Risk factors for COVID-19 hospitalization and mortality in patients with chronic kidney disease: a nationwide cohort study

Background

Several studies have demonstrated an increased risk of severe coronavirus disease 2019 (COVID-19) in chronic kidney disease (CKD) patients. However, few have investigated the impact of CKD stage and dialysis modality. The primary aim of this study was to investigate the association between CKD stage, dialysis modality and risk of severe COVID-19. Secondly, we aimed to study the impact of comorbidities and drugs on the risk of severe COVID-19 in the CKD population.

Methods

This nationwide observational study was based on data from the Swedish Renal Registry and three other national registries. Patients with non-dialysis CKD stage 3b-5 or dialysis on 1 January 2020 were included and followed until 31 December 2021. The primary outcome was COVID-19 hospitalization; the secondary outcome was COVID-19 mortality. Associations were investigated using logistic regression models, adjusting for confounders.

Results

The study population comprised 7856 non-dialysis CKD patients and 4018 dialysis patients. The adjusted odds ratios (aOR) for COVID-19 hospitalization and mortality were highest in the dialysis group [aOR 2.24, 95% confidence interval (CI) 1.79-2.81; aOR 3.10, Cl 95% 2.03-4.74], followed by CKD 4 (aOR 1.33, 95% CI 1.05-1.68; aOR 1.66, Cl 95% 1.07-2.57), as compared with CKD 3b. No difference in COVID-19 outcomes was observed between patients on hemodialysis and peritoneal dialysis. Overall comorbidity burden was one of the strongest risk factors for severe COVID-19 and the risk was also increased in patients prescribed insulin, proton pump inhibitors, diuretics, antiplatelets or immunosuppressants.

Conclusions

Worsening CKD stage and comorbidity are independent risk factors for severe COVID-19 in the Swedish CKD population.

Results of the first nationwide cohort study of outcomes in dialysis and kidney transplant patients before and after vaccination for COVID-19

BACKGROUND

Patients on kidney replacement therapy (KRT) have been identified as a vulnerable group during the coronavirus disease 2019 (COVID-19) pandemic. This study reports the outcomes of COVID-19 in KRT patients in Sweden, a country where patients on KRT were prioritized early in the vaccination campaign.

METHODS

Patients on KRT between January 2019 and December 2021 in the Swedish Renal Registry were included. Data were linked to national healthcare registries. The primary outcome was monthly all-cause mortality over 3 years of follow-up. The secondary outcomes were monthly COVID-19-related deaths and hospitalizations. The results were compared with the general population using standardized mortality ratios. The difference in risk for COVID-19-related outcomes between dialysis and kidney transplant recipients (KTRs) was assessed in multivariable logistic regression models before and after vaccinations started.

RESULTS

On 1 January 2020, there were 4097 patients on dialysis (median age 70 years) and 5905 KTRs (median age 58 years). Between March 2020 and February 2021, mean all-cause mortality rates increased by 10% (from 720 to 804 deaths) and 22% (from 158 to 206 deaths) in dialysis and KTRs, respectively, compared with the same period in 2019. After vaccinations started, all-cause mortality rates during the third wave (April 2021) returned to pre-COVID-19 mortality rates among dialysis patients, while mortality rates remained increased among transplant recipients. Dialysis patients had a higher risk for COVID-19 hospitalizations and death before vaccinations started {adjusted odds ratio [aOR] 2.1 [95% confidence interval (CI) 1.7-2.5]} but a lower risk after vaccination [aOR 0.5 (95% CI 0.4-0.7)] compared with KTRs.

CONCLUSIONS

The COVID-19 pandemic in Sweden resulted in increased mortality and hospitalization rates among KRT patients. After vaccinations started, a distinct reduction in hospitalization and mortality rates was observed among dialysis patients, but not in KTRs. Early and prioritized vaccinations of KRT patients in Sweden probably saved many lives.

Healthcare costs after kidney transplantation compared to dialysis based on propensity score methods and real world longitudinal register data from Sweden

This study aimed to estimate the healthcare costs of kidney transplantation compared with dialysis using a propensity score approach to handle potential treatment selection bias. We included 693 adult wait-listed patients who started renal replacement therapy between 1998 and 2012 in Region Skåne and Stockholm County Council in Sweden. Healthcare costs were measured as annual and monthly healthcare expenditures. In order to match the data structure of the kidney transplantation group, a hypothetical kidney transplant date of persons with dialysis were generated for each dialysis patient using the one-to-one nearest-neighbour propensity score matching method. Applying propensity score matching and inverse probability-weighted regression adjustment models, the potential outcome means and average treatment effect were estimated. The estimated healthcare costs in the first year after kidney transplantation were €57,278 (95% confidence interval (CI) €54,467-60,088) and €47,775 (95% CI €44,313-51,238) for kidney transplantation and dialysis, respectively. Thus, kidney transplantation leads to higher healthcare costs in the first year by €9,502 (p = 0.066) compared to dialysis. In the following two years, kidney transplantation is cost saving [€36,342 (p < 0.001) and €44,882 (p < 0.001)]. For patients with end-stage renal disease, kidney transplantation reduces healthcare costs compared with dialysis over three years after kidney transplantation, even though the healthcare costs are somewhat higher in the first year. Relating the results of existing estimates of costs and health benefits of kidney transplantation shows that kidney transplantation is clearly cost-effective compared to dialysis in Sweden.

The association between long-term glycemic control and all-cause mortality is different among older versus younger patients with diabetes mellitus and maintenance hemodialysis treatment

AIMS

Knowledge about association between glycated hemoglobin (HbA1c) and risk of all-cause mortality in patients with diabetes mellitus on maintenance hemodialysis (HD)-treatment is sparse. The study aims to investigate association between HbA1c and all-cause mortality in patients with diabetes and maintenance HD-treatment, separately for two age groups- above and below 75 years.

METHODS

2487 patients (mean age 66 years, 66 % men) were separated in two age groups: ≤75 years (n = 1810) and > 75 years (n = 677) and followed up between 2008 and 2018. Hazard ratios (HR) and 95 % confidence intervals (CI) for associations between HbA1c and all-cause mortality were calculated using Cox-regression-models.

RESULTS

1295 (52 %) patients died and 473 (70 %) among the patients above 75 years old. In the multivariate analysis, HbA1c5-6 % was used as reference. In patients ≤ 75 years old, only increased HbA1c > 9.7 %, HR2.03(CI1.43-2.89) was associated with increased risk of all-cause mortality. In patients > 75 years, HbA1c ≤ 5 %, HR1.67(CI1.16-2.40); HbA1c6.9-7.8 %, HR1.41(CI1.03-1.93) and HbA1c8.7-9.7 %, HR1.79 (CI1.08-2.96) were associated with increased risk of all-cause mortality.

CONCLUSIONS

We found a J-shaped association between HbA1c and mortality only in diabetic HD-patients > 75 years. This probably indicates that in an old population of diabetic HD-patients, both intensive glucose control and hyperglycemia could be harmful and associated with higher risk of death.

Trends in Mortality Due to Myocardial Infarction, Stroke, and Pulmonary Embolism in Patients Receiving Dialysis

IMPORTANCE

During the past decades, improvements in the prevention and management of myocardial infarction, stroke, and pulmonary embolism have led to a decline in cardiovascular mortality in the general population. However, it is unknown whether patients receiving dialysis have also benefited from these improvements.

OBJECTIVE

To assess the mortality rates for myocardial infarction, stroke, and pulmonary embolism in a large cohort of European patients receiving dialysis compared with the general population.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, adult patients who started dialysis between 1998 and 2015 from 11 European countries providing data to the European Renal Association Registry were and followed up for 3 years. Data were analyzed from September 2020 to February 2022.

EXPOSURES

Start of dialysis.

MAIN OUTCOMES AND MEASURES

The age- and sex-standardized mortality rate ratios (SMRs) with 95% CIs were calculated by dividing the mortality rates in patients receiving dialysis by the mortality rates in the general population for 3 equal periods (1998-2003, 2004-2009, and 2010-2015).

RESULTS

In total, 220 467 patients receiving dialysis were included in the study. Their median (IQR) age was 68.2 (56.5-76.4) years, and 82 068 patients (37.2%) were female. During follow-up, 83 912 patients died, of whom 7662 (9.1%) died because of myocardial infarction, 5030 (6.0%) died because of stroke, and 435 (0.5%) died because of pulmonary embolism. Between the periods 1998 to 2003 and 2010 to 2015, the SMR of myocardial infarction decreased from 8.1 (95% CI, 7.8-8.3) to 6.8 (95% CI, 6.5-7.1), the SMR of stroke decreased from 7.3 (95% CI, 7.0-7.6) to 5.8 (95% CI, 5.5-6.2), and the SMR of pulmonary embolism decreased from 8.7 (95% CI, 7.6-10.1) to 5.5 (95% CI, 4.5-6.6).

CONCLUSIONS AND RELEVANCE

In this cohort study of patients receiving dialysis, mortality rates for myocardial infarction, stroke, and pulmonary embolism decreased more over time than in the general population.

Long-term glycemic variability and the risk of mortality in diabetic patients receiving peritoneal dialysis

Background

The large amount of glucose in the dialysate used in peritoneal dialysis (PD) likely affects the glycemic control. The aim of this study was to investigate the association between HbA1c variability, as a measure of long-term glycemic variability, and the risk of all-cause mortality in diabetic patients with PD.

Methods

325 patients with diabetes and ESRD were followed (2008–2018) in the Swedish Renal Registry. Patients were separated in seven groups according to level of HbA1c variability. The group with the lowest variability was denoted the reference. The ratio of the standard deviation (SD) to the mean of HbA1c, HbA1c (SD)/HbA1c (mean), i.e. the coefficient of variation (CV), was defined as HbA1c variability. Hazard ratios (HR) and 95% confidence intervals (CI) were examined using Cox regression analyses.

Results

During follow-up, 170 (52%) deaths occurred. The highest mortality was among patients with the second highest HbA1c variability, CV≥2.83 [n = 44 of which 68% patients died]. In the multivariate analyses where lowest HbA1c variability (CV≤0.51) was used as the reference group, HbA1c CV 2.83–4.60 (HR 3.15, 95% CI 1.78–5.55; p<0.001) and CV> 4.6 (HR 2.48, 95% CI 1.21–5.11; p = 0.014) were associated with increased risk of death.

Conclusion

The high risk of all-cause mortality in patients with diabetes and PD increased significantly with elevated HbA1c variability, as measure of long-term glycemic control. This indicates that stable glycemia is associated with an improvement of survival; whereas more severe glycemic fluctuations, possibly caused by radical changes in dialysis regimes or peritonitis, are associated with a higher risk of mortality in diabetic patients with PD.

Treatment practices and outcomes in incident peritoneal dialysis patients: the Swedish Renal Registry 2006-2015

BACKGROUND

Therapeutic developments have contributed to markedly improved clinical outcomes in peritoneal dialysis (PD) during the 1990s and 2000s. We investigated whether recent advances in PD treatment are implemented in routine Swedish care and whether their implementation parallels improved patient outcomes.

METHODS

We conducted an observational study of 3122 patients initiating PD in Sweden from 2006 to 2015. We evaluated trends of treatment practices (medications, PD-related procedures) and outcomes [patient survival, major adverse cardiovascular events (MACEs), peritonitis, transfer to haemodialysis (HD) and kidney transplantation] and analysed associations of changes of treatment practices with changes in outcomes.

RESULTS

Over the 10-year period, demographics (mean age 63 years, 33% women) and comorbidities remained essentially stable. There were changes in clinical characteristics (body mass index and diastolic blood pressure increased), prescribed drugs (calcium channel blockers, non-calcium phosphate binders and cinacalcet increased and the use of renin-angiotensin system inhibitors, erythropoietin and iron decreased) and dialysis treatment (increased use of automated PD, icodextrin and assisted PD). The standardized 1- and 2-year mortality and MACE risk did not change over the period. Compared with the general population, the risk of 1-year mortality was 4.1 times higher in 2006-2007 and remained stable throughout follow-up. However, the standardized 1- and 2-year peritonitis rate decreased and the incidence of kidney transplantation increased while transfers to HD did not change.

CONCLUSIONS

Over the last decade, treatment advances in PD patients were accompanied by a substantial decline in peritonitis frequency and an increased rate of kidney transplantations, while 1- and 2-year survival and MACE risk did not change.

[COVID-19 related mortality in Swedish patients with renal replacement therapy]

Data from the Swedish Renal Registry (SRR) show that during the period March 16, 2020 to March 15, 2021 0.4% of all renal transplant recipients and 3% of all dialysis patients died due to COVID-19 in Sweden. Of all registered deaths, 20% were attributed to COVID-19.  In the age group 50-59 years the risk ratio for COVID-19 related mortality was 16 (95% CI 6.5-38) among transplant recipients and 22 (95% CI 7.1-69) among dialysis patients, compared to the background population in the same age group. Excess mortality, compared to the five years preceding the pandemic, was 30% for transplant recipients and 8.7% for dialysis patients, compared to 7.7% for the entire Swedish population. Detailed reports were sent to SRR for 864 patients with confirmed COVID-19 infection representing 5.0% of all transplant recipients and 13% of all dialysis patients. The case fatality rate was 7.0% and 21% respectively.

Effect of comorbidities on survival in patients >80 years of age at onset of renal replacement therapy: data from the ERA-EDTA Registry

BACKGROUND

The number of elderly patients on renal replacement therapy (RRT) is increasing. The survival and quality of life of these patients may be lower if they have multiple comorbidities at the onset of RRT. The aim of this study was to explore whether the effect of comorbidities on survival is similar in elderly RRT patients compared with younger ones.

METHODS

Included were 9333 patients ≥80 years of age and 48 352 patients 20-79 years of age starting RRT between 2010 and 2015 from 15 national or regional registries submitting data to the European Renal Association-European Dialysis and Transplantation Association Registry. Patients were followed until death or the end of 2016. Survival was assessed by Kaplan-Meier curves and the relative risk of death associated with comorbidities was assessed by Cox regression analysis.

RESULTS

Patients ≥80 years of age had a greater comorbidity burden than younger patients. However, relative risks of death associated with all studied comorbidities (diabetes, ischaemic heart disease, chronic heart failure, cerebrovascular disease, peripheral vascular disease and malignancy) were significantly lower in elderly patients compared with younger patients. Also, the increase in absolute mortality rates associated with an increasing number of comorbidities was smaller in elderly patients.

CONCLUSIONS

Comorbidities are common in elderly patients who enter RRT, but the risk of death associated with comorbidities is less than in younger patients. This should be taken into account when assessing the prognosis of elderly RRT patients.

CKD Progression and Mortality Among Men and Women: A Nationwide Study in Sweden

RATIONALE & OBJECTIVE

Chronic kidney disease (CKD) is a global health problem with increasing prevalence. Several sex-specific differences have been reported for disease progression and mortality. Selection and survival bias might have influenced the results of previous cohort studies. The objective of this study was to investigate sex-specific differences of CKD progression and mortality among patients with CKD not receiving maintenance dialysis.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

Adult patients with incident CKD glomerular filtration rate categories 3b to 5 (G3b-G5) identified between 2010 and 2018 within the nationwide Swedish Renal Registry-CKD (SRR-CKD).

EXPOSURE

Sex.

OUTCOMES

Time to CKD progression (defined as a change of at least 1 CKD stage or initiation of kidney replacement therapy [KRT]) or death. Repeated assessments of estimated glomerular filtration rate (eGFR).

ANALYTICAL APPROACH

CKD progression and mortality before KRT were assessed by the cumulative incidence function methods and Fine and Gray models, with death handled as a competing event. Sex differences in eGFR slope were estimated using mixed effects linear regression models.

RESULTS

7,388 patients with incident CKD G3b, 18,282 with incident CKD G4, and 9,410 with incident CKD G5 were identified. Overall, 19.6 (95% CI, 19.2-20.0) patients per 100 patient-years progressed, and 10.1 (95% CI, 9.9-10.3) patients per 100 person-years died. Women had a lower risk of CKD progression (subhazard ratio [SHR], 0.88 [95% CI, 0.85-0.92]), and a lower all-cause (SHR, 0.90 [95% CI, 0.85-0.94]) and cardiovascular (SHR, 0.83 [95% CI, 0.76-0.90]) mortality risk. Risk factors related to a steeper decline in eGFR included age, sex, albuminuria, and type of primary kidney disease.

LIMITATIONS

Incomplete data for outpatient visits and laboratory measurements and regional differences in reporting.

CONCLUSIONS

Compared to women, men had a higher rate of all-cause and cardiovascular mortality, an increased risk of CKD progression, and a steeper decline in eGFR.

Association Between Implementation Of Novel Therapies And Improved Survival In Patients Starting Hemodialysis: The Swedish Renal Registry 2006-2015

BACKGROUND

The recent years have witnessed significant therapeutic advances for patients on hemodialysis. We evaluated temporal changes in treatments practices and survival rates among incident hemodialysis patients.

METHODS

Observational study of patients initiating hemodialysis in Sweden 2006-2015. Trends of hemodialysis-related practices, medications, and routine laboratory biomarkers were evaluated. The incidence of death and major cardiovascular events (MACE) across calendar years were compared against the age-sex-matched general population. Via Cox regression, we explored whether adjustment for implementation of therapeutic advances modified observed survival and MACE risks.

RESULTS

Among 6,612 patients, age and sex were similar, but the burden of co-morbidities increased over time. The proportion of patients receiving treatment by hemodiafiltration, >3 sessions/week, lower ultrafiltration rate, and working fistulas increased progressively, as did use of non-calcium phosphate binders, cinacalcet, and vitamin D3. The standardized 1-year mortality decreased from 13.2% in 2006/07 to 11.1% in 2014/15. The risk of death decreased by 6% (HR 0.94, 95% CI 0.90-0.99) every two years, and the risk of MACE by 4% (HR 0.96; 0.92-1.00). Adjustment for changes in treatment characteristics abrogated these associations (HR 1.00; 0.92-1.09 for death and 1.00; 0.94-1.06 for MACE). Compared with the general population, the risk of death declined from 6 times higher 2006/2007 [standardized incidence rate ratio, sIRR 6.0 (5.3-6.9)], to 5.6 higher 2014/15 [sIRR 5.57 (4.8-6.4)].

CONCLUSIONS

Gradual implementation of therapeutic advances over the last decade was associated with a parallel reduction in short-term risk of death and MACE among hemodialysis patients.

Survival of patients treated with extended-hours haemodialysis in Europe: an analysis of the ERA-EDTA Registry

Background

Previous US studies have indicated that haemodialysis with ≥6-h sessions [extended-hours haemodialysis (EHD)] may improve patient survival. However, patient characteristics and treatment practices vary between the USA and Europe. We therefore investigated the effect of EHD three times weekly on survival compared with conventional haemodialysis (CHD) among European patients.

Methods

We included patients who were treated with haemodialysis between 2010 and 2017 from eight countries providing data to the European Renal Association–European Dialysis and Transplant Association Registry. Haemodialysis session duration and frequency were recorded once every year or at every change of haemodialysis prescription and were categorized into three groups: CHD (three times weekly, 3.5–4 h/treatment), EHD (three times weekly, ≥6 h/treatment) or other. In the primary analyses we attributed death to the treatment at the time of death and in secondary analyses to EHD if ever initiated. We compared mortality risk for EHD to CHD with causal inference from marginal structural models, using Cox proportional hazards models weighted for the inverse probability of treatment and censoring and adjusted for potential confounders.

Results

From a total of 142 460 patients, 1338 patients were ever treated with EHD (three times, 7.1 ± 0.8 h/week) and 89 819 patients were treated exclusively with CHD (three times, 3.9 ± 0.2 h/week). Crude mortality rates were 6.0 and 13.5/100 person-years. In the primary analyses, patients treated with EHD had an adjusted hazard ratio (HR) of 0.73 [95% confidence interval (CI) 0.62–0.85] compared with patients treated with CHD. When we attributed all deaths to EHD after initiation, the HR for EHD was comparable to the primary analyses [HR 0.80 (95% CI 0.71–0.90)].

Conclusions

EHD is associated with better survival in European patients treated with haemodialysis three times weekly.

P1444CHANGES IN TREATMENTS AND OUTCOMES OF PATIENTS INITIATING PERITONEAL DIALYSIS DURING THE LAST 10 YEARS: DATA FROM SWEDISH RENAL REGISTRY

Background and Aims

The recent years have witnessed several therapeutic improvements regarding both peritoneal dialysis (PD) treatment itself and the prevention and management of complications. We evaluated trends in implementation of therapeutic improvements and their relationship with survival and other relevant clinical outcomes in PD patients from Sweden.

Method

Using the Swedish Renal Registry (SRR), clinical data from all patients initiating PD in Sweden between 2006 and 2015 were linked to other national healthcare registries to obtain information on vital status, hospitalization and diagnoses during in and out-patient care, along with information on all dispensed drugs, from inclusion to the end of 2017. We first evaluated trends in the use of PD-related treatments and of selected key medications within 2-year blocks. We then evaluated the incidence of death, major cardiovascular events (MACE), technique failure, transplantation and peritonitis episodes within one and two years from PD initiation using standardized incidence rates via logistic regression to account for differences in patient characteristics over time. In subsequent Cox regression models, we studied whether adjustment for implementation of these therapeutic changes modified observed trends in clinical outcomes. Finally, patient survival was compared against the age-sex matched general Swedish population using standardized incidence ratios (SIR).

Results

3,312 patients (mean age 63±15 years; 34% women) initiated PD in Sweden during the study period. Across 2-year time blocks, there was no difference over time in the distribution of age, sex or comorbidities with the exception of an increased proportion of patients with chronic pulmonary disease. The proportion of patients undergoing automated peritoneal dialysis and using icodextrin increased over time, while mean standard Kt/V and weekly creatinine clearance did not change. The use of non-calcium phosphate binders, cinacalcet and calcium-channel blockers increased, and the use of angiotensin-converting enzyme inhibitors /angiotensin receptor blockers, erythropoietin, iron, and calcium supplements showed decreasing trends.

After standardization for differences in demography and comorbidities, the one-year incidence of peritonitis decreased by 13% and the rate of kidney transplantation increased by 52% in 2014/15 compared to 2006/07. The rates of death, MACE or technique failure did not show differences over time. Similar results were observed with 2-years of follow up and when applying Cox models; Per 2-year period, the risk of peritonitis within one year decreased by 8% (HR 0.92, 95% CI 0.87-0.98) regardless of age, sex, comorbidity and the abovementioned therapeutic changes. The risk of death for PD patients was in 2006/2007 4 times higher [SIR 4.08 (3.15–5.29)] and in 2014/15 3.7 times higher [SIR 3.65 (2.70–4.94)] than the general population, corresponding to a reduction of SIR by 11%.

Conclusion

During the last 10 years, there has been a gradual implementation of new and established evidence-based treatments in patients starting PD in Sweden. Although survival rates are improving compared to the general population, there were no clear differences in the rates of technique failure, MACE or death across PD patients over time. We observed, however, consistent improvements in peritonitis frequency and access to transplantation.

SO068EFFECTS OF BASELINE PHYSICAL FUNCTION AND 12 MONTHS EXERCISE TRAINING ON SURVIVAL IN PATIENTS WITH NON DIALYSIS DEPENDENT CHRONIC KIDNEY DISEASE

Background and Aims

Low physical function is associated with increased mortality in patients on dialysis. Observational studies have shown an association between self-reported physical activity and survival in patients with chronic kidney disease (CKD). It is unclear whether exercise training can affect survival in patients with CKD. The purpose of this study was to investigate, whether level of physical function and exercise training, respectively, affect survival in patients with non-dialysis dependent CKD stages 3-5.

Method

The patients studied had participated in the RENEXC study comprising 12 months of endurance training in combination with either strength- or balance training. In this study the whole group was analyzed as both groups had improved their physical function with no between group differences. Physical function at baseline and after 12 months was assessed with a battery of tests. Patients were divided into 4 groups for each test: improved physical function by &gt;10 %, no improvement, did not complete 12 months of exercise training and missing data. Effects of physical function at baseline and improvement in physical function after 12 months of exercise training on survival were analyzed using univariate and multivariate Cox regression analyses. Multivariate analyses were adjusted for age, sex, co-morbidity, time on dialysis and time as transplanted.

Results

This study comprised 151 patients, mean age 66±14 years, 65% men, measured GFR 22.5±8.2 ml/min/1.73 m2. Median follow-up was 60 months.

Physical function at baseline was associated with a significantly better survival in univariate Cox regression analysis in the following tests: 6 Minute Walk Test (6MWT), handgrip strength right, functional reach and 30 seconds Sit-To-Stand (30s-STS). The decline in hazard ratio (HR) per unit in each test was 0.5 % in the 6MWT, 2.9 % in handgrip strength, 6.4 % in functional reach and 10.8 % in 30s-STS. Multivariate analyses showed that only 6MWT and 30s-STS were significantly related to survival. The decline in hazard ratio (HR) per unit in the multivariate analyses was 0.4 % in the 6MWT (HR 0.996, CI 0.994-0.998) and 5.7 % in 30s-STS (HR 0.943, CI 0.892-0.996).

Patients who completed 12 months of exercise training and improved their results by 10 % or more showed a significantly better survival compared with patients who completed 12 months of exercise training but failed to improve by at least 10 % in the following tests in the univariate analyses: handgrip strength right and left, isometric quadriceps strength left and 30s-STS. There was also a significantly better survival in the group that improved compared with the group that did not complete 12 months of exercise in the 6MWT, handgrip strength right and left, isometric quadriceps strength left and 30s-STS. In the multivariate analyses there were no significant differences between the group that improved and the group that did not improve in any of the physical function tests. The significant differences between the group that improved and the group that did not complete remained in the following tests: handgrip strength right (HR 7.83, CI 2.10-29.2) and left (HR 3.95, CI 1.31-11.9), isometric quadriceps strength left (HR 3.94, CI 1.78-8.74) and 30s-STS (HR 3.50, CI 1.58-7.77). The difference between the group that improved and the group that did not complete the training became significant in functional reach (HR 4.22, CI 1.99-8.94) and isometric quadriceps strength right (HR2.80, CI 1.35-5.80).

Conclusion

After adjustment for age, sex, co-morbidity, time on dialysis and time as transplanted overall endurance and muscular endurance at baseline were associated with a better survival. Patients who improved muscle strength, muscular endurance and balance showed a better survival compared with those who did not complete the study. There were no statistically significant differences between those who improved their physical function by at least 10% compared with those who did not.

P1159MILD BLOOD PRESSURE VARIABILITY IS ASSOCIATED WITH BETTER SURVIVAL IN PATIENTS WITH END STAGE RENAL DISEASE AND PERITONEAL DIALYSIS

Background and Aims

Recently, variability in blood pressure (BP) has been recognized as a risk factor for mortality and cardiovascular events in the general population. However, most studies included patients with normal or near normal kidney function.

Aim

To study the association between BP variability and the risk of all-cause mortality in patients with end stage renal disease (ESRD) and peritoneal dialysis (PD) treatment.

Method

From 2008 until the end of 2017, 2329 patients with ESRD and at least three months of PD (mean age: 63.8 years, men: 67.5%) were followed for 16 months in median (interquartile range: 11-28 months). Data were extracted from the Swedish Renal Register (SNR).

The coefficient variation (CV = the ratio of the standard deviation (SD) to the mean value) was defined as BP variability in terms of systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) [SBP(SD)/SBP(mean), DBP(SD)/ DBP(mean), and MAP(SD)/MAP(mean), respectively].

The relationships between BP variability and mortality were examined by time-dependent Cox models to estimate hazard ratios (HR) and 95% confidence intervals (CI) in univariate and multivariate analyses, with adjustment for demographics, laboratory findings and comorbidity.

Results

During the follow-up period, 1054 (45%) deaths occurred. The mean level of BP variability was CV=0.10± 0.1.

The highest rate of mortality was observed in the patients with the highest variability in SBP (CV&gt;0.25; 64% of those patients died).

In the multivariate model, for each of the BP variables, we compared the risk of mortality in the lowest variability group (CV≤ 0.05) with that in the CV=0.10-0.15 group (reference):

SBP: (HR 1.74, 95% CI 1.44- 2.09; p&lt;0.001); DBP: (HR 1.91, 95% CI 1.59- 2.23; p&lt;0.001); and MAP: (HR 1.73, 95% CI 1.44- 2.06; p&lt;0.001). Thus, for all BP variables, the lowest variability was associated with increased mortality risk.

We then compared the highest variability group (CV&gt;0.25) with the CV=0.10-0.15 group (reference):

SBP: (HR 1.60, 95% CI 1.14- 2.25; p&lt;0.001); DPB: (HR 1.74, 95% CI 1.44- 2.09; p&lt;0.001); and MAP: (HR 1.98, 95% CI 1.21- 3.27; p&lt;0.001). Thus, for all BP variables, the highest variability was related to increased mortality risk.

Conclusion

In this study, the association between BP variability and the risk of mortality was U-shaped in patients with ESRD and PD. Thus, both very low and high levels of BP variability were related to higher risk of mortality. Mild BP variability was associated with the lowest risk of mortality, which could suggest that, non-intensive and long duration of ultrafiltration (UF) with PD was probably beneficial in terms of survival

P1437RELATIONS BETWEEN IMPLEMENTATIONS OF EVIDENCE-BASED TREATMENTS AND IMPROVED OUTCOMES IN PATIENTS STARTING HEMODIALYSIS DURING THE LAST 10 YEARS: EXPERIENCES FROM THE SWEDISH RENAL REGISTRY 2006-2015

Background and Aims

Although few randomized controlled trials have been able to demonstrate benefits of single treatments in improving outcomes of patients undergoing hemodialysis (HD), the last decades have witnessed significant therapeutic advances. This relates both to the HD treatment itself and to the management of patient complications. We here evaluated temporal changes in the use of evidence-based treatments and survival rates in incident HD patients.

Method

We included all patients initiating HD in Sweden between 2006-2015 and followed them until the end of 2017. Data were linked to national registries to retrieve information on date of death, cardiovascular events, comorbidity, and drug prescriptions. We first evaluated trends in the use of different HD related therapies and selected key therapeutic targets and medications in 2-year blocks. We then evaluated the incidence of death and major cardiovascular events (MACE) within one and two years from start of dialysis through standardized incidence rates via logistic regression models to account for differences in patient characteristics over time. Via Cox regression models, we explored whether adjustment for implementation of evidence-based treatments (e.g. hemodiafiltration (HDF), frequent HD, working fistula, drugs to control CKD-MBD, anemia) modified the observed survival and MACE risks. Finally, survival trends were also compared against an age-sex-calendar year-matched general Swedish population using standardized incidence ratios.

Results

We identified 6,612 patients starting HD in Sweden during the study period. There was no difference in mean age or proportion of women over time, but body mass index, serum parathyroid hormone levels and the proportion of patients with cerebrovascular disease, atrial fibrillation and cancer increased. Conversely, mean serum hemoglobin, phosphate and albumin values decreased over time. The proportion of patients who underwent HDF, had more than three HD sessions/week, and had a working fistula increased progressively, as well as the use of phosphate binders (particularly non-calcium), cinacalcet, and vitamin D3. After standardization for differences in demography and comorbidities, the one-year risk of mortality or MACE risk decreased by 7% and 16%, respectively, in 2014/15 compared to 2006/07. Similarly, the two-year risk of death or MACE decreased by 16 and 21%. In multivariable Cox models, we explored the linear association between calendar year blocks and study outcomes. Per 2-year period, the risk of death within one year decreased by 6% (HR 0.94, 95% CI 0.92-1.00), and of MACE by 5% (0.94, 95% CI 0.92-0.98). Adjustment for changes in the evidence-based treatments over time abrogated these associations (HR 1.00, 95% CI 0.91-1.09 for death and 1.00, 95% CI 0.94-1.06 for MACE). Similar results were obtained for 2-year outcomes. Compared with the general population, the one-year risk of death for a HD patient was 6 times higher in 2006/2007 [standardized incidence rate ratio, SIR 6.05 (5.30–6.91)], but decreased to 5.5 times higher in 2014/15 [SIR 5.57 (4.82–6.44)], corresponding to a SIR reduction of 8%.

Conclusion

In patients initiating HD therapy in Sweden, there has been a gradual implementation of new and established evidence-based treatments during the last 10 years, which was associated with a parallel reduction in the risk of death and MACE.

Fewer hospitalizations and prolonged technique survival with home hemodialysis- a matched cohort study from the Swedish Renal Registry

BACKGROUND

Patients on home hemodialysis (HHD) exhibit superior survival compared with patients on institutional hemodialysis (IHD) and peritoneal dialysis (PD). There is a sparsity of reports comparing morbidity between HHD and IHD or PD and none in a European population. The aim of this study is to compare morbidity between modalities in a Swedish population.

METHODS

The Swedish Renal Registry was used to retrieve patients starting on HHD, IHD or PD. Patients were matched according to sex, age, comorbidity and start date. The Swedish Inpatient Registry was used to determine comorbidity before starting renal replacement therapy (RRT) and hospital admissions during RRT. Dialysis technique survival was compared between HHD and PD.

RESULTS

RRT was initiated with HHD for 152 patients; these were matched with 608 patients with IHD and 456 with PD. Patients with HHD had significantly lower annual admission rate and number of days in hospital. (median 1.7 admissions; 12 days) compared with IHD (2.2; 14) and PD (2.8; 20). The annual admission rate was significantly lower for patients with HHD compared with IHD for cardiovascular diagnoses and compared with PD for infectious disease diagnoses. Dialysis technique survival was significantly longer with HHD compared with PD.

CONCLUSIONS

Patients choosing HHD as initial RRT spend less time in hospital compared with patients on IHD and PD and they were more likely than PD patients, to remain on their initial modality. These advantages, in combination with better survival and higher likelihood of renal transplantation, are important incentives for promoting the use of HHD.

Changes in co-morbidity pattern in patients starting renal replacement therapy in Europe-data from the ERA-EDTA Registry

Background

Patients starting renal replacement therapy (RRT) for end-stage renal disease often present with one or more co-morbidities. This study explored the prevalence of co-morbidities in patients who started RRT in Europe during the period from 2005 to 2014.

Methods

Using data from patients aged 20 years or older from all 11 national or regional registries providing co-morbidity data to the European Renal Association - European Dialysis and Transplant Association Registry, we examined the prevalence of the following co-morbidities: diabetes mellitus (DM) (primary renal disease and/or co-morbidity), ischaemic heart disease (IHD), congestive heart failure (CHF), peripheral vascular disease (PVD), cerebrovascular disease (CVD) and malignancy.

Results

Overall, 70% of 7578 patients who initiated RRT in 2014 presented with at least one co-morbidity: 39.0% presented with DM, 25.0% with IHD, 22.3% with CHF, 17.7% with PVD, 16.4% with malignancy and 15.5% with CVD. These percentages differed substantially between countries. Co-morbidities were more common in men than in women, in older patients than in younger patients, and in patients on haemodialysis at Day 91 when compared with patients on peritoneal dialysis. Between 2005 and 2014 the prevalence of DM and malignancy increased over time, whereas the prevalence of IHD and PVD declined.

Conclusions

More than two-thirds of patients initiating RRT in Europe have at least one co-morbidity. With the rising age at the start of RRT over the last decade, there have been changes in the co-morbidity pattern: the prevalence of cardiovascular co-morbidities decreased, while the prevalence of DM and malignancy increased.

Improved long-term survival with home hemodialysis compared with institutional hemodialysis and peritoneal dialysis: a matched cohort study

Background

The survival rate for dialysis patients is poor. Previous studies have shown improved survival with home hemodialysis (HHD), but this could be due to patient selection, since HHD patients tend to be younger and healthier. The aim of the present study is to analyse the long-term effects of HHD on patient survival and on subsequent renal transplantation, compared with institutional hemodialysis (IHD) and peritoneal dialysis (PD), taking age and comorbidity into account.

Methods

Patients starting HHD as initial renal replacement therapy (RRT) were matched with patients on IHD or PD, according to gender, age, Charlson Comorbidity Index and start date of RRT, using the Swedish Renal Registry from 1991 to 2012. Survival analyses were performed as intention-to-treat (disregarding changes in RRT) and per-protocol (as on initial RRT).

Results

A total of 152 patients with HHD as initial RRT were matched with 608 IHD and 456 PD patients, respectively. Median survival was longer for HHD in intention-to-treat analyses: 18.5 years compared with 11.9 for IHD (p <  0.001) and 15.0 for PD (p = 0.002). The difference remained significant in per-protocol analyses omitting the contribution of subsequent transplantation. Patients on HHD were more likely to receive a renal transplant compared with IHD and PD, although treatment modality did not affect subsequent graft survival (p > 0.05).

Conclusion

HHD as initial RRT showed improved long-term patient survival compared with IHD and PD. This survival advantage persisted after matching and adjusting for a higher transplantation rate. Dialysis modality had no impact on subsequent graft survival.

The Effect of Peritoneal Dialysis on Labor Market Outcomes Compared with Institutional Hemodialysis

BACKGROUND

The aim of this study is to compare the impact of peritoneal dialysis (PD) and institutional hemodialysis (IHD), the 2 most common dialysis modalities, on employment, work income, and disability pension in Sweden.

METHODS

Included in this study were 4,734 patients in IHD and PD, aged 20 - 60 years, starting treatment in Sweden during 1995 - 2012, and surviving the first year of dialysis therapy. Both "intention to treat" and "on treatment" analyses were performed by including transplant patients into the former and censoring them at the date of transplant in the latter analysis. A reduced bias treatment effect of PD vs IHD on labor market outcomes was estimated while accounting for non-random selection into treatment.

RESULTS

Peritoneal dialysis was found to be associated with a 4-percentage-point increased probability of employment compared with IHD in the "on treatment" analysis. Also, PD was associated with a reduced disability pension by 6 percentage points, as well as increased work income (EUR 3,477 for employed) compared with IHD during the first year of treatment. The "intention to treat" analysis tended to give higher effect sizes compared with "on treatment."

CONCLUSIONS

The results indicate that PD is associated with a treatment advantage over IHD in terms of increased employment, work income, and reduced disability pension in the Swedish population after controlling for non-random selection into treatment.

Socioeconomic Inequalities in the Kidney Transplantation Process: A Registry-Based Study in Sweden

BACKGROUND

Few studies have examined the association between individual-level socioeconomic status and access to kidney transplantation. This study aims to investigate the association between predialysis income and education, and access to (i) the kidney waitlist (first listing), and (ii) kidney transplantation conditional on waitlist placement. Adjustment will be made for a number of medical and nonmedical factors.

METHODS

The Swedish Renal Register was linked to national registers for adult patients in Sweden who started dialysis during 1995 to 2013. We employed Cox proportional hazards models.

RESULTS

Nineteen per cent of patients were placed on the waitlist. Once on the waitlist, 80% received kidney transplantation. After adjusting for covariates, patients in the highest income quintile were found to have higher access to both the waitlist (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.53-1.96) and kidney transplantation (HR, 1.33; 95% CI, 1.16-1.53) compared with patients in the lowest income quintile. Patients with higher education also had better access to the waitlist and kidney transplantation (HR, 2.16; 95% CI, 1.94-2.40; and HR, 1.16; 95% CI, 1.03-1.30, respectively) compared with patients with mandatory education.

CONCLUSIONS

Socioeconomic status-related inequalities exist with regard to both access to the waitlist, and kidney transplantation conditional on listing. However, the former inequality is substantially larger and is therefore expected to contribute more to societal inequalities. Further studies are needed to explore the potential mechanisms and strategies to reduce these inequalities.

Home- or Institutional Hemodialysis? - a Matched Pair-Cohort Study Comparing Survival and Some Modifiable Factors Related to Survival

BACKGROUND/AIMS

Survival for dialysis patients is poor. Earlier studies have shown better survival in home-hemodialysis (HHD). The aims of this study are to compare survival for matched patients with HHD and institutional hemodialysis (IHD) and to elucidate the effect on factors related to survival such as hyperphosphatemia, fluid overload and anemia.

METHODS

In this retrospective, observational study, incident patients starting HHD and IHD were matched according to sex, age, comorbidity and date of start. Survival analysis was performed both as "intention to treat" including renal transplantation and "on treatment" with censoring at the date of transplantation. Dialysis doses, laboratory parameters and prescriptions of medications were compared.

RESULTS

After matching, 41 pairs of patients, with HHD and IHD, were included. Survival among HHD patients was longer compared with IHD, median survival being 17.3 and 13.0 years (p=0.016), respectively. The "on treatment" analysis, also favoured HHD (p=0.015). HHD patients had lower phosphate, 1.5 mmol/L compared with 2.1 mmol/L (p<0.001) and no antihypertensives and diuretics compared with 2 for IHD patients at 6 (p=0.001) and 18 months (p=0.014). There were no differences in hemoglobin or albumin.

CONCLUSION

HHD shows better survival compared with IHD, also after controlling for patient selection. This could be caused by better phosphate and/or fluid balance associated with higher dialysis doses.

Excellent long time survival for Swedish patients starting home-hemodialysis with and without subsequent renal transplantations

Survival for patients on dialysis is poor. Earlier reports have indicated that home-hemodialysis is associated with improved survival but most of the studies are old and report only short-time survival. The characteristics of patient populations are often incompletely described. In this study, we report long-term survival for patients starting home-hemodialysis as first treatment and estimate the impact on survival of age, comorbidity, decade of start of home-hemodialysis, sex, primary renal disease and subsequent renal transplantation. One hundred twenty-eight patients starting home-hemodialysis as first renal replacement therapy 1971-1998 in Lund were included. Data were collected from patient files, the Swedish Renal Registry and Swedish census. Survival analysis was made as intention-to-treat analysis (including survival after transplantation) and on-dialysis-treatment analysis with patients censored at the day of transplantation. Ten-, twenty- and thirty-year survival were 68%, 36% and 18%. Survival was significantly affected by comorbidity, age and what decade the patients started home-hemodialysis. For patients younger than 60 years and with no comorbidities, the corresponding figures were 75%, 47% and 23% and a subsequent renal transplantation did not significantly influence survival. Long-term survival for patients starting home-hemodialysis is good, and improves decade by decade. Survival is significantly affected by patient age and comorbidity, but the contribution of subsequent renal transplantation was not significant for younger patients without comorbidities.

Final Desiccation of the Afar Rift, Ethiopia

Stable and radioactive isotope studies of ancient corals and mollusks from a fossil atoll in the Afar Rift indicate that final separation of the Afar Depression from the Red Sea occurred not earlier than 32,000 years ago. Desiccation followed within a few thousand years. The events recorded in the Afar Rift illustrate the processes occurring in the incipient stages leading to the formation of an oceanic body by rifting of a continental block.