Renal involvement in sarcoidosis: histological patterns and prognosis, an Italian survey.

BACKGROUND: Granulomatous interstitial nephritis in sarcoidosis (sGIN) is generally clinically silent, but in <1% causes acute kidney injury (AKI). METHODS: This Italian multicentric retrospective study included 39 sarcoidosis-patients with renal involvement at renal biopsy: 31 sGIN-AKI, 5 with other patterns (No-sGIN-AKI), 3 with nephrotic proteinuria. We investigate the predictive value of clinical features, laboratory, radiological parameters and histological patterns regarding steroid response. Primary endpoint: incident chronic kidney disease (CKD) beyond the 1°follow-up (FU) year; secondary endpoint: response at 1°line steroid therapy; combined endpoint: the association of initial steroid response and outcome at the end of FU. RESULTS: Complete recovery in all 5 No-sGIN-AKI-patients, only in 45% (13/29) sGIN-AKI-patients (p=0.046) (one lost in follow-up, for another not available renal function after steroids). Nobody had not response. Primary endpoint of 22 sGIN-AKI subjects: 65% (13/20) starting with normal renal function developed CKD (2/22 had basal CKD; median FU 77 months, 15-300). Combined endpoint: 29% (6/21) had complete recovery and final normal renal function (one with renal relapse), 48% (10/21) had partial recovery and final CKD (3 with renal relapse, of whom one with basal CKD) (p=0.024). Acute onset and hypercalcaemia were associated to milder AKI and better recovery than subacute onset and patients without hypercalcaemia, women had better endpoints than men. Giant cells, severe interstitial infiltrate and interstitial fibrosis seemed negative predictors in terms of endpoints. CONCLUSIONS: sGIN-AKI-patients with no complete recovery at 1°line steroid should be treated with other immunosuppressive to avoid CKD, in particular if males with subacute onset and III stage-not hypercalcaemic AKI.

Kidney transplant patients with SARS-CoV-2 infection: The Brescia Renal COVID task force experience.

The outcome of kidney transplant patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is still unclear. Here we describe the clinical characteristics, disease outcome, and risk factors for acute respiratory distress syndrome (ARDS) and death of a cohort of 53 kidney transplant patients with coronavirus disease 2019 (COVID-19). Eight of 53 have been handled as outpatients because of mild disease, on average with immunosuppression reduction and the addition of hydroxychloroquine and azithromycin; no patients required admission, developed ARDS, or died. Because of severe symptoms, 45/53 required admission: this cohort has been managed with immunosuppression withdrawal, methylprednisolone 16 mg/d, hydroxychloroquine, and antiviral drugs. Dexamethasone and tocilizumab were considered in case of ARDS. About 33% of the patients developed acute kidney injury, 60% ARDS, and 33% died. In this group, thrombocytopenia was associated to ARDS whereas lymphopenia at the baseline, higher D-dimer, and lack of C-reactive protein reduction were associated with risk of death. In the overall population, dyspnea was associated with the risk of ARDS and age older than 60 years and dyspnea were associated with the risk of death with only a trend toward an increased risk of death for patients on tacrolimus. In conclusion, SARS-CoV-2 infection may have a variable outcome in renal transplant patients, with higher risk of ARDS and death in the ones requiring admission.

Homoarginine and mortality in pre-dialysis chronic kidney disease (CKD) patients.

BACKGROUND AND AIMS: Homoarginine, a precursor of nitric oxide, is an inverse predictor of death in dialysis patients and in subjects with cardiovascular disease and normal kidney function but its relationship with clinical outcomes in chronic kidney disease (CKD) patients not yet on dialysis is unknown. DESIGN SETTING PARTICIPANTS AND MEASUREMENTS: We enrolled 168 consecutive predialysis CKD patients (Age: 70 ± 11 yrs; 26% Diabetics; eGFR 34 ± 18 ml/min/1.73 m(2)) referred to a tertiary care centre and measured laboratory data on kidney function and cardiovascular risk factors. We modeled progression to dialysis or death as a function of homoarginine, using Cox's regression, accounting for clinical characteristics, baseline levels of kidney function, and markers of inflammation. RESULTS: On crude and adjusted analyses homoarginine was directly associated with the eGFR and patients with more compromised renal function exhibited lower homoarginine levels. Furthermore homoarginine was also independently related to L-arginine, serum albumin and body mass index, and inversely related to proteinuria, C-reactive protein and age. During the study (follow up median time 4 years, inter-quartile range 1.7 to 7.0 years) 56 patients started dialysis and 103 died and homoarginine was a strong inverse predictor of the incidence rate of both outcomes (P=0.002 and P=0.017). CONCLUSIONS: Homoarginine declines with advancing renal disease and is inversely related to progression to dialysis and mortality. The nature of the link between homoarginine and clinical outcomes is amenable to testing in clinical trials.

IgA nephropathy with severe chronic renal failure: a randomized controlled trial of corticosteroids and azathioprine.

BACKGROUND: Therapeutic nihilism is common in IgA nephropathy (IgAN) and renal insufficiency. METHODS: In a randomized controlled trial comparing steroids alone or combined with azathioprine in 253 IgAN patients, we used a separate randomization list for patients with creatinine >2.0 mg/dL. Twenty patients (group 1) were randomized to 3 intravenous pulses of methylprednisolone 1 g at months 1, 3 and 5, and oral prednisone 0.5 mg/kg every other day plus azathioprine 1.5 mg/kg/day for 6 months, followed by oral prednisone 0.2 mg/kg every other day plus azathioprine 50 mg/day for a further 6 months; 26 patients (group 2) received steroids alone. The primary outcome was renal survival (50% increase in plasma creatinine from baseline); secondary outcomes were proteinuria over time and adverse events. RESULTS: Six-year renal survival was not different between the 2 groups (50% vs. 57%; log-rank p=0.34). Median proteinuria decreased during follow-up in the whole population (from 2.45 g/day [interquartile range (IQR) 1.50-3.78] to 1.09 g/day [IQR 0.56- 2.46]; p<0.001), with no between-group difference. Multivariate predictors associated with renal survival were sex of patient, proteinuria during follow-up, number of antihypertensive drugs, angiotensin-converting enzyme inhibitors and treatment including azathioprine. Six patients in group 1 (30%) and 4 in group 2 (15%) did not complete the therapy, because of side effects (p=0.406). CONCLUSIONS: Six-year renal survival was similar in the 2 groups. At Cox analysis the addition of azathioprine may be slightly more effective than corticosteroids alone in patients with chronic renal insufficiency, although with an increase of side effects.

Measuring asymmetric dimethylarginine (ADMA) in CKD: a comparison between enzyme-linked immunosorbent assay and liquid chromatography-electrospray tandem mass spectrometry.

BACKGROUND: Asymmetric dimethylarginine (ADMA) is increasingly being investigated as a renal and cardiovascular risk factor in chronic kidney disease (CKD). We assessed the degree of agreement of an enzyme-linked immunosorbent assay (ELISA) of ADMA and the gold standard liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). METHODS: ADMA was measured in an incident cohort of 126 stable CKD patients. Correlations between methods were studied by estimating the interclass Pearson coefficient (IPC), Lin's concordance correlation coefficient (CCC) and the maximum likelihood intraclass correlation coefficient (ICC). Limits of agreement (LOA) were estimated using the Bland-Altman method. RESULTS: ADMA values were normally distributed with means of 0.78 ± 0.16 (ELISA) and 0.59 ± 0.09 mol/L (LC-MS/MS). IPC was 0.69 (95% confidence interval [95% CI], 0.59-0.78). Overall CCC was 0.29 (95% CI, 0.23-0.37), with a difference in means of 0.19 mol/L (95% LOA, -0.043 to 0.43), delta slope of 0.577 and delta intercept of 0.14 (vs. perfect agreement line). Data were similar across categories of clinical characteristics. Mixed models provided an ICC of 0.58 (95% CI, 0.46-0.69). Bias was larger among patients with glomerular filtration rate (GFR) <30 ml/min. When values obtained from ELISA were corrected using the slope and intercept estimates from concordance analyses, the adjusted ICC improved to 0.67 (95% CI, 0.57-0.76), and bias modification by GFR levels canceled out. CONCLUSIONS: In CKD, ELISA overestimates ADMA concentration as compared with LC-MS/MS. Appropriate calibration is needed when ADMA is measured by ELISA in CKD patients.

Vitamin D levels and patient outcome in chronic kidney disease.

Vitamin D deficiency has been linked to cardiovascular disease and early mortality in patients on hemodialysis; however, it is not known if the same association exists at earlier stages of chronic kidney disease. To determine this we enrolled 168 consecutive new referrals to a chronic kidney disease clinic over a 2 year period and followed them for up to 6 years. All patients were clinically stable and had an estimated glomerular filtration rate (eGFR) at stage 2 or less and were without an imminent need for dialysis. Baseline 25-hydroxyvitamin D levels directly and significantly correlated with eGFR. After an average follow-up of 48 months, 48 patients started dialysis and 78 had died. In crude analyses, 25-hydroxyvitamin D predicted both time to death and end-stage renal disease. A dual-event Cox's model confirmed 25-hydroxyvitamin D as an independent predictor of study outcomes when adjusted for age, heart failure, smoking, C-reactive protein, albumin, phosphate, use of converting enzyme inhibitors or angiotensin receptor blockers, and eGFR. Our study shows that plasma 25-hydroxyvitamin D is an independent inverse predictor of disease progression and death in patients with stage 2-5 chronic kidney disease.