Trends in the incidence of renal replacement therapy by type of primary kidney disease in Japan, 2006-2020

Kidney lesions and risk of cardiovascular events in biopsy-proven diabetic kidney disease with type 2 diabetes

BACKGROUND

This study assessed the association of pathological kidney lesions with cardiovascular events in biopsy-proven diabetic kidney disease (DKD) with type 2 diabetes.

METHODS

This multicenter, retrospective study involved 244 patients with no previous cardiovascular events before biopsy, estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m2 at biopsy (baseline), and ≥ 1 year of observation after biopsy. The outcomes were the first occurrence of cardiovascular events (cardiovascular death, non-fatal myocardial infarction, coronary intervention, or non-fatal stroke), and non-cardiovascular deaths before cardiovascular events were considered competing events. The association between the severity of each pathological lesion and cardiovascular events was investigated.

RESULTS

During follow-up (median: 6.4 years), 43 patients experienced cardiovascular events. The baseline clinical characteristics did not differ according to cardiovascular events. The cumulative incidence of cardiovascular events was higher in patients with mesangiolysis, global glomerulosclerosis ≥ 50%, moderate/severe interstitial inflammation, and moderate/severe arteriolar hyalinosis than in those having less advanced each lesion. Fine-Gray regression models revealed that global glomerulosclerosis ≥ 50% (subdistribution hazard ratio [SHR]: 3.85; 95% confidence interval [95% CI] 1.28-11.52), moderate/severe interstitial inflammation (SHR: 2.49; 95% CI 1.18-5.29), and moderate/severe arteriolar hyalinosis (SHR: 3.51; 95% CI 1.15-10.69) were linked to increased risk of cardiovascular events, after adjusting for clinical variables including RAAS inhibitors use at baseline. Adding the severity of these lesions to clinical variables improved the predictive value for cardiovascular events.

CONCLUSIONS

In DKD with type 2 diabetes, advanced glomerulosclerosis, interstitial inflammation, and arteriolar hyalinosis were associated with cardiovascular events, adding predictive value to clinical features.

An increasing trend of overweight and obesity in the Japanese incident end-stage kidney disease population

AIM

The global prevalence of overweight/obesity has been rising, and this trend is apparent in US and European incident end-stage kidney disease (ESKD) populations. We aimed to examine temporal trends in the prevalence of overweight/obesity and underweight among adult incident ESKD patients in Japan by year of dialysis initiation between 2006 and 2019 in comparison with those observed in the Japanese adult population during the same period.

METHODS

Using data from the Japanese Society of Dialysis Therapy Renal Data Registry and the National Health and Nutrition Survey, the sex-specific prevalence of overweight/obesity and that of underweight (BMI ≥ 25 kg/m2 and <18.5 kg/m2, respectively) were calculated, adjusted for age according to the 2019 Population Census via the direct method. Average annual percentage changes (AAPCs) and corresponding 95% confidence intervals (CIs) were calculated to examine trends.

RESULTS

From 2006 to 2019, the age-adjusted prevalence of overweight/obesity in the incident ESKD population increased for males (AAPC 3.36 [95% CI, 2.70 to 4.09]) and females (AAPC 2.86 [95% CI, 1.65 to 4.19]). The age-adjusted prevalence of overweight/obesity in the general population increased for males (AAPC 0.87 [95% CI, 0.26 to 1.42]) but not for females (AAPC 0.01 [95% CI, -0.55 to 0.57]). The age-adjusted prevalence of underweight in the incident ESKD population significantly decreased but was higher than that in the general population for both sexes.

CONCLUSION

An increasing trend of overweight/obesity was observed in the incident ESKD population in Japan. There is a pressing need to address both underweight and overweight/obesity in the incident ESKD population.

Trends in the Incidence of Renal Replacement Therapy Due to Rapidly Progressive Glomerulonephritis in Japan, 2006-2021

Objective Patients with rapidly progressive glomerulonephritis (RPGN) are at a high risk of progression to end-stage kidney disease (ESKD), requiring renal replacement therapy (RRT). The present study examined recent trends in the incidence of RRT due to RPGN in Japan. Methods The number of patients with incident RRT due to RPGN by sex from 2006 to 2021 was extracted from the Japanese Society of Dialysis Therapy Registry. The incidence rates of RRT were calculated for four-year periods with the census population as the denominator. Standardized incidence ratios (SIRs) and age-specific incidence rates were also calculated. Results From 2006 to 2021, the crude number of patients with incident RRT due to RPGN increased by 34% and 58% in men and women, respectively. The SIRs decreased significantly in 2010-2013 relative to the first period (2006-2009) for both men [0.90 (95% confidence interval (CI) 0.85-0.96)] and women [0.92 (0.86-0.99)] but then increased to 1.01 (0.96-1.07) for men and 1.20 (1.13-1.27) for women in 2018-2021. In the older age groups (≥70 years old), age-specific incidence rates initially decreased in 2010-2013 but increased thereafter, peaking in 2018-2021. Conclusion From 2006 to 2021, the number of patients with incident RRT due to RPGN increased, with an increase in the age-specific incidence of RRT due to RPGN in the older age groups (≥70 years old), suggesting that the number of patients with incident RRT due to RPGN will continue to increase as the population ages in Japan.

Heterogeneous afferent arteriolopathy: a key concept for understanding blood pressure-dependent renal damage

Hypertension, aging, and other factors are associated with arteriosclerosis and arteriolosclerosis, primary morphological features of nephrosclerosis. Although such pathological changes are not invariably linked with renal decline but are prevalent across chronic kidney disease (CKD), understanding kidney damage progression is more pragmatic than precisely diagnosing nephrosclerosis itself. Hyalinosis and medial thickening of the afferent arteriole, along with intimal thickening of small arteries, can disrupt the autoregulatory system, jeopardizing glomerular perfusion pressure given systemic blood pressure (BP) fluctuations. Consequently, such vascular lesions cause glomerular damage by inducing glomerular hypertension and ischemia at the single nephron level. Thus, the interaction between systemic BP and afferent arteriolopathy markedly influences BP-dependent renal damage progression in nephrosclerosis. Both dilated and narrowed types of afferent arteriolopathy coexist throughout the kidney, with varying proportions among patients. Therefore, optimizing antihypertensive therapy to target either glomerular hypertension or ischemia is imperative. In recent years, clinical trials have indicated that combining renin-angiotensin system inhibitors (RASis) and sodium-glucose transporter 2 inhibitors (SGLT2is) is superior to using RASis alone in slowing renal function decline, despite comparable reductions in albuminuria. The superior efficacy of SGLT2is may arise from their beneficial effects on both glomerular hypertension and renal ischemia. A comprehensive understanding of the interaction between systemic BP and heterogeneous afferent arteriolopathy is pivotal for optimizing therapy and mitigating renal decline in patients with CKD of any etiology. Therefore, in this comprehensive review, we explore the role of afferent arteriolopathy in BP-dependent renal damage.

Incidence and outcomes of kidney replacement therapy for end-stage kidney disease due to primary glomerular disease in Europe: findings from the ERA Registry

BACKGROUND

Primary glomerular disease (PGD) is a major cause of end-stage kidney disease (ESKD) leading to kidney replacement therapy (KRT). We aimed to describe incidence (trends) in individuals starting KRT for ESKD due to PGD and to examine their survival and causes of death.

METHODS

We used data from the European Renal Association (ERA) Registry on 69 854 patients who started KRT for ESKD due to PGD between 2000 and 2019. ERA primary renal disease codes were used to define six PGD subgroups. We examined age and sex standardized incidence, trend of the incidence and survival.

RESULTS

The standardized incidence of KRT for ESKD due to PGD was 16.6 per million population (pmp), ranging from 8.6 pmp in Serbia to 20.0 pmp in France. Immunoglobulin A nephropathy (IgAN) and focal segmental glomerulosclerosis (FSGS) had the highest incidences, of 4.6 pmp and 2.6 pmp, respectively. Histologically non-examined PGDs represented over 50% of cases in Serbia, Bosnia and Herzegovina, and Romania and were also common in Greece, Estonia, Belgium and Sweden. The incidence declined from 18.6 pmp in 2000 to 14.5 pmp in 2013, after which it stabilized. All PGD subgroups had 5-year survival probabilities above 50%, with crescentic glomerulonephritis having the highest risk of death [adjusted hazard ratio 1.8 (95% confidence interval 1.6-1.9)] compared with IgAN. Cardiovascular disease was the most common cause of death (33.9%).

CONCLUSION

The incidence of KRT for ESKD due to PGD showed large differences between countries and was highest and increasing for IgAN and FSGS. Lack of kidney biopsy facilities in some countries may have affected accurate assignment of the cause of ESKD. The recognition of the incidence and outcomes of KRT among different PGD subgroups may contribute to a more individualized patient care approach.

Effect of proteinuria on the rapid kidney function decline in chronic kidney disease depends on the underlying disease: A post hoc analysis of the BRIGHTEN study

AIMS

It is unclear whether the effect of proteinuria on rapid kidney function decline is equivalent among diabetic kidney disease (DKD), non-DKD with diabetes (NDKD+DM), and nephrosclerosis without diabetes (NS-DM), particularly in advanced chronic kidney disease patients.

METHODS

In total, 1038 chronic kidney disease patients who participated in the BRIGHTEN study were included in the present study. A linear mixed effect model was applied to estimate the annual estimated glomerular filtration rate decline in each disease group.

RESULTS

The prevalence of rapid decliners (rapid kidney function decline, defined as an eGFR loss of > 5 mL/min/1.73 m2/year) in the DKD group (44.6 %) was significantly higher compared with the NDKD+DM (27.9 %) and NS-DM (27.0 %) groups. By contrast, the prevalence of rapid decliners in different urine total protein to creatinine ratio (UPCR) categories (<0.5, 0.5 to < 1.0, 1.0 to < 3.5, and ≥ 3.5 g/g) were equivalent between the DKD and NS-DM groups. Moreover, the prevalence of a UPCR < 1.0 g/g in rapid decliners of the NS-DM group was more than double than in those of the DKD and NDKD+DM groups.

CONCLUSIONS

The risk of rapid kidney function decline in NS-DM patients with low levels of proteinuria may be greater than initially predicted.

Integrating Community Care for the Prevention and Treatment of Diabetes

Introduction

This paper describes 'Project 8', a campaign that aims to reduce glycated haemoglobin (HbA1c) to 8% or more among patients with diabetes mellitus, utilising healthcare professionals and local community residents and focusing on education and support. The study is based in Uonuma-a small rural city in Japan with a declining population and an increased number of older people.

Description

'Project 8' began in Uonuma's Koide Hospital in 2008. The Uonuma School for Community Health and Social Care was established in 2011 with the cooperation of a clinic's general practitioner. Medical students, trainees, doctors, and health care professionals have been holding 'open schools' (daytime lectures) and 'night schools' (evening lectures) to educate the community residents about various health issues. Through repeated lectures, the residents have been made aware of lifestyle-related diseases, including diabetes, and the meaning of 'Project 8'.

Discussion

Over the last decade, the hospital's campaign has expanded within the community, showing a statistically significant reduction of diabetic patients with HbA1c ≥ 8%, which successfully deferred the start of dialysis for many of them.

Conclusion

Well-integrated community care requires interprofessional education, collaborative practice, and the participation of community residents in health education.

Establishment of a novel mouse model of renal artery coiling-based chronic hypoperfusion-related kidney injury

Renal artery stenosis-induced chronic renal ischemia is an important cause of renal dysfunction, especially in older adults, and its incidence is currently increasing. To elucidate the mechanisms underlying chronic renal hypoperfusion-induced kidney damage, we developed a novel mouse model of renal artery coiling-based chronic hypoperfusion-related kidney injury. This model exhibits decreased renal blood flow and function, atrophy, and parenchymal injury in the coiled kidney, along with compensatory hypertrophy in the non-coiled kidney, without chronic hypertension. The availability of this mouse model, which can develop renal ischemia without genetic modification, will enhance kidney disease research by serving as a new tool to investigate the effects of acquired factors (e.g., obesity and aging) and genetic factors on renal artery stenosis-related renal parenchymal damage.

Regional variation in pre-dialysis blood pressure and its association with cardiovascular mortality rates in Japanese patients undergoing dialysis

Adequate blood pressure (BP) management poses a significant challenge in improving the prognosis of patients undergoing dialysis. We aimed to investigate the relationship between pre-dialysis systolic blood pressure (SBP) and underlying disease in Japanese patients undergoing dialysis, based on prefectural location, and assess the association between pre-dialysis SBP and cardiovascular disease (CVD) mortality rate. We extracted the basic information of 336,182 patients who were undergoing dialysis in 2021 from the Web-based Analysis of Dialysis Data Archives database. Data on average pre-dialysis SBP were analyzed according to sex, prefectural location, and diabetic status, and the CVD mortality rate for each prefecture was calculated. The mean pre-dialysis SBP of the patients (males, 66.3%; mean age, 69.7 ± 12.5 years) was 151.9 ± 24.7 mmHg. Overall, 133,037 patients had underlying diabetic kidney disease (DKD). The patients with DKD were younger, had a shorter dialysis duration, and a higher pre-dialysis SBP than those with non-DKD comorbidities. The prefecture-based mean pre-dialysis SBP values were all higher than 140 mmHg. At the prefectural level, CVD mortality rate was positively correlated with pre-dialysis SBP (r = 0.3127, p = 0.0324) and diastolic blood pressure (r = 0.3378, p = 0.0202) among female patients. At the prefectural level, pre-dialysis SBP is >140 mmHg in Japanese patients undergoing dialysis, especially in those with DKD. The positive association between pre-dialysis SBP and CVD mortality rate suggests that optimal BP management at the prefectural level may reduce CVD mortality rates. At the prefectural level, pre-dialysis SBP is higher than 140 mmHg in Japanese patients undergoing dialysis, especially higher in those with DKD.

Real-world trends in pre-dialysis blood pressure levels of patients undergoing dialysis in Japan using a web-based national database

The prevalence of hypertension is high among patients undergoing dialysis. We extracted data of patients undergoing dialysis between 2012 and 2020 with recorded pre-dialysis systolic blood pressure (SBP) using a web-based national database in Japan. Following the 2019 Japanese Society of Hypertension guidelines, we classified SBP and assessed its trends over time based on sex, age, diabetes status, and the anti-hypertensive medication use. Using the 2020 database, we examined 336,759 Japanese patients undergoing dialysis (114,249 female; 222,510 male). The mean age was 69.4 ± 12.5 years, and the mean SBP was 152.3 ± 24.7 mm Hg. The prevalence rate of pre-dialysis hypertension was 70.2%, with 32.5%, 24.5%, and 13.2% of patients having grade I, grade II, and grade III hypertension, respectively. From 2014 to 2020, prevalence rate of pre-dialysis hypertension and absolute values of pre-dialysis SBP were higher in dialysis patients with diabetes than in those without diabetes across all age groups and sexes. Younger patients with diabetes or those on anti-hypertensive medication exhibited an SBP of approximately 160 mm Hg. Cerebrovascular death in patients with diabetes was associated with a higher rate of pre-dialysis hypertension than that in those without diabetes, and there was a significant difference in the prevalence of grade III hypertension between the two groups. In conclusion, the mean pre-dialysis SBP among patients undergoing dialysis remained high, and younger patients with diabetes or those receiving anti-hypertensive medications had poor blood pressure control. Optimal blood pressure management may be necessary to reduce the risk of cardiovascular mortality.

Birth cohort effects in incident renal replacement therapy in Japan, 1982-2021

BACKGROUND

This study aimed to investigate the long-term trends of incident end-stage kidney disease (ESKD) requiring renal replacement therapy (RRT) in Japan using age-period-cohort analysis and evaluated birth cohort effects for incident ESKD requiring RRT.

METHODS

The number of incident RRT patients aged between 20 and 84 years by sex from 1982 to 2021 was extracted from the Japanese Society of Dialysis Therapy registry data. Annual incidence rates of RRT were calculated using census population as denominators, and changes in the incidence rates were evaluated using an age-period-cohort model. The age and survey year period categories generated 20 birth cohorts with 5-year intervals (from 1902-1907 to 1997-2001).

RESULTS

The incidence rates of RRT in both sexes initially rose in the birth cohorts born in the early 1900s, and then decelerated and peaked during 1940-1960s in men and 1930-1940s in women, following a steady decline in both sexes. Compared with the reference 1947-1951 birth cohort, the highest cohort rate ratio was 1.14 (95% CI, 1.04-1.25) in the 1967-1971 birth cohort in men and 1.04 (95% CI, 0.98-1.10) in the 1937-1941 birth cohort in women.

CONCLUSIONS

Significant cohort effects were identified in both sexes, but the peak of RRT was different for each sex. Our findings suggest that men born between 1940 and 1960s and women born between 1930 and 40 s may be important target populations to consider when decreasing incidence rates of RRT among the general Japanese population.

Mechanism and treatment for chronic antibody-mediated rejection in kidney transplant recipients

Chronic antibody-mediated rejection of kidney transplantation is a major cause of late-stage graft loss. Donor-specific antibodies are the main cause of antibody-mediated rejection; in particular, de novo donor-specific antibodies are a risk factor for chronic active antibody-mediated rejection. The level of de novo donor-specific antibodies tends to increase with time throughout long-term graft survival. Donor-specific antibodies induce humoral rejection through complement activation, which results in tissue injury and coagulation. Additionally, complement activation promotes the migration of inflammatory cells through the innate immune response, causing endothelial injury. This inflammatory response may cause persistent glomerulitis and peritubular capillaritis, leading to fixed pathological lesions that impair graft function. No treatment has been established for chronic antibody-mediated rejection, a condition in which antibody-mediated rejection becomes irreversible. Thus, antibody-mediated rejection must be detected and treated while it is still reversible. In this review, we discuss the development of de novo donor-specific antibodies and the mechanisms leading to chronic antibody-mediated rejection and summarize the current treatment options and the latest biomarkers for detecting chronic antibody-mediated rejection at an earlier stage.

Sex differences in risk factors for end-stage kidney disease and death in type 2 diabetes: A retrospective cohort study

BACKGROUND

This study investigated the sex differences in the risk of end-stage kidney disease (ESKD) and mortality, as well as the effect modification of sex on associated factors in patients with type 2 diabetes.

METHODS

This multicenter observational cohort study included 4328 patients with type 2 diabetes. Hazard ratios (HRs) with 95% confidence intervals (CIs) of sex for ESKD and death were estimated using Cox proportional regression with adjustment for baseline covariates. For assessing risk modification, HRs and incidence rates for ESKD and death were compared between sexes across patient characteristics using Cox proportional and Poisson regression models.

RESULTS

During a median follow-up of 7 years, 276 patients (70% men) developed ESKD, and 241 patients (68% men) died. Men had higher risks of ESKD (HR 1.34; 95% CI 1.02-1.75; p = .034) and death (HR 1.64; 95% CI 1.24-2.16; p = .001) versus women after adjusting for multiple covariates. Among patients with microalbuminuria, men had a substantially higher risk of ESKD versus women, compared to those with normo- and macroalbuminuria (p for interaction .04). Incidence rates were also increased in men versus women with albuminuria of around 300 mg/g. No differences were detected in the association of sex and death across baseline patient subgroups.

CONCLUSIONS

In type 2 diabetes, men had an increased risk of ESKD and death versus women. Moderately increased albuminuria was strongly associated with sex difference in developing ESKD.