{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T17:18:58Z","timestamp":1778001538670,"version":"3.51.4"},"reference-count":37,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2025,2,17]],"date-time":"2025-02-17T00:00:00Z","timestamp":1739750400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2025,2,17]],"date-time":"2025-02-17T00:00:00Z","timestamp":1739750400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100003130","name":"Fonds Wetenschappelijk Onderzoek","doi-asserted-by":"publisher","award":["G047524N"],"award-info":[{"award-number":["G047524N"]}],"id":[{"id":"10.13039\/501100003130","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Statistics in Medicine"],"published-print":{"date-parts":[[2025,2,28]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>Shared\u2010parameter joint modeling is a useful technique for properly associating longitudinal and time\u2010to\u2010event data. When the interest is in the survival outcome, the conditional logarithm of the hazard function for an event is conventionally presumed to be linearly related over time to a set of explanatory covariates, among other terms. However, this hypothesis is quite restrictive and may yield misleading results. Our objective here is to easily check such a modeling assumption for any continuous fixed covariate. For this purpose, we examine the appropriateness of a nonparametric test criterion based on a penalty\u2010modified version of the Akaike information criterion. An extensive numerical study is conducted to check the validity of the test within the joint modeling framework, while determining the extent to which the function embedding the continuous covariate deviates from linearity. Furthermore, once a deviation from linearity is detected, the improvement in the model's predictive performance is examined. The usefulness of the testing procedure is illustrated using a clinical trial with HIV\u2010infected subjects. Specifically, our example focuses on properly accounting for the effect of nadir CD4 cell count within a predictive joint model for the time to immune recovery.<\/jats:p>","DOI":"10.1002\/sim.10340","type":"journal-article","created":{"date-parts":[[2025,2,17]],"date-time":"2025-02-17T07:11:16Z","timestamp":1739776276000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Testing for the Functional Form of a Continuous Covariate in the Shared\u2010Parameter Joint Model"],"prefix":"10.1002","volume":"44","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2150-6273","authenticated-orcid":false,"given":"Xavier","family":"Piulachs","sequence":"first","affiliation":[{"name":"Department of Statistics and Operations Research Polytechnic University of Catalonia  Terrassa Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3805-726X","authenticated-orcid":false,"given":"Anouar","family":"El Ghouch","sequence":"additional","affiliation":[{"name":"Institute of Statistics, Biostatistics and Actuarial Sciences UCLouvain  Louvain\u2010la\u2010Neuve Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8827-7642","authenticated-orcid":false,"given":"Ingrid","family":"Van Keilegom","sequence":"additional","affiliation":[{"name":"Institute of Statistics, Biostatistics and Actuarial Sciences UCLouvain  Louvain\u2010la\u2010Neuve Belgium"},{"name":"Research Centre for Operations Research and Statistics KU Leuven  Leuven Belgium"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,2,17]]},"reference":[{"key":"e_1_2_11_2_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4757-2722-7"},{"key":"e_1_2_11_3_1","doi-asserted-by":"publisher","DOI":"10.1137\/0909024"},{"key":"e_1_2_11_4_1","doi-asserted-by":"publisher","DOI":"10.1080\/01621459.1994.10476834"},{"key":"e_1_2_11_5_1","doi-asserted-by":"publisher","DOI":"10.1080\/01621459.1995.10476491"},{"key":"e_1_2_11_6_1","doi-asserted-by":"publisher","DOI":"10.1093\/biostatistics\/3.1.101"},{"key":"e_1_2_11_7_1","doi-asserted-by":"publisher","DOI":"10.1214\/aos\/1015362185"},{"issue":"1","key":"e_1_2_11_8_1","first-page":"1","article-title":"Goodness\u2010Of\u2010Fit Tests in Proportional Hazards Models With Random Effects","volume":"65","author":"Gonz\u00e1lez\u2010Manteiga W.","year":"2022","journal-title":"Biometrical Journal"},{"key":"e_1_2_11_9_1","doi-asserted-by":"publisher","DOI":"10.1093\/biostatistics\/1.4.465"},{"issue":"3","key":"e_1_2_11_10_1","first-page":"809","article-title":"Joint Modeling of Longitudinal and Time\u2010To\u2010Event Data: An Overview","volume":"14","author":"Tsiatis A. A.","year":"2004","journal-title":"Statistica Sinica"},{"key":"e_1_2_11_11_1","doi-asserted-by":"publisher","DOI":"10.1201\/b12208"},{"key":"e_1_2_11_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/rssb.12060"},{"key":"e_1_2_11_13_1","doi-asserted-by":"publisher","DOI":"10.1214\/aos\/1176347753"},{"key":"e_1_2_11_14_1","doi-asserted-by":"publisher","DOI":"10.1080\/01621459.1990.10476211"},{"key":"e_1_2_11_15_1","doi-asserted-by":"publisher","DOI":"10.1214\/aos\/1176348775"},{"key":"e_1_2_11_16_1","doi-asserted-by":"publisher","DOI":"10.1109\/TAC.1974.1100705"},{"key":"e_1_2_11_17_1","doi-asserted-by":"publisher","DOI":"10.1080\/01621459.1999.10474192"},{"key":"e_1_2_11_18_1","doi-asserted-by":"publisher","DOI":"10.1002\/sim.5368"},{"key":"e_1_2_11_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/biom.12276"},{"key":"e_1_2_11_20_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0224723"},{"key":"e_1_2_11_21_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1541-0420.2006.00570.x"},{"key":"e_1_2_11_22_1","volume-title":"Nonparametric Curve Estimation","author":"Efromovich S.","year":"1999"},{"key":"e_1_2_11_23_1","doi-asserted-by":"publisher","DOI":"10.1093\/biomet\/77.1.1"},{"key":"e_1_2_11_24_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4899-2887-0"},{"key":"e_1_2_11_25_1","volume-title":"Information Theory and Statistics","author":"Kullback S.","year":"1959"},{"key":"e_1_2_11_26_1","doi-asserted-by":"publisher","DOI":"10.1214\/aos\/1176345983"},{"key":"e_1_2_11_27_1","doi-asserted-by":"publisher","DOI":"10.1090\/S0002-9947-1956-0079851-X"},{"key":"e_1_2_11_28_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.0006-341X.2001.00795.x"},{"key":"e_1_2_11_29_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.2517-6161.1977.tb01600.x"},{"key":"e_1_2_11_30_1","doi-asserted-by":"publisher","DOI":"10.1002\/bimj.201600238"},{"key":"e_1_2_11_31_1","doi-asserted-by":"publisher","DOI":"10.1111\/biom.12814"},{"key":"e_1_2_11_32_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4757-3462-1"},{"key":"e_1_2_11_33_1","doi-asserted-by":"publisher","DOI":"10.1017\/CBO9780511790485"},{"key":"e_1_2_11_34_1","doi-asserted-by":"publisher","DOI":"10.1198\/016214501753208591"},{"key":"e_1_2_11_35_1","doi-asserted-by":"publisher","DOI":"10.1198\/0003130042854"},{"key":"e_1_2_11_36_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0227124"},{"key":"e_1_2_11_37_1","doi-asserted-by":"publisher","DOI":"10.1093\/biomet\/asm087"},{"key":"e_1_2_11_38_1","doi-asserted-by":"publisher","DOI":"10.1093\/biomet\/87.2.405"}],"container-title":["Statistics in Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/sim.10340","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/sim.10340","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/sim.10340","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T16:48:59Z","timestamp":1777999739000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/sim.10340"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,2,17]]},"references-count":37,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2025,2,28]]}},"alternative-id":["10.1002\/sim.10340"],"URL":"https:\/\/doi.org\/10.1002\/sim.10340","archive":["Portico"],"relation":{},"ISSN":["0277-6715","1097-0258"],"issn-type":[{"value":"0277-6715","type":"print"},{"value":"1097-0258","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,2,17]]},"assertion":[{"value":"2024-06-14","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-12-30","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-02-17","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e10340"}}