Death From Stroke in End-Stage Kidney Disease

Kidney replacement therapy: trends in incidence, treatment, and outcomes of myocardial infarction and stroke in a nationwide Scottish study

BACKGROUND AND AIMS

Patients with kidney failure have a higher risk of cardiovascular disease compared with the general population. Whilst temporal trends of myocardial infarction and stroke are declining in the general population, these have not been evaluated in patients with kidney failure. This study aimed to describe national trends in the incidence, treatment, and outcomes of myocardial infarction and stroke in patients with kidney failure (i.e. on dialysis or with a kidney transplant) over a 20-year period, stratified by age and sex.

METHODS

In this retrospective national data linkage study, all patients with kidney failure in Scotland (UK) receiving kidney replacement therapy between January 1996 and December 2016 were linked to national hospitalization, prescribing, and death records. The primary outcomes were the incidence of myocardial infarction and stroke, and subsequent cardiovascular death. Generalized additive models were constructed to estimate age-standardized, sex-stratified incidence rates and trends in cardiovascular and all-cause death.

RESULTS

Amongst 16 050 patients with kidney failure [52 (SD 15) years; 41.5% women], there were 1992 [66 (SD 12) years; 34.8% women] and 996 [65 (SD 13) years; 45.1% women] incident myocardial infarctions and strokes, respectively, between January 1996 and December 2016. During this period, the age-standardized incidence of myocardial infarction per 100 000 decreased in men {from 4376 [95% confidence interval (CI) 3998-4785] to 1835 (95% CI 1692-1988)} and women [from 3268 (95% CI 2982-3593) to 1369 (95% CI 1257-1491)]. Similarly, the age-standardized incidence of stroke per 100 000 also decreased in men [from 1978 (95% CI 1795-2175) to 799 (95% CI 729-875)] and women [from 2234 (95% CI 2031-2468) to 903 (95% CI 824-990)]. Compared with the general population, the incidence of myocardial infarction was four- to eight-fold higher in patients with kidney failure, whilst for stroke it was two- to four-fold higher. The use of evidence-based cardioprotective treatment increased over the study period, and the predicted probability of cardiovascular death within 1 year of myocardial infarction for a 66-year-old patient with kidney failure (mean age of the cohort) fell in men (76.6% to 38.6%) and women (76.8% to 38.8%), and also decreased in both sexes following stroke (men, from 63.5% to 41.4%; women, from 67.6% to 45.8%).

CONCLUSIONS

The incidence of myocardial infarction and stroke has halved in patients with kidney failure over the past 20 years but remains significantly higher than in the general population. Despite improvements in treatment and outcomes, the prognosis of these patients following myocardial infarction and stroke remains poor.

Outcomes of acute ischemic stroke in kidney transplant recipients: An analysis of US Nationwide inpatient sample

A kidney transplant is often the treatment of choice for end-stage kidney disease, compared with a lifetime on dialysis. Kidney transplant recipients (KTRs) have a reduced risk for new strokes than patients with chronic kidney disease (CKD) G5 treated by dialysis (CKD G5D). However, the benefit of Kidney transplant on post-stroke hospitalization outcomes has not been well studied. This study aimed to evaluate the outcomes of hospitalization after acute ischemic stroke (AIS) in KTRs and patients with CKD G5D. This retrospective study used patient data from the US Nationwide Inpatient Sample database. From 2005 to 2018, patients hospitalized with AIS were classified into 3 groups, including KTRs (n = 1,833), patients with CKD G5D (n = 26,767), and those without CKD (CKD-free, n = 986,945). Patients with CKD G1–G4 or unspecified stage, and graft failure requiring dialysis were excluded. In-hospital mortality, medical complications, transfer to nursing homes, and length of stay (LOS) were compared. Compared to CKD-free group, KTRs had no significant higher risks for in-hospital mortality, transfer to nursing homes, and LOS, but a greater risk for medical complications after adjusting for relevant factors. CKD G5D group had higher risks for in-hospital mortality (adjusted odds ratio (aOR): 2.04, 95% confidence interval (CI): 1.93–2.15), medical complications (aOR: 1.49, 95% CI: 1.45–1.54), and transfer to nursing homes (aOR: 1.10, 95% CI: 1.07–1.13), and a 0.07 day (95% CI: 0.06–0.08) longer LOS than CKD-free group. In conclusion, the outcomes of AIS hospitalization were more favorable in KTRs as compared with CKD G5D. Furthermore, the risks for in-hospital mortality, transfer to long-term care facilities, and LOS were not significantly different between KTRs and CKD-free patients.

Blood-brain barrier and gut barrier dysfunction in chronic kidney disease with a focus on circulating biomarkers and tight junction proteins

Kidney failure and associated uraemia have implications for the cardiovascular system, brain, and blood–brain barrier (BBB). We aim to examine BBB disruption, by assessing brain-derived neurotropic factor (BDNF), neuron-specific enolase (NSE) levels, and gut-blood barrier (GBB) disruption by trimethylamine N-oxide (TMAO), in chronic kidney disease (CKD) patients. Additionally, endothelial tight-junction protein expressions and modulation via TMAO were assessed. Serum from chronic kidney disease (CKD) female and male haemodialysis (HD) patients, and controls, were used to measure BDNF and NSE by enzyme-linked immunosorbent assays, and TMAO by mass spectrometry. Immunofluorescent staining of subcutaneous fat biopsies from kidney transplant recipients, and controls, were used to measure microvascular expression of tight-junction proteins (claudin-5, occludin, JAM-1), and control microvasculature for TMAO effects. HD patients versus controls, had significantly lower and higher serum levels of BDNF and NSE, respectively. In CKD biopsies versus controls, reduced expression of claudin-5, occludin, and JAM-1 were observed. Incubation with TMAO significantly decreased expression of all tight-junction proteins in the microvasculature. Uraemia affects BBB and GBB resulting in altered levels of circulating NSE, BDNF and TMAO, respectively, and it also reduces expression of tight-junction proteins that confer BBB maintenance. TMAO serves as a potential candidate to alter BBB integrity in CKD.

Epidemiology of cardiovascular death in kidney failure: An Australian and New Zealand cohort study using data linkage

Aim

Cardiovascular mortality risk evolves over the lifespan of kidney failure (KF), as patients develop comorbid disease and transition between treatment modalities. Absolute cardiovascular death rates would help inform clinical practice and health‐care provision, but are not well understood across a continuum of dialysis and transplant states. We aimed to characterize cardiovascular death across the natural history of KF using a lifespan approach.

Methods

We performed a population‐based cohort study of incident patients commencing kidney replacement therapy in Australia and New Zealand. Cardiovascular deaths were identified using data linkage to national death registers. We estimated the probability of death and kidney transplant using multi‐state models, and calculated rates of graft failure and cardiovascular death across demographic factors and comorbidities.

Results

Among 60 823 incident patients followed over 381 874 person‐years, 25% (8492) of deaths were from cardiovascular disease. At 15 years from treatment initiation, patients had a 15.2% probability of cardiovascular death without being transplanted, but only 2.3% probability of cardiovascular death post‐transplant. Females had a 3% lower probability of cardiovascular death at 15 years (15.3% vs. 18.6%) but 4% higher probability of non‐cardiovascular death (54.5% vs. 50.8%). Within the first year of dialysis, cardiovascular mortality peaked in the second month and showed little improvement across treatment era.

Conclusion

Despite improvements over time, cardiovascular death remains common in KF, particularly among the dialysis population and in the first few months of treatment. Multi‐state models can provide absolute measures of cardiovascular mortality across both dialysis and transplant states.

In this population‐based cohort study using multi‐state models (alive without kidney transplant [KT], CV death without KT, non‐CV death without KT, alive after first KT, CV death after first KT and non‐CV death after first KT), the probability of CV death was higher in non‐KT than KT patients at 15 years from treatment. In patients on dialysis, CV mortality was highest from the second month after commencing dialysis and remained high thereafter. Thus, the use of multi‐state models provides helpful information on impacts of different treatments with respect to serious outcomes.

Sex differences in mortality among binational cohort of people with chronic kidney disease: population based data linkage study

OBJECTIVE

To evaluate sex differences in mortality among people with kidney failure compared with the general population.

DESIGN

Population based cohort study using data linkage.

SETTING

The Australian and New Zealand Dialysis and Transplant Registry (ANZDATA), which includes all patients receiving kidney replacement therapy in Australia (1980-2019) and New Zealand (1988-2019). Data were linked to national death registers to determine deaths and their causes, with additional details obtained from ANZDATA.

PARTICIPANTS

Of 82 844 people with kidney failure, 33 329 were female (40%) and 49 555 were male (60%); 49 376 deaths (20 099 in female patients; 29 277 in male patients) were recorded over a total of 536 602 person years of follow-up.

MAIN OUTCOME MEASURES

Relative measures of survival, including standardised mortality ratios, relative survival, and years of life lost, using general population data to account for background mortality (adjusting for country, age, sex, and year). Estimates were stratified by dialysis modality (haemodialysis or peritoneal dialysis) and for the subpopulation of kidney transplant recipients.

RESULTS

Few differences in outcomes were found between male and female patients with kidney failure. However, compared with the general population, female patients with kidney failure had greater excess all cause deaths than male patients (female patients: standardised mortality ratio 11.3, 95% confidence interval 11.2 to 11.5, expected deaths 1781, observed deaths 20 099; male patients: 6.9, 6.8 to 6.9, expected deaths 4272, observed deaths 29 277). The greatest difference was observed among younger patients and those who died from cardiovascular disease. Relative survival was also consistently lower in female patients, with adjusted excess mortality 11% higher (95% confidence interval 8% to 13%). Average years of life lost was 3.6 years (95% confidence interval 3.6 to 3.7) greater in female patients with kidney failure compared with male patients across all ages. No major differences were found in mortality by sex for haemodialysis or peritoneal dialysis. Kidney transplantation reduced but did not entirely remove the sex difference in excess mortality, with similar relative survival (P=0.83) and years of life lost difference reduced to 2.3 years (95% confidence interval 2.2 to 2.3) between female and male patients.

CONCLUSIONS

Compared with the general population, female patients had greater excess deaths, worse relative survival, and more years of life lost than male patients, however kidney transplantation reduced these differences. Future research should investigate whether systematic differences exist in access to care and possible strategies to mitigate excess mortality among female patients.

Stroke in Hemodialysis Patients Randomized to Different Intravenous Iron Strategies: A Prespecified Analysis from the PIVOTAL Trial

Background

People with kidney failure treated with hemodialysis (HD) are at increased risk of stroke compared with similarly aged people with normal kidney function. One concern is that treatment of renal anemia might increase stroke risk. We studied risk factors for stroke in a prespecified secondary analysis of a randomized, controlled trial of intravenous iron treatment strategies in HD.

Methods

We analyzed data from the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL) trial, focusing on variables associated with risk of stroke. The trial randomized 2141 adults who had started HD <12 months earlier and who were receiving an erythropoiesis-stimulating agent (ESA) to high-dose IV iron administered proactively or low-dose IV iron administered reactively in a 1:1 ratio. Possible stroke events were independently adjudicated. We performed analyses to identify variables associated with stroke during follow-up and assessed survival following stroke.

Results

During a median 2.1 years of follow-up, 69 (3.2%) patients experienced a first postrandomization stroke. Fifty-seven (82.6%) were ischemic strokes, and 12 (17.4%) were hemorrhagic strokes. There were 34 postrandomization strokes in the proactive arm and 35 postrandomization strokes in the reactive arm (hazard ratio, 0.90; 95% confidence interval, 0.56 to 1.44; P=0.66). In multivariable models, women, diabetes, history of prior stroke at baseline, higher baseline systolic BP, lower serum albumin, and higher C-reactive protein were independently associated with stroke events during follow-up. Hemoglobin, total iron, and ESA dose were not associated with risk of stroke. Fifty-eight percent of patients with a stroke event died during follow-up compared with 23% without a stroke.

Conclusions

In patients on HD, stroke risk is broadly associated with risk factors previously described to increase cardiovascular risk in this population. Proactive intravenous iron does not increase stroke risk.Clinical Trial registry name and registration number: Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), 2013-002267-25.

A long-term nationwide study on chronic kidney disease-related mortality in Italy: trends and associated comorbidity

BACKGROUND

Chronic kidney diseases (CKDs) represent a major public health concern worldwide with increasing incidence and prevalence. However, the epidemiological dimension of CKD in Italy is still under evaluation. By analyzing all the conditions reported on death certificates (multiple causes of death), we aimed to investigate the real burden of CKD mortality in Italy over 15 years and identify the main conditions contributing to death in association with CKD.

METHODS

Death certificates of all deaths occurring in Italy from 2003 to 2017 were analyzed. Certificates reporting CKD were identified as CKD-related deaths. CKD-related mortality was investigated through age-standardized mortality rates, by sex and age. Conditions associated with CKD were identified through an indicator (age-standardized proportion ratio) measuring the excess proportion (value > 1) of having such conditions mentioned in the death certificate with and without CKD.

RESULTS

From 2003 to 2017, multiple-cause-based CKD mortality rates increased by 60% in males and by 54% in females. The overall increase was mostly attributable to people aged 80 years or more. Several conditions were associated with CKD, the most relevant being diabetes (age-standardized proportion ratio = 2.2), obesity (2.1), systemic connective tissue disorders (2.3), anemia (2.7), and genitourinary system diseases (2.6).

CONCLUSIONS

Multiple-cause-of-death data revealed a significant increase in CKD-related mortality in recent years, providing a measure of the burden of CKD on overall mortality in Italy. Moreover, multiple cause analysis allowed to identify the main conditions contributing to death in association with CKD, which should be aggressively targeted by clinicians to prevent CKD adverse outcomes.

Diagnostic utility of flow cytometry based coated-platelets assay as a biomarker to predict thrombotic or hemorrhagic phenotype in acute stroke

BACKGROUND

Coated-platelets are sub-population of platelets "coated" with highly procoagulant proteins and phosphatidylserine that sustains thrombin generation. They are produced upon dual agonist stimulation by collagen and thrombin. This study was conducted to assess if there was any difference in the levels of coated-platelets in patients with primary intracranial hemorrhage (PICH) and ischemic stroke due to large artery atherosclerosis (LAA) as compared to healthy controls, and to see if coated-platelet levels had any influence on the hemorrhagic transformation (HT) of ischemic stroke.

METHODS

Coated-platelet levels were determined by flow cytometry using fluorescently tagged Annexin V antibody to identify phosphatidylserine exposed on the surface of platelets activated by dual agonists (convulxin and thrombin) in cross-sectional cohort of 75 patients with stroke and 34 controls.

RESULTS

Patients with PICH (n = 35) had significantly lower coated-platelets than the controls (adjusted mean ± SE, 21.0 ± 1.9% vs. 36.1 ± 1.7%, p < 0.001), while patients with LAA (n = 30) had significantly higher coated-platelets than controls (adjusted mean ± SE, 51.9 ± 1.5% vs. 36.1 ± 1.7%, p < 0.001). Patients with subsequent HT of ischemic stroke (n = 10) had significantly lower coated-platelet levels at admission compared to those without HT (adjusted mean ± SE, 18.1 ± 2.6% vs. 51.9 ± 1.5%, p < 0.001).

CONCLUSIONS

Coated-platelet levels are significantly different in patients with hemorrhagic and ischemic stroke as compared with controls. Lower levels of coated-platelets measured by flow cytometry may be earliest predictor of subsequent HT in patients with ischemic stroke even before the radiological changes suggestive of HT are visualized.

Chronic Kidney Disease and Cerebrovascular Disease: Consensus and Guidance From a KDIGO Controversies Conference

The global health burden of chronic kidney disease is rapidly rising, and chronic kidney disease is an important risk factor for cerebrovascular disease. Proposed underlying mechanisms for this relationship include shared traditional risk factors such as hypertension and diabetes, uremia-related nontraditional risk factors, such as oxidative stress and abnormal calcium-phosphorus metabolism, and dialysis-specific factors such as cerebral hypoperfusion and changes in cardiac structure. Chronic kidney disease frequently complicates routine stroke risk prediction, diagnosis, management, and prevention. It is also associated with worse stroke severity, outcomes and a high burden of silent cerebrovascular disease, and vascular cognitive impairment. Here, we present a summary of the epidemiology, pathophysiology, diagnosis, and treatment of cerebrovascular disease in chronic kidney disease from the Kidney Disease: Improving Global Outcomes Controversies Conference on central and peripheral arterial disease with a focus on knowledge gaps, areas of controversy, and priorities for research.

Chronic Kidney Disease is a Risk Factor for Stroke

Chronic kidney disease (CKD) is a sustained reduction in estimated glomerular filtration rate (eGFR), and/or presence of albuminuria. People with CKD have adverse cardiovascular outcomes including stroke. CKD and stroke share several risk factors, most notably older age, diabetes and hypertension, but CKD is also an independent risk factor for stroke. Relative burden of increased risk is worse for younger people and women, with <40 years with end stage CKD having more than 11 times the risk of their age-matched peers. Risk also varies by CKD treatment, with a risk peak for those starting dialysis, but dropping after the first month of treatment. Proposed mechanisms for increased risk are uraemia, cerebral blood flow dysregulation, vascular calcification, arterial stiffness, chronic inflammation, vascular access impacts, and for those on haemodialysis the use of anticoagulation to maintain dialysis circuits. Outcomes for people with CKD and stroke are poorer; functional outcomes may be impacted by reduced access to specialised stroke care. Stroke mortality is higher for those with CKD; with standardised mortality ratio more than three times higher than expected, but for some groups higher still (young women <40 years with a kidney transplant have 19 times the risk of stroke mortality than women without a transplant). Interventions to prevent and treat stroke lack the evidence base in CKD patients that is present for the general population.