Seasonal variation in hemodialysis initiation: A single-center retrospective analysis

Seasonal variations in renal biopsy numbers and primary glomerular disease features based on the Japan renal biopsy registry

We analyzed the seasonal variations in the number of renal biopsies and clinical characteristics of primary glomerular disease in Japan using the Japan Renal Biopsy Registry (J-RBR). We retrospectively collected clinical and pathological data of patients with primary glomerular disease who were registered in the J-RBR between 2007 and 2018. Immunoglobulin A nephropathy (IgAN), minimal change nephrotic syndrome (MCNS), membranous nephropathy (MN), and postinfectious acute glomerulonephritis (PIAGN) constituted the four major glomerular disorders included in this study (total, 13,989; IgAN, 9121; MCNS, 2298; MN, 2447; and PIAGN, 123). The number of patients with IgAN or MCNS was higher during summer. However, no overt seasonal variations were observed in patients with MN or PIAGN. Subgroup analyses suggested that in the patients with IgAN, more renal biopsies of severe cases were performed during winter, probably owing to age and blood pressure. Furthermore, more renal biopsies of severe cases were performed during spring and winter in patients with MCNS even after adjusting for the abovementioned host factors. This study suggests that seasonal factors influence the decision to perform renal biopsy as well as the pathogenesis of primary glomerular disease. Thus, our findings may provide important insights regarding the pathophysiology of primary glomerular disease.

Monthly trends and seasonality of hemodialysis treatment and outcomes of newly initiated patients from the national database (NDB) of Japan

BACKGROUND

The numbers of patients treated with hemodialysis (HD) in Japan are currently quantified by manual survey. As this method requires much effort from medical institutions and cannot achieve 100% response, a more practical method is required. We aimed to establish a novel method for determining the static and dynamic numbers of patients treated with HD.

METHODS

This observational study used the national medical billing database (termed NDB) of Japan, based on the records of the universal healthcare insurance system. Medical billing data registered in the NDB between April 2011 and March 2015 were analyzed. From 130 billion records, we extracted and analyzed records of patients who had undergone HD at least once per month. Patients' monthly condition was classified as newly initiated HD, chronic HD, or presumed death, using conditional expressions. We also investigated renal outcome and presumed survival in newly initiated HD patients.

RESULTS

In the last month of the study period, 274,100 patients were identified as receiving chronic HD, which is estimated as > 95% of the number of these patients identified in the manual survey so far. The monthly data showed clear seasonality in the incidence of transient HD, which increased in winter and decreased in summer.

CONCLUSION

Analysis of a large national database revealed a significant increase in transient HD in winter and decrease in summer. Applied to additional epidemiological exploratory studies or clinical research, this analytical technique would enable collection of the dynamics of almost all HD patients nationwide.

Seasonal variation in emergent hemodialysis initiation in the late elderly: A single-center study

BACKGROUND

The number of new dialysis patients, particularly among the elderly population, has been globally increasing. In Japan, patients aged ≥65 years and ≥75 years comprised 72% and 45% of patients on dialysis in 2018, respectively. Few studies have reported seasonal variations in the initiation of dialysis. We investigated the seasonal prevalence of the emergent hemodialysis initiation in the elderly.

METHODS

We reviewed 479 elderly patients who initiated hemodialysis between January 2006 and December 2018. Early elderly patients were defined as patients aged between 65 and 74 years, and late elderly patients were defined as those aged ≥75 years. Emergent hemodialysis initiation was defined as initiation with a temporary vascular catheter without elective permanent vascular access or unplanned hemodialysis initiation due to patients requiring critical care regardless of elective permanent vascular access. The information collected included age, sex, and details of the initiation of hemodialysis.

RESULTS

The early elderly group consisted of 199 patients, and the late elderly group consisted of 279 patients. In the late elderly group, hemodialysis initiation was most frequent in winter, followed by spring, autumn, and summer (p = 0.018). Moreover, emergent hemodialysis initiation was most frequent in winter, followed by spring, autumn, and summer (p = 0.009). Emergent hemodialysis initiation due to fluid overload was most frequent in winter, followed by autumn, spring, and summer (p < 0.001). Among late elderly patients who initiated hemodialysis, 78% did not have permanent hemodialysis access at the time of the initiation of hemodialysis.

CONCLUSION

In the late elderly group, hemodialysis initiation and emergent hemodialysis initiation were significantly more frequent in the winter than in the remaining seasons. In addition, emergent hemodialysis initiation due to fluid overload was most frequent in winter in the late elderly group.

Seasonal variations in cause-specific mortality and transition to renal replacement therapy among patients with end-stage renal disease

Despite some studies showing seasonal variations in mortality and the transition to renal replacement therapy in patients with end-stage renal disease, detailed evidence is still scarce. We investigated seasonal variations in patients with end-stage renal disease using a large Japanese database for dialysis patients. We compared the fractions of all-cause and cause-specific mortality and the transition to renal replacement therapy among seasons and performed a mixed-effects Poisson regression analysis to compare the mortality among seasons after adjustment for some variables. The initiation of hemodialysis was highest in winter and lowest in summer. Seasonality in the initiation of peritoneal dialysis and transition to kidney transplantation differed from hemodialysis. All-cause mortality was highest in the winter and lowest in the summer. Death from coronary artery disease, heart failure, cerebral hemorrhage, and infectious pneumonia had similar seasonality, but death from cerebral infarction, septicemia, or malignant tumor did not have similar seasonality. In conclusion, the initiation of hemodialysis, all-cause mortality, and mortality from coronary heart disease, heart failure, cerebral hemorrhage, and infectious pneumonia were significantly highest in winter and lowest in summer. However, the initiation of peritoneal dialysis, transition to kidney transplantation, or mortality from cerebral infarction, septicemia, or malignant tumor did not have similar seasonal variations.