Serious hemorrhage and secondary prevention after stroke and TIA

Background: The number of stroke survivors is growing worldwide, and these patients have an increased risk of new vascular events and death. This risk decreases with secondary treatment medications recommended in guidelines. However, the characteristics of unselected stroke patients differ from patients included in randomized controlled trials (RCTs). Thus, the efficacy of these treatments based on RCT results may not be directly transferable to the patients treated in clinical practice. A treatment may be associated with a higher risk of serious side-effects or less benefit than expected:1) Antithrombotic treatment increases the risk of a serious hemorrhage, a risk that is not well studied in an unselected population with older age and more comorbidities; 2) Treatment of modifiable risk factors after a stroke can be improved. Many patients do not reach treatment targets, which indicates a need for strategies to improve secondary prevention and increase treatment benefit.It is therefore essential to evaluate recommended treatments through studies in a real-world setting. Aims: The aims of this thesis were to assessincidence, temporal trends, effect on mortality, and factors associated with an increased risk of a serious hemorrhage after ischemic stroke (IS) or transient ischemic attack (TIA); andif a nurse-led, telephone-based intervention including medical titration could improve modifiable risk factors in patients after stroke or TIA. Methods: In paper I, all patients registered with an IS in the national stroke register Riksstroke during 1998–2009 were studied. The register was combined with the In-Patient Register and a diagnosis of intracranial haemorrhage (ICrH) within 1 year after IS was identified. In paper II, any diagnosis of serious hemorrhage was identified during follow-up up to 2015 in all patients with an IS or TIA diagnosis, 2010–2013, at Östersund hospital. The incidences of ICrH (papers I and II) and all serious hemorrhages (paper II) were calculated. Kaplan–Meier analysis was used to assess any temporal trend in paper I and if a serious hemorrhage affected survival in study II. Cox regression analysis was used in both studies I and II to assess any factor associated with hemorrhage. In the randomized controlled NAILED stroke trial, all patients with acute stroke or TIA treated at Östersund hospital during 2010–2013 were screened for participation. Patients whose condition permitted a telephone-based follow-up were randomized to either a control group with follow-up according to usual care or to an intervention group with a nurse-led, telephone-based follow-up including titration of medication. Blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) were assessed at 1, 12, 24, and 36 months. We assessed the effect of the intervention on mean levels of BP and LDL-C and on the proportion of patients reaching treatment targets at 12 months (Study III) and at 36 months (Study IV). Study III also assessed for interactions between group allocation and measurement levels at baseline with BP and LDL-C at the 12-month follow-up. Study IV also explored temporal trends. Results: The risk of an ICrH was 1.97% per year at risk, within the first year after IS, and 0.85% excluding the first 30 days. Between 1998 and 2009, the risk of an ICrH increased during the first 30 days after an IS but decreased during days 31–365. The risk of a serious hemorrhage was 2.48% per year at risk in paper II. It was more common in elderly. The incidence rate was higher in patients discharged with AP compared with RCTs. A hemorrhage increased the risk of death in patients with good functional status but did not affect the already high mortality in patients with impaired functional status. Male sex and previous ICrH were associated with an increased risk of ICrH during the first year after IS, thrombolytic treatment, atrial fibrillation and warfarin were associated with an increased risk in the acute phase. A previous diagnosis of hypertension was associated with an increased risk of all serious hemorrhages. The NAILED trial intervention group had a significantly lower mean systolic BP (SBP), diastolic BP (DBP), and LDL-C at 12 and 36 months. The mean SBP at 36 months was 128.1 mmHg (95% confidence interval (CI): 125.8–130.5) in the intervention group, 6.1 mmHg (95% CI: 3.6–8.6; p<0.001) lower than the control group. The interaction analysis at 12 months showed that the effect of the intervention was confined to patients whose values were above the respective targets at baseline and therefore had their medication adjusted. At 36 months, a significantly higher proportion of patients in the intervention group reached treatment targets for SBP, DBP, and LDL-C. The mean differences and differences in proportions reaching treatment target for BP increased during the 36 months of follow-up. Conclusion: A serious hemorrhage after an IS or TIA is fairly common. It is more common in elderly and patients with impaired functional status. The incidence is higher in patients discharged with AP compared with RCTs. A serious hemorrhage could affect survival in patients with good functional status. The nurse-led, telephone-based intervention including medical titration used in the NAILED stroke trial improved risk factor levels after stroke and TIA, and more patients reached treatment targets. The effect increased over time.