{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T23:27:48Z","timestamp":1777418868721,"version":"3.51.4"},"reference-count":28,"publisher":"SAGE Publications","issue":"11","license":[{"start":{"date-parts":[[2007,11,1]],"date-time":"2007-11-01T00:00:00Z","timestamp":1193875200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Ann Pharmacother"],"published-print":{"date-parts":[[2007,11]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Warfarin sodium is commonly prescribed for the prophylaxis and treatment of venous thromboembolism. Dosing algorithms have not been widely adopted because they require a fixed initial warfarin dose (eg, 5 mg) and are not tailored to other factors that may affect the international normalized ratio (INR).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective:<\/jats:title>\n                    <jats:p>To develop an algorithm that could predict a therapeutic warfarin dose based on drug interactions. INR response after the initial warfarin doses, and other clinical factors.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>We used stepwise regression to quantify the relationship between these factors in patients beginning prophylactic warfarin therapy immediately prior to joint replacement. In the derivation cohort (n = 271), we separately modeled the therapeutic dose after 2 and 3 initial doses. We prospectively validated these 2 models in an independent cohort (n = 105).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      About half of the therapeutic dose variability was predictable after 3 days of therapy: R\n                      <jats:sup>2<\/jats:sup>\n                      was 53% in the derivation cohort and 42% in the validation cohort. INR response after 3 warfarin doses (INR\n                      <jats:sub>3<\/jats:sub>\n                      ) inversely correlated with therapeutic dose (p &lt; 0.001). Intraoperative blood loss transiently, but significantly, elevated the postoperative INR values. Other significant (p &lt; 0.03) predictors were the first and second warfarin doses (+7% and +6%, respectively, per 1 mg), and statin use (\u201315.0%). The model derived after 2 warfarin doses explained 32% of the variability in therapeutic dose.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>\n                      We developed and validated algorithms that estimate therapeutic warfarin doses based on clinical factors and INR response available after 2\u20133 days of warfarin therapy. The algorithms are implemented online at\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"www.WarfarinDosing.org\">www.WarfarinDosing.org<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1345\/aph.1k197","type":"journal-article","created":{"date-parts":[[2007,10,2]],"date-time":"2007-10-02T20:25:09Z","timestamp":1191356709000},"page":"1798-1804","source":"Crossref","is-referenced-by-count":23,"title":["Anticoagulation: Optimal Initial Dose Adjustment of Warfarin in Orthopedic Patients"],"prefix":"10.1177","volume":"41","author":[{"given":"Petra A","family":"Lenzini","sequence":"first","affiliation":[{"name":"Research Statistician, Washington University in St. Louis, St. Louis, MO"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gloria R","family":"Grice","sequence":"additional","affiliation":[{"name":"Saint Louis College of Pharmacy, St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Paul E","family":"Milligan","sequence":"additional","affiliation":[{"name":"Clinical Pharmacist, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Susan K","family":"Gatchel","sequence":"additional","affiliation":[{"name":"CCRC, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elena","family":"Deych","sequence":"additional","affiliation":[{"name":"Research Statistician, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Charles S","family":"Eby","sequence":"additional","affiliation":[{"name":"Pathology and Immunology, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R Stephen J","family":"Burnett","sequence":"additional","affiliation":[{"name":"FRCS(C), Orthopaedic Surgeon, Vancouver Island Health Authority, Division of Orthopaedic Surgery, Adult Reconstructive Surgery, Vancouver, British Columbia, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John C","family":"Clohisy","sequence":"additional","affiliation":[{"name":"Orthopaedic Surgery, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robert L","family":"Barrack","sequence":"additional","affiliation":[{"name":"C &amp; J Knight Distinguished Professor of Orthopaedic Surgery, Department of Orthopaedic Surgery, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Brian F","family":"Gage","sequence":"additional","affiliation":[{"name":"Medicine, Department of Medicine, Washington University in St. Louis"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2007,11]]},"reference":[{"key":"e_1_2_1_2_2","doi-asserted-by":"publisher","DOI":"10.1161\/01.CIR.0000063575.17904.4E"},{"key":"e_1_2_1_3_2","doi-asserted-by":"publisher","DOI":"10.1378\/chest.119.1_suppl.22S"},{"key":"e_1_2_1_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.amjmed.2004.11.015"},{"key":"e_1_2_1_5_2","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-138-9-200305060-00007"},{"key":"e_1_2_1_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.amjmed.2004.07.053"},{"key":"e_1_2_1_7_2","doi-asserted-by":"publisher","DOI":"10.1093\/ageing\/29.1.31"},{"key":"e_1_2_1_8_2","doi-asserted-by":"publisher","DOI":"10.1345\/aph.1A372"},{"key":"e_1_2_1_9_2","doi-asserted-by":"publisher","DOI":"10.1136\/bmj.288.6426.1268"},{"key":"e_1_2_1_10_2","doi-asserted-by":"publisher","DOI":"10.1093\/ageing\/27.5.655"},{"key":"e_1_2_1_11_2","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-127-4-199708150-00019"},{"key":"e_1_2_1_12_2","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-126-2-199701150-00006"},{"key":"e_1_2_1_13_2","doi-asserted-by":"publisher","DOI":"10.1378\/chest.124.6_suppl.349S"},{"key":"e_1_2_1_14_2","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.165.10.1095"},{"key":"e_1_2_1_15_2","doi-asserted-by":"publisher","DOI":"10.1345\/aph.1G407"},{"key":"e_1_2_1_16_2","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.162.17.1966"},{"key":"e_1_2_1_17_2","doi-asserted-by":"publisher","DOI":"10.1160\/TH04-08-0542"},{"key":"e_1_2_1_18_2","doi-asserted-by":"publisher","DOI":"10.1002\/bdd.249"},{"key":"e_1_2_1_19_2","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2007-01-069609"},{"key":"e_1_2_1_20_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1445-5994.1999.tb01623.x"},{"key":"e_1_2_1_21_2","doi-asserted-by":"publisher","DOI":"10.1378\/chest.127.6.2049"},{"key":"e_1_2_1_22_2","doi-asserted-by":"publisher","DOI":"10.1097\/01.fpc.0000184955.08453.a8"},{"key":"e_1_2_1_23_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.clpt.2005.11.006"},{"key":"e_1_2_1_24_2","doi-asserted-by":"publisher","DOI":"10.1124\/jpet.105.091181"},{"key":"e_1_2_1_25_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1538-7836.2006.01974.x"},{"key":"e_1_2_1_26_2","doi-asserted-by":"publisher","DOI":"10.1182\/blood-2005-03-1108"},{"key":"e_1_2_1_27_2","doi-asserted-by":"publisher","DOI":"10.1038\/sj.tpj.6500313"},{"key":"e_1_2_1_28_2","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.159.1.46"},{"key":"e_1_2_1_29_2","doi-asserted-by":"publisher","DOI":"10.1160\/TH03-06-0379"}],"container-title":["Annals of Pharmacotherapy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1345\/aph.1K197","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1345\/aph.1K197","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T11:08:32Z","timestamp":1777374512000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1345\/aph.1K197"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007,11]]},"references-count":28,"journal-issue":{"issue":"11","published-print":{"date-parts":[[2007,11]]}},"alternative-id":["10.1345\/aph.1K197"],"URL":"https:\/\/doi.org\/10.1345\/aph.1k197","relation":{},"ISSN":["1060-0280","1542-6270"],"issn-type":[{"value":"1060-0280","type":"print"},{"value":"1542-6270","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,11]]}}}