Hospital readmission after ischemic stroke or TIA
Doctoral thesis
Åpne
Permanent lenke
https://hdl.handle.net/1956/20828Utgivelsesdato
2019-09-06Metadata
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Sammendrag
Background: Considerable advances in the field of stroke medicine have led to declining trends in stroke incidence, disability, and mortality in the Western world. Despite this, the absolute number of people affected by stroke has increased. The majority of stroke patients in Norway are 75 years or older. With increasing numbers of stroke survivors and an aging population, stroke represents a major challenge to healthcare systems and public health. Complications and readmissions are frequent after stroke and lead to increased morbidity, mortality and health care costs. Readmission is also considered a quality-metric for health care services. Studies on which subgroups of Norwegian stroke patients that are at highest risk of readmission have not been performed in Norway. Further knowledge on the causes of readmission and which subgroups of stroke patients that are at highest risk for readmission is important, as it may help avoid preventable readmissions after stroke. Methods and materials: The thesis is based on studies I-IV, in which data from the Norwegian Stroke Research Registry (NORSTROKE) have been used. For the present studies, all 1874 surviving patients admitted with ischemic stroke or transient ischemic attack (TIA) to the stroke unit at Haukeland University Hospital between July 2007 and December 2013 have been followed by review of medical records for identification of unplanned readmissions up to five years after discharge from the stroke unit. Stroke etiology was classified according to the TOAST criteria as large-artery atherosclerosis (LAA), cardioembolism (CE), small vessel occlusion (SVO), stroke of other determined etiology (SOE), or stroke of undetermined etiology (SUE). Patients with residency outside the catchment area of Haukeland University Hospital were excluded due to difficulty on follow-up. Results: Thirty-day readmission (Study I): The 30-day readmission rate among 1874 ischemic stroke and TIA patients was 10.7%. The most frequent cause of readmission was a stroke-related event, followed by infection, recurrent stroke/ TIA, and cardiac disease. Factors that independently increased the risk of 30-day readmission were increasing age, peripheral artery disease, enteral feeding, and LAA stroke subtype. The risks of all-cause readmission, recurrent stroke, and stroke-related events were increased in patients with LAA or SOE subtype, whereas the risk of cardiac disease was increased in patients with CE subtype. Thirty-day readmission increased the risk of one-year mortality. Readmission within 90 days versus day 91-365 (Study II): Of 1175 ischemic stroke patients, the first unplanned readmission occurred within 90 days in 18.8% and between day 91 and 365 in 24.5%. Infections, recurrent stroke, cardiac disease, and stroke-related events were the most common causes of readmission during both periods. Increasing age, poorer functional outcome, LAA subtype, atrial fibrillation, and an increased risk factor burden were associated with 90-day readmission, whereas increasing age and prior myocardial infarction were associated with readmission between day 91 and 365. Patients readmitted within 90 days had a shorter length of stay during the index admission, a poorer physical function and higher frequencies of LAA subtype, atrial fibrillation, and complications with infections during the index admission compared to patients readmitted between day 91 and 365. Readmission within one year versus the second and fifth year (Study III): Of the 1453 ischemic stroke and TIA patients followed for five years, 39% were readmitted within one year, whereas 53% of the patients that survived for one year without any unplanned readmissions were readmitted within five years. Peripheral artery disease was associated with readmission within one year, whereas atrial fibrillation was associated with readmission between the second and fifth year. Increasing age, poorer functional outcome, coronary artery disease, and hypertension were associated with readmission during both periods. Patients readmitted within one year were older, had more severe strokes, a poorer functional outcome, and more complications during the index admission than patients readmitted between the second and fifth year, but they did not differ in the occurrence of cardiovascular comorbidity or prescribed medication at discharge or at the time of the first readmission. Readmission and death within five years (Study IV): Among 1453 ischemic stroke and TIA patients, the five-year incidences of readmission and mortality were 72.6% and 34.5%, respectively. Both varied significantly between stroke subtypes, with the highest incidences in patients with CE or LAA subtype, and the lowest incidences in patients with SVO or SOE subtype. After adjusting for age, sex, mRS score, premorbid carestatus, and the risk factor burden, CE subtype had a 25% higher risk of all-cause readmission and a 34% higher risk of death compared to other subtypes, whereas SVO subtype had a 21% lower risk of all-cause readmission and a 48% lower risk of death. Within five years, 30% had been readmitted due to an infection, 20% due to cardiac disease, 15% due to a stroke-related event, 14% due to recurrent stroke, and 12% due to a fracture. The incidence of readmission due to infection, cardiac disease, and fractures varied significantly among stroke subtypes, with the highest incidences of all observed in patients with CE subtype. There was no difference in the incidence of five-year recurrent stroke or stroke-related events among stroke subtypes. Conclusions: The vast majority of ischemic stroke and TIA patients were readmitted within five years after discharge from our stroke unit, with more than one-fourth presenting during the first three months. Infections, stroke-related events, and cardiovascular events including recurrent stroke were the main contributors to readmission. Age, poor functional outcome and atherosclerosis in other territories than the cerebrovascular one, were important predictors of readmission. Our results also demonstrate that the incidence and causes of readmission vary by ischemic stroke subtype, and that readmission contributes to higher mortality in stroke patients.
Består av
Paper I: Bjerkreim AT, Khanevski AN, Selvik HA, Waje-Andreassen U, Thomassen L, Naess H, Logallo N. The impact of ischaemic stroke subtype on 30-day hospital readmissions. Stroke Res Treat. 2018; 2018:7195369. The article is available at: http://hdl.handle.net/1956/20826Paper II: Bjerkreim AT, Thomassen L, Brogger J, Waje-Andreassen U, Naess H. Causes and predictors for hospital readmission after ischemic stroke. J Stroke Cerebrovasc Dis. 2015;24:2095-2101. The article is available in the main thesis. The article is also available at: https://doi.org/10.1016/j.jstrokecerebrovasdis.2015.05.019
Paper III: Bjerkreim AT, Naess H, Khanevski AN, Thomassen L, Waje-Andreassen U, Logallo N. One-year versus five-year hospital readmission after ischemic stroke and TIA. BMC Neurol. 2019;19:15. The article is available at: http://hdl.handle.net/1956/20827
Paper IV: Bjerkreim AT, Khanevski AN, Thomassen L, Selvik HA, Waje-Andreassen U, Naess H, Logallo N. Five-year readmission and mortality differ by ischemic stroke subtype. J Neurol Sci. 2019;403:31-37. Submitted version of the article is available in the main thesis. The published version is available at: https://doi.org/10.1016/j.jns.2019.06.007