Secular trends in end‐stage kidney disease requiring renal replacement therapy in Japan: Japanese Society of Dialysis Therapy Registry data from 1983 to 2016

Impact of dialysis on intravesical recurrence and survival outcomes in upper tract urothelial cancer patients undergoing radical nephroureterectomy

BACKGROUND

Upper tract urothelial carcinoma (UTUC) presents a significant recurrence risk following radical nephroureterectomy (RNU). Patients on dialysis may experience unique clinical trajectories due to uremic states and altered immune responses.

OBJECTIVE

To evaluate the impact of dialysis on intravesical recurrence and survival outcomes in patients with UTUC undergoing RNU, and to identify predictive factors influencing prognosis.

METHODS

A retrospective cohort study analyzed 402 patients with non-metastatic UTUC treated with RNU between 2001 and 2014. Patients were stratified into dialysis (n = 66) and non-dialysis (n = 336) groups. Survival and recurrence outcomes were assessed using Kaplan-Meier and Cox regression analyses.

RESULTS

Dialysis patients were predominantly female, younger, and exhibited less advanced pathological tumor stages. Dialysis was associated with higher intravesical recurrence rates (p = 0.009), which were largely attributable to a history of bladder cancer (42.4% vs. 26.5%; p = 0.009). After adjustment for bladder cancer history, dialysis was not an independent predictor of bladder recurrence-free survival (BRFS). Advanced pT stages (HR: 3.9, p = 0.012) and prior bladder cancer were the primary factors influencing BRFS.

CONCLUSIONS

Dialysis does not independently worsen surgical outcomes or BRFS in UTUC patients post-RNU when accounting for prior bladder cancer. Prognostic models should integrate these findings to enhance individualized surveillance and treatment strategies.

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.

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.

Ketone Body Metabolism in Diabetic Kidney Disease

Ketone bodies have a negative image because of ketoacidosis, one of the acute and serious complications in diabetes. The negative image persists despite the fact that ketone bodies are physiologically produced in the liver and serve as an indispensable energy source in extrahepatic organs, particularly during long-term fasting. However, accumulating experimental evidence suggests that ketone bodies exert various health benefits. Particularly in the field of aging research, there is growing interest in the potential organoprotective effects of ketone bodies. In addition, ketone bodies have a potential role in preventing kidney diseases, including diabetic kidney disease (DKD), a diabetic complication caused by prolonged hyperglycemia that leads to a decline in kidney function. Ketone bodies may help alleviate the renal burden from hyperglycemia by being used as an alternative energy source in patients with diabetes. Furthermore, ketone body production may reduce inflammation and delay the progression of several kidney diseases in addition to DKD. Although there is still insufficient research on the use of ketone bodies as a treatment and their effects, their renoprotective effects are being gradually proven. This review outlines the ketone body-mediated renoprotective effects in DKD and other kidney diseases.

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.

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

AIM

Age-standardized incidence of end stage kidney disease requiring renal replacement therapy (RRT) has stabilized in men and declined in women in Japan since 1996. However, recent trends by primary kidney disease are unknown. The present study aimed to examine recent trends in incidence rates of RRT by primary kidney disease in Japan.

METHODS

Numbers of incident RRT patients aged ≥20 years by sex and primary kidney disease from 2006 to 2020 were extracted from the Japanese Society of Dialysis Therapy registry. Using the census population as the denominator, annual incidence rates of RRT were calculated and standardized to the WHO World Standard Population (2000-2025). Average annual percentage change (AAPC) and corresponding 95% confidence intervals (CIs) were calculated for trends using Joinpoint regression analysis.

RESULTS

From 2006 to 2020, the crude number of incident RRT patients due to nephrosclerosis increased by 132% for men and 62% for women. Age-standardized incidence rates of RRT due to nephrosclerosis increased significantly, by 3.3% (95% CI: 2.9-3.7) and 1.4% (95% CI: 0.8-1.9) per year for men and women, respectively. The AAPC of chronic glomerulonephritis (-4.4% [95% CI: -5.3 to -3.8] for men and -5.1% [95% CI: -5.5 to -4.6] for women) and diabetic nephropathy (-0.6% [95% CI: -0.9 to -0.3] for men and -2.8% [95% CI: -3.1 to -2.6] for women) significantly decreased from 2006 to 2020.

CONCLUSION

Incident RRT due to chronic glomerulonephritis and diabetic nephropathy decreased, while the number and incident rates of RRT due to nephrosclerosis increased, from 2006 to 2020 in Japan.

Prefecture-specific prevalence of overweight/obesity is associated with regional variation in the incidence of treated ESKD in Japan

BACKGROUND

Overweight/obesity is a significant risk factor for chronic kidney disease and end-stage kidney disease (ESKD) in the general population. This study evaluated the impact of sex- and prefecture-specific prevalence of overweight/obesity on standardized incidence rates (SIRs) of treated ESKD in Japan.

METHODS

We conducted an ecological study of all prefectures in Japan (n = 47) using data from the Japanese Society of Dialysis Therapy, national census, the NDB Open Data, and the Statistics of Physicians, Dentists and Pharmacists. We calculated the prevalence of overweight/obesity and proteinuria, standardized mortality ratio, and ratio of nephrology specialists for each prefecture, and explored associations of these variables with sex- and prefecture-specific SIRs of treated ESKD using bivariate association analysis, multiple regression analysis, and structural equation modeling (SEM).

RESULTS

Prefecture-specific SIRs ranged from 0.72 to 1.24 for men and 0.69-1.41 for women. Prefecture-specific SIRs were significantly correlated with both the prevalence of overweight/obesity and prevalence of proteinuria. The prevalence of overweight/obesity showed direct, positive, and significant associations with prefecture-specific SIRs in men (standardized estimate (β) = 0.43, p < 0.001) and women (β = 0.40, p < 0.001). The prevalence of proteinuria showed a significant association with prefecture-specific SIRs only in women (β = 0.33, p = 0.01). The SEM models explained 26% of the variance in SIR for men and 28% for women.

CONCLUSIONS

Our findings provide evidence that the prefecture-specific prevalence of overweight/obesity in Japan can explain regional variation in prefecture-specific SIRs of treated ESKD in both sexes.

Nephron overload as a therapeutic target to maximize kidney lifespan

Kidney lifespan is a patient-oriented outcome that provides much needed context for understanding chronic kidney disease (CKD). Nephron endowment, age-associated decline in nephron number, kidney injury history and the intrinsic capacity of nephrons to adapt to haemodynamic and metabolic overload vary widely within the population. Defining percentiles of kidney function might therefore help to predict individual kidney lifespan and distinguish healthy ageing from progressive forms of CKD. In response to nephron loss, the remaining nephrons undergo functional and structural adaptations to meet the ongoing haemodynamic and metabolic demands of the organism. When these changes are no longer sufficient to maintain kidney cell homeostasis, remnant nephron demise occurs and CKD progression ensues. An individual's trajectory of glomerular filtration rate and albuminuria reflects the extent of nephron loss and adaptation of the remaining nephrons. Nephron overload represents the final common pathway of CKD progression and is largely independent of upstream disease mechanisms. Thus, interventions that efficiently attenuate nephron overload in early disease stages can protect remnant kidney cells and nephrons, and delay CKD progression. This Review provides a conceptual framework for individualized diagnosis, monitoring and treatment of CKD with the goal of maximizing kidney lifespan.

Nonsteroidal anti-inflammatory drugs use in patients with chronic kidney disease are often prescribed from different clinicians than those who diagnosed them

PURPOSE

When prescribing nonsteroidal anti-inflammatory drugs (NSAIDs) for chronic kidney disease (CKD), patients' pathology and concomitant medications should be considered. In our pharmaceutical experience, NSAIDs are often prescribed by departments that are different from those that diagnosed CKD. That is, NSAIDs may be prescribed for patients without the advice of the clinicians who diagnosed them. In this study, we aimed to elucidate how frequently such cases occur.

METHODS

We used the large health insurance claims database constructed by JMDC Inc., Tokyo. We evaluated the proportions of CKD diagnosis and NSAID prescription by different clinical departments and institutions.

RESULTS

A total of 224 014 out-patients were included in the analysis; they were divided into CKD (n = 1501) and non-CKD groups (n = 222 513). The internal medicine departments diagnosed CKD most frequently (74.8% of the patients) and surgical departments rarely diagnosed CKD. However, the proportion of prescribed NSAIDs was high in other departments, especially surgical departments. In the CKD group, 50.4% of the patients received CKD diagnosis and NSAID prescription from different clinical departments; 72.8% of the patients received a diagnosis and prescription from different medical institutions.

CONCLUSION

Our study revealed that NSAIDs are often prescribed to patients with CKD from different clinicians than those who diagnosed them.