@article {677241,
	title = {Identifying Medicare beneficiaries with dementia},
	journal = {J Am Geriatr Soc},
	year = {2021},
	month = {2021 Apr 26},
	abstract = {BACKGROUND/OBJECTIVES: No data exist regarding the validity of International Classification of Disease (ICD)-10 dementia diagnoses against a clinician-adjudicated reference standard within Medicare claims data. We examined the accuracy of claims-based diagnoses with respect to expert clinician adjudication using a novel database with individual-level linkages between electronic health record (EHR) and claims.

DESIGN: In this retrospective observational study, two neurologists and two psychiatrists performed a standardized review of patients{\textquoteright} medical records from January 2016 to December 2018 and adjudicated dementia status. We measured the accuracy of three claims-based definitions of dementia against the reference standard.

SETTING: Mass-General-Brigham Healthcare (MGB), Massachusetts, USA.

PARTICIPANTS: From an eligible population of 40,690 fee-for-service (FFS) Medicare beneficiaries, aged 65 years and older, within the MGB Accountable Care Organization (ACO), we generated a random sample of 1002 patients, stratified by the pretest likelihood of dementia using administrative surrogates.

INTERVENTION: None.

MEASUREMENTS: We evaluated the accuracy (area under receiver operating curve [AUROC]) and calibration (calibration-in-the-large [CITL] and calibration slope) of three ICD-10 claims-based definitions of dementia against clinician-adjudicated standards. We applied inverse probability weighting to reconstruct the eligible population and reported the mean and 95\% confidence interval (95\% CI) for all performance characteristics, using 10-fold cross-validation (CV).

RESULTS: Beneficiaries had an average age of 75.3 years and were predominately female (59\%) and non-Hispanic whites (93\%). The adjudicated prevalence of dementia in the eligible population was 7\%. The best-performing definition demonstrated excellent accuracy (CV-AUC 0.94; 95\% CI 0.92-0.96) and was well-calibrated to the reference standard of clinician-adjudicated dementia (CV-CITL \&lt;0.001, CV-slope 0.97).

CONCLUSION: This study is the first to validate ICD-10 diagnostic codes against a robust and replicable approach to dementia ascertainment, using a real-world clinical reference standard. The best performing definition includes diagnostic codes with strong face validity and outperforms an updated version of a previously validated ICD-9 definition of dementia.},
	issn = {1532-5415},
	doi = {10.1111/jgs.17183},
	author = {Moura, Lidia M V R and Festa, Natalia and Price, Mary and Volya, Margarita and Benson, Nicole M and Sahar Zafar and Weiss, Max and Blacker, Deborah and Normand, Sharon-Lise and Joseph P. Newhouse and Hsu, John}
}
