Haskóli ÍslandsUniversity of IcelandLundarháskóliBjörn Guðbjörnsson, Meliha C KapetanovicPalsson, Olafur2026-03-022026-03-022026-02-13978-9935-567-07-9https://hdl.handle.net/20.500.11815/8032Sóragigt er langvinnur, mögulega alvarlegur bólgusjúkdómur í liðum tengdur húðsjúkdómnum psoriasis. Hann getur haft djúpar og langvarandi afleiðingar, bæði fyrir sjúklinga sem þjást af honum og fyrir samfélagið. Eftirlit og meðferð sóragigtar er afar fjölþætt og getur þarfnast þverfaglegs samstarfs. Meðferðarleiðbeiningar við sóragigt byggja að miklu leyti á niðurstöðum slembiraðaðra tvíblindra rannsókna, en við vitum að einungis um þriðjungur sjúklinga uppfyllir inntökuskilyrðin í rannsóknirnar, oft vegna aldurs eða of lítillar sjúkdómsvirkni við inntöku. Í fyrstu greininni sýnum við fram á að sjúklingar með sóragigt sem uppfylla ekki inntökuskilyrði slembiraðaðra rannsókna á líftæknilyfjum fá jafn mikinn ávinning af slíkum lyfjum og halda áfram notkun þeirra í sama mæli eins og þeir sem uppfylla inntökuskilyrðin. Einn þáttur meðferðar við sóragigt er að stilla langvinna liðverki. Bólgueyðandi gigtarlyf eru hornsteinn verkjameðferðar sóragigtar en af þeim er hægt að fá aukaverkanir sem geta jafnvel verið alvarlegar. Í annarri greininni sýnum við fram á að við upphaf líftæknilyfjameðferðar með TNF hemlum minnkar notkunin á bólgueyðandi gigtarlyfjum um 40-50%. Þetta gefur til kynna óbeinan öryggisávinning af því að hefja slíka meðferð. Markmið meðferðar við sóragigt er að upphefja öll einkenni og teikn um sjúkdóminn ef það er hægt, með öðrum orðum að koma sjúklingum í sjúkdómshlé, helst án nokkurra aukaverkana meðferðar. Að ná og viðhalda sjúkdómshlé yfir lengri tíma, svo kallað viðvarandi sjúkdómshlé, hefur sýnt sig bæta langtímahorfur í iktsýki í gegnum aukið líkamlegt hreysti, betri lífsgæði og minni þróun liðskemmda. Áhrif viðvarandi sjúkdómshlés hefur hingað til ekki verið mikið rannsakað í sóragigt. Í þriðju og fjórðu greininni skoðum við tíðni viðvarandi sjúkdómshlés og forspárþætti fyrir því bæði í Svíþjóð og á Íslandi. Þrátt fyrir gott aðgengi að lyfjameðferðum upplifir helmingur sjúklinga aldrei sjúkdómshlé og færri en þriðjungur þeirra fá viðvarandi sjúkdómshlé. Karlkyn og minni þreyta við upphaf meðferðar spá fyrir betri líkum á að ná viðvarandi sjúkdómshlé.Psoriatic arthritis (PsA) is a chronic inflammatory joint disease that occurs in some people who have the skin condition psoriasis. The disease can cause pain, swelling, stiffness and progressive joint damage, as well as fatigue and reduced quality of life. The condition varies greatly: some patients experience only mild joint inflammation, while others develop severe arthritis leading to joint destruction and permanent disability. PsA can also affect the tendons, the spine, and the skin, and is associated with other health problems such as obesity, depression and cardiovascular disease. In recent decades, biologic and targeted synthetic drugs have revolutionised PsA treatment. These medications target specific components of the immune system and can thereby reduce inflammation and prevent joint damage. They have made remission – a state without signs or symptoms of disease – an attainable goal for many patients. However, most of the knowledge about the effects of biologic treatments comes from randomised controlled trials (RCTs), which include carefully selected participants and follow them for a relatively short period of time. As a result, it is not always clear how well these treatments work in the broader and more diverse population of patients seen in rheumatology clinics, such as older patients or those with other chronic conditions. The overall aim of this thesis was to explore the gap between clinical trials and realworld practice in PsA. Using nationwide rheumatology registries from Iceland (ICEBIO) and Sweden (SRQ), the studies examined how effective biologic and targeted synthetic therapies are when used in routine care, and how often patients achieve sustained remission – meaning long-term disease control. The first study compared patients in Iceland who met the strict inclusion criteria used in RCTs for biologic drugs with those who would have been excluded. Two-thirds of realworld patients would not have qualified for the trials, mainly because of milder joint inflammation or coexisting health conditions. Nevertheless, their treatment response and drug persistence were similar to those of RCT-eligible patients, indicating that the benefits of biologic therapy extend to a broader group than those investigated in the RCTs. The second study linked registry data with a national prescription database in Iceland and showed that initiating biologic therapy reduced the consumption of non-steroidal anti-inflammatory drugs (NSAIDs) by 40-50%. This suggests improved inflammatory control and reduces the need for NSAIDs which may have side effects such as stomach ulcers, heart or kidney disease. vii The third and fourth studies investigated the frequency of sustained remission, or the ability to keep inflammation under control for an extended period. About one in four patients achieved sustained remission based on objective measures and only half of the patients ever experienced remission at least once. Male sex and fewer swollen joints at the start of treatment predicted better outcomes. These results highlight the benefits of biologic and targeted synthetic therapies, but also the ongoing challenge of maintaining long-term disease control. In summary, this thesis shows that the benefits of biologic therapy extend beyond narrowly defined trial populations, that effective disease control reduces the need for NSAIDs, and that sustained remission remains an important but challenging goal. Continued registry-based research will help refine treatment strategies, guide personalised care, and ensure that advances in therapy translate into genuine, longterm improvements for all people living with PsA.info:eu-repo/semantics/closedAccessPsoriatic arthritisBiologic treatmentRemissionSustained remissionDoktorsritgerðirSóragigtLíftæknilyfinfo:eu-repo/semantics/doctoralThesis