Prevalence of sarcopenia in elderly maintenance hemodialysis patients: the impact of different diagnostic criteria

The prevalence of sarcopenia on elderly maintenance hemodialysis (MHD) has been scarcely investigated.

OBJECTIVES

To investigate the prevalence of decreased muscle mass and strength alone or combined (true sarcopenia) in elderly patients on MHD according to different methods and cutoff limits. Additionally, we evaluated the agreement between dual energy x-ray absorptiometry (DXA) and surrogate methods for the assessment of muscle mass.

DESIGN

Observational and cross-sectional study.

PARTICIPANTS

Non-institutionalized 102 elderly (age > 60 years) patients on MHD.

MEASUREMENTS

Sarcopenia was considered when the patient fit one criteria for low muscle mass assessed by DXA, bioelectrical impedance (BIA), sum of skinfold thicknesses (SKF), calf circumference and mid-arm muscle circumference (MAMC) and one for low muscle strength evaluated by handgrip dynamometer.

RESULTS

Decreased muscle strength was found in 85% of the patients. The prevalence of decreased muscle mass varied from 4 to 73.5% and of sarcopenia (decreased muscle mass and strength combined) from 4 to 63%, depending on the method and cutoff limit applied. A small percentage of patients (2 to 15%) were classified as sarcopenic by more than one diagnostic criteria. The agreement between DXA and the surrogate methods to assess muscle mass showed better kappa coefficients with BIA (r=0.36; P<0.01) and SKF (r=0.40; P<0.01).

CONCLUSION

A wide prevalence of sarcopenia is observed depending on the method and cutoff limit applied. This may limit extrapolate on to clinical practice. BIA and SKF were the surrogate methods to assess muscle mass with the best concordance with DXA in elderly MHD patients.

Resting energy expenditure and its determinants in hemodialysis patients

OBJECTIVE

Chronic kidney disease is associated with several metabolic disturbances that can affect energy metabolism. As resting energy expenditure (REE) is scarcely investigated in patients on hemodialysis (HD) therapy, we aimed to evaluate the REE and its determinants in HD patients.

DESIGN

Cross-sectional study.

SETTING

Dialysis Unit of the Nephrology Division, Federal University of São Paulo, Brazil.

SUBJECTS

The study included 55 patients (28 male, 41.4+/-12.6 years old) undergoing HD therapy thrice weekly for at least 2 months, and 55 healthy individuals pair matched for age and gender. Subjects underwent fasting blood tests, as well as nutritional assessment, and the REE was assessed by indirect calorimetry.

RESULTS

REE of HD patients was similar to that of pair-matched controls (1379+/-272 and 1440+/-259 kcal/day, respectively), even when adjusted for fat-free mass (P=0.24). REE of HD patients correlated positively with fat-free mass (r=0.74; P<0.001) and body mass index (r=0.37; P<0.01), and negatively with dialysis adequacy (r=-0.46; P<0.001). No significant univariate correlation was found between REE and age, dialysis vintage, serum creatinine, urea, albumin, bicarbonate, parathyroid hormone (PTH) or high-sensitivity C-reactive protein (CRP). In the multiple linear regression analysis, using REE as dependent variable, the final model showed that besides the well-recognized determinants of REE such as fat-free mass and age, PTH and CRP were the independent determinants of REE in HD patients (R (2)=0.64).

CONCLUSIONS

In this study, the REE of HD patients was similar to that of healthy individuals, even with the positive effect of secondary hyperparathyroidism and inflammation on REE of these patients.

Influence of renal function on spontaneous dietary intake and on nutritional status of chronic renal insufficiency patients

OBJECTIVE

To analyze the spontaneous food intake and the nutritional parameters of patients with different degrees of chronic renal insufficiency (CRI) at the onset of predialysis treatment.

DESIGN

Cross-sectional.

SETTING

Outpatient Clinic of the Nephrology Division of Federal University of São Paulo, Brazil.

SUBJECTS

The analysis involved 487 (187 women and 300 men) patients with moderate to advanced CRI who were evaluated in the first visit to the clinic.

RESULTS

Patients were divided according to creatinine clearance (CrCl) quartiles. CrCl in the first quartile was lower than 19.9 ml/min/1.73 m(2) and in the fourth one was higher than 43 ml/min/1.73 m(2). Energy intake was significantly (P<0.05) lower in the first quartile when compared with the fourth one while protein intake estimated by protein equivalent of nitrogen appearance (PNA) was significantly lower in the first, second and third quartiles in comparison with the fourth (P<0.05). Body mass index (BMI) and percentage of ideal body weight were significantly decreased in the three lowest levels of renal function. Standard per cent of triceps skinfold thickness was lower in the first quartile when compared with the fourth one. Compared with the fourth quartile, standard per cent of midarm muscle circumference (MAMC) was lower in the second and in the third quartile. CrCl correlated directly and significantly with PNA (r=0.30; P<0.01), energy intake (r=0.17; P<0.01), and MAMC (r=0.20; P<0.01). In a multiple linear regression analysis, controlling for energy and protein intake, CrCl correlated significantly and positively with BMI and MAMC.

CONCLUSION

This study suggests that a spontaneous decrease in energy and protein intake as well as in anthropometric indices follows a decline in renal function in patients with no previous dietary intervention.

Resting energy expenditure in pre-dialysis diabetic patients

BACKGROUND

The metabolic derangements of diabetes mellitus (DM) associated with those of chronic renal failure (CRF) may interfere with the energy and protein balance of patients with both diseases. The aim of this study was to verify whether the resting energy expenditure (REE) of non-dialysis chronic renal failure diabetic patients differs from that of chronic renal failure patients without DM.

METHODS

REE was measured by indirect calorimetry in 24 CRF diabetic patients (CRF diabetes group), matched for age, gender, and degree of renal impairment to 24 CRF patients without DM (CRF control group).

RESULTS

The CRF diabetes group had a significantly higher REE (1538+/-230 kcal/day) than the CRF control group (1339+/-315 kcal/day, P = 0.009). This difference was maintained even when the REE was adjusted for lean body mass (LBM; 30.3+/-4.3 vs 26.3+/-5.4 kcal/kg LBM/day, P = 0.004). Mean protein intake was significantly higher in the CRF diabetes than in the CRF control group (0.89+/-0.20 vs 0.76+/-0.25 g/kg/day, P = 0.02). Mean protein equivalent of nitrogen appearance (PNA) was also significantly higher in the CRF diabetes patients (1.21+/-0.31 vs 1.03+/-0.22 g/kg/day, P = 0.02), reflecting a higher protein intake and/or elevated protein breakdown. Accordingly, REE was directly correlated with PNA mainly in the CRF diabetes group (r = 0.57, P < 0.003).

CONCLUSION

Metabolic disturbances of poorly controlled DM may account for the higher REE observed in the CRF diabetes group. The role of the apparently higher protein breakdown in this increased REE remains to be clarified.