ABSTRACT
BACKGROUND: The difficulty of adhering to a low-protein diet is a serious limitation of randomized controlled trials aimed at validating the efficacy of this therapy. In this observational study of patients with diabetic nephropathy, we examined the association of dietary protein intake (DPI) with renal outcome and mortality, taking into account the nutritional status. METHODS: We conducted a single-center historical cohort study of 449 adult Japanese patients with type 2 diabetes and the urinary albumin-to-creatinine ratio of ≥ 300 mg/g or estimated glomerular filtration rate of < 30 mL/min/1.73 m2. DPI was estimated with a formula using nitrogen levels in spot urine and body mass index. Malnutrition was defined as the Geriatric Nutritional Risk Index of ≤ 98. The primary and secondary endpoints were renal replacement therapy (RRT) initiation and mortality before RRT initiation, respectively. The Fine and Gray subdistribution hazard model was used to determine the relative effects of DPI on the respective endpoint. RESULTS: Decreased DPI was associated with lower incidence of RRT with an adjusted hazard ratio of 0.81 (95% confidence interval: 0.72-0.92, p < 0.001). The interaction between DPI and nutritional status with respect to mortality was significant (p interaction = 0.047). Decreased DPI was a risk factor for mortality in patients with malnutrition (p = 0.009) but not in those without malnutrition (p = 0.559). CONCLUSIONS: In patients with type 2 diabetic nephropathy, lower DPI was associated with lower incidence of RRT initiation, suggesting beneficial effects of a low-protein diet on kidneys. Conversely, lower DPI might lead to increased mortality in patients with malnutrition.
Subject(s)
Diabetic Nephropathies/diet therapy , Diet, Protein-Restricted/mortality , Malnutrition/mortality , Nutritional Status , Aged , Databases, Factual , Diabetic Nephropathies/diagnosis , Diabetic Nephropathies/mortality , Diabetic Nephropathies/physiopathology , Diet, Protein-Restricted/adverse effects , Disease Progression , Female , Humans , Japan , Male , Malnutrition/diagnosis , Malnutrition/physiopathology , Middle Aged , Renal Replacement Therapy/mortality , Risk Assessment , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND: Most existing data regarding effects of uric acid (UA) on diabetic kidney disease have considered patients with preserved kidney function. We examined a hypothesis that there are differences in the effects of serum UA levels on the decline in kidney function depending on baseline kidney function in diabetic patients. METHODS: In this historical cohort study, 7033 type 2 diabetic patients were analyzed and classified into two groups as follows: nonchronic kidney disease (non-CKD), with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 (n = 4994), and CKD, with an eGFR <60 mL/min/1.73 m2 (n = 2039). The composite endpoint was a ≥30% decrease in eGFR from baseline or the initiation of renal replacement therapy. The hazard ratio (HR) of serum UA levels at baseline was estimated using multivariate Cox proportional hazards models. RESULTS: There was a significant interaction between UA levels and baseline eGFR with respect to the endpoint (P < 0.001). The HRs of 1 mg/dL increase in UA levels were 1.13 [95% confidence interval (CI) 1.05-1.22, P = 0.002] and 0.93 (95% CI 0.88-0.99, P = 0.02) in the non-CKD and CKD groups, respectively. When patients were classified by quintile of UA levels, the HRs of those in the 5th quintile (versus 1st quintile) were 1.64 (95% CI 1.23-2.18, P < 0.001) and 0.76 (95% CI 0.58-0.99, P = 0.05) in the non-CKD and CKD groups, respectively. CONCLUSIONS: The effects of UA on kidney function decline might differ depending on baseline kidney function in type 2 diabetic patients. High UA levels are the prognostic factor only in patients with preserved kidney function.
Subject(s)
Diabetes Mellitus, Type 2/blood , Hyperuricemia/blood , Renal Insufficiency, Chronic/blood , Uric Acid/blood , Aged , Cohort Studies , Female , Glomerular Filtration Rate , Humans , Japan , Kidney/physiology , Kidney/physiopathology , Male , Middle Aged , Prognosis , Proportional Hazards Models , Renal Insufficiency, Chronic/therapy , Renal Replacement Therapy/methods , Treatment OutcomeABSTRACT
We conducted this cross-sectional study to assess quality of life (QOL) in Japanese patients with type 1 diabetes mellitus (T1DM) and end-stage renal disease (ESRD) undergoing simultaneous pancreas and kidney transplantation (SPK). Japanese patients with T1DM without diabetic nephropathy (N = 10), and those undergoing chronic dialysis (N = 52), kidney transplantation alone (KTA, N = 25), and SPK (N = 16) were studied. Comprehensive health-related QOL was assessed using the Short Form 36 version 2 (SF-36v2). Emotional functioning in diabetes was measured by the Problem Area In Diabetes (PAID) scale. Severity of impaired hypoglycemic awareness was assessed using the Clarke hypoglycemic score. SPK patients had significantly higher (or tended to have higher) subscale and summary SF-36 scores than dialysis patients and KTA patients. PAID scores were significantly lower in SPK patients than in dialysis patients and KTA patients. Clarke hypoglycemic scores were also significantly lower in SPK patients than dialysis patients. In KTA and dialysis patients, there were no significant differences in the SF-36 subscale/summary scores, PAID scores, or Clarke hypoglycemic scores. In conclusion, QOL for Japanese patients receiving SPK may be superior to that of dialysis patients and KTA patients. Whether SPK actually improves QOL needs to be clarified in longitudinal studies.
