Body weight change associated kidney outcomes of sodium-glucose cotransporter new users.

AIM: To investigate the clinical significance of body weight changes on kidney outcomes among individuals with diabetes using sodium-glucose cotransporter-2 (SGLT2) inhibitors. MATERIALS AND METHODS: This is a retrospective cohort study using a nationwide epidemiological database, and we conducted an analysis involving 11 569 individuals with diabetes who were newly prescribed SGLT2 inhibitors. The main outcome was the rate of decline in estimated glomerular filtration rate (eGFR), determined through a linear mixed-effects model with an unstructured covariance structure. RESULTS: The median age of the patients was 52 (Q1-Q3: 47-58) years, and the median fasting plasma glucose and glycated haemoglobin (HbA1c) levels were 144 (Q1-Q3: 124-175) mg/dL and 7.4 (Q1-Q3: 6.8-8.3)%, respectively. The median estimated eGFR was 77.7 (Q1-Q3: 67.2-89.1) mL/min/1.73 m2. The median follow-up period was 1.7 (Q1-Q3: 1.0-2.6) years. Participants were stratified into three groups based on the body mass index change rate tertiles between baseline and 1 year after (tertile 1: <-4.55%, tertile 2: -4.55% to -1.43%, tertile 3: >-1.43%). The annual change in eGFR was -0.78 (-0.94 to -0.63) mL/min/1.73 m2 in tertile 1, -0.95 (-1.09 to -0.81) mL/min/1.73 m2 in tertile 2, and -1.65 mL/min/1.73 m2 (-1.84 to -1.47) in tertile 3 (pinteraction < 0.001). A variety of sensitivity analyses confirmed the relationship between the 1-year body mass index decrease and favourable kidney outcomes after SGLT2 inhibitor administration. CONCLUSIONS: Our analysis of a nationwide epidemiological cohort revealed that kidney outcomes following the initiation of SGLT2 inhibitors would be more favourable, with greater body weight loss observed after the initiation of SGLT2 inhibitors.

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.

Pancreatic cancer risk in diabetic patients using the Japanese Regional Insurance Claims.

Pancreatic cancer presents a critical health issue characterized by low survival rates. Identifying risk factors in specific populations, such as those with diabetes, is crucial for early detection and improved outcomes. This study aimed to identify risk factors for pancreatic cancer in diabetic patients using a longitudinal cohort from the Shizuoka Kokuho database, spanning April 2012 to September 2021. Diabetic patients were identified and monitored for the onset of pancreatic cancer. Factors analyzed included age, sex, the Elixhauser comorbidity index, and specific comorbidities. Statistical analyses involved univariate and multivariate Cox proportional hazards regression. The study identified 212,775 as diabetic patients and 1755 developed pancreatic cancer during the period. The annual incidence rate of pancreatic cancer in this group was 166.7 cases per 100,000 person-years. The study identified older age, male sex, a history of liver disease, chronic pancreatitis, and pancreatic cystic lesions as significant risk factors for pancreatic cancer in diabetic patients. The study also highlighted the absence of a significant association between diabetes type or diabetic complications and the onset of pancreatic cancer. These findings may aid in the early diagnosis of pancreatic cancer in diabetic patients and may inform revisions in screening practices in diabetic patients.

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.

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.

Efficacy of sucrose and povidone-iodine mixtures in peritoneal dialysis catheter exit-site care.

BACKGROUND: Exit-site infection (ESI) is a common recurring complication in patients undergoing peritoneal dialysis (PD). Sucrose and povidone-iodine (SPI) mixtures, antimicrobial ointments that promote wound healing, have been used for the treatment of ulcers and burns, but their efficacy in exit-site care is still unclear. METHODS: This single-center retrospective observational study included patients who underwent PD between May 2010 and June 2022 and presented with episodes of ESI. Patients were divided into SPI and non-SPI groups and followed up from initial ESI onset until PD cessation, death, transfer to another facility, or June 2023. RESULTS: Among the 82 patients (mean age 62, [54-72] years), 23 were treated with SPI. The median follow-up duration was 39 months (range, 14-64), with an overall ESI incidence of 0.70 episodes per patient-year. Additionally, 43.1% of second and 25.6% of third ESI were caused by the same pathogen as the first. The log-rank test demonstrated significantly better second and third ESI-free survival in the SPI group than that in the non-SPI group (p < 0.01 and p < 0.01, respectively). In a Cox regression analysis, adjusting for potential confounders, SPI use was a significant predictor of decreased second and third ESI episodes (hazard ratio [HR], 0.22; 95% confidence interval [CI], 0.10-0.52 and HR, 0.22; 95%CI, 0.07-0.73, respectively). CONCLUSIONS: Our results showed that the use of SPI may be a promising option for preventing the incidence of ESI in patients with PD. TRIAL REGISTRATION: This study was approved by the Keio University School of Medicine Ethics Committee (approval number 20231078) on August 28, 2023. Retrospectively registered.

Predicting exacerbation of renal function by DNA methylation clock and DNA damage of urinary shedding cells: a pilot study.

Recent reports have shown the feasibility of measuring biological age from DNA methylation levels in blood cells from specific regions identified by machine learning, collectively known as the epigenetic clock or DNA methylation clock. While extensive research has explored the association of the DNA methylation clock with cardiovascular diseases, cancer, and Alzheimer's disease, its relationship with kidney diseases remains largely unexplored. In particular, it is unclear whether the DNA methylation clock could serve as a predictor of worsening kidney function. In this pilot study involving 20 subjects, we investigated the association between the DNA methylation clock and subsequent deterioration of renal function. Additionally, we noninvasively evaluated DNA damage in urinary shedding cells using a previously reported method to examine the correlation with the DNA methylation clock and worsening kidney function. Our findings revealed that patients with an accelerated DNA methylation clock exhibited increased DNA damage in urinary shedding cells, along with a higher rate of eGFR decline. Moreover, in cases of advanced CKD (G4-5), the DNA damage in urinary shedding cells was significantly increased, highlighting the interplay between elevated DNA damage and eGFR decline. This study suggests the potential role of the DNA methylation clock and urinary DNA damage as predictive markers for the progression of chronic kidney disease.

Adipocyte-specific inactivation of NAMPT, a key NAD+ biosynthetic enzyme, causes a metabolically unhealthy lean phenotype in female mice during aging.

Nicotinamide adenine dinucleotide (NAD+) is a universal coenzyme regulating cellular energy metabolism in many cell types. Recent studies have demonstrated the close relationships between defective NAD+ metabolism and aging and age-associated metabolic diseases. The major purpose of the present study was to test the hypothesis that NAD+ biosynthesis, mediated by a rate-limiting NAD+ biosynthetic enzyme, nicotinamide phosphoribosyltransferase (NAMPT), is essential for maintaining normal adipose tissue function and whole body metabolic health during the aging process. To this end, we provided in-depth and comprehensive metabolic assessments for female adipocyte-specific Nampt knockout (ANKO) mice during aging. We first evaluated body fat mass in young (≤4-mo-old), middle aged (10-14-mo-old), and old (≥18-mo-old) mice. Intriguingly, adipocyte-specific Nampt deletion protected against age-induced obesity without changing energy balance. However, data obtained from the hyperinsulinemic-euglycemic clamp procedure (HECP) demonstrated that, despite the lean phenotype, old ANKO mice had severe insulin resistance in skeletal muscle, heart, and white adipose tissue (WAT). Old ANKO mice also exhibited hyperinsulinemia and hypoadiponectinemia. Mechanistically, loss of Nampt caused marked decreases in WAT gene expression of lipogenic targets of peroxisome proliferator-activated receptor gamma (PPAR-γ) in an age-dependent manner. In addition, administration of a PPAR-γ agonist rosiglitazone restored fat mass and improved metabolic abnormalities in old ANKO mice. In conclusion, these findings highlight the importance of the NAMPT-NAD+-PPAR-γ axis in maintaining functional integrity and quantity of adipose tissue, and whole body metabolic function in female mice during aging.NEW & NOTEWORTHY Defective NAD+ metabolism is associated with aging and age-associated metabolic diseases. In the present study, we provided in-depth metabolic assessments in female mice with adipocyte-specific inactivation of a key NAD+ biosynthetic enzyme NAMPT and revealed an unexpected role of adipose tissue NAMPT-NAD+-PPAR-γ axis in maintaining functional integrity and quantity of adipose tissue and whole body metabolic health during the aging process.

Combining hemodialysis with peritoneal dialysis improves cognitive function: a three-case report.

Chronic kidney disease (CKD) is associated with multiple complications, with recent scholarly attention underscoring cognitive impairment as a salient manifestation. Considering societal aging, preserving cognitive function has emerged as an urgent medical concern. Prolonged dialysis, encompassing hemodialysis (HD) and peritoneal dialysis (PD), has been associated with a decline in cognitive function. Here, we present the cases of three patients undergoing PD who exhibited a noticeable improvement in cognitive function upon the initiation of HD. One patient had exhibited mild cognitive decline, whereas the remaining two presented more severe impairment. Apart from a mild tendency for fluid retention, none of the three patients exhibited abnormalities in physical or imaging examinations. Evaluation using the Japanese version of the Montreal Cognitive Assessment (MoCA-J) yielded decreased scores across multiple domains, notably in executive and attention functions. However, after HD initiation, all patients demonstrated a marked enhancement in multiple MoCA-J parameters, accompanied by a significant improvement in subjective symptoms. Moreover, improvements in anemia and hypoalbuminemia were observed in all three patients, whereas consistent trends in other parameters were absent. These clinical observations suggest that the integration of HD into the therapeutic regimen of patients undergoing PD may enhance cognitive function, highlighting the contributory roles of hemoglobin and albumin in CKD-associated cognitive impairment.

Renal sinus fat is associated with intrarenal hemodynamic abnormalities independent of visceral fat in patients with chronic kidney disease.

OBJECTIVE: Obesity is a risk factor of chronic kidney disease (CKD), contributing to the rising incidence of cardiometabolic diseases. Renal sinus fat (RSF) is an ectopic fat depot located at the renal cavity that could impair renal function and hemodynamic through compression of renal structures. The major purpose of this study was to explore the relationship between RSF accumulation and renal dysfunction in CKD patients. METHODS: We evaluated the associations between computed tomography measured RSF volume and key clinical and histologic parameters involved in renal function and hemodynamics in 132 well-characterized CKD patients who underwent renal biopsy (median age: 62 years; 63.6% men). RESULTS: RSF volume normalized by renal volume (RSF%) positively correlated with obesity-related traits such body mass index and visceral fat volume (VFV) (all P < 0.001) whereas it negatively correlated with estimated glomerular filtration rate (eGFR) (ρ = -0.42, P < 0.001) and 24-h urinary creatinine clearance (CCr) (ρ = -0.34, P < 0.001). Notably, we found robust positive correlations between RSF% and renal resistive index (RRI) measured by the Doppler ultrasound (ρ = 0.40, P < 0.001), and the histological severity of global glomerular sclerosis (ρ = 0.48, P < 0.001) and interstitial fibrosis and tubular atrophy (IFTA) (ρ = 0.35, P < 0.001). In the multivariate linear regression models, after accounting for potential confounders including VFV, RSF% remained significantly associated with CCr (ß = -0.26, P < 0.001), RRI (ß = 0.17, P = 0.022), global glomerular sclerosis (ß = 0.21, P = 0.002), and IFTA (ß = 0.17, P = 0.012). CONCLUSION: RSF accumulation is associated with renal dysfunction and hemodynamic abnormalities independent of visceral adiposity. Our results suggest that RSF may have a potential unique role in the pathogenesis of CKD.

Podocyte Ercc1 is indispensable for glomerular integrity.

As life expectancy continues to increase, age-related kidney diseases are becoming more prevalent. Chronic kidney disease (CKD) is not only a consequence of aging but also a potential accelerator of aging process. Here we report the pivotal role of podocyte ERCC1, a DNA repair factor, in maintaining glomerular integrity and a potential effect on multiple organs. Podocyte-specific ERCC1-knockout mice developed severe proteinuria, glomerulosclerosis, and renal failure, accompanied by a significant increase in glomerular DNA single-strand breaks (SSBs) and double-strand breaks (DSBs). ERCC1 gene transfer experiment in the knockout mice attenuated proteinuria and glomerulosclerosis with reduced DNA damage. Notably, CD44+CD8+ memory T cells, indicative of T-cell senescence, were already elevated in the peripheral blood of knockout mice at 10 weeks old. Additionally, levels of senescence-associated secretory phenotype (SASP) factors were significantly increased in both the circulation and multiple organs of the knockout mice. In older mice and human patients, we observed an accumulation of DSBs and an even greater buildup of SSBs in glomeruli, despite no significant reduction in ERCC1 expression with age in mice. Collectively, our findings highlight the crucial role of ERCC1 in repairing podocyte DNA damage, with potential implications for inflammation in various organs.

Hemodialysis treatment of vancomycin-induced drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome in a patient undergoing peritoneal dialysis.

Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as drug-induced hypersensitivity syndrome (DIHS), is a severe drug-induced hypersensitivity reaction with 10% mortality. To date, there is insufficient evidence regarding the association between DRESS/DIHS and serum levels of vancomycin (VCM). Here, we report the case of a 46-year-old woman undergoing peritoneal dialysis who developed VCM-induced DRESS/DIHS. She was hospitalized for peritonitis with abdominal pain and treated with VCM. On day 10 of hospitalization, her abdominal symptoms improved; however, fever, skin rash, lymphadenopathy, eosinophilia, atypical lymphocytes, and liver and renal dysfunction developed. Based on the clinical course and laboratory findings, we diagnosed the patient with DRESS/DIHS due to VCM. Since her serum VCM concentration was high at 39.8 µg/mL, hemodialysis (HD) was performed to remove VCM, which caused her symptoms to improve. However, serum levels of VCM rebounded and the same symptoms recurred. Therefore, we re-performed HD; no further relapse occurred. This clinical course showed that increased serum VCM levels were associated with DRESS/DIHS onset and severity, suggesting that it is a blood level-dependent disease and that removal of VCM by HD is a potential therapeutic option.

Safety and efficacy of long-term nicotinamide mononucleotide supplementation on metabolism, sleep, and nicotinamide adenine dinucleotide biosynthesis in healthy, middle-aged Japanese men.

Obesity and aging are major risk factors for several life-threatening diseases. Accumulating evidence from both rodents and humans suggests that the levels of nicotinamide adenine dinucleotide (NAD+), a regulator of many biological processes, declines in multiple organs and tissues with aging and obesity. Administration of an NAD+ intermediate, nicotinamide mononucleotide (NMN), replenishes intracellular NAD+ levels and mitigates aging- and obesity-associated derangements in animal models. In this human clinical study, we aimed to investigate the safety and effects of 8-week oral administration of NMN on biochemical, metabolic, ophthalmologic, and sleep quality parameters as well as on chronological alterations in NAD+ content in peripheral tissues. An 8-week, single-center, single-arm, open-label clinical trial was conducted. Eleven healthy, middle-aged Japanese men received two 125-mg NMN capsules once daily before breakfast. The 8-week NMN supplementation regimen was well-tolerated; NAD+ levels in peripheral blood mononuclear cells increased over the course of NMN administration. In participants with insulin oversecretion after oral glucose loading, NMN modestly attenuated postprandial hyperinsulinemia, a risk factor for coronary artery disease (n = 3). In conclusion, NMN overall safely and effectively boosted NAD+ biosynthesis in healthy, middle-aged Japanese men, showing its potential for alleviating postprandial hyperinsulinemia.

Secular trends and age-specific distribution of blood pressure in Japanese adolescents aged 12-18 years in 2000-2019.

Adolescent blood pressure is a predictor of future risk for hypertension and cardiovascular diseases, and therefore its status needs to be accurately determined. However, limited evidence is available regarding the secular trends and distribution of adolescent blood pressure. In the present study, we assessed the secular trends and age-specific distributions of blood pressure in Japanese adolescents aged 12-18 years by using data drawn from 20 years of annual health checkups conducted between 2000 and 2019. Participants underwent health checkups every year for three years at the same school and the data were divided into four 5-year cycles: 2000-2004, 2005-2009, 2010-2014, and 2015-2019. From a total of 124,460 records (33,496 individuals) retrieved, 3000 records (3000 individuals) from each year-cycle were randomly selected to avoid duplicating data from the same individuals. In the study period, in males systolic blood pressure showed a decreasing trend over time, whereas in females diastolic blood pressure showed an increasing trend. Subgroup analyses by school category (junior/senior high school) and by obesity category showed similar blood pressure trends as in the overall analysis. Age-specific blood pressure values in Japanese adolescents increased with age in males but not in females. Thus, different patterns of change in blood pressure values over the past 20 years were observed between males and females. Age-specific blood pressure distributions are also presented. Together, these findings will be useful for understanding blood pressure trends among adolescents.

Association Between Renal Sinus Fat and Cardiometabolic and Renin-Angiotensin System Parameters in Primary Aldosteronism.

Context: Renal sinus fat (RSF) accumulation is associated with cardiometabolic diseases, such as obesity, diabetes, hypertension, and chronic kidney disease. However, clinical implications of RSF in primary aldosteronism (PA) remain unclear. Objective: We aimed to investigate relationships between RSF volume and key cardiometabolic and renin-angiotensin system (RAS) parameters in PA patients and clarify the differences in these relationships between unilateral and bilateral subtypes. Methods: We analyzed data obtained from well-characterized PA patients that involved 45 unilateral (median age: 52 years; 42.2% men) and 92 bilateral patients (51 years; 42.4% men). Results: RSF volume normalized by renal volume (RSF%) was greater in the unilateral group than in the bilateral group (P < .05). RSF% was greater in men than in women (P < .05). RSF% positively correlated with parameters related to cardiometabolic risk, including age, body mass index, visceral fat volume, creatinine, triglycerides/high-density lipoprotein cholesterol ratio, uric acid, fasting glucose, and C-reactive protein regardless of PA subtypes (all P < .05). Intriguingly, RSF% positively correlated with plasma aldosterone concentration (PAC), aldosterone-to-renin ratio, and intact parathyroid hormone (iPTH) (all P < .05) in bilateral patients but did not correlate with RAS parameters and even showed an opposite trend in unilateral patients. In subgroup analyses by sex, these distinctions became more evident in women. After adjustment for potential confounders, RSF% remained positively correlated with PAC and iPTH in bilateral patients. Conclusion: Our results indicate that RSF accumulation is involved in cardiometabolic dysfunction associated with PA. However, there were distinct correlations between RSF volume and RAS parameters according to sex and PA subtypes.

Antineutrophil cytoplasmic antibody-associated vasculitis predominantly manifesting tubulointerstitial nephritis: A case report.

The common histopathology of antineutrophil cytoplasmic antibody-associated vasculitis comprises pauci-immune crescentic glomerulonephritis with concomitant tubulointerstitial nephritis. Tubulointerstitial nephritis in the absence of glomerular involvement in patients with antineutrophil cytoplasmic antibody-associated vasculitis is uncommon. We report a case of antineutrophil cytoplasmic antibody-associated vasculitis-associated acute kidney injury manifesting as tubulointerstitial nephritis without glomerulonephritis. A 75-year-old woman with fever, cough, and myalgia developed kidney dysfunction with inflammatory reactions and tubular-type proteinuria, without glomerular hematuria. A kidney biopsy revealed tubulointerstitial nephritis with arteritis. We ruled out important underlying etiologies of tubulointerstitial nephritis, including infection, drug reactions, and autoimmune diseases. Since chest high-resolution computed tomography demonstrated mild interstitial pneumonia in bilateral lower lung fields, myeloperoxidase antineutrophil cytoplasmic antibody was measured and found to be positive. Therefore, we diagnosed the patient with antineutrophil cytoplasmic antibody-associated vasculitis-associated tubulointerstitial nephritis but not glomerulonephritis, and interstitial pneumonia. The patient's kidney function and symptoms markedly improved with prednisolone treatment. Clinicians should maintain high-level vigilance for antineutrophil cytoplasmic antibody-associated vasculitis as a possible underlying component of tubulointerstitial nephritis, particularly when kidney function deteriorates with tubulointerstitial injuries without glomerular features.