Effects of Diet Intervention on Body Composition in the Elderly with Chronic Kidney Disease

The safety of a low-protein diet in older adults with advanced chronic kidney disease

BACKGROUND

A low-protein diet (LPD) is recommended to patients with advanced chronic kidney disease (CKD), whereas geriatric guidelines recommend a higher amount of protein. The aim of this study was to evaluate the safety of LPD treatment in older adults with advanced CKD.

METHODS

The EQUAL study is a prospective, observational study including patients ≥65 years of age with an incident estimated glomerular filtration rate <20 ml/min/1.73 m2 in six European countries with follow-up through 6 years. Nutritional status was assessed by a 7-point subjective global assessment (SGA) every 3-6 months. Prescribed diet (g protein/kg of bodyweight) was recorded on every study visit; measured protein intake was available in three countries. Time to death and decline in nutritional status (SGA decrease of ≥2 points) were analysed using marginal structural models with dynamic inverse probability of treatment and censoring weights.

RESULTS

Of 1738 adults (631 prescribed LPD at any point during follow-up), there were 1319 with repeated SGA measurements, of which 267 (20%) decreased in SGA ≥2 points and 565 (32.5%) who died. There was no difference in survival or decrease in nutritional status for patients prescribed a LPD ≤0.8 g/kg ideal bodyweight {odds ratio [OR] for mortality 1.15 [95% confidence interval (CI) 0.86-1.55)] and OR for decrease in SGA 1.11 [95% CI 0.74-1.66]} in the adjusted models. In patients prescribed a LPD <0.6 g/kg ideal bodyweight, the results were similar. There was a significant interaction with LPD and older age >75 years, lower SGA and higher comorbidity burden for both mortality and nutritional status decline.

CONCLUSIONS

In older adults with CKD approaching end-stage kidney disease, a traditional LPD prescribed and monitored according to routine clinical practice in Europe appears to be safe.

Current status of the assessment of sarcopenia, frailty, physical performance and functional status in chronic kidney disease patients

PURPOSE OF REVIEW

Low physical function, frailty, and sarcopenia are common complications of chronic kidney disease (CKD). In this article, we review the epidemiology and pathogenesis of low physical function, as well as its associations with adverse outcomes in CKD patients. Additionally, we present various traditional and novel methods for assessment of physical function in CKD patients.

RECENT FINDINGS

In nondialysis dependent (NDD) and dialysis-dependent CKD patients, the prevalence of low physical function, frailty, and sarcopenia are substantially higher than in the general population. The potential mechanisms of low physical function, frailty, and sarcopenia in CKD patients are due to various factors including underlying kidney disease, co-existing comorbidities, and certain therapeutic interventions utilized in CKD. Increasing evidence has also uncovered the ill effects of impaired physical function on clinical outcomes in CKD patients.

SUMMARY

Routine assessment of physical function is an under-utilized yet important component in the management of CKD patients. Future studies are needed to determine how prescription of exercise and increased daily physical activity can be tailored to optimize the health and well-being of NDD and dialysis-dependent CKD patients in pursuit of successful aging.

Effects of ketoanalogues on skeletal muscle mass in patients with advanced chronic kidney disease: real-world evidence

OBJECTIVE

Ketoanalogue (KA) supplementation in patients with chronic kidney disease (CKD) on a restricted protein diet has been shown to maintain their nutritional status in clinical trials. However, a gap existed between the findings of the clinical trials and the real-world practice. The aim of this prospective observational study was to evaluate the KA effect on skeletal muscle mass in patients with stage 4-5 CKD.

METHODS

Among 170 patients with CKD screened, 148 were recruited. Patients were defined as KA or non-KA users. During a 12-mo follow-up, skeletal muscle and body fat mass were measured via bioelectrical impedance analysis at baseline, 6 mo (n = 108), and 12 mo (n = 85).

RESULTS

Among the patients (mean age, 66.5 ± 12.9 y), KA users tended to maintain skeletal muscle and body fat mass, whereas non-KA users had a significantly reduced muscle mass (P = 0.011) and body fat gain (P = 0.004). Stratified by median age, in patients ≥68 y of age, non-KA users yielded the most significant muscle mass reduction and fat mass gain, whereas KA users revealed no changes in skeletal muscle and fat mass.

CONCLUSION

In real-world practice, we concluded that KA supplementation favorably prevents skeletal muscle mass loss and fat mass gain in elderly patients with stage 4-5 CKD.

The effect of oral nutritional supplement on muscle fitness of patients undergoing dialysis: A systematic review and meta-analysis

AIM

To summarize evidence regarding the effects of oral nutritional supplement on muscle fitness of patients undergoing dialysis.

DESIGN

A systematic review and meta-analysis.

REVIEW SOURCES

Five English databases (CENTRAL, PubMed, EMBASE, CINHAL, and Web of Science) and four Chinese databases (CNKI, WanFang, SinoMed, and VIP) were searched from inception to 31 July 2019 and only randomized controlled trials were included.

REVIEW METHODS

Two reviewers independently searched these databases, selected trials, conducted bias assessment, extracted the data. Random-effects meta-analysis was conducted to assess the effect size. The predetermined subgroup included type of oral nutritional supplement (a mixture of macronutrients, whey protein, essential amino-acids, and other nutrients) and intervention duration (over and less than 48 weeks). The subgroup analyses and sensitivity analyses were conducted to explore source of heterogeneity and robustness of results.

RESULTS

Sixteen studies (910 participants) meeting the inclusion criteria were identified and included in this systematic review. Subgroup analysis showed that supplying a mixture of macronutrients (MD [MD] = 2.36 kg, 95% CI [0.45, 4.26], I²  = 0.00%), an intervention duration of 48 weeks (MD = 4.05 kg, 95% CI [1.43, 6.67], I²  = 0.00%) had some effects on increasing lean body mass. No effects of oral nutritional supplement were found on improving muscle strength or physical performance.

CONCLUSION

A mixture of macronutrients and an intervention duration as long as 48 weeks had some significant effects on improving lean body mass of patients undergoing dialysis. No effect of oral nutritional supplement on muscle strength or physical performance were found but with limited evidence.

IMPACT

No existing reviews have ever focused on improving muscle fitness of patients undergoing dialysis. This systematic review and meta-analysis provided evidence of oral nutritional supplement on keeping muscle fitness of these patients and suggested possible type of oral nutritional supplement and intervention duration for clinical practice.

Medical Nutritional Therapy for Patients with Chronic Kidney Disease not on Dialysis: The Low Protein Diet as a Medication

The 2020 Kidney Disease Outcome Quality Initiative (KDOQI) Clinical Practice Guideline for Nutrition in chronic kidney disease (CKD) recommends protein restriction to patients affected by CKD in stages 3 to 5 (not on dialysis), provided that they are metabolically stable, with the goal to delay kidney failure (graded as evidence level 1A) and improve quality of life (graded as evidence level 2C). Despite these strong statements, low protein diets (LPDs) are not prescribed by many nephrologists worldwide. In this review, we challenge the view of protein restriction as an "option" in the management of patients with CKD, and defend it as a core element of care. We argue that LPDs need to be tailored and patient-centered to ensure adherence, efficacy, and safety. Nephrologists, aligned with renal dietitians, may approach the implementation of LPDs similarly to a drug prescription, considering its indications, contra-indications, mechanism of action, dosages, unwanted side effects, and special warnings. Following this framework, we discuss herein the benefits and potential harms of LPDs as a cornerstone in CKD management.

The low-protein diet for chronic kidney disease: 8 years of clinical experience in a nephrology ward

BACKGROUND

Guidelines indicate that a low-protein diet (LPD) delays dialysis in severe chronic kidney disease (CKD). We assessed the value of these guidelines by performing a retrospective analysis in our renal clinical practice.

METHODS

The analysis was performed from 1 January 2010 to 31 March 2018 in 299 CKD Stage 4 patients followed for 70 months in collaboration with a skilled nutritionist. The patients included 43 patients on a controlled protein diet (CPD) of 0.8 g/kg/day [estimated glomerular filtration rate (eGFR) 20-30 mL/min/1.73 m2 body surface (b.s.)], 171 patients on an LPD of 0.6 g/kg/day and 85 patients on an unrestricted protein diet (UPD) who were not followed by our nutritionist (LPD and UPD, eGFR <20 mL/min/1.73 m2 b.s.).

RESULTS

eGFR was higher in CPD patients than in UPD and LPD patients (21.9 ± 7.4 mL/min/1.73 m2 versus 17.6 ± 8.00 mL/min/1.73 m2 and 17.1 ± 7.5 mL/min/1.73 m2; P = 0.008). The real daily protein intake was higher in UPD patients than in LPD and CDP patients (0.80 ± 0.1 g/kg/day versus 0.6 ± 0.2 and 0.63 ± 0.2 g/kg/day; P = 0.01). Body mass index (BMI) was stable in the LPD and CPD groups but decreased from 28.5 ± 4.52 to 25.4 ± 3.94 kg/m2 in the UPD group (P < 0.001). The renal survival of UPD, LPD and CPD patients was 47.1, 84.3 and 90.7%, respectively, at 30 months (P < 0.001), 42.4, 72.0 and 79.1%, respectively, at 50 months (P < 0.001) and 42.4, 64.1 and 74.4%, respectively, at 70 months (P < 0.001). The LPD patients started dialysis nearly 24 months later than the UPD patients. Diet was an independent predictor of dialysis [-67% of RR reduction (hazard ratio = 0.33; confidence interval 0.22-0.48)] together with a reduction in BMI.

CONCLUSIONS

An LPD recommended by nephrologists in conjunction with skilled dietitians delays dialysis and preserves nutritional status in severe CKD.

Prevalence and Correlates of Sarcopenia among Elderly CKD Outpatients on Tertiary Care

Background: Sarcopenia is a widespread concern in chronic kidney disease (CKD) as well in elderly patients and is one of the main reasons why low-protein diets for this population are controversial. The aim of this study was to assess the prevalence and correlates of sarcopenia among elderly male patients affected by CKD followed up in an outpatient nephrology clinic, where moderate protein restriction (0.6–0.8 g/Kg/day) is routinely recommended to patients in CKD stage 3b-5 not on dialysis. Methods: This observational study included 80 clinically-stable male out-patients aged >60, affected by stage 3b-4 CKD. Forty patients aged ≥75 (older seniors) were compared to the other forty patients aged 60–74 (younger seniors). All patients underwent a comprehensive nutritional and functional assessment. Results: Older seniors showed lower serum albumin, hand-grip strength, body mass index (BMI), skeletal muscle mass, and resting energy expenditure. Protein intake was significantly lower in older seniors whereas energy intake was similar. Average daily physical activity was lower in the older seniors than in the younger ones. Sarcopenia was more prevalent in older than in younger seniors. Among older seniors, sarcopenic and non-sarcopenic ones differed in age and performance on the Six-Minute Walk test, whereas the estimated glomerular filtration rate (eGFR), biochemistry, dietary protein, and energy intakes were similar. Conclusions: Older senior CKD male patients have lower muscle mass, muscle strength, and physical capacity and activity levels, with a higher prevalence of sarcopenia than younger patients. This occurs at the same residual renal function and metabolic profile and protein intake. Energy intake was at the target in both subgroups. In this CKD cohort, sarcopenia was associated with age and physical capacity, but not with eGFR or dietary intakes.