Higher participation rates for specific health checkups are associated with a lower incidence of treated ESKD in Japan.

BACKGROUND: A Japanese cohort study previously reported that not attending health checkups was associated with an increased risk of treated end-stage kidney disease (ESKD). The present study aimed to examine this association at the prefecture level. METHODS: We conducted an ecological study of all prefectures in Japan (n = 47) using five sources of nationwide open data. We explored associations of participation rates for Specific Health Checkups (SHC participation rates), the estimated prevalence of chronic kidney disease (CKD), and the ratio of nephrology specialists for each prefecture with prefecture-specific standardized incidence rates (SIRs) of treated ESKD using structural equation modeling. RESULTS: Prefecture-specific SHC participation rates ranged from 44.2% to 65.9%, and were negatively correlated with prefecture-specific SIRs and prevalence of CKD, and positively correlated with the ratio of nephrology specialists. SHC participation rates had significant negative effects on prefecture-specific SIRs (standardized estimate (ß) = - 0.38, p = 0.01) and prefecture-specific prevalence of CKD (ß = - 0.32, p = 0.02). Through SHC participation rates, the ratio of nephrology specialists had a significant indirect negative effect on prefecture-specific SIRs (ß= - 0.14, p = 0.02). The model fitted the data well and explained 14% of the variance in SIRs. CONCLUSIONS: Our findings support the importance of increasing SHC participation rates at the population level and may encourage people to undergo health checkups.

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 (ß) = 0.43, p < 0.001) and women (ß = 0.40, p < 0.001). The prevalence of proteinuria showed a significant association with prefecture-specific SIRs only in women (ß = 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.

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.

Vegetable and Fruit Intake Frequency and Mortality in Patients With and Without Chronic Kidney Disease: A Hospital-Based Cohort Study.

OBJECTIVE: Patients with advanced chronic kidney disease (CKD) are generally discouraged from consuming high amounts of vegetables and fruits given the potential risk of hyperkalemia. In the general population, however, lower vegetable and fruit intake is associated with higher mortality. This Japanese hospital-based prospective cohort study including non-CKD and CKD participants examined whether the frequency of vegetable and fruit intake is associated with mortality, and whether the presence of CKD modifies this association. METHODS: Participants were 2,006 patients who visited the outpatient department of a general hospital between June 2008 and December 2016 (55% men; mean age, 69 years). Among these participants, 902 (45%) and 131 (7%) were non-dialysis-dependent patients with CKD and hemodialysis patients, respectively. The frequency of vegetable and fruit intake was determined by a self-report questionnaire using an ordinal scale, "never or rarely," "sometimes," and "every day." Multivariable Cox proportional hazards analysis was conducted, adjusting for potential confounders. RESULTS: Vegetable and fruit intake frequency decreased with worsening CKD stage (P for trend < .001). Baseline serum potassium levels stratified by CKD stage were similar across the three vegetable and fruit intake frequency groups. During a median follow-up of 5.7 years, 561 participants died (47.1/1,000 person-years). Adjusted hazard ratios relative to the "every day" group were 1.25 (95% confidence interval, 1.04-1.52) and 1.60 (95% confidence interval, 1.23-2.08) for the "sometimes" and "never or rarely" groups, respectively, after adjusting for demographic factors, comorbidities, and CKD status. When stratified by CKD status, a similar, albeit non-significant, dose-dependent relationship was observed between vegetable and fruit intake frequency and all-cause mortality irrespective of CKD status, with no effect modification by CKD status (Pinteraction = .69). CONCLUSION: A lower frequency of vegetable and fruit intake is significantly associated with a higher risk of death regardless of CKD status.

Smoking and risk of fractures requiring hospitalization in haemodialysis patients: a nationwide cohort study in Japan.

BACKGROUND: Smoking is a well-established lifestyle risk factor for fractures in the general population, but evidence specific to haemodialysis populations is lacking. This nationwide cohort study used data from the Japanese Society for Dialysis Therapy Renal Data Registry to examine the association between smoking status and fractures. METHODS: A total of 154 077 patients (64.2% men; mean age 68 years) aged ≥20 years undergoing maintenance haemodialysis thrice weekly at the end of 2016 were followed for 1 year. Among these, 19 004 (12.3%) patients were current smokers. Standardized incidence rate ratios of hospitalization due to any fracture were calculated and analysed by multivariable logistic regression analysis, controlling for potential confounders. Propensity score (PS) matching and subgroup analyses were also performed as sensitivity analyses. RESULTS: During the 1-year follow-up period, 3337 fractures requiring hospitalization (1201 hip, 479 vertebral and 1657 other fractures) occurred in 3291 patients. The age- and sex-standardized incidence ratio for current smokers was 1.24 (95% confidence interval 1.12-1.39) relative to non-smokers. Standardized incidence ratios were similar after stratification by age group and sex. Multivariable logistic regression analysis revealed a 1.25-fold higher risk of any fracture requiring hospitalization (95% confidence interval 1.10-1.42) in current smokers relative to non-smokers in a fully adjusted model. PS matching showed similar results (odds ratio 1.25; 95% confidence interval 1.05-1.48). Subgroup analyses for baseline covariates revealed no significant interactions. CONCLUSIONS: Smoking is a significant risk factor for any fracture requiring hospitalization in haemodialysis patients.

Impact of adherence to CKD-MBD guidelines on mortality among Japanese dialysis patients: an ecological study.

INTRODUCTION: This study evaluated the association between prefecture-level achievement of chronic kidney disease-mineral and bone disorder (CKD-MBD) parameter targets and mortality in Japanese dialysis patients. MATERIALS AND METHODS: We conducted an ecological study of all prefectures in Japan using data from the Japanese Society of Dialysis Therapy and National Vital Statistics between 2016 and 2017. We calculated adherence rates to recommend target ranges for CKD-MBD parameters, including phosphate, corrected calcium, and parathyroid hormone (PTH), and explored associations of these rates with prefecture-specific standardized mortality rates (SMRs) among the general population and among prevalent dialysis patients using bivariate association analysis and structural equation modeling. RESULTS: Prefecture-level adherence to the target phosphate range was significantly and negatively associated with prefecture-specific SMRs in men (standardized estimate (ß) = - 0.61, p < 0.001) and women (ß = - 0.41, p < 0.001). However, prefecture-level adherence to the target corrected calcium range was significantly and negatively associated with prefecture-specific SMRs only in men (ß = - 0.28, p = 0.01). Meanwhile, prefecture-level adherence to the target PTH range was significantly and positively associated with prefecture-specific SMRs in men (ß = 0.23, p = 0.04). Prefecture-level SMRs of females in the general population had a significant impact on prefecture-level SMRs of female dialysis patients (ß = 0.27, p = 0.03). The models explained 52% of variance in SMR for men and 33% for women. CONCLUSION: A higher prefecture-level achievement rate of the target phosphate range recommended by the Japanese CKD-MBD guidelines was associated with a lower prefecture-specific SMR in the Japanese dialysis population.

Polypharmacy, chronic kidney disease, and incident fragility fracture: a prospective cohort study.

INTRODUCTION: Polypharmacy is associated with an increased risk of fracture in aging populations, but no study has accounted for the impact of kidney function on this association. This study aimed to examine the association between polypharmacy and incident fragility fracture based on chronic kidney disease (CKD) status. MATERIALS AND METHODS: Participants were 2023 patients (55% men; mean age, 69 years) of Sado General Hospital enrolled in the Project in Sado for Total Health (PROST) between June 2008 and December 2016. Among these, 65%, 28%, and 7% had non-CKD, non-dialysis-dependent CKD, and dialysis-dependent CKD, respectively. Multivariable Cox proportional hazards analysis was conducted with adjustments for potential confounders. RESULTS: Prevalences of polypharmacy (≥ 5 medications) and hyperpolypharmacy (≥ 10 medications) among participants were 43% and 9% for non-CKD, 62% and 23% for non-dialysis-dependent CKD, and 85% and 34% for dialysis-dependent CKD, respectively. During a median follow-up of 5.6 years, 256 fractures occurred. More medications were associated with a higher risk of fractures. Specifically, compared to participants without polypharmacy, adjusted hazard ratios were 1.32 (95% CI 0.96-1.79) and 1.99 (1.35-2.92) for those with polypharmacy and hyperpolypharmacy, respectively, after adjusting for osteoporosis risk factors, CKD status, and comorbidities. No effect modification by CKD status was observed (interaction P = 0.51). Population-attributable fractions of hyperpolypharmacy for fracture were 9.9% in the total cohort and 42.1% in dialysis-dependent CKD patients. CONCLUSION: Hyperpolypharmacy is associated with an increased risk of fragility fracture regardless of CKD status, and has a strong impact on incident fragility fractures in dialysis-dependent CKD patients.

Stroke incidence and chronic kidney disease: A hospital-based prospective cohort study.

AIM: This prospective cohort study aimed to (i) examine stroke incidence and stroke subtypes by chronic kidney disease (CKD) stage, (ii) examine whether CKD patients with or without proteinuria have a high risk of stroke independent of traditional cardiovascular risk factors, and (iii) determine precise estimates of stroke risk by CKD stage while accounting for competing mortality risk. METHODS: Participants were 2023 patients enrolled in the Project in Sado for Total Health between June 2008 and December 2016 (55% men; mean age, 69 years), of whom 52% had CKD (stage 1-2, 10%; G3a, 48%; G3b, 17%; G4-5, 11% and G5D, 14%). RESULTS: During a median follow-up of 5.7 years, 157 participants developed stroke and 448 died without developing stroke. Most stroke cases were ischaemic among non-dialysis-dependent CKD participants, but the relative frequency of ischaemic stroke was near that of intracerebral haemorrhage among dialysis-dependent CKD participants. After adjustment, stage 1-2 (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.60-5.51) and stage G3-5 participants with proteinuria (HR, 2.50; 95% CI, 1.56-4.02), but not stage G3-5 participants without proteinuria (HR, 0.64; 95% CI, 0.38-1.08), had a higher stroke risk compared to non-CKD participants. In competing risk analyses, the association was attenuated but remained significant. CONCLUSION: Although the distribution of stroke subtypes differed, CKD participants with proteinuria and those with CKD stage 5D had a 2- and 4-times higher risk of stroke, respectively, than that of non-CKD participants, after accounting for competing mortality risk and traditional risk factors.

Long-term excess mortality after hip fracture in hemodialysis patients: a nationwide cohort study in Japan.

INTRODUCTION: Fracture dialysis patients have a higher risk of 1-year mortality compared with non-fracture dialysis patients. However, it is unclear whether excess mortality persists for more than a year. MATERIALS AND METHODS: We conducted a nationwide cohort study in 162,360 hemodialysis patients in Japan. Study outcomes were 5-year all-cause mortality and cause-specific mortality. Cox proportional hazards regression was used to examine the association between hip fracture and mortality in two cohorts: the full cohort, which included potential confounders as covariates in multivariable-adjusted regression models, and the propensity score-matched cohort. RESULTS: Crude mortality rates for fracture patients were double those of non-fracture patients and persisted during the 5-year period. The association between hip fracture and mortality was significant even after adjusting for premorbid conditions (hazard ratio (HR) 1.22, 95% confidence interval (CI) 1.13-1.32). Similar findings were observed in the propensity score-matched cohort of 2410 patients (HR 1.20, 95% CI 1.05-1.36). While cause-specific mortality rates for all categories, with the exception of sudden deaths, were higher for fracture patients relative to non-fracture patients in the full unmatched cohort, only the mortality rate for heart disease was significantly higher for fracture patients relative to non-fracture patients in the propensity score-matched cohort. CONCLUSION: Excess mortality persisted for many years after hip fracture in hemodialysis patients, and was still present after adjusting for several premorbid conditions and propensity score matching.

Lifetime and age-conditional risk estimates of end-stage kidney disease requiring maintenance dialysis in Japan.

BACKGROUND: Lifetime risk is an epidemiologic measure that expresses the probability of disease in the remaining lifetime for an index age. It is also an easily understandable statistical measure used to communicate the absolute risk of disease to the lay population. The lifetime risk of end-stage kidney disease (ESKD) has never been reported for the Japanese population. Here, we used data from the Japanese Society of Dialysis Therapy (JSDT) to estimate the lifetime risk of ESKD by sex in Japan. METHODS: The lifetime risk of ESKD was estimated using life-table methods. We defined an incident case of ESKD as a patient with loss of kidney function that resulted in maintenance dialysis therapy. The number of incident cases of ESKD and number of ESKD deaths in 2017 were obtained from data published by the JSDT. The population and total number of deaths in Japan for the same year were obtained from National Vital Statistics. By including all-cause mortality, risks were adjusted for competing causes of death. RESULTS: The cumulative incidence of ESKD from birth until age 95 years was 3.14% [95% confidence interval (CI) 3.10-3.18] for men and 1.42% (1.39-1.44) for women. These probabilities illustrate that approximately 1 in 32 men and 1 in 71 women in Japan will develop ESKD that results in maintenance dialysis therapy in their lifetime. CONCLUSIONS: Considerable sex differences were found in the lifetime risk of ESKD in Japan. This easily understandable information could be used to assist in public health education and planning.

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

AIM: We aimed to describe secular trends in the incidence of end-stage kidney disease (ESKD) requiring renal replacement therapy (RRT) in Japan, and to assess the effect of population aging on the incidence of ESKD. METHODS: The national incidence of ESKD requiring RRT was calculated using published data and Japan's population statistics. Age-standardized incidence was calculated by direct standardization using the World Standard Population. The average annual percentage of change (APC) in rates and corresponding 95% confidence interval (CI) were computed for trends by joinpoint regression analysis. To assess the effect of population aging on the incidence of ESKD requiring RRT, we used the method proposed by Bashir and Estève, which splits the crude incidence into three components: population structure, population size, and age-independent risk. RESULTS: Age-standardized incidence trends (1983-1996) increased significantly in both men (APC 6.33, 95% CI: 5.39-7.29) and women (APC 5.25, 95% CI: 4.26-6.24). With a significant inflection point in 1996, the trend was stable for men (APC -0.16, 95% CI: -0.48 to 0.17) but significantly decreased for women (APC -1.98, 95% CI: -2.38 to -1.59) from 1996 to 2016. The main reason for the increase in those with ESKD requiring RRT has changed; before 1996, the change in age-independent risk was the main contributor, but after 1996, the change in age structure with a higher proportion of older individuals was the main contributor. CONCLUSION: The increase in number of ESKD patients requiring RRT dramatically changed in Japan during the 1983 to 2016 period.

Functional impairment attenuates the association between high serum phosphate and mortality in dialysis patients: a nationwide cohort study.

BACKGROUND: Both functional impairment and abnormalities in mineral and bone disorder (MBD) parameters are well-known predictors of mortality in dialysis patients. However, previous studies have not evaluated whether functional impairment modifies the association between MBD parameters and mortality. METHODS: A nationwide prospective cohort study was conducted using data from the Japanese Society for Dialysis Therapy Renal Data Registry collected at the end of 2009 and 2010. The Eastern Cooperative Oncology Group performance status (PS) was used to assess functional status. Cox proportional hazards models were used to assess the associations of baseline functional status, serum phosphate, albumin-corrected calcium and intact parathyroid hormone (PTH) with 1-year all-cause mortality. RESULTS: By 31 December 2010, 18 447 of 220 054 prevalent dialysis patients (8.4%) had died. Mortality significantly increased with worsening PS grade. PS grade modified the association of serum phosphate levels with mortality (Pinteraction = 0.001). Worsening PS grade attenuated the association of hyperphosphatemia (≥7.4 mg/dL) with mortality, and hyperphosphatemia was no longer significant on mortality among patients with the worst PS grade (hazard ratio = 1.1, 95% confidence interval 0.88-1.39), compared with the level between 3.5 and 4.7 mg/dL. In contrast, hypophosphatemia (<3.5 mg/dL) had a greater adjusted risk of mortality irrespective of PS grade. Serum-corrected calcium (Pinteraction = 0.26) and intact PTH (Pinteraction = 0.17) showed consistent associations with mortality irrespective of PS grade. Findings were robust in several sensitivity analyses. CONCLUSIONS: Functional impairment was significantly associated with 1-year mortality and attenuated the effect of hyperphosphatemia on mortality among prevalent dialysis patients.

Hip Fracture Trends in Japanese Dialysis Patients, 2008-2013.

BACKGROUND: Contrary to observations of decreasing rates in Western nations for the past 2 decades, age-adjusted rates of hip fracture in the general population in Japan have continually increased. This study aimed to analyze recent changes in trends of hip fracture incidence among Japanese dialysis patients between 2008 and 2013. STUDY DESIGN, SETTING, & PARTICIPANTS: Using data from the Japanese Society for Dialysis Therapy Renal Data Registry database from 2007 to 2013, we created a point-prevalent study cohort for each study year. Prevalent dialysis cohorts included patients 20 years or older without a history of hip fracture who were receiving maintenance dialysis in Japan on December 31 of each year. FACTORS: Age, sex, and calendar year. OUTCOMES: Hip fracture incidence rates. MEASUREMENTS: Unadjusted hip fracture rates were estimated using number of events per 1,000 patient-years in each year and then standardized for age to the 2013 dialysis population. Average annual percentage of change in rates and corresponding 95% CI were computed for trend by joinpoint regression analysis. RESULTS: During the study period, 6,615 and 4,963 hip fractures were recorded among female and male dialysis patients, respectively. Age-standardized hip fracture rates decreased steadily from 2008 (21.1/1,000 patient-years) to 2013 (17.7/1,000 patient-years) among women, but remained constant from 2008 (8.6/1,000 patient-years) through 2013 (8.2/1,000 patient-years) among men. Decreases in the joinpoint trend for hip fracture were significant among female (-3.6% [95% CI, -6.9 to -0.2] per year), but not among male, dialysis patients (-1.4% [95% CI, -5.7 to 3.0] per year) from 2008 through 2013. LIMITATIONS: Only the first hip fracture event was considered in calculations of fracture rates. CONCLUSIONS: In contrast to the increasing incidence of hip fracture in the general Japanese population, we found that the incidence of hip fracture in Japanese dialysis patients between 2008 and 2013 decreased among women, but did not change in men.

Premature mortality due to nephrotic syndrome and the trend in nephrotic syndrome mortality in Japan, 1995-2014.

BACKGROUND: This study analysed the trend in mortality from nephrotic syndrome in Japan from 1995 to 2013. Moreover, to better understand premature death from nephrotic syndrome, the average years of life lost due to nephrotic syndrome were estimated. METHODS: National death certificate data were evaluated. Age-standardised mortality rates from nephrotic syndrome were calculated by direct standardisation using the World Standard Population. Trends for average annual changes in percentages were determined by joinpoint regression analysis. Average years of life lost were estimated by dividing total years of life lost by the number of deaths from nephrotic syndrome. Years of life lost were estimated by the constant end-point method, with 65 years as the endpoint. Average years of life lost due to malignant neoplasms, the leading cause of death in Japan, were estimated for comparison. RESULTS: There were 9945 deaths (4872 men and 5073 women) during the study period. The numbers of deaths and crude overall mortality rates increased, while age-standardised mortality rates continuously decreased, for both sexes. The annual percentage changes were -1.9% [95% confidence interval (CI), -2.3 to -1.4%] for men and -3.5% (95% CI -4.1 to -2.9%) for women. The average years of life lost due to nephrotic syndrome decreased during the study period, but were greater than for patients who died of malignant neoplasm. CONCLUSIONS: Mortality and premature mortality rates from nephrotic syndrome significantly decreased in Japan between 1995 and 2014. Despite these improvements, nephrotic syndrome patients ≤65 years of age still have a poor prognosis.

[Fragility Fractures in Hemodialysis Patients. Is osteoporosis liaison service applicable for the patients on hemodialysis?]

Intervention of the osteoporosis liaison service for hemodialysis patients is considered essential, because hemodialysis patients are at higher risk of fracture and fall than individuals not undergoing dialysis. It may help to maintain the activity of hemodialysis patients to practice interprofessional collaboration for consistent prevention of primary fracture, thereby supporting discharge planning. We expect to organize a specialized fracture prevention team for dialysis patients to manage their anti-osteoporosis medication and nutritive support, as well as to evaluate their physical statuses and prevent falls.

Mortality trends among Japanese dialysis patients, 1988-2013: a joinpoint regression analysis.

BACKGROUND: Evaluation of mortality trends in dialysis patients is important for improving their prognoses. The present study aimed to examine temporal trends in deaths (all-cause, cardiovascular, noncardiovascular and the five leading causes) among Japanese dialysis patients. METHODS: Mortality data were extracted from the Japanese Society of Dialysis Therapy registry. Age-standardized mortality rates were calculated by direct standardization against the 2013 dialysis population. The average annual percentage of change (APC) and the corresponding 95% confidence interval (CI) were computed for trends using joinpoint regression analysis. RESULTS: A total of 469 324 deaths occurred, of which 25.9% were from cardiac failure, 17.5% from infectious disease, 10.2% from cerebrovascular disorders, 8.6% from malignant tumors and 5.6% from cardiac infarction. The joinpoint trend for all-cause mortality decreased significantly, by -3.7% (95% CI -4.2 to -3.2) per year from 1988 through 2000, then decreased more gradually, by -1.4% (95% CI -1.7 to -1.2) per year during 2000-13. The improved mortality rates were mainly due to decreased deaths from cardiovascular disease, with mortality rates due to noncardiovascular disease outnumbering those of cardiovascular disease in the last decade. Among the top five causes of death, cardiac failure has shown a marked decrease in mortality rate. However, the rates due to infectious disease have remained stable during the study period [APC 0.1 (95% CI -0.2-0.3)]. CONCLUSIONS: Significant progress has been made, particularly with regard to the decrease in age-standardized mortality rates. The risk of cardiovascular death has decreased, while the risk of death from infection has remained unchanged for 25 years.

Association between hypouricemia and reduced kidney function: a cross-sectional population-based study in Japan.

BACKGROUND: Hypouricemia, conventionally defined as a serum uric acid level of ≤2 mg/dl, is considered a biochemical disorder with no clinical significance. However, individuals with renal hypouricemia have a high risk of urolithiasis and exercise-induced acute kidney injury, both of which are risk factors for reduced kidney function. METHODS: To test the hypothesis that individuals with hypouricemia would be at a higher risk of reduced kidney function, we conducted a population-based cross-sectional study using data from the Specific Health Checkups and Guidance System in Japan. Logistic analysis was used to examine the relationship between hypouricemia and reduced kidney function, defined as estimated glomerular filtration rate <60 ml/min/1.73 m(2). RESULTS: Among 90,710 men (mean age, 63.8 years) and 136,935 women (63.7 years), 193 (0.2%) and 540 (0.4%) were identified as having hypouricemia, respectively. The prevalence of hypouricemia decreased with age in women (p for trend <0.001), but not in men (p for trend = 0.24). Hypouricemia was associated with reduced kidney function in men (odds ratio, 1.83; 95% confidence interval, 1.23-2.74), but not in women (0.61; 0.43-0.86), relative to the reference category (i.e., serum uric acid levels of 4.1-5.0 mg/dl) after adjusting for age, drinking, smoking, diabetes, hypertension, hypercholesterolemia, obesity, and history of renal failure. Sensitivity analyses stratified by diabetic status yielded similar results. CONCLUSIONS: This study is the first to provide evidence that hypouricemia is associated with reduced kidney function in men. Further research will be needed to determine the long-term prognosis of individuals with hypouricemia.