{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T07:44:59Z","timestamp":1769154299145,"version":"3.49.0"},"reference-count":19,"publisher":"Wiley","issue":"S2","license":[{"start":{"date-parts":[[2012,5,3]],"date-time":"2012-05-03T00:00:00Z","timestamp":1336003200000},"content-version":"vor","delay-in-days":2,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100000016","name":"US Department of Health and Human Services","doi-asserted-by":"crossref","award":["HHSA2902010000161"],"award-info":[{"award-number":["HHSA2902010000161"]}],"id":[{"id":"10.13039\/100000016","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["P60AR056116"],"award-info":[{"award-number":["P60AR056116"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"name":"CSR&D","award":["2-031-09S"],"award-info":[{"award-number":["2-031-09S"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmacoepidemiology and Drug"],"published-print":{"date-parts":[[2012,5]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>This paper introduces an improved tool for designing matched\u2010pairs randomized trials. The tool allows the incorporation of clinical and other knowledge regarding the relative importance of variables used in matching and allows for multiple types of missing data. The method is illustrated in the context of a cluster\u2010randomized trial. A Web application and an R package are introduced to implement the method and incorporate recent advances in the area.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Reweighted Mahalanobis distance (RMD) matching incorporates user\u2010specified weights and imputed values for missing data. Weight may be assigned to missingness indicators to match on missingness patterns. Three examples are presented, using real data from a cohort of 90 Veterans Health Administration sites that had at least 100 incident metformin users in 2007. Matching is utilized to balance seven factors aggregated at the site level. Covariate balance is assessed for 10\u2009000 randomizations under each strategy: simple randomization, matched randomization using the Mahalanobis distance, and matched randomization using the RMD.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The RMD matching achieved better balance than simple randomization or MD randomization. In the first example, simple and MD randomization resulted in a 10% chance of seeing an absolute mean difference of greater than 26% in the percent of nonwhite patients per site; the RMD dramatically reduced that to 6%. The RMD achieved significant improvement over simple randomization even with as much as 20% of the data missing.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Reweighted Mahalanobis distance matching provides an easy\u2010to\u2010use tool that incorporates user knowledge and missing data. Copyright \u00a9 2012 John Wiley &amp; Sons, Ltd.<\/jats:p><\/jats:sec>","DOI":"10.1002\/pds.3260","type":"journal-article","created":{"date-parts":[[2012,5,3]],"date-time":"2012-05-03T05:59:44Z","timestamp":1336024784000},"page":"148-154","source":"Crossref","is-referenced-by-count":28,"title":["Reweighted Mahalanobis distance matching for cluster\u2010randomized trials with missing data"],"prefix":"10.1002","volume":"21","author":[{"suffix":"Jr.","given":"Robert A.","family":"Greevy","sequence":"first","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Biostatistics Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Carlos G.","family":"Grijalva","sequence":"additional","affiliation":[{"name":"Department of Preventive Medicine Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christianne L.","family":"Roumie","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Medicine Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cole","family":"Beck","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Biostatistics Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adriana M.","family":"Hung","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Medicine Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Harvey J.","family":"Murff","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Medicine Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xulei","family":"Liu","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Biostatistics Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marie R.","family":"Griffin","sequence":"additional","affiliation":[{"name":"VA Tennessee Valley Geriatric Research Education Clinical Center (GRECC)  Nashville TN USA"},{"name":"Department of Medicine Vanderbilt University  Nashville TN USA"},{"name":"Department of Preventive Medicine Vanderbilt University  Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2012,5,3]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1093\/biostatistics\/5.2.263"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1214\/08-STS274"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1002\/sim.4780120315"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1214\/09-STS274B"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1198\/jcgs.2011.09219"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1198\/tast.2011.08294"},{"key":"e_1_2_8_8_1","unstructured":"W\u00f6lfelM EkenelH.Feature weighted Mahalanobis distance: improved robustness for Gaussian classifiers. 13th European Signal Processing Conference (EUSIPCO) Antalya Turkey. 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