{"id":6468,"date":"2026-10-19T09:48:56","date_gmt":"2026-10-19T09:48:56","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-laeknavisindum-aron-hjalti-bjornsson\/"},"modified":"2026-10-19T09:48:56","modified_gmt":"2026-10-19T09:48:56","slug":"doktorsvorn-i-laeknavisindum-aron-hjalti-bjornsson","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-laeknavisindum-aron-hjalti-bjornsson\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00e6knav\u00edsindum – Aron Hjalti Bj\u00f6rnsson"},"content":{"rendered":"
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Fimmtudaginn 30. apr\u00edl ver Aron Hjalti Bj\u00f6rnsson doktorsritger\u00f0 s\u00edna \u00ed l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: Ikts\u00fdki og s\u00fdkingar: \u00c1hrif TNF-hemla. \u201eInfections in Patients with Rheumatoid Arthritis: The Impact of Tumour Necrosis Factor Inhibitors.<\/p>\n

Andm\u00e6lendur eru dr. Philip Helliwell, pr\u00f3fessor vi\u00f0 University of Leeds, og dr. Erna Milunka Kojic, yfirl\u00e6knir vi\u00f0 Landsp\u00edtalann.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi var \u00deorvar\u00f0ur L\u00f6ve, pr\u00f3fessor. Auk hans s\u00e1tu \u00ed doktorsnefnd Agnar Bjarnason, lektor, Ger\u00f0ur Mar\u00eda Gr\u00f6ndal, d\u00f3sent, M\u00e1r Kristj\u00e1nsson, s\u00e9rfr\u00e6\u00f0ingar, og P\u00e9tur Gunnarsson, kl\u00edn\u00edskur lyfjafr\u00e6\u00f0ingur.<\/p>\n

S\u00e6d\u00eds S\u00e6varsd\u00f3ttir, pr\u00f3fessor og deildarforseti L\u00e6knadeildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 13.00.<\/p>\n

\u00c1grip<\/strong><\/p>\n

Ikts\u00fdki og a\u00f0rir li\u00f0b\u00f3lgusj\u00fakd\u00f3mar tengjast aukinni h\u00e6ttu \u00e1 s\u00fdkingum, b\u00e6\u00f0i vegna sj\u00fakd\u00f3msins sj\u00e1lfs og \u00f3n\u00e6misb\u00e6landi me\u00f0fer\u00f0ar. \u00cd \u00feessari doktorsritger\u00f0 er s\u00fdkingabyr\u00f0i me\u00f0al \u00edslenskra li\u00f0b\u00f3lgusj\u00faklinga sem fengu me\u00f0fer\u00f0 me\u00f0 TNF-hemlum ranns\u00f6ku\u00f0, me\u00f0 \u00e1herslu \u00e1 ikts\u00fdki, \u00fer\u00f3un alvarlegra s\u00fdkinga yfir t\u00edma og afdrif sj\u00faklinga \u00ed upphafi COVID-19 faraldursins.<\/p>\n

Ritger\u00f0in byggist \u00e1 \u00feremur \u00edslenskum skr\u00e1arranns\u00f3knum sem unnar voru me\u00f0 g\u00f6gnum \u00far ICEBIO og \u00f6\u00f0rum heilbrig\u00f0isskr\u00e1m. Grein I s\u00fdndi a\u00f0 sj\u00faklingar me\u00f0 ikts\u00fdki notu\u00f0u oftar s\u00fdkingalyf en almenningur og a\u00f0 me\u00f0fer\u00f0 me\u00f0 TNF-hemlum tengdist 25% aukningu \u00ed fj\u00f6lda lyfse\u00f0la, en einungis 6,5% aukningu \u00ed heildarfj\u00f6lda dagskammta. Grein II s\u00fdndi a\u00f0 t\u00ed\u00f0ni alvarlegra s\u00fdkinga me\u00f0al sj\u00faklinga \u00e1 TNF-hemlame\u00f0fer\u00f0 l\u00e6kka\u00f0i markt\u00e6kt \u00e1 ranns\u00f3knart\u00edmabilinu og a\u00f0 \u00e1h\u00e6ttan var minni hj\u00e1 \u00feeim sem h\u00f3fu me\u00f0fer\u00f0 \u00e1 seinni hluta ranns\u00f3knart\u00edmabilsins. Sj\u00faklingar sem h\u00f3fu me\u00f0fer\u00f0 \u00e1 \u00e1runum 2015 til 2018 h\u00f6f\u00f0u helmingi minni \u00e1h\u00e6ttu \u00e1 alvarlegum s\u00fdkingum en \u00feeir sem h\u00f3fu me\u00f0fer\u00f0 \u00e1 \u00e1runum 2003 til 2006. Fyrri s\u00fdkingar, notkun sykurstera og skert l\u00edkamleg f\u00e6rni reyndust mikilv\u00e6gir forsp\u00e1r\u00fe\u00e6ttir. Grein III s\u00fdndi a\u00f0 \u00ed fyrstu bylgju COVID-19 faraldursins voru sj\u00faklingar \u00e1 l\u00edft\u00e6knime\u00f0fer\u00f0 oftar skima\u00f0ir en h\u00f6f\u00f0u svipa\u00f0a s\u00fdkingart\u00ed\u00f0ni og almenningur. Hins vegar voru \u00feeir oftar lag\u00f0ir inn \u00e1 sj\u00fakrah\u00fas \u00ed kj\u00f6lfar s\u00fdkingar, \u00fe\u00f3tt heildarhorfur v\u00e6ru g\u00f3\u00f0ar.<\/p>\n

Ni\u00f0urst\u00f6\u00f0urnar benda til \u00feess a\u00f0 \u00fe\u00f3tt me\u00f0fer\u00f0 me\u00f0 TNF-hemlum tengist aukinni s\u00fdkingabyr\u00f0i hafi h\u00e6tta \u00e1 alvarlegum s\u00fdkingum minnka\u00f0 me\u00f0 t\u00edmanum. Ranns\u00f3knin varpar n\u00fdju lj\u00f3si \u00e1 \u00f6ryggi TNF-hemla vi\u00f0 me\u00f0fer\u00f0 li\u00f0b\u00f3lgusj\u00fakd\u00f3ma og hefur \u00fe\u00fd\u00f0ingu fyrir \u00e1h\u00e6ttumat og eftirfylgd \u00ed kl\u00edn\u00edsku starfi.<\/p>\n

Abstract<\/strong><\/p>\n

Rheumatoid arthritis (RA) and other inflammatory arthritides are associated with an increased risk of infection due to both the underlying disease and immunosuppressive treatment. This thesis investigates the burden of infections in Icelandic patients treated with tumour necrosis factor inhibitors (TNFi), with particular emphasis on RA, temporal trends in serious infections, and patient outcomes during the early phase of the COVID-19 pandemic.<\/p>\n

The thesis is based on three nationwide registry studies using data from the Icelandic Registry of Biologic Treatment (ICEBIO), linked with other national health registries.\u00a0Paper I<\/strong>\u00a0showed that patients with RA had higher use of antimicrobial drugs than the general population, and that TNFi treatment was associated with a 25% increase in the number of antimicrobial prescriptions, but only a 6.5% increase in total defined daily doses.\u00a0Paper II<\/strong>\u00a0showed that the incidence of serious infections among TNFi-treated patients declined significantly over the study period, and that the risk was lower among patients who initiated treatment in more recent years. Patients who started TNFi therapy in 2015\u20132018 had approximately half the incidence rate ratio of serious infection compared with those who initiated treatment in 2003\u20132006. Prior infections, glucocorticoid use, and poorer physical function were identified as important predictors of serious infection.\u00a0Paper III<\/strong>\u00a0showed that during the first wave of the COVID-19 pandemic, patients receiving biologic therapy were tested more frequently but had a similar infection rate to that of the general population. However, they were more often hospitalised following infection, although overall outcomes were favourable.<\/p>\n

Overall, the findings indicate that although TNFi treatment is associated with an increased burden of infections, the risk of serious infections has declined over time. The thesis provides new insights into TNFi safety in RA and has implications for risk assessment and clinical follow-up.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Aron Hjalti Bj\u00f6rnsson er f\u00e6ddur \u00e1ri\u00f0 1990 \u00ed Upps\u00f6lum \u00ed Sv\u00ed\u00fej\u00f3\u00f0. Hann lauk st\u00fadentspr\u00f3fi fr\u00e1 n\u00e1tt\u00farufr\u00e6\u00f0ideild Menntask\u00f3lans \u00ed Reykjav\u00edk \u00e1ri\u00f0 2010 og emb\u00e6ttispr\u00f3fi me\u00f0 meistaragr\u00e1\u00f0u \u00ed l\u00e6knisfr\u00e6\u00f0i cum laude \u00e1ri\u00f0 2017 vi\u00f0 H\u00e1sk\u00f3lann \u00ed Debrecen \u00ed Ungverjalandi. A\u00f0 loknu kand\u00eddats\u00e1ri starfa\u00f0i Aron Hjalti sem s\u00e9rn\u00e1msl\u00e6knir \u00e1 lyfl\u00e6knasvi\u00f0i og g\u00f6ngudeild gigtarl\u00e6kninga \u00e1 Landsp\u00edtala. Hann lauk s\u00e9rn\u00e1mi \u00ed almennum lyfl\u00e6kningum vi\u00f0 H\u00e1sk\u00f3lasj\u00fakrah\u00fasi\u00f0 \u00ed Lundi \u00ed Sv\u00ed\u00fej\u00f3\u00f0 \u00e1ri\u00f0 2025 og starfar \u00fear \u00e1fram sem s\u00e9rn\u00e1msl\u00e6knir \u00ed gigtarl\u00e6kningum auk \u00feess a\u00f0 sinna kl\u00edn\u00edskum ranns\u00f3knum.<\/p>\n

Foreldrar Arons Hjalta eru Bj\u00f6rn Gu\u00f0bj\u00f6rnsson, pr\u00f3fessor emeritus og gigtarl\u00e6knir, og Kolbr\u00fan Albertsd\u00f3ttir sv\u00e6fingahj\u00fakrunarfr\u00e6\u00f0ingur. Eiginkona Arons Hjalta er \u00deorbj\u00f6rg \u00d3lafsd\u00f3ttir l\u00e6knir og doktorsnemi. B\u00f6rn \u00feeirra eru Bj\u00f6rn \u00d3lafur og Eyd\u00eds Huld.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5887,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2026-04-30T13:00:00+00:00","_phd_date_end":"2026-04-30T16:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Ikts\u00fdki og s\u00fdkingar: \u00c1hrif TNF-hemla. \u201eInfections in Patients with Rheumatoid Arthritis: The Impact of Tumour Necrosis Factor Inhibitors","_phd_source_url":"https:\/\/gamli.hi.is\/vidburdir\/doktorsvorn_i_laeknavisindum_aron_hjalti_bjornsson","_phd_source_node_id":"443838","_phd_source_type":"vidburdir","_phd_member_id":1012,"footnotes":""},"phd_school":[60,67],"phd_discipline":[69],"class_list":["post-6468","phd_defence","type-phd_defence","status-publish","has-post-thumbnail","hentry","phd_school-heilbrigdisvisindasvid","phd_school-laeknadeild","phd_discipline-phd-i-laeknavisindum"],"_links":{"self":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6468","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence"}],"about":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/types\/phd_defence"}],"version-history":[{"count":0,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_defence\/6468\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media\/5887"}],"wp:attachment":[{"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/media?parent=6468"}],"wp:term":[{"taxonomy":"phd_school","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_school?post=6468"},{"taxonomy":"phd_discipline","embeddable":true,"href":"https:\/\/phd.hi.is\/en\/wp-json\/wp\/v2\/phd_discipline?post=6468"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}