Benefit of cyclophosphamide therapy in IgA nephritis may have been obscured by warfarin-related nephropathy in the randomized trials in which warfarin and dipyridamole were used in combination with cyclophosphamide

Pathology of IgA nephropathy

IgA nephropathy is defined by the presence of IgA-dominant or co-dominant immune deposits within glomeruli. Biopsy specimens meeting these diagnostic criteria have a range of histological changes that are reflected in the variable clinical course of IgA nephropathy. The impact of histology on outcomes in IgA nephropathy has been clarified in a number of large retrospective clinicopathological studies. These studies have consistently demonstrated that the stage of disease at presentation, as indicated by the extent of interstitial fibrosis and tubular atrophy in the biopsy, is the strongest histological predictor of renal survival. The effect of active proliferative lesions on the disease course is less clear cut, owing in part to considerable treatment bias in most published retrospective studies. There is evidence that endocapillary hypercellularity and cellular crescents are responsive to immunosuppressive therapy, but this observation requires confirmation in prospective randomized controlled trials. Future challenges include improving the reproducibility of histological scoring, particularly for the presence and extent of endocapillary lesions, and to improve prognostic modelling by combining histological data with clinical variables and biomarker data.

Differential diagnosis of glomerular disease: a systematic and inclusive approach

BACKGROUND

Glomerular disease is a complex and evolving topic. In evaluating a specific case it is not unusual for the clinician to ask: 'Am I missing something? Should I biopsy? When? Should I treat first, then biopsy?' This work, which is both evidence and experience based, is intended to address each of these concerns and many other issues relevant to the differential diagnosis of glomerular disease.

SUMMARY

The central approach is the use of diagnostic algorithms that are based on quantitative measures routinely obtained early in the course of the diagnostic evaluation. The algorithms are designed to be easy to navigate, systematic, and inclusive. Also provided is a detailed and prioritized list of recommended diagnostic testing, and the rationale for each test.

KEY MESSAGE

This work is intended to facilitate accurate diagnosis in the individual patient presenting with evidence of glomerular disease.

The occurrence of warfarin-related nephropathy and effects on renal and patient outcomes in korean patients

BACKGROUND

Warfarin-related nephropathy (WRN) is a recently described disease entity, in which excessive warfarinization (international normalized ratio (INR) >3.0) causes acute kidney injury. Previous reports regarding WRN included few Asian patients who might have differed from the western WRN patients in terms of genetic and environmental factors.

METHODS

During the period of March 2003 to December 2011, the data about a total of 1297 patients who had serum creatinine (sCr) level measured within 1 week after INR >3.0 and within 6 months before INR >3.0 was analyzed through the retrospective review of electronic medical records of a single tertiary hospital in Korea.

RESULT

WRN developed in 19.3% of patients having excessive warfarinization. The incidence was higher in the chronic kidney disease (CKD) group than the non-CKD group. The risk of WRN increased as the basal serum albumin level decreased and was strongly associated with highest quartile serum AST level at post INR elevation and the presence of congestive heart failure. But the presence of atrial fibrillation was protective against the development of WRN. Neither the presence of CKD nor basal estimated glomerular filtration rate (eGFR) was an independent risk factor for WRN. Despite no difference in the basal sCr level, the sCr level was higher in patients with WRN than those without WRN after follow-up. The mortality rates were also higher in patients with WRN.

CONCLUSIONS

WRN developed in 19.3% of patients having excessive warfarinization. A lower basal serum albumin, highest quartile serum AST level at post INR elevation, and congestive heart failure were associated with the occurrence of WRN. The development of WRN adversely affected renal and patient outcomes.

Haematuria and acute kidney injury in elderly patients admitted to hospital with supratherapeutic warfarin anticoagulation

BACKGROUND AND OBJECTIVES

Warfarin-related nephropathy is reported to occur with an INR >3.0 as a result of glomerular bleeding. There is a lack of prospective studies examining the effect of supratherapeutic warfarin anticoagulation on haematuria and acute kidney injury (AKI). Older patients may be susceptible due to greater warfarin use, prevalence of kidney disease and comorbidities. The objective of this study was to determine the incidence and nature of haematuria and AKI in older patients on warfarin and to determine any association with high INR levels.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

This was a prospective, observational study of 150 elderly patients receiving warfarin anticoagulation who were acutely hospitalised in a tertiary hospital. AKI was assessed using RIFLE criteria. Urinalysis was performed to quantify haematuria, characterise erythrocyte morphology and measure the albumin-creatinine ratio. Positive cases received follow-up at 4-6 weeks to determine resolution.

RESULTS

An INR >3.0 was found in 54 % of patients. Pre-admission antibiotic use increased the risk of excessive anticoagulation. The incidence of isolated AKI, isolated haematuria and both was 18.7, 13.3 and 12 %, respectively. Factors associated with a higher risk of haematuria were an INR >4.0, non-urinary infection, catheterisation and albuminuria. Most cases of AKI were mild, and there was no demonstrable correlation between the admission INR and AKI. Admission with heart failure was significantly associated with an increased risk of persistent kidney impairment at follow-up.

CONCLUSIONS

Supratherapeutic warfarin anticoagulation was associated with an increased risk of haematuria, but not with AKI. The majority of cases of haematuria were transient.