Epidemiology, contributors to, and clinical trials of mortality risk in chronic kidney failure

Patients with chronic kidney failure--defined as a glomerular filtration rate persistently below 15 mL/min per 1·73 m(2)--have an unacceptably high mortality rate. In developing countries, mortality results primarily from an absence of access to renal replacement therapy. Additionally, cardiovascular and non-cardiovascular mortality are several times higher in patients on dialysis or post-renal transplantation than in the general population. Mortality of patients on renal replacement therapy is affected by a combination of socioeconomic factors, pre-existing medical disorders, renal replacement treatment modalities, and kidney failure itself. Characterisation of the key pathophysiological contributors to increased mortality and cardiorenal risk staging systems are needed for the rational design of clinical trials aimed at decreasing mortality. Policy changes to improve access to renal replacement therapy should be combined with research into low-cost renal replacement therapy and optimum clinical care, which should include multifaceted approaches simultaneously targeting several of the putative contributors to increased mortality.

Renal replacement therapy in Europe: the results of a collaborative effort by the ERA-EDTA registry and six national or regional registries

BACKGROUND

In June 2000 a new ERA-EDTA Registry Office was opened in Amsterdam. This Registry will only collect core data on renal replacement therapy (RRT) through national and regional registries. This paper reports the technical and epidemiological results of a pilot study combining the data from six registries.

METHODS

Data from the national renal registries of Austria, Finland, French-Belgium, The Netherlands, Norway, and Scotland were combined. Patients starting RRT between 1980 and 1999 (n=57371) were included in the analyses. Cox proportional hazards regression was used to predict survival.

RESULTS

The use of different coding systems for ESRD treatment by the registries made it difficult to merge the data. Incidence and prevalence of RRT showed a continuous increase with a marked variation in rates between countries. The 2-, 5- and 10-year patient survival was 67, 35 and 11% in dialysis patients and 90, 81 and 64% after a first renal allograft. Multivariate analysis showed a slightly better survival on dialysis in the 1990-1994 (RR 0.94, 95% CI 0.90-0.98) and the 1995-1999 cohort (RR 0.88, 95% CI 0.84-0.92) compared to the 1980-1984 cohort. In contrast, there was a much greater improvement in transplant-patient survival, resulting in a 56% reduction in the risk of death within the 1995-1999 cohort (RR 0.44, 95% CI 0.39-0.50) compared to the 1980-1984 cohort.

CONCLUSIONS

This study provides support for the feasibility of a "new style" ERA-EDTA registry and the collection of data is now being extended to other countries. The improvement in patient survival over the last two decades has been much greater in transplant recipients than in dialysis patients.

Long-term outcomes in acute renal failure patients treated with continuous renal replacement therapies

BACKGROUND

Limited health care budgets have raised the issue of how much therapy should be dedicated to critically ill patients with multiorgan and acute renal failure (ARF). No data are available on patients with ARF after hospital discharge.

METHODS

We assessed long-term survival and quality of life after discharge. Nine hundred seventy-nine patients with ARF who needed continuous renal replacement therapies were analyzed retrospectively. Contact was achieved by questionnaires assessing health status and mental and physical well-being.

RESULTS

The in-hospital mortality rate was 69% (n = 678). Postdischarge information was obtained from 89% (n = 267). Kaplan-Meier analyses showed surprisingly good postdischarge survival. Discharged patients had a 77% probability to survive the first 6 months. Those who did so had a probability of 89% to survive the following 6 months. After 5 years, the survival probability was 50%. Age and more than one comorbidity before hospitalization were associated with significantly lower postdischarge survival. Seventy-seven percent of questionnaire responders assessed their current health status as good to excellent, 57% were self-sustaining, and 49% stated that their quality of life had improved. Renal insufficiency remained in 41%, whereas 10% required chronic dialysis therapy.

CONCLUSION

ARF is associated with a high in-hospital mortality rate. Nevertheless, patients leaving the hospital had a reasonable survival rate and good quality of life. We conclude that aggressive intensive care unit treatment is justified in these patients.

Costs of care, long-term prognosis and quality of life in patients requiring renal replacement therapy during intensive care

OBJECTIVE

To assess (1) the long-term outcome of patients requiring renal replacement therapy (RRT) in terms of 6-month and 5-year mortality, (2) quality of life and (3) costs of the intensive care.

DESIGN

A retrospective observational cohort study.

SETTING

Twenty-three-bed multidisciplinary intensive care unit (ICU) in a tertiary care center.

PATIENTS AND PARTICIPANTS

Out of 3,447 intensive care patients admitted, 62 patients with no end-stage renal failure required RRT.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The incidence rate of acute renal failure (ARF) was 8/100,000 inhabitants/ year. The majority of patients (71%) had ARF in conjunction with multiple organ failure. The mortality in the ICU and in the hospital was 34 % and 45%, respectively. Mortality was 55% at 6 months and 65 % at 5 years. Renal function recovered in 82 % of the survivors during hospitalization. Loss of energy and limitations of physical mobility assessed by Nottingham Health Profile were the most frequently reported complaints at 6 months. Functional ability, as assessed by the Activities of Daily Living score was fairly good at 6 months. The cost per ARF 6-month survivor was $80,000.

CONCLUSIONS

There was only a minor increase in mortality after discharge from hospital among patients treated for ARF in intensive care. The costs related to ARF in intensive care are high, but the almost complete physical and functional recovery seen in ARF survivors should be noted in cost-effective analyses.

Weight-based determination of fluid overload status and mortality in pediatric intensive care unit patients requiring continuous renal replacement therapy

PURPOSE

In pediatric intensive care unit (PICU) patients, fluid overload (FO) at initiation of continuous renal replacement therapy (CRRT) has been reported to be an independent risk factor for mortality. Previous studies have calculated FO based on daily fluid balance during ICU admission, which is labor intensive and error prone. We hypothesized that a weight-based definition of FO at CRRT initiation would correlate with the fluid balance method and prove predictive of outcome.

METHODS

This is a retrospective single-center review of PICU patients requiring CRRT from July 2006 through February 2010 (n = 113). We compared the degree of FO at CRRT initiation using the standard fluid balance method versus methods based on patient weight changes assessed by both univariate and multivariate analyses.

RESULTS

The degree of fluid overload at CRRT initiation was significantly greater in nonsurvivors, irrespective of which method was used. The univariate odds ratio for PICU mortality per 1% increase in FO was 1.056 [95% confidence interval (CI) 1.025, 1.087] by the fluid balance method, 1.044 (95% CI 1.019, 1.069) by the weight-based method using PICU admission weight, and 1.045 (95% CI 1.022, 1.07) by the weight-based method using hospital admission weight. On multivariate analyses, all three methods approached significance in predicting PICU survival.

CONCLUSIONS

Our findings suggest that weight-based definitions of FO are useful in defining FO at CRRT initiation and are associated with increased mortality in a broad PICU patient population. This study provides evidence for a more practical weight-based definition of FO that can be used at the bedside.

Optimal follow-up time after continuous renal replacement therapy in actual renal failure patients stratified with the RIFLE criteria

BACKGROUND

We wished to determine the optimal duration of follow-up for patients with acute renal failure (ARF) treated with continuous renal replacement therapy (CRRT) and tested the hypothesis that a 6 month follow-up would be the minimum to catch most of the mortalities. In addition, we evaluated the association between mortality and the RIFLE classification in the same patients.

METHODS

We analysed the data of 8152 consecutive patients who had been admitted to the intensive care unit (ICU) of a Swedish university hospital between 1995 and 2001. Of that population, 207 patients were treated with CRRT, excluding 16 treated for non-renal indications.

RESULTS

ICU mortality in this cohort was 34.8% and 30 day and in-hospital mortalities were 45.9% and 50.2%, respectively. The cohort's all-cause mortality 6 months after inclusion was 59.9%, but 54.6% died as early as after 60 days. Patients in the more severe RIFLE category, F (failure), had a 30 day mortality of 57.9% compared with 23.5% for those in the RIFLE-R (risk) category and 22.0% for RIFLE-I (injury) patients.

CONCLUSIONS

In our opinion, a 60 day follow-up is sufficient to catch the majority of deaths in ARF patients treated with CRRT. The patients in the RIFLE-F category had a significantly higher mortality than RIFLE-R and -I patients.

Twice-weekly and incremental hemodialysis treatment for initiation of kidney replacement therapy

Mortality is highest in the first months of maintenance hemodialysis (HD) therapy. In many Western countries, patients who transition to kidney replacement therapy usually begin thrice-weekly HD regardless of their level of residual kidney function (RKF). RKF is a major predictor of survival. RKF may decline more rapidly with thrice-weekly HD treatments, is associated with a reduced need for dialytic solute clearance, and is an important factor in the prescription of peritoneal dialysis. In this article, we review the concept of incremental HD, in which weekly dialysis dose, in particular HD treatment frequency, is based on a variety of clinical factors, such as RKF (including urine output > 0.5 L/d), volume status, cardiovascular symptoms, body size, potassium and phosphorus levels, nutritional status, hemoglobin level, comorbid conditions, hospitalizations, and health-related quality of life. These 10 clinical criteria may identify which patients might benefit from beginning maintenance HD therapy twice weekly. Periodic monitoring of these criteria will determine the timing for increasing dialysis dose and frequency. We recognize that twice-weekly HD represents a major paradigm shift for many clinicians and jurisdictions. Therefore, we propose conducting randomized controlled trials of twice-weekly versus thrice-weekly HD to assess the potential of twice-weekly HD to improve survival and health-related quality of life while simultaneously reducing costs, protecting fragile vascular accesses, and optimizing resource use during the first year of hemodialysis therapy. Such incremental and individualized HD therapy may prove to be the most appropriate approach for transitioning to dialytic therapy.

Survival of liver transplant candidates with acute renal failure receiving renal replacement therapy

BACKGROUND

Acute renal failure (ARF) in the setting of end-stage liver disease has a dismal prognosis without liver transplantation. Renal replacement therapy (RRT) is a common bridge to liver transplant despite a paucity of supportive data. We investigated our single-center patient population to determine efficacy of RRT in liver transplant candidates with ARF.

METHODS

We identified 102 liver transplant candidates receiving RRT for ARF between April 30, 1999 and January 31, 2004. Patients that had initiated RRT intra- or postoperatively or received outpatient hemodialysis or peritoneal dialysis prior to admission were excluded. Survival to liver transplant, short-term mortality following liver transplant, and selected clinical characteristics were examined.

RESULTS

Of patients who received RRT, 35% survived to liver transplant or discharge. Mortality was 94% in patients not receiving a liver and was associated with a higher Acute Physiological and Chronic Health Evaluation (APACHE) II, lower mean arterial pressure, and the use of continuous renal replacement therapy (CRRT). Patients receiving CRRT had greater severity of illness than those on hemodialysis. The 1-year mortality of patients initiating RRT prior to liver transplant was 30% versus 9.7% for all other liver recipients (P < 0.0045).

CONCLUSION

RRT is justifiable for liver transplant candidates with ARF. Though mortality was high, a substantial percentage (31%) of patients survived to liver transplant. Postoperative mortality is increased compared with all other liver transplant recipients, but is acceptable considering the near-universal mortality without transplantation.

Death during the first 90 days of dialysis: a case control study

Comparison of survival data among centers may be used to assess performance, but may be influenced by the number of patients who die during the first 90 days of renal replacement therapy (RRT). Data published by registries in Europe do not detail these deaths, and US data generally exclude them from analysis for financial reasons. To study factors influencing such deaths we compared 42 patients who died within 90 days of first commencing RRT in one Scottish renal unit (group A) between 1971 and 1992 with 42 age- and sex-matched controls who started RRT over the same period and survived longer (group B). Patients who died within 90 days of RRT ranged in age from 25.3 to 83.7 years and had a mean age of 65.2 (SEM, 1.6; 95% confidence interval, 61.9 to 68.4). The proportion of patients who died during the first 90 days of RRT increased from 2% of all patients treated before 1981 to 12% in subsequent years. Thirty-three patients in group A received emergency dialysis via temporary venous access compared with only nine in group B (P < 0.055). There were more patients in group A with a diagnosis of arteriosclerotic renal artery stenosis (14 v 1) and with a history of smoking (15 v 2) than in group B (P < 0.0005). Median renal or nonrenal follow-up before RRT was 1.1 month in group A and 10.6 months in group B (P < 0.0001). Fewer patients in group A had no coexisting disease (1 v 17; P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative mortality risks of chronic dialysis and cadaveric transplantation in black end-stage renal disease patients

In view of the relatively low mortality risk on dialysis and the high risk of allograft loss among black compared with white end-stage renal disease (ESRD) patients, we studied the relative mortality risks of all black renal transplant candidates in Michigan from 1984 to 1989. There were 770 black ESRD patients followed from wait-listing for cadaveric (CAD) kidney transplantation until the time of transplantation, death, or December 31, 1989. The time on dialysis prior to wait-listing exceeded 1 year in 24% of these patients. Black diabetic patients on the waiting list have more than twofold relative mortality risk (RR) compared with nondiabetic individuals (RR = 2.73, P < 0.001) while the RR by diabetes status among CAD transplant recipients was small. Overall, CAD transplantation was associated with elevated risk of mortality in the first month posttransplantation (RR = 3.39, P < 0.03). Cadaveric donor transplant and wait-listed dialysis patients have equal death rates 112 days after transplantation. Thereafter, death rates were lower for transplant recipients compared with transplant candidates on dialysis. One year after transplantation, CAD transplant recipients on the average have approximately half the risk of death compared with dialysis patients who remain on the waiting list (RR = 0.49, P < 0.03). The cumulative survival probabilities are superior in transplant recipients just beyond 1 year after transplantation. Therefore, CAD transplantation in black ESRD patients is associated with a high risk of mortality in the early period after transplantation. Beyond 1 year, black transplant recipients have a substantial survival advantage over corresponding dialysis patients on the waiting list.

Mortality in chronic kidney disease and renal replacement therapy: a population-based cohort study

OBJECTIVE

To compare mortality in chronic kidney disease (CKD) stages 4 and 5 (estimated glomerular filtration rate <30 mL/min/1.73 m(2)), peritoneal dialysis, haemodialysis and transplanted patients.

DESIGN

Population-based cohort study.

SETTING

Swedish national healthcare system.

PARTICIPANTS

Swedish adult patients with CKD stages 4 and 5 (n=3040; mean age 66 years), peritoneal dialysis (n=725; 60 years), haemodialysis (n=1791; 62 years) and renal transplantation (n=606; 48 years) were identified in Stockholm County clinical quality registers for renal disease between 1999 and 2010. Five general population controls were matched to each patient by age, sex and index year.

EXPOSURE

CKD status (stage 4 or 5/peritoneal dialysis/haemodialysis/transplanted).

PRIMARY OUTCOME

All-cause mortality was ascertained from the Swedish Causes of Death Register. Mortality HRs were estimated using Cox regression conditioned on age, sex, diabetes status, education level and index year.

RESULTS

During 6553 person-years, 766 patients with CKD stages 4 and 5 died (deaths/100 person-years 12, 95% CI 11 to 13) compared with 186 deaths during 1113 person-years in peritoneal dialysis (17, 95% CI 15 to 19), 924 deaths during 3680 person-years in haemodialysis (25, 95% CI 23 to 27) and 53 deaths during 2935 person-years in transplanted patients (1.8, 95% CI 1.4 to 2.4). Against matched general population controls, the mortality HR was 3.6 (95% CI 3.2 to 4.0) for CKD, 5.6 (95% CI 3.5 to 8.9) for transplanted patients, 9.2 (95% CI 6.6 to 12.7) for peritoneal dialysis and 12.6 (95% CI 10.8 to 14.6) for haemodialysis. In direct comparison versus CKD, the mortality HR was 1.7 (95% CI 1.4 to 2.1) for peritoneal dialysis, 2.6 (95% CI 2.3 to 2.9) for haemodialysis and 0.5 (95% CI 0.3 to 0.7) for transplanted patients.

CONCLUSIONS

We did not find support for mortality in CKD to be similar to dialysis mortality. The patients with CKD stages 4 and 5 had considerably lower mortality risk than dialysis patients, and considerably higher risk than transplanted patients and matched general population controls.

Report of the annual statistical survey of the Japanese Society for Dialysis Therapy in 1996

BACKGROUND

Nearly 170,000 patients were treated by maintenance renal replacement therapy (RRT) in Japan in 1996. The current status of Japanese patients on RRT might, in some way, be suggestive for patients on RRT in other countries.

METHODS

The Japanese Society for Dialysis Therapy conducts a questionnaire survey of virtually every dialysis facility in Japan at the end of each year. Here we present the results of our survey of patients undergoing RRT as of the end of 1996, as well as five-year trends (1992-1996) in some of the data.

RESULTS

The response rate was 99.8%. At the end of 1996, there were 167,192 patients on maintenance RRT in Japan (1,328 persons per million population). The numbers of patients on maintenance RRT continued to increase during the five-year period. The gross mortality rate for that period ranged from 9.4% to 9.7%. Cuprammonium rayon was the most commonly used material (24.0%) for dialyzer membranes, followed by cellulose triacetate (18.7%). Approximately 5.0% of hemodialysis (HD) patients had a prior history of surgical release of carpal tunnel. The longer the years on HD therapy, the greater the proportion of patients with a history of such an operation. The predialysis plasma beta 2-microglobulin concentration was highest in patients aged 30 to 45 years and declined slightly after the age of 45. There was no significant difference in the HbA1c level between continuous ambulatory peritoneal dialysis and HD patients, both in whom diabetes was the disease causing renal failure. Moreover, among HD patients with diabetes, there was a clear tendency for the HbA1c level to be higher when the normalized protein catabolic rate was higher.

CONCLUSION

This report summarizes the latest results of the survey on Japanese patients on RRT.

Report on management of renale failure in Europe, XXVI, 1995. Rare diseases in renal replacement therapy in the ERA-EDTA Registry

The proportion of centres returning the ERA-EDTA Registry questionnaires has decreased considerably in recent years. Demographic information, based on the response rate of centres in 1994 (44%), does not allow reasonable projections for management of renal failure in Europe. To encourage the participation of non-responding centres, the timing was right to show the powerful impact of the ERA-EDTA Registry as a supra-national registry, by studying patients in renal replacement therapy (RRT) suffering from rare diseases. Four such diseases, Fabry's disease, nephropathy due to cyclosporin (CsA), nephropathy due to cisplatin and scleroderma, were studied using the records of 440665 patients on file up to 31 December 1993. There were 83 patients with Fabry's disease (0.0188%), 85 patients with CsA nephropathy (0.0193%), 120 patients with cisplatin nephropathy (0.0272%) and 625 patients with scleroderma (0.142%). Scleroderma was introduced as a primary renal disease (PRD) in the ERA-EDTA Registry in 1977. Seven patients were accepted for RRT in that year, whereas the number increased to over 50 new patients per year after 1986. More than half of the patients were aged over 55 years, and 68% of them were women. Survival rate of dialysis patients suffering from scleroderma was 22% at 5 years, compared to 51% in patients with standard primary renal diseases. The main causes of death were cardiovascular complications (41%), cachexia (15%) and infection (10%). Survival of first graft in a small number of 28 patients was 44% at 3 years, compared to 60% in standard PRD. Patient survival after first transplant, however, was higher by 32% at 3 years compared to that of dialysis patients. Cisplatin nephropathy was introduced as a PRD in the ERA-EDTA Registry in 1985, and since then six to 19 new patients have been accepted for RRT each year. The main reason for undergoing cisplatin treatment was ovarian (32%) and testicular cancer (21%), and the mean interval from treatment to RRT was 21.5 months, ranging widely from 0.1 to 131 months. Patient survival on dialysis was 22% at 5 years, compared to 51% in patients with standard PRD. Malignancy and cachexia accounted for over 60% of the total number of deaths. CsA nephropathy was introduced as a PRD in the ERA-EDTA Registry in 1985 and, despite its rarity, is of particular interest as a new iatrogenic entity resulting from CsA administration, mainly in solid organ transplantation. In 1985, two new patients commenced RRT in Europe, and the number increased to 59 in 1991-93. The main reason for undergoing CsA treatment was heart (68%) and liver transplant (22%), and the mean interval from treatment to RRT was 50.2 months, ranging from 5 to 90 months. Patient survival on dialysis was 46% at 4 years, compared to 58% in patients with standard primary nephropathies. Cardiovascular causes (48%) and infection (17%) were the main causes of death. Fabry's disease was introduced as a PRD in the ERA-EDTA Registry in 1985, and since the four to 13 new patients per year have commenced RRT in Europe. It is a sex-linked recessive disorder primarily affecting males (87%), and the mean age at start of RRT was 38 years. Proteinuria, skin lesions and painful paresthesiae were the most common presenting symptoms, and over 70% of the patients were hypertensive and had significant cardiovascular problems at RRT. Patient survival on dialysis was 41% at 5 years, compared to 68% in patients with standard primary nephropathies. Cardiovascular complications (48%) and cachexia (17%) were the main causes of death. Graft survival at 3 years in 33 patients was not inferior to that of patients with standard nephropathies (72% vs 69%), and patient survival after transplantation was comparable to that of patients under 55 years of age with standard PRD. (ABSTRACT TRUNCATED)

The growing volume of diabetes-related dialysis: a population based study

BACKGROUND

End-stage renal failure requiring dialysis is one of the most serious complications of diabetes mellitus, and diabetes is the most common cause of end-stage renal failure. The aim of this large, observational study is to describe the population-based incidence and prevalence rates and outcomes of diabetic individuals in Ontario, Canada who require dialysis therapy.

METHODS

Two cohorts of patients, those with diabetes and those without, were created between April 1, 1994 and March 31, 2000 (total of approximately 8.4 million) and followed until March 31, 2001 using several large, linked administrative databases at the Institute for Clinical Evaluative Sciences. The incidence, prevalence and mortality on dialysis for each cohort were determined. A multivariate Cox proportional hazards analysis, adjusting for age, sex and co-morbidity, was used to determine the independent impact of diabetes on patient survival.

RESULTS

The average annual incidence rate of dialysis was 12 times greater in persons with diabetes (130 per 100,000) vs without diabetes (11 per 100,000). By 1999-2000, diabetic patients comprised 51% of the incident dialysis population. The average annual prevalence rate was 10 times greater in the diabetic cohort. Patients with diabetes had more co-morbidities at the start of dialysis and poorer 3 year survival (55 vs 68%; P < 0.0001).

CONCLUSIONS

The incident and prevalent rates of dialysis for patients with diabetes mellitus are many times the rates of those without diabetes. Patients with diabetes mellitus often start dialysis with significant co-morbidities, which may contribute to the relatively high rate of mortality on dialysis.

Predicting renal replacement therapy and mortality in CKD

BACKGROUND

Prognostic risk scores can help clinicians intervene on higher risk patients and counsel them. Our objective is to identify characteristics that predict the rate of progression to renal replacement therapy (RRT) and evaluate how those characteristics predict mortality and a composite end point (RRT and mortality).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We conducted the study at Kaiser Permanente Northwest, a health maintenance organization. We followed up members with an estimated glomerular filtration rate (eGFR) that indicated chronic kidney disease (2 eGFRs < 60 mL/min/1.73 m(2) [<1.0 mL/s/1.73 m(2)] at least 90 days apart).

PREDICTORS

We measured baseline clinical characteristics between January 1997 and June 2000 by using electronic medical records and patients' histories of hospitalization.

OUTCOMES & MEASUREMENTS

We calculated adjusted hazard ratios and concordance statistics for progression to RRT, mortality, and the composite by using Cox regression.

RESULTS

Patients (n = 6,541) were followed up for up to 5 years. We observed 1.6 progressions to RRT/100 person-years and 11.4 deaths/100 person-years. The 6 characteristics of age, sex, eGFR, diabetes, hypertension, and anemia predicted RRT effectively (c statistic, 0.91). However, hypertension and age predicted in the opposite direction for mortality and its composite end point. The c statistic decreased: mortality (0.70), mortality and RRT (0.71).

LIMITATIONS

Characteristics were measured without a protocol; extensive missing data prevented the evaluation of known risk factors (eg, proteinuria).

CONCLUSIONS

Predicting RRT effectively requires a separate risk score. Predicting the composite end point would favor characteristics that predict mortality because it is 7 times as common as RRT.

Impact of graft failure on patient survival on dialysis: a comparison of transplant-naive and post-graft failure mortality rates

BACKGROUND

While the number of patients returning to dialysis after graft failure (GF) is increasing steadily, the impact of a failed kidney transplant on mortality among dialysis patients has not been studied well.

METHODS

Data from the Canadian Organ Replacement Register were utilized to examine the outcomes of an incident cohort of patients (n = 25,632) initiating renal replacement therapy (RRT) between 1990 and 1998. Cox regression was used to compare covariate-adjusted mortality among five RRT categories: transplant-naive dialysis, cadaveric primary renal transplant, living-donor primary renal transplant, post-GF dialysis and retransplant. RRT category-specific hazard ratios (HR) were estimated using Cox regression and adjusting for age, sex, race, calendar period, primary renal diagnosis and comorbid conditions.

RESULTS

Mortality among post-GF dialysis patients was approximately equal to that of transplant-naive patients (HR = 0.90; P = 0.30) while the HR for retransplanted patients was significantly decreased, relative to the transplant-naive group (HR = 0.35; P<0.01). Diabetes was found to be a significantly (P<0.01) stronger mortality risk factor among post-GF dialysis patients (HR = 3.71) compared with the transplant-naive group (HR = 1.73). In the post-GF group, cardiovascular disease (HR = 1.66) and 'other serious illness' (HR = 2.07) were found to be much stronger risk factors for mortality than in the transplant-naive group (HR = 1.33 and 1.43, respectively), although the differences failed to reach statistical significance.

CONCLUSIONS

These results suggest that transplant-naive and post-GF dialysis patients have equivalent mortality risk and that mortality is significantly reduced upon retransplantation. In addition, the results highlight the importance of diabetes and, possibly, comorbid conditions as potential modifiable risk factors in the management of post-GF dialysis patients.

Incidence and consequence of acute kidney injury in unselected emergency admissions to a large acute UK hospital trust

BACKGROUND

AKI is common among hospital in-patients and places a huge financial burden on the UK National Health Service, causing increased length of hospital stay and use of critical care services, with increased requirement for complex interventions including dialysis. This may account for up to 0.6% of the total Health Service budget. To investigate the incidence and consequences of AKI, all unselected emergency admissions to a large acute UK single centre University Teaching Hospital over two separate 7 day periods were reviewed.

METHODS

A retrospective audit of 745 case records was undertaken (54.6% male) including laboratory data post-discharge or death, with classification of AKI by RIFLE, AKIN and AKIB criteria. Participants were included whether admitted via their general practitioners, the emergency department, or as tertiary specialty transfers. Outcome measures were presence or absence of AKI recorded using each of the three AKI criteria, length of hospital stay (LOS), admission to, and LOS in critical care, and mortality. The most severe grade of AKI only, at any time during the admission, was recorded to prevent double counting. Renal outcome was determined by requirement for renal replacement therapy (RRT), and whether those receiving RRT remained dialysis dependent or not.

RESULTS

AKI incidence was 25.4% overall. With approximately one third present on admission and two thirds developing post admission. The AKI group had LOS almost three times higher than the non AKI group (10 vs 4 days). Requirement for critical care beds was 8.1% in the AKI group compared to 1.7% in non AKI group. Overall mortality was 5.5%, with the AKI group at 11.4% versus 3.3% in the non AKI group.

CONCLUSIONS

AKI in acute unselected hospital admissions is more common than existing literature suggests, affecting 25% of unselected admissions. In many this is relatively mild and may resolve spontaneously, but is associated with increased LOS, likelihood of admission to critical care, and risk of death. If targeted effective interventions can be developed it seems likely that substantial clinical benefits for the patient, as well as financial and structural benefits for the healthcare organisation may accrue.

High serum hyaluronan indicates poor survival in renal replacement therapy

Atherosclerotic cardiovascular disease (CVD), malnutrition, and inflammation are common clinical features of chronic renal failure and are associated with increased mortality. Elevated levels of C-reactive protein (CRP) and cytokines are commonly observed in dialysis patients and have been shown to predict mortality. Serum hyaluronan previously has been used as a marker of an inflammatory reaction, irrespective of its cause. We have determined serum levels of albumin and hyaluronan, as well as the prevalence of malnutrition (subjective global assessment, 2 to 4), inflammation (CRP >/= 10 mg/L), and overt CVD in a cohort of 97 predialysis patients (52 +/- 13 years). Moreover, we determined the outcome of these patients 29 +/- 11 months after the basal measurement of hyaluronan. Serum levels of hyaluronan (median) were markedly elevated in predialysis patients with signs of malnutrition (127.1 v 50.5 ng/mL; P < 0.0001), inflammation (130.1 v 55.0 ng/mL; P < 0.0001) and CVD (118.8 v 56.0 ng/mL; P < 0.001). The levels of log hyaluronan correlated significantly to log CRP (R = 0.35; P < 0.001), serum albumin (R = -0.40; P < 0.0001), CVD (R = 0.36; P < 0.001), and age (R = 0.40; P < 0.0001), respectively. Survival analysis by the Cox regression model showed that elevated hyaluronan levels were, independent of CVD, CRP, and age, significantly related to an increased mortality rate. The current study showed that markedly elevated serum hyaluronan levels are found in predialysis patients with malnutrition, inflammation, and CVD and that serum hyaluronan is a risk predictor of poor survival in dialysis.

End-stage renal disease and survival in people with diabetes: a national database linkage study

BACKGROUND

Increasing prevalence of diabetes worldwide is projected to lead to an increase in patients with end-stage renal disease (ESRD) requiring renal replacement therapy (RRT).

AIM

To provide contemporary estimates of the prevalence of ESRD and requirement for RRT among people with diabetes in a nationwide study and to report associated survival.

METHODS

Data were extracted and linked from three national databases: Scottish Renal Registry, Scottish Care Initiative-Diabetes Collaboration and National Records of Scotland death data. Survival analyses were modelled with Cox regression.

RESULTS

Point prevalence of chronic kidney disease (CKD)5 in 2008 was 1.63% of 19 414 people with type 1 diabetes (T1DM) compared with 0.58% of 167 871 people with type 2 diabetes (T2DM) (odds ratio for DM type 0.97, P = 0.77, on adjustment for duration. Although 83% of those with T1DM and CKD5 and 61% of those with T2DM and CKD5 were receiving RRT, there was no difference when adjusted for age, sex and DM duration (odds ratio for DM type 0.83, P = 0.432). Diabetic nephropathy was the primary renal diagnosis in 91% of people with T1DM and 58% of people with T2DM on RRT. Median survival time from initiation of RRT was 3.84 years (95% CI 2.77, 4.62) in T1DM and 2.16 years (95% CI: 1.92, 2.38) in T2DM.

CONCLUSION

Considerable numbers of patients with diabetes continue to progress to CKD5 and RRT. Almost half of all RRT cases in T2DM are considered to be due to conditions other than diabetic nephropathy. Median survival time for people with diabetes from initiation of RRT remains poor. These prevalence data are important for future resource planning.

Antithrombin supplementation for anticoagulation during continuous hemofiltration in critically ill patients with septic shock: a case-control study

Introduction

Acquired antithrombin III (AT) deficiency may induce heparin resistance and premature membrane clotting during continuous renal replacement therapy (CRRT). The purpose of this study was to evaluate the effect of AT supplementation on filter lifespan in critically ill patients with septic shock requiring CRRT.

Methods

We conducted a retrospective case-control analysis based on a 4-year observational study with prospectively collected data in two medical intensive care units in a university hospital. In all, 106 patients with septic shock underwent CRRT during the study period (55 during 2001 to 2002 and 51 during 2003 to 2004). Of these, 78 had acquired AT deficiency (plasma level below 70%) at onset of renal supportive therapy, 40 in the first 2-year period and 38 in the last 2-year period. In the latter intervention period, patients received AT supplementation (50 IU/kg) during CRRT each time that plasma AT activity, measured once daily, fell below 70%.

Results

In a case-control analysis of the 78 patients with acquired AT deficiency, groups were similar for baseline characteristics, except in severity of illness as assessed by a higher Simplified Acute Physiology Score (SAPS) II after 2002. In comparison with controls, cases had a significantly greater AT level after AT supplementation, but not at baseline, and a smaller number of episodes of clots, without excess bleeding risk. The median hemofilter survival time was longer in the AT group than in the heparin group (44.5 versus 33.4 hours; p = 0.0045). The hemofiltration dose, assessed by the ratio of delivered to prescribed ultrafiltration, increased during intervention. AT supplementation was independently associated with a decrease in clotting rate, whereas femoral angioaccess and higher SAPS II were independent predictors of filter failure. However, mortality did not differ between periods, in the control period the observed mortality was significantly higher than predicted by the SAPS II score, unlike in the treatment period.

Conclusion

In sepsis patients requiring CRRT and with acquired AT deficiency, anticoagulation with unfractionated heparin plus AT supplementation prevent premature filter clotting and may contribute to improving outcome, but the cost-effectiveness of AT remains to be determined.

Early versus late initiation of renal replacement therapy in patients with acute kidney injury-a systematic review & meta-analysis of randomized controlled trials

BACKGROUND

Acute kidney injury (AKI) is a common complication in the critically ill patients and associated with a substantial morbidity and mortality. Severe AKI may be associated with up to 60% hospital mortality. Over the years, renal replacement therapy (RRT) has emerged as the mainstay of the treatment for AKI. However, the exact timing of initiation of RRT for better patient outcome is still debatable with conflicting data from randomized controlled trials. Thus, a systematic review and meta-analysis was performed to assess the impact of "early" versus "late" initiation of RRT.

METHODS

All the published literature through the major databases including Medline/Pubmed, Embase, and Google Scholar were searched from 1970 to October 2016. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved papers concerning the effect of "early/prophylactic" RRT versus "late/as and when required" RRT were reviewed by the authors, and the data were extracted using a standardized data collection tool. Randomized trials (RCTs) comparing early initiation of RRT or prophylactic RRT with late or as and when required RRT were included. The primary outcome measures were all cause mortality and dialysis dependence on day 90. The secondary outcome measures were: length of ICU stay, length of hospital stay, recovery of renal function and adverse events.

RESULTS

Of the 547 citation retrieved, full text of 44 articles was assessed for eligibility. Of these a total of 10 RCTs with 1,636 participants were included. All the trials were open label; six trials have unclear or high risk of bias for allocation concealment while four trials have low risk of bias for allocation concealment. There was a variable definition of early versus late in different studies. Thus, the definition of early or late was taken according to individual study definition. Compared to late RRT, there was no significant benefit of early RRT on day 30 mortality [6 studies; 1301 participants; RR, 0.92;95% CI: 0.76, 1.12); day 60 mortality [3 trials;1075 participants; RR, 0.94; 95% CI: 0.78, 1.14)]; day 90 mortality [3 trials; 555 participants; RR,0.94;95% CI: 0.67, 1.33)]; overall ICU or hospital mortality; dialysis dependence on day 90 [3 trials; (RR, 1.06; 95% CI:0.53, 2.12)]. There was no significant difference between length of ICU or hospital stay or recovery of renal functions. A subgroup analysis based on modality of RRT or mixed medical and surgical vs. surgical or based on severity of illness showed no difference in outcome measure. The trials with high or unclear risk of bias for allocation concealment showed benefit of early RRT (RR, 0.74; 95% CI: 0.59, 0.91) while the trials with low risk of bias for allocation concealment showed no difference in the mortality (RR, 1.02; 95% CI: 0.89, 1.17). Grade evidence generated for most of the outcomes was "low quality".

CONCLUSION

This updated meta-analysis showed no added benefit of early initiation of RRT for patients with AKI. The grade evidence generated was of "low quality" and there was a high heterogeneity in the included trials.

PROSPERO REGISTRATION NUMBER

CRD42016043092 .

Effect of general population mortality on the north-south mortality gradient in patients on replacement therapy in Europe

In Europe there is considerable variation in mortality on renal replacement therapy (RRT). The causes of this variation are still poorly understood. We hypothesized that differences in mortality in the general population contribute to differences in mortality on RRT. To evaluate this relationship, we studied general population statistics obtained from Eurostat and the individual data of 67,692 patients on RRT from 15 national and regional renal registries. These 15 registries were divided into two geographical regions: North and South Europe. Cox regression was used to assess the relative risk of death (RR) for each region with adjustment for age, gender, diabetes, and additionally general population mortality. In patients on RRT the age, gender and diabetes adjusted RR of death was 0.65 (95% CI (0.64-0.66)) for South compared to North, while in the general population the age and gender standardized RR of death was 0.91. After adjustment for general population mortality in addition to age, gender, and diabetes, the RR of death for patients on RRT in the South changed from 0.65 to 0.74 (95% CI (0.72-0.75)), which indicates that general population mortality accounted for 26% of the region-related mortality difference on RRT. In conclusion, within Europe there exist considerable international differences in the mortality of patients on RRT. Twenty-six percent of the European north-south mortality difference in RRT could be attributed to differences in general population mortality. Our data support the hypothesis that general population mortality is an important factor to take into account when making RRT mortality comparisons.

Timing of renal replacement therapy initiation by AKIN classification system

INTRODUCTION

Previous studies using Acute Kidney Injury Network (AKIN)/RIFLE criteria to classify early initiation of renal replacement therapy (RRT) have defined it as the therapy started in less severe AKIN/RIFLE stages. Generally, these studies failed in demonstrating measurable benefits.

METHODS

We compared RRT initiation in critically ill patients and defined early or late RRT in reference to timing after stage 3 AKIN was met: patients beginning RRT within 24 hours after acute kidney injury (AKI) stage 3 were considered early starters. AKIN criteria were evaluated by both urine output (UO) and serum creatinine (sCr) and patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables.

RESULTS

A total of 358 critically ill patients were submitted to RRT. Only 150 patients with pure AKI at stage 3 were analyzed. Mortality was lower in the early RRT group (51.5 vs. 77.9%, P=0.001). After achieving balance between the groups using a propensity score, there was a significant 30.5 (95% confidence interval [CI] 14.4 to 45.2%, P=0.002) relative decrease of mortality in the early RRT group. Moreover, patients on the early RRT group had lower duration of mechanical ventilation, time on RRT and a trend to lower intensive care unit (ICU) length of stay.

CONCLUSIONS

For the first time, AKIN was used with UO criterion to evaluate early and late RRT. Using a time-based approach could be a better parameter to access the association between RRT initiation and outcomes in patients with AKI.

Establishing Surrogate Kidney End Points for Lupus Nephritis Clinical Trials: Development and Validation of a Novel Approach to Predict Future Kidney Outcomes

OBJECTIVE

End points currently used in lupus nephritis (LN) clinical trials lack uniformity and questionably reflect long-term kidney survival. This study was undertaken to identify short-term end points that predict long-term kidney outcomes for use in clinical trials.

METHODS

A database of 944 patients with LN was assembled from 3 clinical trials and 12 longitudinal cohorts. Variables from the first 12 months of treatment after diagnosis of active LN (prediction period) were assessed as potential predictors of long-term outcomes in a 36-month follow-up period. The long-term outcomes examined were new or progressive chronic kidney disease (CKD), severe kidney injury (SKI), and the need for permanent renal replacement therapy (RRT). To predict the risk for each outcome, hazard index tools (HITs) were derived using multivariable analysis with Cox proportional hazards regression.

RESULTS

Among 550 eligible subjects, 54 CKD, 55 SKI, and 22 RRT events occurred. Variables in the final CKD HIT were prediction-period CKD status, 12-month proteinuria, and 12-month serum creatinine level. The SKI HIT variables included prediction-period CKD status, International Society of Nephrology (ISN)/Renal Pathology Society (RPS) class, 12-month proteinuria, 12-month serum creatinine level, race, and an interaction between ISN/RPS class and 12-month proteinuria. The RRT HIT included age at diagnosis, 12-month proteinuria, and 12-month serum creatinine level. Each HIT validated well internally (c-indices 0.84-0.92) and in an independent LN cohort (c-indices 0.89-0.92).

CONCLUSION

HITs, derived from short-term kidney responses to treatment, correlate with long-term kidney outcomes, and now must be validated as surrogate end points for LN clinical trials.

U-curve association between timing of renal replacement therapy initiation and in-hospital mortality in postoperative acute kidney injury

Background

Postoperative acute kidney injury (AKI) is associated with poor outcomes in surgical patients. This study aims to evaluate whether the timing of renal replacement therapy (RRT) initiation affects the in-hospital mortality of patients with postoperative AKI.

Methodology

This multicenter retrospective observational study, which was conducted in the intensive care units (ICUs) in a tertiary hospital (National Taiwan University Hospital) and its branch hospitals in Taiwan between January, 2002, and April, 2009, included adult patients with postoperative AKI who underwent RRT for predefined indications. The demographic data, comorbid diseases, types of surgery and RRT, and the indications for RRT were documented. Patients were categorized according to the period of time between the ICU admission and RRT initiation as the early (EG, ≦1 day), intermediate (IG, 2–3 days), and late (LG, ≧4 days) groups. The in-hospital mortality rate censored at 180 day was defined as the endpoint.

Results

Six hundred forty-eight patients (418 men, mean age 63.0±15.9 years) were enrolled, and 379 patients (58.5%) died during the hospitalization. Both the estimated probability of death and the in-hospital mortality rates of the three groups represented U-curves. According to the Cox proportional hazard method, LG (hazard ratio, 1.527; 95% confidence interval, 1.152–2.024; P = 0.003, compared with IG group), age (1.014; 1.006–1.021), diabetes (1.279; 1.022–1.601; P = 0.031), cirrhosis (2.147; 1.421–3.242), extracorporeal membrane oxygenation support (1.811; 1.391–2.359), initial neurological dysfunction (1.448; 1.107–1.894; P = 0.007), pre-RRT mean arterial pressure (0.988; 0.981–0.995), inotropic equivalent (1.006; 1.001–1.012; P = 0.013), APACHE II scores (1.055; 1.037–1.073), and sepsis (1.939; 1.536–2.449) were independent predictors of the in-hospital mortality (All P<0.001 except otherwise stated).

Conclusions

The current study found a U-curve association between the timing of the RRT initiation after the ICU admission and patients’ in-hospital mortalities, and alerts physicians of certain factors affecting the outcome after the RRT initiation.