Propensity score matching for multilevel spatial data: accounting for geographic confounding in health disparity studies. Int J Health Geogr 2021 Feb 27;20(1):10
Date
03/01/2021Pubmed ID
33639940Pubmed Central ID
PMC7913404DOI
10.1186/s12942-021-00265-1Scopus ID
2-s2.0-85101813250 (requires institutional sign-in at Scopus site) 2 CitationsAbstract
BACKGROUND: Diabetes is a public health burden that disproportionately affects military veterans and racial minorities. Studies of racial disparities are inherently observational, and thus may require the use of methods such as Propensity Score Analysis (PSA). While traditional PSA accounts for patient-level factors, this may not be sufficient when patients are clustered at the geographic level and thus important confounders, whether observed or unobserved, vary by geographic location.
METHODS: We employ a spatial propensity score matching method to account for "geographic confounding", which occurs when the confounding factors, whether observed or unobserved, vary by geographic region. We augment the propensity score and outcome models with spatial random effects, which are assigned scaled Besag-York-Mollié priors to address spatial clustering and improve inferences by borrowing information across neighboring geographic regions. We apply this approach to a study exploring racial disparities in diabetes specialty care between non-Hispanic black and non-Hispanic white veterans. We construct multiple global estimates of the risk difference in diabetes care: a crude unadjusted estimate, an estimate based solely on patient-level matching, and an estimate that incorporates both patient and spatial information.
RESULTS: In simulation we show that in the presence of an unmeasured geographic confounder, ignoring spatial heterogeneity results in increased relative bias and mean squared error, whereas incorporating spatial random effects improves inferences. In our study of racial disparities in diabetes specialty care, the crude unadjusted estimate suggests that specialty care is more prevalent among non-Hispanic blacks, while patient-level matching indicates that it is less prevalent. Hierarchical spatial matching supports the latter conclusion, with a further increase in the magnitude of the disparity.
CONCLUSIONS: These results highlight the importance of accounting for spatial heterogeneity in propensity score analysis, and suggest the need for clinical care and management strategies that are culturally sensitive and racially inclusive.
Author List
Davis ML, Neelon B, Nietert PJ, Burgette LF, Hunt KJ, Lawson AB, Egede LEAuthor
Leonard E. Egede MD Center Director, Chief, Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
BiasHumans
Propensity Score
Spatial Analysis
