure the same underlying construct of delirium severity. Relative locations of items may inform design of refined measurement instruments. Mapping of overall delirium severity scores across the delirium severity instruments enabled us to derive crosswalks, which allow scores to be translated across instruments, facilitating comparison and combination of delirium studies for integrative analysis.
AB - BACKGROUND: This study aimed to describe the level of agreement of three commonly used delirium instruments: the Delirium Rating Scale-Revised-98 (DRS-R-98), Memorial Delirium Assessment Scale (MDAS), and Confusion Assessment Method-Severity (CAM-S). METHODS: We used data from a prospective clinical research study, in which a team of trained lay interviewers administered each instrument along with supporting interview and cognitive assessments in the same group of patients daily while in the hospital (N = 352). We used item response theory methods to co-calibrate the instruments. RESULTS: The latent traits underlying the three measures, capturing the severity of a delirium assessment, had a high degree of correlation (r's > .82). Unidimensional factor models fit well, facilitating co-calibration of the instruments. Across instruments, the less intense symptoms were generally items reflecting cognitive impairment. Although the intensity of delirium severity for most in the sample was relatively low, many of the item thresholds for the delirium severity scales are high (i.e., in the more severe range of the latent ability distribution). This indicates that even people with severe delirium may have a low probability of endorsing the highest severity categories for many items. Co-calibration enabled us to derive crosswalks to map delirium severity scores among the delirium instruments. CONCLUSION: These delirium instruments measure the same underlying construct of delirium severity. Relative locations of items may inform design of refined measurement instruments. Mapping of overall delirium severity scores across the delirium severity instruments enabled us to derive crosswalks, which allow scores to be translated across instruments, facilitating comparison and combination of delirium studies for integrative analysis.
KW - Delirium
KW - Elderly
KW - Item response theory
KW - Psychometrics
KW - Severity
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U2 - 10.1186/s12874-018-0552-4
DO - 10.1186/s12874-018-0552-4
M3 - Article
C2 - 30200896
AN - SCOPUS:85064239415
VL - 18
SP - 92
JO - BMC Medical Research Methodology
JF - BMC Medical Research Methodology
SN - 1471-2288
IS - 1
M1 - 92
ER -