A prospective national study of acute renal failure treated with RRT: incidence, aetiology and outcomes.

BACKGROUND: Acute renal failure (ARF) is a diverse condition with no standardized definition and is managed in several sub-specialty areas within hospitals. Its incidence and aetiology are unknown and studies show a wide range of incidences. ARF is becoming more common as the population ages leading to the hypothesis that the incidence is much higher than previous estimates. METHODS: This prospective population study investigated the incidence, aetiology and outcomes of ARF based on a standardized classification of ARF treated by renal replacement therapy (RRT) in all sub-specialty areas within hospitals where such treatment takes place. Data were collected prospectively on all patients starting RRT for ARF within three 12-week periods in 2002. RESULTS: Two hundred eighty-six adults per million population (pmp) per year received RRT for ARF. The incidence increased with age and pre-existing comorbid illness. Two hundred twelve adults pmp per year had no evidence of pre-existing chronic kidney disease (CKD) and the remainder had acute on CKD. The median age was 67 years. Fifty-one percent of the patients received their first RRT treatment in a critical care setting. Sepsis was the most common aetiological insult contributing to ARF in 48% of the patients. Mortality was high with 48% dying within 90 days of starting RRT. Age, comorbidity, sepsis and recent surgery were independent risk factors for death in those with no pre-existing CKD. DISCUSSION: This is the first national study to describe ARF treated with RRT in all hospital locations. The hypothesis that ARF occurs more frequently than previously thought has been confirmed. This study provides data upon which to base effective decision making for prevention, patient care and resource planning for patients with ARF.

A primer on survival analysis.

Survival analysis is the statistical method for studying the time between entry to a study and a subsequent event. Survival is often the most important outcome in both observational and intervention studies. The analysis of survival, however, is not simple because of a number of factors. The time between entry to a study and the end of follow-up varies during the study period, as recruitment time for each subject is different. In addition, most studies have a finite duration during which not all subjects would have experienced the outcome of interest, while some patients might leave the study or are lost to follow-up. Survival analysis is not just concerned with time from treatment to death. The outcome could be any defined event such as time to doubling of serum creatinine concentration or first rejection episode following transplantation. An understanding of the principles involved in the statistical analyses of survival is essential for critical appraisal of studies, which employ these methods, and for designing clinical studies. This brief review describes the principles of survival analysis and its application to studies in nephrology.

End-stage renal disease in Scotland: outcomes and standards of care.

BACKGROUND: The number of patients starting renal replacement therapy (RRT) for end-stage renal disease (ESRD) in the United Kingdom rises annually. Patients are increasingly elderly with a greater prevalence of comorbid illness. Unadjusted survival, from the time of starting RRT, is not improving. The United Kingdom Renal Association has published recommended standards of treatment, which all United Kingdom nephrologists strive to attain. This study was devised to define the impact of attaining recommended treatment standards, adjusting for patient age and comorbid illnesses, upon survival on RRT in the United Kingdom population. METHODS: A prospective, registry based, observational study of all patients starting RRT in Scotland over a 1-year period, followed for the first 2 years of RRT. RESULTS: Of the 523 patients who were studied, 217 (41.5%) had died by 2 years of follow-up, 32% excluding deaths within the first 90 days. Age, comorbidity, weight when starting RRT, and attaining the recommended standards for albumin and hemoglobin had a significant impact upon survival. CONCLUSION: This study has emphasized the very high mortality of patients starting RRT in Scotland. By paying close attention to the attainment of recommended standards of care for patients with ESRD, it may be possible to improve upon current mortality figures. The monitoring of such success is only possible if correction is made for age and comorbidity.

Early referral and planned initiation of dialysis: what impact on quality of life?

BACKGROUND: Early patient referral correlates with improved patient survival on dialysis. We examine whether early referral and a planned first dialysis affect quality of life (QoL). METHODS: All patients commencing dialysis in nine centres in seven European countries between 1 July 1998 and 31 October 1999 were recruited. DEFINITIONS: early referral=followed by a nephrologist >1 month before first dialysis (<1 month=late referral); planned=early referral and previous serum creatinine >300 micro mol/l and non-urgent first dialysis (early referral and no creatinine >300 micro mol/l or urgent first dialysis=unplanned). QoL was measured at 8 weeks using a visual analogue scale (VAS) and Short Form 36 (SF-36). RESULTS: VAS was significantly higher in early referral patients [mean (SD) 58.4 (20) vs 50.4 (19), P=0.005], particularly if the first dialysis was planned [60.7 (20) vs 54.2 (20), P=0.03]. Planned patients also had higher SF-36 mental summary scores [45.4 (12) vs 39.7 (11), P=0.003], role emotional scores [58.0 (43) vs 30.9 (38), P=0.003], and mental health scores [63.7 (24) vs 54.6 (22), P=0.01] than unplanned patients. Adjusting for centre and other confounding variables showed that having a planned first dialysis had an independent effect on QoL (VAS, and the SF-36's mental summary score, physical functioning, role physical, general health, role emotional and mental health). Early referral had no independent effect on QoL. Socio-economic status had an important positive effect on physical QoL. CONCLUSIONS: While the effect of early referral to a nephrologist on QoL appeared centre dependent, a smooth transition onto dialysis was associated with significantly better early QoL, independent of other variables.