Dietary sodium intake is associated with hypertension and cardiovascular risk in the general population. In patients with chronic kidney disease, sodium intake has been associated with progressive renal disease, but not independently of proteinuria. We studied the relationship between urinary sodium (UNa) excretion and UNa to creatinine ratio and mortality or requirement for renal replacement therapy in chronic kidney disease. Adult patients attending a renal clinic who had ≥1 24-hour UNa measurement were identified. Twenty-four-hour UNa measures were collected and UNa to creatinine ratio calculated. Time to renal replacement therapy or death was recorded. Four hundred twenty-three patients were identified with mean estimated glomerular filtration rate of 48 mL/min per 1.73 m(2). Ninety patients required renal replacement therapy and 102 patients died. Mean slope decline in estimated glomerular filtration rate was -2.8 mL/min per 1.73 m(2) per year. Median follow-up was 8.5 years. Patients who died or required renal replacement therapy had significantly higher UNa excretion and UNa to creatinine ratio, but the association with these parameters and poor outcome was not independent of renal function, age, and albuminuria. When stratified by albuminuria, UNa to creatinine ratio was a significant cumulative additional risk for mortality, even in patients with low-level albuminuria. There was no association between low UNa and risk, as observed in some studies. This study demonstrates an association between UNa excretion and mortality in chronic kidney disease, with a cumulative relationship between sodium excretion, albuminuria, and reduced survival. These data support reducing dietary sodium intake in chronic kidney disease, but additional study is required to determine the target sodium intake.
Abstract Background and Aims Since 2014, all adult native kidney biopsies undertaken in Scotland have been recorded by the Scottish Renal Registry (SRR). We aimed to report current data on indications for kidney biopsy, and outcomes following biopsy including requirement for kidney replacement therapy (KRT) and mortality. Method All 9 adult nephrology centres covering a population of over 5 million people report complete data on all kidney biopsies undertaken to the SRR. This includes indication, age, gender and diagnosis. The SRR collects requirement for KRT and death. Death or KRT at 6 months, 1 year and 2 years from date of first native kidney biopsy in patients with IgAN, MGN or ATIN were recorded. Results 5095 native kidney biopsies undertaken in 4702 patients between 01/01/2014 and 31/12/2021 were included. This averages 117.1 biopsies per million population / year. 54.7% were male with mean age 57.2 (SD 17.2) years. 98.2% of kidney biopsies were deemed adequate for diagnosis. Data completeness is over 99%. The commonest indications for native kidney biopsy were acute kidney injury query cause (AKI - 30.0%), chronically reduced eGFR (CKD) (28.1%) and nephrotic syndrome (19.7%). Overall, the commonest diagnoses made were: IgA nephropathy (IgAN 13.1%), tubulointerstitial nephritis (ATIN 8.5%) and membranous nephropathy (MGN 7.2%). Table 1 shows diagnoses made by biopsy indication. Conclusion In a complete national dataset, AKI is the commonest indication for native kidney biopsy and most commonly leads to a diagnosis of ATIN. IgAN remains the commonest primary glomerulopathy diagnosed on kidney biopsy, with MGN being the most likely diagnosis in patients biopsied for indication of nephrotic syndrome. Kidney and patient survival varies at 2 years depending on diagnosis. Table 2 shows that at 2 years the cmortality rate (Fig. 1) is highest in patients with MGN (11.4%) and risk of KRT highest in patients with IgAN (10.2%).
Aims The clinical significance of common histological parameters in acute interstitial nephritis (AIN) is uncertain. We aimed to evaluate the utility of histology in predicting clinical outcomes in patients with AIN. Methods and results Adult renal biopsies yielding a diagnosis of AIN between 2000 and 2015 were re‐examined. Patients were divided into groups based on: (i) the percentage of non‐fibrotic cortex containing inflammation (NFI score) (NFI‐1 = 0–24%; NFI‐2 = 25–74%; NFI‐3 = 75–100%) and (ii) the percentage of cortex containing tubular atrophy (TA score) (TA1 = 0–9%; TA2 = 10–24%; TA3 = 25–100%). The primary outcome was a composite of ≥50% reduction in serum creatinine (sCr) or an estimated glomerular filtration rate (eGFR) > 60 ml/min/1.73 m 2 1 year post‐biopsy. From a total of 2817 native renal biopsies, there were 120 patients with AIN and adequate data for analysis. Of these, 66 (56%) achieved the primary outcome. On univariable logistic regression, NFI‐3 was associated with a 16 times increased likelihood of achieving the primary outcome compared to NFI‐1 [odds ratio (OR) = 16, 95% confidence interval (CI) = 5.2–50)]. In contrast, TA3 was associated with a 90% reduced likelihood of achieving the primary outcome compared to TA1 (OR = 0.10, 95% CI = 0.0–0.3). Maximal clinical utility was achieved by combining TA and NFI into a single prognostic ‘TANFI’ score, which had an independent predictive effect on the primary outcome in a multivariable regression model consisting of age, sex, baseline sCr and identified drug cause. Conclusions In patients with biopsy‐proven AIN, a lower percentage of cortical tubular atrophy and, paradoxically, a higher percentage of inflammation in non‐fibrosed cortex were associated with an increased likelihood of a positive clinical outcome.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)
