{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,29]],"date-time":"2025-08-29T00:03:56Z","timestamp":1756425836483,"version":"3.44.0"},"reference-count":15,"publisher":"BMJ","issue":"4","license":[{"start":{"date-parts":[[2021,4,11]],"date-time":"2021-04-11T00:00:00Z","timestamp":1618099200000},"content-version":"unspecified","delay-in-days":10,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006680","name":"Takeda Medical Research Foundation","doi-asserted-by":"publisher","award":["GHOL 6238"],"award-info":[{"award-number":["GHOL 6238"]}],"id":[{"id":"10.13039\/501100006680","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001826","name":"ZonMw","doi-asserted-by":"publisher","award":["836011011"],"award-info":[{"award-number":["836011011"]}],"id":[{"id":"10.13039\/501100001826","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2021,3,3]]},"published-print":{"date-parts":[[2021,4]]},"abstract":"<jats:p>We explored the effects of extreme weight loss after gastric bypass surgery on factor VIII concentrate pharmacokinetic (PK) parameters in a patient with haemophilia A. We present a 32-year-old man with severe haemophilia A, with a body mass index (BMI) of 42.6\u2009kg\/m<jats:sup>2<\/jats:sup> who underwent laparoscopic sleeve gastrectomy. We showed that a population PK model with ideal body weight as morphometric variable instead of bodyweight led to an adequate description of the individual PKs in this patient with a variable BMI. Strikingly, no differences were observed in the individual PK parameters after extreme weight loss. Therefore, the resulting extreme weight loss after surgery did not lead to prophylactic dose changes in this patient with severe haemophilia. We carefully conclude that population PK\u2013pharmacodynamic models are still obligatory to give more insight into functional effects of significant weight loss on the haemostatic balance.<\/jats:p>","DOI":"10.1136\/bcr-2020-238036","type":"journal-article","created":{"date-parts":[[2021,4,12]],"date-time":"2021-04-12T11:40:37Z","timestamp":1618227637000},"page":"e238036","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of extreme weight loss on factor VIII concentrate pharmacokinetics in haemophilia"],"prefix":"10.1136","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0248-4710","authenticated-orcid":false,"given":"Iris","family":"van Moort","sequence":"first","affiliation":[{"name":"Department of Paediatric Haematology, Erasmus University Medical Center\u2014Sophia Childrens Hospital Rotterdam, Rotterdam, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laura H","family":"Bukkems","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology\u2014Hospital Pharmacy, Amsterdam UMC Locatie AMC, Amsterdam, North Holland, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laurens","family":"Nieuwenhuizen","sequence":"additional","affiliation":[{"name":"Department of Hematology, Maxima Medical Centre Location Veldhoven, Veldhoven, Noord-Brabant, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marjon H","family":"Cnossen","sequence":"additional","affiliation":[{"name":"Department of Paediatric Haematology, Erasmus University Medical Center\u2014Sophia Childrens Hospital Rotterdam, Rotterdam, The Netherlands"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2021,4,12]]},"reference":[{"key":"2025082803465907000_14.4.e238036.1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2516.2012.02909.x"},{"key":"2025082803465907000_14.4.e238036.2","doi-asserted-by":"crossref","first-page":"1569","DOI":"10.1111\/obr.12746","article-title":"Obesity in the global haemophilia population: prevalence, implications and expert opinions for weight management","volume":"19","author":"Wilding","year":"2018","journal-title":"Obes Rev"},{"key":"2025082803465907000_14.4.e238036.3","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1111\/hae.12848","article-title":"Impact of being overweight on factor VIII dosing in children with haemophilia 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