Izhar Khan

Incidence and Outcomes in Acute Kidney Injury: A Comprehensive Population-Based Study

Epidemiological studies of acute kidney injury (AKI) and acute-on-chronic renal failure (ACRF) are surprisingly sparse and confounded by differences in definition. Reported incidences vary, with few studies being population-based. Given this and our aging population, the incidence of AKI may be much higher than currently thought. We tested the hypothesis that the incidence is higher by including all patients with AKI (in a geographical population base of 523,390) regardless of whether they required renal replacement therapy irrespective of the hospital setting in which they were treated. We also tested the hypothesis that the Risk, Injury, Failure, Loss, and End-Stage Kidney (RIFLE) classification predicts outcomes. We identified all patients with serum creatinine concentrations > or =150 micromol/L (male) or > or =130 micromol/L (female) over a 6-mo period in 2003. Clinical outcomes were obtained from each patients case records. The incidences of AKI and ACRF were 1811 and 336 per million population, respectively. Median age was 76 yr for AKI and 80.5 yr for ACRF. Sepsis was a precipitating factor in 47% of patients. The RIFLE classification was useful for predicting full recovery of renal function (P < 0.001), renal replacement therapy requirement (P < 0.001), length of hospital stay [excluding those who died during admission (P < 0.001)], and in-hospital mortality (P = 0.035). RIFLE did not predict mortality at 90 d or 6 mo. Thus the incidence of AKI is much higher than previously thought, with implications for service planning and providing information to colleagues about methods to prevent deterioration of renal function. The RIFLE classification is useful for identifying patients at greatest risk of adverse short-term outcomes.

Measuring the population burden of chronic kidney disease: a systematic literature review of the estimated prevalence of impaired kidney function

BACKGROUND Internationally, there have been substantial efforts to improve the early identification of chronic kidney disease (CKD), with a view to improving survival, reducing progression and minimizing cardiovascular morbidity and mortality. In 2002, a new and globally adopted definition of CKD was introduced. The burden of kidney function impairment in the population is unclear and widely ranging prevalence estimates have been reported. METHODS We conducted a systematic literature review, searching databases to June 2009. We included all adult population screening studies and studies based on laboratory or clinical datasets where the denominator was clear. Studies reporting prevalence estimates based on at least one eGFR <60 mL/min/1.73m(2) or elevated creatinine above a stated threshold were included. Study design and quality were explored as potential factors leading to heterogeneity. RESULTS We identified 43 eligible studies (57 published reports) for inclusion. Substantial heterogeneity was observed with estimated prevalence (0.6-42.6%). The included studies demonstrated significant variation in methodology and quality that impacted on the comparability of their findings. From the higher quality studies, the six studies measuring impaired kidney function (iKF) using estimated glomerular filtration rate in community screening samples reported a prevalence ranging from 1.7% in a Chinese study to 8.1% in a US study, with four reporting an estimated prevalence of 3.2-5.6%. Heterogeneity was driven by the measure used, study design and study population. CONCLUSION In the general population, estimated iKF, particularly eGFR 30-59 mL/min/1.73m(2) was common with prevalence similar to diabetes mellitus. Appropriate care of patients poses a substantial global health care challenge.

Membranous nephropathy and granulomatous interstitial nephritis in sarcoidosis.

A 56-year-old woman developed nephrotic syndrome in association with pulmonary sarcoidosis. Renal biopsy revealed both granulomatous interstitial nephritis and membranous nephropathy. Treatment with steroids resulted in a decrease in proteinuria and there was no deterioration in renal function over a subsequent period of 10 months. This case provides further evidence that secondary membranous nephropathy associated with sarcoidosis should be treated with steroids.

How safe is renal replacement therapy? A national study of mortality and adverse events contributing to the death of renal replacement therapy recipients

BACKGROUND Patients receiving treatment with renal replacement therapy (RRT) have high mortality, and ensuring patient safety in this population is difficult. We aimed to estimate the incidence and nature of medical adverse events contributing to the death of patients being treated with RRT. METHODS This population registry-based retrospective case review study included all patients being treated with RRT for established renal failure in Scotland and who died between 1 January 2008 and 30 June 2011. Deaths were reviewed by consultant nephrologists using a structured questionnaire to identify factors contributing to death occurring in both the inpatient and outpatient setting. Reviewers were able to use any information source deemed relevant, including paper and electronic clinical records, mortality and morbidity meetings and procurator fiscal (Scottish coroner) investigations. Deaths occurring in 2008 and 2009 where avoidable factors were identified that may have or did lead to death of a patient were subject to further review and root cause analysis, in order to identify recurrent themes. RESULTS Of 1551 deaths in the study period, 1357 were reviewed (87.5%). Cumulative RRT exposure in the cohort was 2.78 million person-days. RRT complications were the primary cause of death in 28 (2.1%). Health-care-associated infection had contributed to 9.6% of all deaths. In 3.5% of deaths, factors were identified which may have or did contribute to death. These were both organizational and human error related and were largely due to five main causes: management of hyperkalaemia, prescribing, out of hours care, infection and haemodialysis vascular access. CONCLUSIONS Adverse events contributing to death in RRT recipients mainly relate to the everyday management of common medical problems and not the technical aspects of RRT. Efforts to avoid harm in this population should address these ubiquitous causes of harm.

Outcomes in CKD: What We Know and What We Need to Know

Chronic kidney disease (CKD) is a major public health concern. The high prevalence of reduced estimated glomerular filtration (eGFR) in the elderly has led to speculation as to whether it should really be regarded as a disease in all. Patients with CKD exhibit considerable cardiovascular morbidity and mortality but until recently data regarding the natural history of CKD, particularly in the elderly, has been somewhat lacking. As such the clinical significance of K/DOQI’s CKD definition in terms of additional morbidity, mortality and progression to end-stage renal disease (ESRD) remains uncertain. Data have shown that death from cardiovascular disease is far more common than progression to renal replacement therapy in the elderly. Factors which increase the risks of progression to ESRD include younger age, proteinuria and diabetes. Although the elderly have high rates of cardiovascular death, comparatively younger patients with CKD have substantially increased relative risks of death. Specialist renal review should be targeted towards these high-risk patients while the majority of elderly patients can be safely monitored in primary care. It remains doubtful whether labelling all elderly CKD patients with a ‘disease’ confers any additional benefit.

The changing pattern of referral in acute kidney injury

BACKGROUND Acute kidney injury (AKI) is not only managed by nephrologists, but also by several other subspecialists. The referral rate to nephrologists and the factors influencing it are unknown. AIMS To determine the referral rate, factors affecting referral and outcomes across the spectrum of AKI in a population based study. METHODS We identified all patients with serum creatinine concentrations ≥150 µmol/l (male) or ≥130 µmol/l (female) over a 6-month period. AKI was defined according to the RIFLE classification (risk, injury, failure, loss, end stage renal disease [ESRD]). Clinical information and outcomes were obtained from each patients case records. RESULTS A total of 562 patients were identified as having AKI (incidence 2147 per million population/year [pmp/y]). One hundred and sixty-four patients (29%) were referred to nephrologists-referral rate 627 pmp/y. Forty-nine percent of patients whose serum creatinine rose to >300 µmol/l were referred compared with 22% in our previous study of 1997. Forty-eight patients required renal replacement therapy-incidence 184 pmp/y in comparison to 50 pmp/y in our previous study of 1997. Patients had higher odds of referral if they were male, of younger age and were in the F category of the RIFLE classification. Patients had lower odds of referral if they had multiple co-morbid conditions or if they were managed in a hospital without a nephrology service. CONCLUSION There has been a significant rise in the referral rate of patients with AKI to nephrologists but even during our period of study only one-third of such patients were being referred. With rising incidence and increased awareness, the referral rate will certainly rise putting a significant burden on the nephrology services.