{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T23:29:57Z","timestamp":1787009397003,"version":"build-2736575974"},"reference-count":50,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T00:00:00Z","timestamp":1781136000000},"content-version":"am","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"Department of Clinical Research, Copenhagen University Hospital"},{"name":"Danish Research Unit for Hospital Pharmacy"},{"DOI":"10.13039\/100008733","name":"H\u00f8rslev Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100008733","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000724","name":"Health Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000724","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Jacob and Olga Madsen Foundation"},{"DOI":"10.13039\/501100006442","name":"Faculty of Health and Medical Sciences, University of Copenhagen","doi-asserted-by":"publisher","award":["NNF20SA0064340"],"award-info":[{"award-number":["NNF20SA0064340"]}],"id":[{"id":"10.13039\/501100006442","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background and hypothesis<\/jats:title>\n                    <jats:p>Iohexol and 99m-technetium-diethylenetriaminepentaacid (99mTc-DTPA) are commonly used exogenous filtration markers for determining measured glomerular filtration rate (mGFR). Traditional intravenous sampling is time-consuming and often inconvenient in clinical practice, whereas dried blood spot (DBS) sampling is a promising alternative. This study used population pharmacokinetic (popPK) modelling and traditional performance statistics to investigate whether intravenous and DBS sampling can be used interchangeably for measuring GFR in older medical patients with low appetite.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Older patients aged\u00a0\u226565 years with poor appetite, defined as a Simplified Nutritional Appetite Questionnaire score\u00a0\u226414, received intravenous administration of iohexol and 99mTc-DTPA, followed by sampling over 4\u20138 h intravenously (for both tracers) and by DBS (for iohexol). Gentamicin 5\u00a0mg\/kg was used as a model drug and administered intravenously to all patients, followed by plasma sampling over 22 h. Employing a previously developed gentamicin popPK model, model fit improvement for each mGFR method was evaluated by reduction in objective function value (OFV) and inter-individual variability when including mGFR as a covariate on clearance. Performance of each method relative to intravenous iohexol sampling was also evaluated by bias (median difference) and P15 (percentage of values within 15%).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>In this study, 51 older patients (51% male, aged 67\u201396) were included. All three mGFR methods improved model fit when implemented as covariates on gentamicin clearance in popPK models (\u2212\u0394OFV = 115.6\u2013137.6). The improvements were greater when mGFR was expressed in ml\/min, rather than ml\/min\/1.73 m2. Compared to intravenous sampling of iohexol, DBS sampling of iohexol performed better (bias [95% confidence interval] = 2 [0\u20133] ml\/min, P15 = 98% [94.1%\u2013100%]) than intravenous sampling of 99mTc-DTPA (bias = 4 [3\u20135] ml\/min, P15 = 78.4% [66.7%\u201388.2%]).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Compared to intravenous sampling of iohexol or 99mTc-DTPA, DBS sampling of iohexol yielded similar improvements to model fit when incorporated as a covariate on gentamicin clearance in a popPK model.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ndt\/gfag130","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T11:50:02Z","timestamp":1781178602000},"source":"Crossref","is-referenced-by-count":1,"title":["Dried blood spot versus intravenous iohexol and\u00a099mTc-DTPA for GFR measurement and model-based analysis of renal drug clearance"],"prefix":"10.1093","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4058-3012","authenticated-orcid":false,"given":"Morten B","family":"Houlind","sequence":"first","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]},{"name":"Department of Drug Design and Pharmacology, University of Copenhagen , Copenhagen ,","place":["Denmark"]},{"name":"Department of Nephrology and Endocrinology, Copenhagen University Hospital, Rigshospitalet , Copenhagen ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8650-6595","authenticated-orcid":false,"given":"Ida K","family":"Storgaard","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]},{"name":"Department of Drug Design and Pharmacology, University of Copenhagen , Copenhagen ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Louise W S","family":"Christensen","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rikke L","family":"Nielsen","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aino L","family":"Andersen","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivia","family":"Born\u00e6s","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helle G","family":"Juul-Larsen","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne","family":"Walls","sequence":"additional","affiliation":[{"name":"Department of Drug Design and Pharmacology, University of Copenhagen , Copenhagen ,","place":["Denmark"]},{"name":"Capital Region Hospital Pharmacy, Copenhagen University 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Research, Copenhagen University Hospital , Amager and Hvidovre, Hvidovre ,","place":["Denmark"]},{"name":"Department of Emergency Medicine, Copenhagen University Hospital, Amager and Hvidovre , Hvidovre ,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergio","family":"Luis-Lima","sequence":"additional","affiliation":[{"name":"Laboratory of Renal Function (LFR), Faculty of Medicine, University of La Laguna, La Laguna ,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esteban","family":"Porrini","sequence":"additional","affiliation":[{"name":"Laboratory of Renal Function (LFR), Faculty of Medicine, University of La Laguna, La Laguna ,","place":["Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7558-9257","authenticated-orcid":false,"given":"Esben","family":"Iversen","sequence":"additional","affiliation":[{"name":"Department of Clinical Research, Copenhagen 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