Gross Hematuria after the COVID-19 mRNA Vaccination: Nationwide Multicenter Prospective Cohort Study in Japan.

BACKGROUND: In the past three years, cases of gross hematuria (GH) after the vaccination for coronavirus disease 2019 (COVID-19) in IgA nephropathy (IgAN) patients have been frequently reported worldwide. However, the post-event renal prognosis of these patients, their clinical backgrounds, and underlying mechanisms remain unknown. Therefore, we conducted a nationwide multicenter prospective cohort study in Japan. METHODS: We analyzed laboratory findings at the time of the first presentation to the hospital, and 3 and 6 months after in patients with GH after the vaccination, and histopathological findings in their kidney biopsy specimens. Moreover, changes in pathological biomarkers of IgAN such as galactose-deficient IgA1 (Gd-IgA1) and its immune complexes (ICs) were also evaluated. RESULTS: During the study period, 127 newly presenting with GH after the vaccination were enrolled, with a clear female bias (73.2%). GH was observed after the second or subsequent vaccinations in most patients (92.9%). Of the 37 patients undergoing kidney biopsy prior to the vaccination, 36 patients had been diagnosed with IgAN/IgA vasculitis (IgAV). In remaining 90 patients, 69 of the 70 who newly underwent kidney biopsy were diagnosed with IgAN (N=67)/IgAV (N=2). Their histopathology did not show a high incidence of acute lesions such as endocapillary hypercellularity and crescentic lesions. Most cases showed a temporary increase in proteinuria, but no sustained worsening in renal function. Among the biomarkers measured, serum Gd-IgA1 and ICs were comparable throughout the observation period, however, only urinary Gd-IgA1 was increased at the time of GH. CONCLUSIONS: We found that GH after the vaccination is more likely to occur in IgAN/IgAV patients, with a female bias, but without progressive exacerbation of renal function. Although further investigation is needed regarding causal relationship between vaccination and GH, this study provides many insights into the molecular mechanisms of GH.

Autosomal-dominant tubulointerstitial kidney disease with a novel UMOD mutation, overlapping with Sjogren's syndrome: a case report.

Autosomal-dominant tubulointerstitial kidney disease caused by UMOD (encoding uromodulin) mutation (ADTKD-UMOD) is a rare hereditary disease. A strong family history of hyperuricemia or gout and inherited kidney disease raises the suspicion of ADTKD-UMOD. Genetic testing can confirm the diagnosis without a kidney biopsy. However, when complicated by other diseases that can cause tubulointerstitial disease, renal biopsy is indispensable for the diagnosis and decisions on treatment strategy. We report the case of a 44-year-old woman referred for evaluation of kidney dysfunction. She had an attack of gout 1 month before referral and a family history of hyperuricemia. She was diagnosed with primary Sjogren's syndrome through an immune workup and ophthalmological examination. However, a kidney biopsy revealed histological features suggesting ADTKD rather than gouty kidney or tubulointerstitial nephritis associated with Sjogren's syndrome, and immunostaining revealed a characteristic staining pattern with UMOD. Comprehensive genetic testing of 93 genes responsible for polycystic kidney disease revealed a novel heterozygous missense variant (c.649 T > A:p. Cys217Ser) in UMOD, and the patient was diagnosed with ADTKD-UMOD. In this case, kidney biopsy contributed to the correct diagnosis of tubulointerstitial kidney disease. This case emphasizes the importance of suspecting ADTKD-UMOD based on family history and careful evaluation of kidney biopsy findings.

Association between serum magnesium levels and cognitive function in patients undergoing hemodialysis.

BACKGROUND: The relationship between chronic kidney disease-mineral and bone disorder (CKD-MBD) and cognitive function remains largely unknown. This cross-sectional study aimed to explore the association between CKD-MBD and cognitive function in patients on hemodialysis. METHODS: Hemodialysis patients aged ≥ 65 years without diagnosed dementia were included. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). CKD-MBD markers, serum magnesium, intact parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OHD), fibroblast growth factor (FGF)-23, and soluble α-klotho were measured. RESULTS: Overall, 390 patients with a median age of 74 (interquartile range, 70-80) years, mean serum magnesium level of 2.4 ± 0.3 mg/dL, and median MoCA and MMSE scores of 25 (22-26) and 28 (26-29), respectively, were analyzed. MoCA and MMSE scores were significantly higher (preserved cognitive function) in the high-magnesium group than in the low-magnesium group according to the unadjusted linear regression analysis (ß coefficient [95% confidence interval (CI)] 1.05 [0.19, 1.92], P = 0.017 for MoCA; 1.2 [0.46, 1.94], P = 0.002 for MMSE) and adjusted multivariate analysis with risk factors for dementia (ß coefficient [95% CI] 1.12 [0.22, 2.02], P = 0.015 for MoCA; 0.92 [0.19, 1.65], P = 0.014 for MMSE). CONCLUSIONS: Higher serum magnesium levels might be associated with preserved cognitive function in hemodialysis patients. Conversely, significant associations were not observed between cognitive function and intact PTH, 25-OHD, FGF-23, or soluble α-klotho levels.

Effect of tonsillectomy combined with steroid pulse therapy upon IgA nephropathy depending on proteinuria status at diagnosis: a nationwide multicenter cohort study in Japan.

BACKGROUND: The effects of tonsillectomy combined with steroid pulse (TSP) therapy for IgA nephropathy (IgAN) are little known. Therefore, we examined the effects of TSP therapy on the kidney outcomes of IgAN in a large, nationwide cohort study in Japan. METHODS: Between 2002 and 2004, 632 IgAN patients with ≥ 0.5 g/day proteinuria at diagnosis were divided into three groups with mild (0.50-0.99 g/day; n = 264), moderate (1.00-1.99 g/day, n = 216), or severe (≥ 2.00 g/day; n = 153). Decline in kidney function and urinary remission were compared among the three groups after TSP therapy, corticosteroid (ST) therapy, or conservative therapy during a mean follow-up of 6.2 ± 3.3 years. 10.6% and 5.9% of patients in the ST and conservative therapy group underwent tonsillectomy. RESULTS: The rate of urinary remission at the final observation was significantly higher in the TSP therapy group than in the ST or conservative therapy groups (mild proteinuria: 64%, 43%, and 41%; moderate proteinuria: 51%, 45%, and 28%; severe proteinuria: 48%, 30%, and 22%, respectively). In contrast, the rate of a 50% increase in serum creatinine was lower in groups TSP therapy, than ST or conservative therapy (mild proteinuria: 2.1%, 10.1% and 16.7%; moderate proteinuria: 4.8%, 8.8% and 27.7%; severe proteinuria: 12.0%, 28.9% and 43.1%, respectively). In multivariate analysis, TSP therapy significantly prevented a 50% increase in serum creatinine levels compared with conservative therapy in groups with moderate and severe proteinuria (hazard ratio, 0.12 and 0.22, respectively). CONCLUSION: TSP significantly increased the rate of proteinuria disappearance and urinary remission in IgAN patients with mild-to-moderate urinary protein levels. It may also reduce the decline in kidney function in patients with moderate-to-severe urinary protein levels.

Current Status and Future Perspective of Onco-Hypertension.

Hypertension and cancer are both increasing with age. Recently, the new concept of "Onco-Hypertension" has been proposed to address the mutual risks posed by hypertension and cancer and to provide comprehensive care for patients with these two conditions in an aging society. Hypertension and cancer share common risk factors and may be interrelated in pathogenesis: hypertension is involved in the development of certain cancers, and cancer survivors have a higher incidence of hypertension. With recent advances in cancer therapy, the number of cancer survivors has increased. Cancer survivors not only have a higher risk of incident hypertension but also an increased risk of future cardiovascular events, highlighting the growing importance of comprehensive care. In this review, we provide an overview of the current status and future perspective of the "Onco-Hypertension," including our research findings.

Podocyte density as a predictor of long-term kidney outcome in obesity-related glomerulopathy.

Glomerulomegaly and focal segmental glomerulosclerosis are histopathological hallmarks of obesity-related glomerulopathy (ORG). Podocyte injury and subsequent depletion are regarded as key processes in the development of these glomerular lesions in patients with ORG, but their impact on long-term kidney outcome is undetermined. Here, we correlated clinicopathological findings and podocyte depletion retrospectively in patients with ORG. Relative (podocyte density) and absolute (podocyte number per glomerulus) measures of podocyte depletion were estimated using model-based stereology in 46 patients with ORG. The combined endpoint of kidney outcomes was defined as a 30% decline in estimated glomerular filtration rate (eGFR) or kidney failure. Patients with lower podocyte density were predominantly male and had larger body surface area, greater proteinuria, fewer non-sclerotic glomeruli, larger glomeruli and higher single-nephron eGFR. During a median follow-up of 4.1 years, 18 (39%) patients reached endpoint. Kidney survival in patients with lower podocyte density was significantly worse than in patients with higher podocyte density. However, there was no difference in kidney survival between patient groups based on podocyte number per glomerulus. Cox hazard analysis showed that podocyte density, but not podocyte number per glomerulus, was associated with the kidney outcomes after adjustment for clinicopathological confounders. Thus, our study demonstrates that a relative depletion of podocytes better predicts long-term kidney outcomes than does absolute depletion of podocytes. Hence, the findings implicate mismatch between glomerular enlargement and podocyte number as a crucial determinant of disease progression in ORG.

Acute kidney tubular injury after ingestion of red yeast rice supplement.

A 47-year-old woman developed severe kidney dysfunction after taking a lipid-lowering supplement, Red Yeast Rice Cholestehelp, for approximately 7 months. The patient developed sudden nausea and had an elevated serum creatinine level of 4.26 mg/dL. A kidney biopsy showed findings consistent with acute tubular necrosis. Kidney dysfunction improved with discontinuation of supplementation, and corticosteroid therapy. Similar kidney involvement has been reported, raising concerns regarding supplements in Japan. An investigation of the nephrotoxic ingredients in the same product batches is currently underway. This report underscores the need for public awareness and warnings of health risk concerns associated with unregulated supplements.

Significance of eGFR and proteinuria for cardiovascular disease in individuals beyond 85 years.

BACKGROUND: There are limited data on how advancing age influences prediction of CVD risk based on the estimated glomerular filtration rate (eGFR) and proteinuria, especially in older adults, including those aged ≥ 85 years. This study aimed to clarify the association of eGFR and proteinuria with CVD outcomes and the impact of age on this association. METHODS: The distribution of eGFR and urine protein in Japan was assessed retrospectively using real-world administrative claims and health checkup data collected between April 2014 and November 2022. We investigated the associations of these two parameters with the incidence of CVD, with an emphasis on the impact of aging. RESULTS: We assessed 1 829 020 individuals for distribution of eGFR and proteinuria; after excluding those with known CVD, their association with CVD risk was examined in 1 040 101 individuals aged ≥ 40 years. The prevalence of impaired kidney function (eGFR <60 mL/min/1.73 m2) increased with age, being 0.7%, 9.2%, 21.9%, 40.2%, and 60.2% at the ages of 18-39, 40-64, 65-74, 75-84, and ≥ 85 years (P for trend < 0.001); similarly, the proportion with positive proteinuria increased with age, being 2.7%, 4.3%, 5.6%, 9.2%, and 15.8%, respectively (P for trend < 0.001). Both eGFR and urine protein were identified to be independent risk factors for CVD. Hazard ratios for CVD increased significantly when eGFR was <45 mL/min/1.73 m2 at the ages of 40-64, 65-74, and 75-84 and <30 mL/min/1.73 m2 at ≥ 85 years, while proteinuria remained significantly associated with a high CVD risk regardless of age. These findings were consistent even when analyzed separately by sex. CONCLUSIONS: This study identified eGFR and urine dipstick proteinuria to be independent risk factors for CVD, even among individuals aged ≥ 85 years. However, the contribution of eGFR to the CVD risk was attenuated by aging, whereas proteinuria remained less affected by advancing age.

Long-Term Outcomes, Including Fetal and Neonatal Prognosis, of Renal Oligohydramnios: A Retrospective Study over 22 Years.

OBJECTIVE: To assess the long-term outcome of renal oligohydramnios and risk factors for fetal, neonatal, and postneonatal death. STUDY DESIGN: This retrospective cohort study included fetuses with prenatally detected renal oligohydramnios between 2002 and 2023. Patients who were lost to follow-up were excluded. Fetal, neonatal, and long-term outcomes were evaluated, and their risk factors were analyzed. RESULTS: Of 131 fetuses with renal oligohydramnios, 46 (35%) underwent a termination of pregnancy, 11 (8%) had an intrauterine fetal death, 26 (20%) had a neonatal death, nine (7%) had a postneonatal death, and 39 (30%) survived. Logistic regression analyses showed that an earlier gestational age at onset (OR 1.16, 95% CI 1.01-1.37) was significantly associated with intrauterine fetal death; anhydramnios (OR 12.7, 95% CI 1.52-106.7) was significantly associated with neonatal death as a prenatal factor. Although neonatal survival rates for bilateral renal agenesis, bilateral multicystic dysplastic kidney (MCDK), and unilateral MCDK with contralateral renal agenesis were lower than for other kidney diseases, 1 case of bilateral renal agenesis and two of bilateral MCDK survived with fetal intervention. Kaplan-Meier overall survival rates were 57%, 55%, and 51% for 1, 3, and 5 years, respectively. In the Cox proportional hazards model, birth weight <2000 g (hazard ratio 7.33, 95% CI 1.48-36.1) and gastrointestinal comorbidity (hazard ratio 4.37, 95% CI 1.03-18.5) were significant risk factors for postneonatal death. CONCLUSION: Long-term survival following renal oligohydramnios is a feasible goal and its appropriate risk assessment is important.

Chronic Tonsillitis and IgA Nephropathy: Findings From a Nationwide Japanese Cohort Study.

RATIONALE & OBJECTIVE: Little is known regarding the association between chronic tonsillitis and the onset of IgA nephropathy (IgAN). In the present study, we examined the potential relationship between chronic tonsillitis and a subsequent risk of developing IgAN. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: 4,311,393 individuals without a history of IgAN identified between January 2005 and May 2022 within a Japanese nationwide epidemiological database, the JMDC Claims Database, representing health claims to over 60 insurers. EXPOSURE: Comorbid chronic tonsillitis based on diagnosis codes. OUTCOME: IgAN occurrence. ANALYTICAL APPROACH: Cause-specific Cox proportional hazards analysis adjusting for potential confounding factors was employed to estimate hazard ratios (HRs). RESULTS: Comorbid chronic tonsillitis was identified in 12,842 individuals, constituting 0.3% of the cohort. The cohort had a median age of 44 years (IQR, 36-53), and males accounted for 57.9%, with a follow-up of 1,089 days (IQR, 532-1,797), during which 2,653 cases of IgAN developed. Cumulative incidence curve showed a higher cumulative incidence of IgAN in individuals with chronic tonsillitis compared with their counterparts without this condition. Multivariable cause-specific analysis further demonstrated that individuals with chronic tonsillitis had an elevated risk of developing IgAN, with HR of 2.72 (95% CI, 1.79-4.14). LIMITATIONS: Potential residual confounders, and lack of consideration for ethnic distinctions. CONCLUSIONS: Using a large-scale epidemiological dataset, these findings suggest a relationship between chronic tonsillitis and an elevated risk of IgAN development in the general Japanese population. PLAIN-LANGUAGE SUMMARY: IgA nephropathy (IgAN), the most prevalent form of primary glomerulonephritis worldwide, is associated with unfavorable long-term kidney survival and life expectancy. Despite the substantial implications, the early detection of IgAN still remains challenging due to its commonly asymptomatic clinical presentation. Consequently, the exploration of risk factors assumes a critical research priority. Prior studies have reported the potential role of tonsilitis in the pathogenesis of IgAN. In this study, we assessed whether chronic tonsillitis was associated with the subsequent development of IgAN using a nationwide epidemiological dataset incorporating over 4,000,000 individuals. Within this large-scale cohort, our findings revealed an association between a history of tonsillitis and a greater risk of developing IgAN. These findings should heighten awareness of the potential susceptibility of people with chronic tonsilitis to IgAN.

Analysis of the impact of obesity on the prognosis of IgA nephropathy according to renal function and sex.

BACKGROUND: Few studies have observed the direct effect of obesity on renal prognoses in immunoglobulin A nephropathy (IgAN) or separately evaluated its effects according to sex. We aimed to evaluate the direct and indirect effects of obesity on the renal outcomes of IgAN and observe these effects separately according to renal function and sex. METHODS: We extracted patients with body mass index (BMI) descriptions from a multicenter retrospective cohort analysis in Japan, and excluded those with < 30 days of follow-up, diabetes mellitus, and steroid treatment. Patients were divided into normal (n = 720; 18.5 ≤ BMI < 25) and obese (n = 212; BMI ≥ 25) groups, which were then compared. The endpoints were a 1.5-fold increase in serum creatinine levels and the initiation of renal replacement therapy. RESULTS: The obese group was older, included more males, and was more likely have hypertension, dyslipidemia, proteinuria, tubular atrophy, and lower renal function than the normal group. Patients with an eGFR < 60 mL/min/1.73 m2 had well-matched characteristics between the groups; however, hypertension, low high-density lipoprotein cholesterol, and hypertriglyceridemia were more common in the obese group. Obesity contributed to tubular atrophy, even when adjusted for renal function. In addition, it contributed to proteinuria only in females. However, obesity itself was not a significant prognostic factor. CONCLUSIONS: Although no independent effect on renal prognosis was observed during the study period, the obese group had more risk factors for IgAN progression and obesity contributed to tubular atrophy and female proteinuria. Our results suggest that separately analyzing the prognostic effect of obesity according to sex is important.

Estimating baseline creatinine levels based on the kidney parenchymal volume.

BACKGROUND: Acute kidney injury (AKI) diagnosis often lacks a baseline serum creatinine (Cr) value. Our study aimed to create a regression equation linking kidney morphology to function in kidney donors and chronic kidney disease patients. We also sought to estimate baseline Cr in minimal change disease (MCD) patients, a common AKI-predisposing condition. METHODS: We analyzed 119 participants (mean age 60 years, 50% male, 40% donors) with CT scans, dividing them into derivation and validation groups. An equation based on kidney parenchymal volume (PV) was developed in the derivation group and validated in the validation group. We estimated baseline Cr in 43 MCD patients (mean age 45 years, 61% male) using the PV-based equation and compared with their 6 month post-MCD onset Cr values. RESULTS: In the derivation group, the equation for the estimated glomerular filtration rate (eGFR) was: eGFR (mL/min/1.73m2) = 0.375 × PV (cm3) + (- 0.395) × age (years) + (- 2.93) × male sex + (- 13.3) × hypertension + (- 14.0) × diabetes + (- 0.210) × height (cm) + 82.0 (intercept). In the validation group, the eGFR and estimated Cr values correlated well with the measured values (r = 0.46, p = 0.01; r = 0.51, p = 0.004, respectively). In the MCD group, the baseline Cr values were significantly correlated with the estimated baseline Cr values (r = 0.52, p < 0.001), effectively diagnosing AKI (kappa = 0.76, p < 0.001). CONCLUSIONS: The PV-based regression equation established in this study holds promise for estimating baseline Cr values and diagnosing AKI in patients with MCD. Further validation in diverse AKI populations is warranted.

Evaluating the associations between compliance with CKD guideline component metrics and renal outcomes.

Understanding the association between compliance to the Chronic Kidney Disease (CKD) guidelines in real-world clinical settings and renal outcomes remains a critical gap in knowledge. A comprehensive analysis was conducted using data from a national, multicenter CKD registry. This study included 4,455 patients with an estimated glomerular filtration rate (eGFR) measurement on the index date and eight additional metrics recorded within six months. These metrics comprised serum electrolyte levels, low-density lipoprotein cholesterol, hemoglobin, and the use of renin-angiotensin system inhibitors. The primary outcome was a composite of renal events, defined by a decline in eGFR to < 15 mL/min/1.73 m2 or a reduction of ≥ 30% in eGFR, confirmed by follow-up tests. Over a median follow-up of 513 days, 838 renal events were observed. High serum potassium levels (> 5.4 mmol/L) were associated with increased event rates compared to lower levels. Similarly, low serum sodium-chloride levels (< 33) correlated with higher event rates. Usage of renin-angiotensin system inhibitors, low serum calcium (< 8.4 mg/dL), and high uric acid levels (> 7.0 mg/dL) were also linked to increased events. Conversely, higher hemoglobin levels (≥ 13 g/dL) were associated with lower event rates. Compliance to guidelines, categorized into quartiles based on the number of met metrics, revealed a significantly reduced risk of events in the highest compliance group (meeting 8 metrics) compared to the lowest (0-5 metrics). Compliance to CKD guidelines in clinical practice is significantly associated with improved renal outcomes, emphasizing the need for guideline-concordant care in the management of CKD.

Lipoprotein glomerulopathy with markedly increased arterial stiffness successfully treated with a combination of fenofibrate and losartan: a case report.

BACKGROUND: Lipoprotein glomerulopathy (LPG) is a apolipoprotein E (ApoE)-related glomerular disease and has been associated with type III hyperlipidemia. Without appropriate treatment, chronic kidney disease (CKD) caused by LPG progresses, and approximately half of the patients develop end-stage kidney disease within 1-27 years of disease onset. However, few studies have highlighted the clinical course of cardiovascular diseases (CVDs) in patients with LPG. Herein, we report the first case of LPG in which the CVD risk was assessed using arterial stiffness. CASE PRESENTATION: A 32-year-old Japanese man was referred to our hospital due to persistent proteinuria. Kidney biopsy showed markedly dilated capillary lumens containing pale-stained thrombi, which stained positively with Oil Red O. Electron microscopy revealed the presence of thrombi in the capillary lumen with low electron density and vacuoles of various sizes in part of the thrombi. Toluidine blue and Sudan IV stains were used to stain the thin sections of Epon-embedded tissue samples for electron microscopy. Sudan IV-positive droplets were observed in the capillary lumens, vascular walls, and cytoplasm of tubular cells. Increased serum ApoE concentration was observed. Liquid chromatography-tandem mass spectrometry of laser-microdissected glomeruli from paraffin sections revealed an increase in ApoE. Direct deoxyribonucleic acid sequencing of ApoE revealed a heterozygous ApoE Sendai mutation (Arg145Pro). The patient was finally diagnosed with LPG with heterozygosity for ApoE-Sendai mutation (Arg145Pro). Notably, at the time of diagnosis, he had markedly increased arterial stiffness for his age. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV), which was equivalent to that of a 56-year-old man. After three months of treatment with fenofibrate and losartan, a significant reduction in proteinuria was achieved along with an improvement in baPWV. Furthermore, these effects were maintained despite the lack of decrease in serum ApoE levels. CONCLUSION: Herein, we report the case of a patient with LPG with markedly increased arterial stiffness at the time of diagnosis, in whom combination therapy with fenofibrate and losartan successfully improved proteinuria and arterial stiffness. To the best of our knowledge, this is the first case report of LPG in which CVD risk was assessed using arterial stiffness.

Fractional excretion of total protein predicts renal prognosis in Japanese patients with primary membranous nephropathy.

Background: Primary membranous nephropathy (pMN) is one of the most common types of glomerulonephritis, with a third of patients progressing to renal insufficiency. Various prognostic factors have been reported, of which urinary protein and renal function are the most critical parameters. Fractional excretion of total protein (FETP) indicates protein leakage that accounts for creatinine kinetics and serum protein levels. In this study, we investigated the association between FETP and renal prognosis in pMN. Methods: We retrospectively identified 150 patients with pMN. FETP was calculated as follows: (serum creatinine × urine protein)/(serum protein × urine creatinine) %. We divided the patients into three groups according to FETP values and compared the clinicopathological findings. The primary outcome was an estimated glomerular filtration rate (eGFR) decrease of ≥30% from the baseline level. Results: FETP was associated with urinary protein and renal function, Ehrenreich and Churg stage, and global glomerulosclerosis. The primary outcome was observed in 38 patients (25.3%), and the frequency of the primary outcome was higher in the high FETP group (P = .001). FETP is higher than protein-creatinine ratio (PCR) in the area under the curve. In the multivariate analysis adjusted for age, eGFR, PCR and treatment, FETP was significantly associated with primary outcome (adjusted hazard ratio, 8.19; P = .019). Conclusions: FETP is a valuable indicator that can reflect the pathophysiology and is more useful than PCR as a predictor of renal prognosis in patients with Japanese pMN.

Factors affecting the sodium-glucose cotransporter 2 inhibitors-related initial decline in glomerular filtration rate and its possible effect on kidney outcome in chronic kidney disease with type 2 diabetes: The Japan Chronic Kidney Disease Database.

AIM: Sodium-glucose cotransporter 2 (SGLT2) inhibitors often cause a transient decrease in glomerular filtration rate (GFR) shortly after the initiation, referred to as the 'initial drop'. However, the clinical significance of this initial drop in real-world practice remains unclear. MATERIALS AND METHODS: Using the nationwide Japan Chronic Kidney Disease Database, we examined factors that affected the initial drop, in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). We also evaluated the effects of the initial drop on a composite kidney outcome (a decline in GFR of ≥50% or progression to end-stage kidney disease). RESULTS: Data from 2053 patients with CKD and T2DM newly prescribed an SGLT2 inhibitor were analysed. The follow-up period after SGLT2 inhibitor administration was 1015 days (interquartile range: 532, 1678). Multivariate linear regression models revealed that the concomitant use of the renin-angiotensin system inhibitors and diuretics, urinary protein levels ≥2+, and changes in GFR before the initiation of the SGLT2 inhibitor were associated with a larger initial GFR decline (ß = -0.609, p = .039; ß = -2.298, p < .001; ß = -0.936, p = .048; ß = -0.079, p < .001, respectively). Patients in the quartile with the largest initial GFR decline experienced a higher incidence of the subsequent composite kidney outcome than those in the other quartiles (p < .001). CONCLUSIONS: The concomitant use of renin-angiotensin system inhibitors and diuretics, higher urine protein levels and pre-treatment GFR changes were associated with a larger initial GFR decline. Of these factors, the use of a diuretic had the largest effect. Furthermore, patients with CKD and T2DM experiencing an excessive initial GFR drop might be at a higher risk of adverse kidney outcomes.