Factors affecting the outcome of acute renal failure among the elderly population in India: a hospital based study

The spectrum of acute renal failure (ARF) in the elderly population and the factors predicting poor outcome in these patients are not well defined in literature. Identification of risk factors and poor prognostic markers in these patients can help in planning strategies to prevent ARF and to prioritise the utilization of sparse and expensive therapeutic modalities, especially in a developing country like ours. We retrospectively analyzed data of 454 elderly patients (age ≥60 years), detected having ARF in a tertiary care super-speciality hospital in North India, from April 2000 to March 2004. The mean age of this population was 66.4 years with 70.5% being male. 64% patients had more than one precipitating factors for ARF, with volume depletion being the most common precipitating factor (33% cases). Infection/sepsis (21.6%) and drugs (11.5%) were other important precipitating factors. 31.8% were recorded as having oliguric ARF (urine output <400 ml/day) and 33.5% required renal replacement therapy (RRT). Acute peritoneal dialysis was the most frequent form of RRT given (62.5%). Mortality was 41.2% (187 cases), of whom 56 (29.8%) died inspite of recovery from ARF. Among the survivors, 103 patients (22.7%) had complete renal recovery, 141 (31.1%) had partial renal recovery, while 23 (8.6%), remained dialysis dependent. The factors which were found to be associated with increased mortality were; age ≥70 years, presence of previous chronic illness, ARF precipitated by cardiac failure and infection, need for RRT, oliguria and increasing numbers of failed organs. To conclude, ARF among elderly is a common problem in nephrology practice at our institute and is responsible for 48.9% of nephrology admissions/consultations among elderly patients. Majority of these patients are prone to multiple renal insults. Underlying chronic illness, presence of cardiac failure and sepsis, oliguria, need for RRT and increasing number of organ failure is associated with poor outcome.     

Renal failure in the ICU: comparison of the impact of acute renal failure and end-stage renal disease on ICU outcomes

BACKGROUND: Acute renal failure (ARF) is associated with a persistent high mortality in critically ill patients in intensive care units (ICUs). Most studies to date have focused on patients with established, intrinsic ARF or relatively severe ARF due to multiple factors. None have examined outcomes of dialysis-dependent chronic renal failure [end-stage renal disease (ESRD)] patients in the ICU. We examined the incidence and outcomes of ARF in the ICU using a standard definition and compared these to outcomes of ICU patients with either ESRD or no renal failure. We sought to determine the impact of renal dysfunction and/or loss of organ function on outcome. METHODS: We prospectively scored 1530 admissions to eight ICUs over a 10-month period for illness severity at ICU admission using the Acute Physiological and Chronic Health Evaluation (APACHE III) evaluation tool. Patients were defined as having ARF based on the definition of Hou et al (Am J Med 74:243-248,1983) designed to detect significant measurable declines in renal function based on serum creatinine. ESRD patients were identified as being chronically dialysis-dependent prior to ICU admission and the remainder had no renal failure. Clinical characteristics at ICU admission and ICU and hospital outcomes were compared between the three groups. RESULTS: We identified 254 cases of ARF, 57 cases of ESRD and 1219 cases of no renal failure for an incidence of ARF of 17%. Roughly half the ARF patients had ARF at ICU admission and the remainder developed ARF during their ICU stay. Only 11% of ARF patients required dialysis support. ARF patients had significantly higher acute illness severity scores than those with no renal failure, whereas patients with ESRD had intermediate severity scores. ICU mortality was 23% for patients with ARF, 11% for those with ESRD, and 5% for those with no renal failure. There was no difference in outcome between patients who had ARF at ICU admission and those who developed ARF in the ICU. Patients with ARF severe enough to require dialysis had a mortality of 57%. APACHE III predicted outcome very well in patients with no renal failure and patients with ARF at the time of scoring but underpredicted mortality in those who developed ARF after ICU admission and overestimated mortality in patients with ESRD. CONCLUSIONS: ARF is common in ICU patients and has a persistent negative impact on outcomes, although the majority of ARF is not severe enough to require dialysis support. The mortality of patients with ARF from all causes is almost exactly similar to that noted using the same criteria two decades ago. More profound ARF requiring dialysis continues to have an even greater mortality. Nevertheless, acute declines in renal function are associated with a mortality that is not well explained simply by loss of organ function. The majority of ARF patients who did not require dialysis still had a considerably higher mortality than the ESRD patients, all of whom required dialysis; while ARF patients who did require dialysis had a much higher morality than ESRD patients. APACHE III performs well and captures the mortality of patients with ARF at the time of scoring. Development of ARF after scoring has a profound effect on standardized mortality. We were unable to identify a unique mortality associated with ARF, but the presence of measurable renal insufficiency continues to be a sensitive marker for poor outcome.     

Peritoneal Dialysis in Acute Renal Failure

The definition of adequate dialysis in acute renal failure (ARF) is complex and involves the time of referral to dialysis, dose, and dialytic method. Nephrologist experience with a specific procedure and the availability of different dialysis modalities play an important role in these choices. There is no consensus in literature on the best method or ideal dialysis dose in ARF.

Peritoneal dialysis (PD) is used less and less in ARF patients, and is being replaced by continuous venovenous therapies. However, it should not be discarded as a worthless therapeutic option for ARF patients. PD offers several advantages over hemodialysis, such as its technical simplicity, excellent cardiovascular tolerance, absence of an extracorporeal circuit, lack of bleeding risk, and low risk of hydro-electrolyte imbalance. PD also has some limitations, though: it needs an intact peritoneal cavity, carries risks of peritoneal infection and protein losses, and has an overall lower effectiveness. Because daily solute clearance is lower with PD than with daily HD, there have been concerns that PD cannot control uremia in ARF patients. Controversies exist concerning its use in patients with severe hypercatabolism; in these cases, daily hemodialysis or continuous venovenous therapy have been preferred.

There is little literature on PD in ARF patients, and what exists does not address fundamental parameters such as adequate quantification of dialysis and patient catabolism. Given these limitations, there is a pressing need to re-evaluate the adequacy of PD in ARF using accepted standards. Therefore, new studies should be undertaken to resolve these problems.     

Epidemiologic trend changes in acute renal failure--a tertiary center experience from South India

BACKGROUND: There are little data on the incidence of acute renal failure (ARF) from India due to the absence of central registry. The etiology, course, and outcome of ARF differ in various parts of India. Significant trend changes were reported even within a same center over a period of time. AIM: To find out the epidemiologic trend changes in ARF patients, the authors compared the profile of patients admitted by the Department of Nephrology from 1995-2004 with previously published data from 1987-1991. METHODS: Data collected from case records of patients admitted with ARF were systemically analyzed for age, gender, etiology, course, and outcome. A total of 32 variables were collected per person retrospectively. The chi-square test, Fisher's exact test, and student t-test were used as tests of significance (p<0.05 was taken as statistically significant). RESULTS: A total of 1112 patients were diagnosed to have ARF from 1995-2004. The mean age was 37.08 +/- 3.4 yrs. There were 669 (60.1%) males. Medical, obstetric, and surgical causes accounted for 87.6, 8.9, and 3.4 percent of ARF, respectively. Among the medical causes of ARF, acute diarrheal disease was the most common. Other causes of medical ARF included drugs, glomerulonephritis, sepsis, snake bite, leptospirosis, malaria, and copper sulphate, which accounted for 13.4, 9.3, 8.8, 7.8, 7.5, 4.4, and 4.3 percent, respectively. In comparison with the data from 1987-1991, medical ARF remained the most common cause of ARF, though without any statistical significance (87.6 percent vs 89.5 percent, p>0.32). Though surgical ARF had more than doubled from 1.5 percent from 1987-1991 to 3.4 percent (p<0.01) during the present study, it is much less when compared to similar studies in the literature. Obstetric renal failure more or less remained the same (8.9 percent vs 9 percent, p>0.4). A statistically significant decline was noted in overall as well as individual group mortality. The overall mortality declined from 26.4 percent to 19.6 percent (p<0.02). Regarding the outcome of ARF, 611 patients (54.94 percent) showed a total recovery, a partial recovery was noted in 192 patients (17.26 percent), and 91 patients (8.18 percent) had persistent dialysis-dependent renal failure. The factors noted to occur more frequently in the deceased were high entry serum creatinine (>440 micromol), jaundice, sepsis, oliguria, anemia, hypoalbuminemia, and hospital-acquired ARF. The overall requirement of dialysis was 69.0 percent. Hemodialysis was the most common modality of renal replacement therapy. CONCLUSIONS: ARF in South India differs in some important aspects when compared with data from other parts of the country. Significant trend changes were noted with time even within our center. Acute diarrheal disease was the most common cause of ARF. Leptospiral ARF was on the decline, and drugs, sepsis, and malaria were the emerging ARF causes. The incidence of surgical ARF was on the rise. Despite improvements in antenatal care, obstetric renal failure remained a significant cause of ARF. Hemodialysis became the preferred mode of renal replacement therapy.     

Evolution of nephrology. The caldron of its organizations

Nephrology in America was the first and largest of the new internal medical specialties to emerge after World War II. It was a novel fusion of traditional basic sciences and new clinical tools such as renal biopsy, new imaging, molecular target drugs, dialysis, hemoperfusion and transplantation. The immediate roots were provided by great scientists/clinicians like John Peters, Homer Smith and Tom Addis. The caldron was formed by the tensions arising from newly formed organizations such as the AHA (including NYHA and WHA), NIH, ISN, ASN, ASAIO and NKF. Without these tensions, nephrology might have become a much smaller and narrower specialty of clinical physiology, salt and water and acid-base metabolism. The evolution was rapid from attendance 100+ at the first ISN in Evian, France in 1960 to the 1998 ASN meeting in Philadelphia which drew more than 10, 000 nephrologists. This is a personalized history of those tensions and their interactions written by the only nephrologist who has been President of the WHA, ASN, ISN, ASAIO and the NKF.     

Peritoneal dialysis in acute renal failure

The definition of adequate dialysis in acute renal failure (ARF) is complex and involves the time of referral to dialysis, dose, and dialytic method. Nephrologist experience with a specific procedure and the availability of different dialysis modalities play an important role in these choices. There is no consensus in literature on the best method or ideal dialysis dose in ARF. Peritoneal dialysis (PD) is used less and less in ARF patients, and is being replaced by continuous venovenous therapies. However, it should not be discarded as a worthless therapeutic option for ARF patients. PD offers several advantages over hemodialysis, such as its technical simplicity, excellent cardiovascular tolerance, absence of an extracorporeal circuit, lack of bleeding risk, and low risk of hydro-electrolyte imbalance. PD also has some limitations, though: it needs an intact peritoneal cavity, carries risks of peritoneal infection and protein losses, and has an overall lower effectiveness. Because daily solute clearance is lower with PD than with daily HD, there have been concerns that PD cannot control uremia in ARF patients. Controversies exist concerning its use in patients with severe hypercatabolism; in these cases, daily hemodialysis or continuous venovenous therapy have been preferred. There is little literature on PD in ARF patients, and what exists does not address fundamental parameters such as adequate quantification of dialysis and patient catabolism. Given these limitations, there is a pressing need to re-evaluate the adequacy of PD in ARF using accepted standards. Therefore, new studies should be undertaken to resolve these problems.     

Comparison of cellulose diacetate and polysulfone membranes in the outcome of acute renal failure. A prospective randomized study.

BACKGROUND: Whether the nature of haemodialysis (HD) membranes can influence the outcome of acute renal failure (ARF) remains debatable. Recent studies have suggested that dialysis with bioincompatible unsubstituted cellulosic membranes is associated with a less favourable patient outcome than dialysis with biocompatible synthetic membranes. Since we generally use a modified cellulosic membrane with substantially lower complement- and leukocyte-activating potential than cuprophane, for dialysis of patients with ARF, and because there are no data in the literature regarding the influence of modified cellulosic membranes on the outcome of patients with ARF, we compared the outcome of ARF patients dialysed either with cellulose diacetate or with a synthetic polysulfone membrane. We also investigated the potential role of permeability by comparing membranes with high-flux versus low-flux characteristics. METHODS: This prospective, randomized, single centre study included 159 patients with ARF requiring HD. Patients were stratified according to age, gender, and APACHE II score and then randomized in chronological order to one of three dialysis membranes: low-flux polysulfone, high-flux polysulfone and meltspun cellulose diacetate. RESULTS: Aetiologies of ARF and the prevalence of oliguria were similarly distributed among the three groups. There was no significant difference between the three groups for survival (multivariate Cox's proportional hazards model, P=0.57), time necessary to recover renal function (P=0.82), and number of dialysis sessions required before recovery (P=0.86). Multivariate analysis showed that survival was significantly influenced only by the severity of the disease state (APACHE III score, P<0.0001), but not by the nature of the dialysis membrane (P=0.57) or the presence of oliguria (P=0.24). CONCLUSIONS: Among patients with ARF requiring HD survival and recovery time are not significantly influenced by the use of either meltspun cellulose diacetate or the more biocompatible high-flux or low-flux polysulfone. Dialysis using modified cellulose membranes is just as effective as dialysis using synthetic polysulfone membranes, but at a lower cost. In addition, the flux of the membrane did not influence patient outcome.     

Epidemiologic Trend Changes in Acute Renal Failure—A Tertiary Center Experience from South India

Background. There are little data on the incidence of acute renal failure (ARF) from India due to the absence of central registry. The etiology, course, and outcome of ARF differ in various parts of India. Significant trend changes were reported even within a same center over a period of time. Aim. To find out the epidemiologic trend changes in ARF patients, the authors compared the profile of patients admitted by the Department of Nephrology from 1995–2004 with previously published data from 1987–1991. Methods. Data collected from case records of patients admitted with ARF were systemically analyzed for age, gender, etiology, course, and outcome. A total of 32 variables were collected per person retrospectively. The chi-square test, Fisher's exact test, and student t-test were used as tests of significance (p< 0.05 was taken as statistically significant). Results. A total of 1112 patients were diagnosed to have ARF from 1995–2004. The mean age was 37.08 ± 3.4 yrs. There were 669 (60.1%) males. Medical, obstetric, and surgical causes accounted for 87.6, 8.9, and 3.4 percent of ARF, respectively. Among the medical causes of ARF, acute diarrheal disease was the most common. Other causes of medical ARF included drugs, glomerulonephritis, sepsis, snake bite, leptospirosis, malaria, and copper sulphate, which accounted for 13.4, 9.3, 8.8, 7.8, 7.5, 4.4, and 4.3 percent, respectively. In comparison with the data from 1987–1991, medical ARF remained the most common cause of ARF, though without any statistical significance (87.6 percent vs 89.5 percent, p>0.32). Though surgical ARF had more than doubled from 1.5 percent from 1987–1991 to 3.4 percent (p<0.01) during the present study, it is much less when compared to similar studies in the literature. Obstetric renal failure more or less remained the same (8.9 percent vs 9 percent, p>0.4). A statistically significant decline was noted in overall as well as individual group mortality. The overall mortality declined from 26.4 percent to 19.6 percent (p<0.02). Regarding the outcome of ARF, 611 patients (54.94 percent) showed a total recovery, a partial recovery was noted in 192 patients (17.26 percent), and 91 patients (8.18 percent) had persistent dialysis-dependent renal failure. The factors noted to occur more frequently in the deceased were high entry serum creatinine (>440 μmol), jaundice, sepsis, oliguria, anemia, hypoalbuminemia, and hospital-acquired ARF. The overall requirement of dialysis was 69.0 percent. Hemodialysis was the most common modality of renal replacement therapy. Conclusions. ARF in South India differs in some important aspects when compared with data from other parts of the country. Significant trend changes were noted with time even within our center. Acute diarrheal disease was the most common cause of ARF. Leptospiral ARF was on the decline, and drugs, sepsis, and malaria were the emerging ARF causes. The incidence of surgical ARF was on the rise. Despite improvements in antenatal care, obstetric renal failure remained a significant cause of ARF. Hemodialysis became the preferred mode of renal replacement therapy.     

Acute renal failure in intensive care unit: which factors predict future dialysis dependency?

Management of acute renal failure (ARF) in an intensive care unit (ICU) is difficult. The aim of this study was to identify prognostic factors determining ARF outcome in the ICU in terms of dialysis dependency or independency. We included 35 patients who turned out to be dialysis dependent (DD) and 11 patients who turned out to be dialysis independent (DI) after ARF in the ICU, which necessitated renal replacement therapy. In the post-ARF period, acetylsalicylic acid was protective against dialysis dependency (p < 0.05, odds ratio [OR] = 0.078) and dopamine increased the likelihood of dialysis dependency (p = 0.016, OR = 10.6). Multiorgan dysfunction (p = 0.001, OR = 13.6), especially cardiac (p = 0.009) and hepatic failure (p < 0.0001) were determined to increase risk of dialysis dependency. Mean systolic blood pressures during the first 24 hours (p = 0.023) and 24-48 hours (p = or < 0.0001), mean diastolic blood pressures during first the 24-48 hours (p = 0.03) and 48-72 hours of ARF in ICU (p = 0.023) and at discharge (p = 0.03) were significantly lower in the DD group than in the DI group. Mean thrombocyte counts at hospitalization (p = 0.034), during the first 24 hours (p = 0.019) and 24-48 hours of ARF in ICU (p = 0.038) were lower in the DD than DI group. This study demonstrates the very early prognostic factors influencing ARF outcome in terms of dialysis dependency. Early thrombocyte count and systolic blood pressure and follow-up diastolic blood pressure were prognostic factors for ARF outcome. Acetylsalicylic acid seemed to improve renal outcome, whereas dopamine seemed to worsen the disease process.     

Incidence and outcome of acute renal failure complicating autologous stem cell transplantation for AL amyloidosis

BACKGROUND: High-dose intravenous melphalan and autologous peripheral blood stem cell transplantation (HDM/SCT) is an effective treatment for AL amyloidosis but is associated with significant toxicity, including the development of acute renal failure (ARF). The incidence and outcome of ARF as a complication of such treatment is not known. METHODS: All AL amyloidosis patients treated with HDM/SCT at a single institution between July 1, 1994 and May 31, 2000 were included in the analysis unless they were dialysis-dependent prior to treatment. Baseline data were collected prospectively. Treatment-related data were obtained from a prospectively maintained database and medical record review. ARF was defined as either a >/=1 mg/dL increase in serum creatinine or a doubling of serum creatinine to >/=1.5 mg/dL for at least 2 days. Recovery of renal function was defined as a return of serum creatinine to less than or within 0.5 mg/dL of the pretreatment value or the ability to discontinue dialysis initiated as a result of ARF. RESULTS: ARF occurred in 37 of 173 patients (21%). Initiation of dialysis was required in nine patients (5%). Forty-six percent of patients with ARF, including four of nine who required dialysis, had recovery of renal function. Baseline clinical variables that were independent predictors of transplant-associated ARF included creatinine clearance, proteinuria, and cardiac amyloidosis. Treatment-related variables associated with ARF included melphalan dose and bacteremia. ARF was associated with reduced survival at 90 days but did not have an impact on overall survival at a median follow-up of 2.9 years. CONCLUSION: ARF is a frequent but often reversible complication of HDM/SCT for AL amyloidosis. Specific clinical and treatment-related factors are associated with the development of this complication.     

Acute Renal Failure in the Neonatal Period

Acute renal failure (ARF) is a common problem in the neonatal intensive care unit (NICU). In most cases, ARF is associated with a primary condition such as sepsis, metabolic diseases, perinatal asphyxia and/or prematurity. This retrospective study investigated the course of illness, therapeutic interventions, early prognosis and risk factors associated with development of ARF in the neonatal period. A total of 1311 neonates were treated in our NICU during the 42‐month study period, and 45 of these babies had ARF. This condition was defined as serum creatinine level above 1.5 mg/dL despite normal maternal renal function. The data collected for each ARF case were contributing condition, cause and clinical course of ARF, gestational age and birth weight, age at the time of diagnosis, treatment, presence of perinatal risk factors and need for mechanical ventilation. The frequency of ARF in the NICU during the study period was 3.4%. Premature newborns constituted 31.1% of the cases. The mean birth weight in the group was 2863 ± 1082 g, and the mean age at diagnosis was 6.2 ± 7.4 days. The causes of ARF were categorized as prerenal in 29 patients (64.4%), renal in 14 patients (31.1%) and postrenal in 2 patients (4.4%). Forty‐seven percent of the cases were nonoliguric ARF. Asphyxia was the most common condition that contributed to ARF (40.0%), followed by sepsis/metabolic disease (22.2%) and feeding problems (17.8%). Therapeutic interventions were supportive in 77.8% of the cases, and dialysis was required in the other 22.2%. The mortality rate in the 45 ARF cases was 24.4%. Acute renal failure of renal origin, need for dialysis, and need for mechanical ventilation were associated with significantly increased mortality (p < 0.05). There were no statistical correlations between mortality rate and perinatal risk factors, oliguria, prematurity or blood urea nitrogen and creatinine levels. The study showed that, at our institution, ARF in the neonatal period is frequently associated with preventable conditions, specifically asphyxia, sepsis and feeding problems. Supportive therapy is effective in most cases of neonatal ARF. Acute renal failure of renal origin, need for dialysis, and need for mechanical ventilation were identified as indicators of poor prognosis in these infants. Early recognition of risk factors and rapid effective treatment of contributing conditions will reduce mortality in neonatal ARF.     

Dose of dialysis in acute renal failure

Acute renal failure (ARF) is a cause of significant morbidity and mortality. Despite advances in supportive care, outcomes in ARF have improved little over the past decades. The primary goals in management of patients with ARF are to optimize hemodynamic and volume status, minimize further renal injury, correct metabolic abnormalities, and permit adequate nutrition. Renal replacement therapy (RRT) is often required to achieve these goals while awaiting renal recovery, but the optimal dose of dialysis in patients with ARF is not known. Extrapolation of required dialysis dose from recommendations in chronic dialysis is unlikely to be appropriate because of the lack of a steady state and differences in distribution volume of urea that are intrinsic to ARF. The prescribed dialysis dose in ARF is often low, and actual delivered dose is often even less than prescribed. Delivery of dialysis in ARF is often hampered by the patient's hypercatabolic state, hemodynamic instability, and volume status, as well as suboptimal vascular access with temporary venous catheters. The impact of intermittent hemodialysis (IHD) versus continuous renal replacement therapy (CRRT) on outcomes in ARF is also not clear. Patient disease severity impacts more than dialysis modality in patient outcome, but when patients are stratified for equal disease severity, CRRT may have potential benefits over IHD in terms of patient survival, fluid and metabolic control, and renal recovery. Strategies associated with improved outcomes that have emerged thus far in ARF are to aim for a time-averaged blood urea nitrogen (BUN) of less than 60 mg/dl with IHD, varying IHD frequency as necessary, or to achieve a minimum ultrafiltration rate of 35 ml/kg/hr with CRRT.     

Acute renal failure after nonmyeloablative hematopoietic cell transplantation

Acute renal failure (ARF) is a common life-threatening complication after myeloablative allogeneic hematopoietic cell transplantation (HCT). Nonmyeloablative HCT aims to eradicate the malignancy with graft-versus-tumor effect, rather than with high doses of chemoradiotherapy. It may be anticipated that a lower risk of ARF exists in nonmyeloablative HCT as a result of the milder preconditioning regimen. However, the patients who receive the nonmyeloablative HCT are older individuals who are not eligible for the more toxic allogeneic myeloablative procedure. The goal of this study was to evaluate ARF in a large group of patients who received nonmyeloablative HCT. This cohort study enrolled patients who were undergoing nonmyeloablative HCT at four major centers from 1998 to 2001. Conditioning therapy involved total body irradiation 2 Gy +/- fludarabine 30 mg/m2. Posttransplantation immunosuppression consisted of cyclosporine or tacrolimus and mycophenolate mofetil. ARF was classified into four grades, similar to previous studies in the literature. Collectively, 253 patients were recruited into this study. ARF (>50% decrease in GFR) occurred in 40.4% of patients over a 3-mo period, with 4.4% of patients requiring dialysis. The overall mortality in the study population was 34% at 1 yr. The mortality increased with worsening grade of ARF. The combined need for dialysis and artificial ventilation was associated with a mortality exceeding 80%. Although the number of patients who develop ARF is significant, the risk of developing ARF that requires dialysis after nonmyeloablative HCT is infrequent despite the older age of the patients. The data are also suggestive that ARF may contribute to mortality after nonmyeloablative HCT.     

Influence of renal dysfunction on mortality after cardiac surgery: modifying effect of preoperative renal function

BACKGROUND: Acute renal failure (ARF) requiring dialysis is an independent risk factor of mortality after cardiac surgery; the level of preoperative renal function influences the risk of both postoperative ARF and mortality. The relationship between mild renal dysfunction and mortality, and the modifying effect of baseline renal function on this association, is less clear. METHODS: We studied 31,677 patients undergoing cardiac surgery between 1993 and 2002. We used a logistic regression model to assess the relationship between postoperative renal dysfunction and mortality, while adjusting for preoperative renal function, postoperative ARF requiring dialysis, and other risk factors. RESULTS: The overall postoperative mortality rate was 2.2% (698/31,677). For the entire cohort, a clinically relevant increase in the adjusted risk of mortality occurred beyond 30% decline in postoperative GFR. The mortality rate was 5.9% (N, 292/4986) among patients who developed 30% or greater decline in postoperative GFR not requiring dialysis versus 0.4% (N, 106/26,136) among those with <30% decline (P < 0.001). A significant interaction between preoperative GFR and percent change in postoperative GFR (P < 0.001) indicated that at equivalent degrees of renal dysfunction, the mortality risk was greater at a lower preoperative GFR. ARF requiring dialysis was strongly associated with mortality in the model (odds ratio 4.2; 95% CI 3.1-5.7). CONCLUSION: Renal dysfunction not requiring dialysis is an independent risk factor of mortality after cardiac surgery. A better preoperative GFR attenuates the effect of postoperative renal dysfunction on mortality; this interaction needs to be considered while defining a clinically relevant threshold of ARF.     

Incidence and mortality of acute renal failure in Medicare beneficiaries, 1992 to 2001

This study's objective was to determine the incidence and mortality of acute renal failure (ARF) in Medicare beneficiaries. Data were from hospitalized Medicare beneficiaries (5,403,015 discharges) between 1992 and 2001 from the 5% sample of Medicare claims. For 1992 to 2001, the overall incidence rate of ARF was 23.8 cases per 1000 discharges, with rates increasing by approximately 11% per year. Older age, male gender, and black race were strongly associated (P < 0.0001) with ARF. The overall in-hospital death rate was 4.6% in discharges without ARF, 15.2% in discharges with ARF coded as the principal diagnosis, and 32.6% in discharges with ARF as a secondary diagnosis. In-hospital death rates were 32.9% in discharges with ARF that required renal dialysis and 27.5% in those with ARF that did not require dialysis. Death within 90 d after hospital admission was 13.1% in discharges without ARF, 34.5% in discharges with ARF coded as the principal diagnosis, and 48.6% in discharges with ARF as a secondary diagnosis. Discharges with ARF were more (P < 0.0001) likely to have intensive care and other acute organ dysfunction than those without ARF. For discharges both with and without ARF, rates for death within 90 d after hospital admission showed a declining trend. In conclusion, the incidence rate of ARF in Medicare beneficiaries has been increasing. Those of older age, male gender, and black race are more likely to have ARF. These data show ARF to be a major contributor to morbidity and mortality in hospitalized patients.     

Early Prognostic Factors in Patients with Acute Renal Failure Requiring Dialysis

Purpose. Despite improvements in renal therapy and technology, the mortality rate of patients with acute renal failure (ARF) remains high. Because ARF is a heterogeneous syndrome, occurring in patients with diverse etiologies and comorbid conditions, predicting its outcome is difficult. This study aims to identify early clinical and laboratory prognostic factors, including acute-phase reactants such as C-reactive protein (CRP), fibrinogen, and albumin, in ARF patients requiring dialysis. Material and methods. From June 2002 to March 2004, 61 patients with ARF requiring dialysis at Chang Gung Memorial Hospital, Chiayi, were prospectively analyzed. For each patient, the worst values of prognostic variables 24 hr before starting dialysis were prospectively assessed. Results. Oliguria, low plasma fibrinogen levels, hypotension, cardiac disease, and neoplastic disease were statistically significant in predicting hospital mortality. Using Youden's index, the best cut-off value for plasma fibrinogen in predicting mortality was 300 mg/dL with a sensitivity and specificity of 61% and 96%, respectively. Serum CRP and serum albumin were not predictive of hospital mortality. Conclusion. Early prognostic factors in predicting mortality for patients with ARF requiring dialysis identified by multivariate logistic regression were oliguria, low plasma fibrinogen, hypotension, cardiac disease, and neoplastic disease. Serum CRP and albumin were not predictive of hospital mortality, whereas a plasma fibrinogen level ≤300 mg/dL had 61% sensitivity and 96% specificity in predicting mortality.     

Acute renal failure in the neonatal period

Acute renal failure (ARF) is a common problem in the neonatal intensive care unit (NICU). In most cases, ARF is associated with a primary condition such as sepsis, metabolic diseases, perinatal asphyxia and/or prematurity. This retrospective study investigated the course of illness, therapeutic interventions, early prognosis and risk factors associated with development of ARF in the neonatal period. A total of 1311 neonates were treated in our NICU during the 42-month study period, and 45 of these babies had ARF. This condition was defined as serum creatinine level above 1.5 mg/dL despite normal maternal renal function. The data collected for each ARF case were contributing condition, cause and clinical course of ARF, gestational age and birth weight, age at the time of diagnosis, treatment, presence of perinatal risk factors and need for mechanical ventilation. The frequency of ARF in the NICU during the study period was 3.4%. Premature newborns constituted 31.1% of the cases. The mean birth weight in the group was 2863 +/- 1082 g, and the mean age at diagnosis was 6.2 +/- 7.4 days. The causes of ARF were categorized as prerenal in 29 patients (64.4%), renal in 14 patients (31.1%) and postrenal in 2 patients (4.4%). Forty-seven percent of the cases were nonoliguric ARF. Asphyxia was the most common condition that contributed to ARF (40.0%), followed by sepsis/metabolic disease (22.2%) and feeding problems (17.8%). Therapeutic interventions were supportive in 77.8% of the cases, and dialysis was required in the other 22.2%. The mortality rate in the 45 ARF cases was 24.4%. Acute renal failure of renal origin, need for dialysis, and need for mechanical ventilation were associated with significantly increased mortality (p<0.05). There were no statistical correlations between mortality rate and perinatal risk factors, oliguria, prematurity or blood urea nitrogen and creatinine levels. The study showed that, at our institution, ARF in the neonatal period is frequently associated with preventable conditions, specifically asphyxia, sepsis and feeding problems. Supportive therapy is effective in most cases of neonatal ARF. Acute renal failure of renal origin, need for dialysis, and need for mechanical ventilation were identified as indicators of poor prognosis in these infants. Early recognition of risk factors and rapid effective treatment of contributing conditions will reduce mortality in neonatal ARF.     

Adequacy of dialysis in acute renal failure

Renal replacement therapy (RRT) is currently the mainstay of management for patients with acute renal failure (ARF). Adequacy of dialysis in the setting of renal failure is defined poorly and encompasses multiple domains of clinical and biochemical outcomes. Multiple operational factors influence the delivery of adequate dialysis. No current standards exist for RRT for ARF; current RRT practices for ARF generally have been extrapolated from end-stage renal disease (ESRD) literature. The heterogeneity of patient population, variation in RRT practices, and differences in outcomes studied have made it difficult to define or study adequate dialysis in ARF or its impact on clinical outcomes.