A comprehensive description of kidney disease progression after acute kidney injury from a prospective, parallel-group cohort study.

Acute kidney injury (AKI) is associated with adverse long-term outcomes, but many studies are retrospective, focused on specific patient groups or lack adequate comparators. The ARID (AKI Risk in Derby) Study was a five-year prospective parallel-group cohort study to examine this. Hospitalized cohorts with and without exposure to AKI were matched 1:1 for age, baseline kidney function, and diabetes. Estimated glomerular filtration rate (eGFR) and the urinary albumin:creatinine ratio (uACR) were measured at three-months, one-, three- and five-years. Outcomes included kidney disease progression, heart failure episodes and mortality. In 866 matched individuals, kidney disease progression at five years was found to be significantly increased in 30% of the exposed group versus 7% of those non-exposed (adjusted odds ratio 2.49 [95% confidence interval 1.43 to 4.36]). In the AKI group, this was largely characterized by incomplete recovery of kidney function by three months. Further episodes of AKI during follow-up were significantly more common in the exposed group (odds ratio 2.71 [1.94 to 3.77]) and had an additive effect on risk of kidney disease progression. Mortality and heart failure episodes were more frequent in the exposed group, but the association with AKI was no longer significant when models were adjusted for three-month eGFR and uACR. In a general hospitalized population, kidney disease progression after five years was common and strongly associated with AKI. Thus, the time course of changes and the attenuation of associations with adverse outcomes after adjustment for three-month eGFR and uACR suggest non-recovery of kidney function is an important assessment in post-AKI care and a potential future target for intervention. STUDY REGISTRATION: ISRCTN25405995.

Room for improvement: diagnosing and managing acute coronary syndromes in persons with reduced eGFR.

Cardiovascular events are the leading cause of death in chronic kidney disease. A recent analysis from the High-Sensitivity Troponin in the Evaluation of Patients With Suspected Acute Coronary Syndrome trial focused on results in those with reduced estimated glomerular filtration rate. This commentary discusses aspects of acute coronary syndrome diagnosis in this group and the differential approach to acute coronary syndrome management that was observed between those with normal and reduced kidney function.

Three-year outcomes after acute kidney injury: results of a prospective parallel group cohort study.

OBJECTIVES: Using a prospective study design, we aimed to characterise the effect of acute kidney injury (AKI) on long-term changes in renal function in a general hospital population. PARTICIPANTS: Hospitalised patients with AKI (exposed) and hospitalised patients without AKI (non-exposed), recruited at 3 months after hospital admission. DESIGN: Prospective, matched parallel group cohort study, in which renal function and proteinuria were measured at 3 months, 1 year and 3 years. SETTING: Single UK centre. CLINICAL END POINTS: Clinical end points at 3 years were comparison of the following variables between exposed and non-exposed groups: renal function, prevalence of proteinuria and albuminuria and chronic kidney disease (CKD) progression/development at each time point. CKD progression was defined as a decrease in the estimated glomerular filtration rate (eGFR) of ≥25% associated with a decline in eGFR stage. RESULTS: 300 exposed and non-exposed patients were successfully matched 1:1 for age and baseline renal function; 70% of the exposed group had AKI stage 1. During follow-up, the AKI group had lower eGFR than non-exposed patients at each time point. At 3 years, the mean eGFR was 60.7±21 mL/min/1.73 m2 in the AKI group compared with 68.4±21 mL/min/1.73 m2 in the non-exposed group, p=0.003. CKD development or progression at 3 years occurred in 30 (24.6%) of the AKI group compared with 10 (7.5%) of the non-exposed group, p<0.001. Albuminuria was more common in the AKI group, and increased with AKI severity. Factors independently associated with CKD development/progression after AKI were non-recovery at 90 days, male gender, diabetes and recurrent AKI. CONCLUSIONS: AKI is associated with deterioration in renal function to 3 years, even in an unselected population with predominantly AKI stage 1. Non-recovery from AKI is an important factor determining long-term outcome.

Recent developments in electronic alerts for acute kidney injury.

PURPOSE OF REVIEW: Efforts to improve outcomes from acute kidney injury (AKI) have focussed on timely diagnosis and effective delivery of basic patient care. Electronic alerts (e-alerts) for AKI have attracted interest as a tool to facilitate this. Initial feasibility has already been demonstrated; this review will discuss recent advances in alert methodology, implementation beyond single centres and reported effect on outcomes. RECENT FINDINGS: On-going descriptions of e-alerts highlight increasing variation in both detection algorithms and alert processes. In England, this is being addressed by national rollout of a standardized detection algorithm; recent data have shown this to have good diagnostic performance. In critical care, fully automated detection systems incorporating both serum creatinine and urine output criteria have been developed. A recent randomized trial of e-alerts has also been reported, in which isolated use of a text message e-alert did not affect either clinician behaviour or patient outcome. SUMMARY: As e-alerts gain popularity, consideration must be given to both the method of AKI detection and the method by which results are communicated to end-users; these aspects influence the degree of these systems' effectiveness. This approach should be coupled to further work to study the effect on patient outcomes of those interventions that have been demonstrated to influence clinician behaviour.

Long Term Outcomes after Acute Kidney Injury: Lessons from the ARID Study.

The high incidence and poor short-term outcomes of acute kidney injury (AKI) have focused attention on this global healthcare issue. Concurrently, the long-term effects of AKI are increasingly appreciated, namely, increased risk of subsequent chronic kidney disease, end stage kidney disease requiring renal replacement therapies and a higher rate of cardiovascular events. Whilst there is little doubt about the strength of these associations, knowledge gaps remain. To address some of these, the AKI Risk In Derby study commenced in 2013. This is a prospective case-control study investigating the long-term effects of AKI in a general hospitalized population (including those with less severe AKI). This review will summarize the background and rationale of this study, its design and methodology, as well as the 1-year outcome results from a preceding pilot study.

The effects of acute kidney injury on long-term renal function and proteinuria in a general hospitalised population.

BACKGROUND: Acute kidney injury (AKI) is common in hospitalised patients and is associated with adverse long-term consequences. There is an urgent need to understand these sequelae in general hospitalised patients utilising a prospective cohort-based approach. We aimed to test the feasibility of study methodology prior to commencing a large-scale study and investigate the effects of AKI on chronic kidney disease (CKD) progression and proteinuria. METHODS: Pilot study testing novel methodology for remote patient recruitment within a prospective case-control design. 300 cases (hospitalised patients with AKI) and controls (hospitalised patients without AKI) were matched 1:1 for age and baseline estimated glomerular filtration rate (eGFR). 70% of cases had AKI stage 1, 16% AKI stage 2 and 14% AKI stage 3. Renal function and proteinuria were measured 3 and 12 months after hospital admission. RESULTS: The study met pre-defined recruitment, withdrawal and matching criteria. Renal function was worse in the AKI group at 3 (eGFR 61 ± 20 vs. 74 ± 23 ml/min/1.73 m(2), p < 0.001) and 12 months (eGFR 64 ± 23 vs. 75 ± 25 ml/min/1.73 m(2), p < 0.001). More cases than controls had CKD progression at 3 months (14 vs. 0.7%, p < 0.001). This difference persisted to 12 months, but there was no significant change between 3 and 12 months. Proteinuria and albuminuria were more prevalent in the AKI group and associated with CKD progression. CONCLUSIONS: We describe a method of remote patient recruitment which could be employed more widely for prospective observational studies. Even mild AKI is associated with long-term renal dysfunction. Further investigation using this methodology is now underway.