Skipping Breakfast and Progression of Chronic Kidney Disease in the General Japanese Population: the Iki City Epidemiological Study of Atherosclerosis and Chronic Kidney Disease (ISSA-CKD).

INTRODUCTION: Breakfast-skipping habits are associated with adverse health outcomes including coronary heart disease, metabolic syndrome and diabetes mellitus. However, it remains uncertain whether skipping breakfast affects chronic kidney disease (CKD) risk. This study aimed to examine the association between skipping breakfast and progression of CKD. METHODS: We retrospectively conducted a population-based cohort study using the data from the Iki City Epidemiological Study of Atherosclerosis and Chronic Kidney Disease (ISSA-CKD). Between 2008 and 2019, we included 922 participants aged 30 years or older who had CKD (estimated glomerular filtration rate <60 mL/min/1.73m2 and/or proteinuria) at baseline. Breakfast-skippers were defined as participants who skipped breakfast more than 3 times per week. The outcome was CKD progression defined as a decline of at least 30% in the eGFR from the baseline status. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CKD progression, adjusted for other CKD risk factors. RESULTS: During a follow-up period with a mean of 5.5 years, CKD progression occurred in 60 (6.5%) participants. The incidence rate (per 1,000 person-years) of CKD progression was 21.5 in the breakfast-skipping group and 10.7 in the breakfast-eating group (p=0.029), respectively. The multivariable-adjusted HR (95% CI) for CKD progression was 2.60 (95% CI 1.29‒5.26) for the breakfast-skipping group (p=0.028) compared with the group eating breakfast. There were no clear differences in the association of skipping breakfast with CKD progression in subgroup analyses by sex, age, obesity, hypertension, diabetes mellitus, baseline eGFR and baseline proteinuria. CONCLUSION: Skipping breakfast was significantly associated with higher risk of CKD progression in the general Japanese population.

Anemia in Diabetic Patients Reflects Severe Tubulointerstitial Injury and Aids in Clinically Predicting a Diagnosis of Diabetic Nephropathy.

Objective A kidney biopsy is generally performed in diabetic patients to discriminate between diabetic nephropathy (DN) and non-diabetic kidney disease (NDKD) and to provide more specific treatments. This study investigated the impact of anemia on the renal pathology and the clinical course in patients who underwent a kidney biopsy. Methods We reviewed 81 patients with type 2 diabetes who underwent a percutaneous kidney biopsy. Patients were classified into two groups: isolated DN (DN group, n=30) and NDKD alone or concurrent DN (NDKD group, n=51) groups. The laboratory and pathological findings and clinical courses were investigated. Results In the NDKD group, membranous nephropathy was the most common finding (23.5%), followed by IgA nephropathy (17.6%) and crescentic glomerulonephritis (13.7%). In the logistic regression analysis, the absence of severe hematuria and presence of anemia were significantly associated with a diagnosis of DN. Akaike's information criterion (AIC) and net reclassification improvement (NRI) analyses revealed improved predictive performance by adding anemia to the conventional factors (AIC 100.152 to 91.844; NRI 27.0%). The tissues of patients in the DN group demonstrated more severe interstitial fibrosis and tubular atrophy (IF/TA) than those in the NDKD group (p<0.05) regardless of the rate of global glomerulosclerosis, and IF/TA was related to the prevalence of anemia (odds ratio: 7.31, 95% confidence interval: 2.33-23.00, p<0.01) according to a multivariable regression analysis. Furthermore, the isolated DN group demonstrated a poorer prognosis than the NDKD group. Conclusion DN is associated with anemia because of severe IF/TA regardless of the renal function, and anemia helps clinician discriminate clinically between isolated DN and NDKD.