The relationship between kidney function and quality of life among community-dwelling adults varies by age and filtration marker

Association between adequate dietary protein and all-cause and cardiovascular mortality in patients with selective glomerular hypofiltration syndrome

Aims: To determine the impact of dietary protein intake and protein sources on all-cause and cardiovascular mortality of selective glomerular hypofiltration syndrome (SGHS) patients. Methods: This study recruited participants from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2004. Cox proportional hazard models and competing risk models were employed to investigate the effects of dietary protein intake and protein sources on all-cause and cardiovascular mortality in SGHS patients. Additionally, Cox regression models utilizing restricted cubic splines (RCS) were used to explore potential non-linear associations. Results: Over a median follow-up period of 204 months, 20.71% (449/2168) participants died, with 5.40% (117/2168) experiencing cardiovascular mortality. In the fully adjusted model, participants with the highest dietary protein intake (Q4, ≥107.13 g d-1) exhibited a 40% reduced risk of all-cause mortality (HR: 0.60, 95% CI: 0.39 to 0.94) and an 88% reduced risk of cardiovascular mortality (HR: 0.12, 95% CI: 0.04 to 0.35) compared to those with the lowest dietary protein intake (Q1, < 57.93 g d-1). Notably, non-red meat protein sources were found to reduce the risk of all-cause and cardiovascular mortality, whereas no significant association was observed with red meat consumption. Conclusion: Adequate dietary protein intake has been linked to a decreased risk of all-cause and cardiovascular mortality in individuals with selective glomerular hypofiltration syndromes. This protective effect seems to be primarily associated with protein obtained from non-red meat sources.

The complexity of kidney disease and diagnosing it - cystatin C, selective glomerular hypofiltration syndromes and proteome regulation

Estimation of kidney function is often part of daily clinical practice, mostly done by using the endogenous glomerular filtration rate (GFR)-markers creatinine or cystatin C. A recommendation to use both markers in parallel in 2010 has resulted in new knowledge concerning the pathophysiology of kidney disorders by the identification of a new set of kidney disorders, selective glomerular hypofiltration syndromes. These syndromes, connected to strong increases in mortality and morbidity, are characterized by a selective reduction in the glomerular filtration of 5-30 kDa molecules, such as cystatin C, compared to the filtration of small molecules <1 kDa dominating the glomerular filtrate, for example water, urea and creatinine. At least two types of such disorders, shrunken or elongated pore syndrome, are possible according to the pore model for glomerular filtration. Selective glomerular hypofiltration syndromes are prevalent in investigated populations, and patients with these syndromes often display normal measured GFR or creatinine-based GFR-estimates. The syndromes are characterized by proteomic changes promoting the development of atherosclerosis, indicating antibodies and specific receptor-blocking substances as possible new treatment modalities. Presently, the KDIGO guidelines for diagnosing kidney disorders do not recommend cystatin C as a general marker of kidney function and will therefore not allow the identification of a considerable number of patients with selective glomerular hypofiltration syndromes. Furthermore, as cystatin C is uninfluenced by muscle mass, diet or variations in tubular secretion and cystatin C-based GFR-estimation equations do not require controversial race or sex terms, it is obvious that cystatin C should be a part of future KDIGO guidelines.

Reduced kidney function is associated with poorer domain-specific cognitive performance in community-dwelling older adults

OBJECTIVES

Whilst chronic kidney disease has been associated with cognitive impairment, the association between reduced estimated Glomerular Filtration Rate (eGFR) and domain-specific cognitive performance is less clear and may represent an important target for the promotion of optimal brain health in older adults.

METHODS

Participants aged >60 years from the Trinity-Ulster-Department of Agriculture study underwent detailed cognitive assessment using the Mini-Mental State Examination (Mini-Mental State Examination (MMSE)), Frontal Assessment Battery (FAB) and Repeatable Battery for Assessment of Neuropsychological Status (RBANS). Poisson and linear regression models assessed the relationship between eGFR strata and cognitive performance.

RESULTS

In 4887 older adults (73.9 ± 8.3 years; 67.7% female), declining eGFR strata was associated with greater likelihood of error on the MMSE/FAB and poorer overall performance on the RBANS. Following robust covariate adjustment, findings were greatest for GFR <45 ml/ml/1.73 m² (Incidence Rate Ratio: 1.17; 95% CI 1.08, 1.27; p < 0.001 for MMSE; IRR: 1.13; 95% CI 1.04, 1.13; p < 0.001 for FAB; β: -3.66; 95% CI -5.64, -1.86; p < 0.001 for RBANS). Additionally, eGFR <45 ml/ml/1.73 m² was associated with poorer performance on all five RBANS domains, with greatest effect sizes for immediate memory, delayed memory and attention. Associations were strongest in those aged 60-70, with no associations observed in those >80 years.

CONCLUSIONS

Reduced kidney function was associated with poorer global and domain-specific neuropsychological performance. Associations were strongest with eGFR <45 ml/min/1.73 m² and in those aged 60-70 years, suggesting that this population may potentially benefit from potential multi-domain interventions aimed at promoting optimal brain health in older adults.

Quality of life and cognitive assessment in healthy older Asian people with early and moderate chronic kidney disease: The NAHSIT 2013–2016 and validation study

Background

Taiwan has the highest prevalence of chronic kidney disease (CKD). Impaired cognition and quality of life are significant phenomena in the late stages of CKD. We sought to obtain an overview and the attributable effect of impaired glomerular filtration on multiple domains in cognition and dimensions of quality of life for community-based healthy older adults in Taiwan.

Methods

The study was derived from the Nutrition and Health Survey in Taiwan (NAHSIT) 2013–2016, a nationwide cross-sectional study conducted to sample healthy, community-based older adults aged ≥65 years in Taiwan. Participants were categorized into four CKD groups: CKD stage 1, stage 2, stages 3a and 3b, and stages 4–5. The Mini-Mental State Examination (MMSE) and the QoL questionnaire derived from the 12-item Short Form Health Survey (SF-12) were measured. Generalized linear mixed models (GLMMs) and principal component regressions were employed for the analysis and validation, respectively.

Results

Participants with moderate CKD (stages 3a and 3b) showed deficits in global MMSE, domain orientation to time, calculation, complex commands, and role-physical and vitality in QoL questionnaires. In GLMMs, impaired eGFR per 30 mL/min/1.73 m² was associated with lower global MMSE scores (β = -0.807, standard error [SE] = 0.235, P = 0.0007), domain orientation to time (β = -0.155, SE = 0.047, P = 0.0011), calculation (β = -0.338, SE = 0.109, P = 0.0020), complex commands (β = -0.156, SE = 0.079, P = 0.0494), and role-physical (β = -2.219, SE = 0.779, P = 0.0046) dimensions of QoL.

Conclusions

Elderly Han Chinese adults with moderately impaired renal filtration could manifest cognitive deficits in orientation to time, calculation, and impaired quality of life in physical role functioning.

Health-Related Quality of Life according to Renal Function: Results from a Nationwide Health Interview and Examination Survey

BACKGROUND

Most studies on health-related quality of life (HRQoL) in chronic kidney disease (CKD) focus on patients with end-stage kidney disease although they represent a small proportion of patients with CKD. We aimed to analyze HRQoL according to glomerular filtration rate (GFR) categories in a population-based sample of adults living in Germany.

METHODS

Data from the German health interview and examination survey conducted from 2008 to 2011 were used. Participants with valid interview and examination data aged 40-79 years were included (n = 5,159). Serum creatinine levels were used to calculate estimated GFR via the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. We classified kidney function in GFR categories according to the Kidney Disease Improving Global Outcomes Initiative (KDIGO) guidelines on CKD: G1 (high): ≥90 mL/min/1.73 m2, G2 (normal): 60-89 mL/min/1.73 m2, G3a (mildly decreased): 45-59 mL/min/1.73 m2, G3b (moderately decreased): 30-44 mL/min/1.73 m2, G4/5 (severely decreased/end-stage kidney disease): <30 mL/min/1.73 m2. HRQoL was evaluated with the Short Form Health Survey (SF-36). Different multivariate linear and logistic regression models were used to analyze the association of HRQoL with GFR categories.

RESULTS

Overall, 5.9% had a GFR <60 mL/min/1.73 m2 (corresponding to categories G3a, G3b, and G4/5). Compared to category G2 linear regression showed a decline in physical HRQoL in categories G3a (-2.34, p = 0.004), G3b (-5.37, p = 0.009), and G4/5 (-4.82, p = 0.117). No decline in mental HRQoL was detected with increasing GFR categories. Categories G3a to G4/5 were significantly associated with a low perceived general state of health (G3a: odds ratio [OR] = 2.03, p = 0.001; G3b: OR = 3.01, p = 0.009; G4/5: OR = 8.70, p = 0.016) when compared to category G2.

CONCLUSION

In a representative sample of adults living in Germany, both physical HRQoL and the perceived general state of health are already significantly reduced in category G3a.

Impaired kidney function is associated with lower quality of life among community-dwelling older adults : The screening for CKD among older people across Europe (SCOPE) study

Background

Quality of life (QoL) refers to the physical, psychological, social and medical aspects of life that are influenced by health status and function. The purpose of this study was to measure the self-perceived health status among the elderly population across Europe in different stages of Chronic Kidney Disease (CKD).

Methods

Our series consisted of 2255 community-dwelling older adults enrolled in the Screening for Chronic Kidney Disease (CKD) among Older People across Europe (SCOPE) study. All patients underwent a comprehensive geriatric assessment (CGA), including included demographics, clinical and physical assessment, number of medications taken, family arrangement, Geriatric Depression Scale (GDS), Cumulative Illness Rating Scale, History of falls, Lower urinary tract symptoms, and Short Physical Performance Battery (SPPB). Estimated glomerular filtration rate (eGFR) was calculated by Berlin Initiative Study (BIS) equation. Quality of life was assessed by Euro Qol questionnaire (Euro-Qol 5D) and EQ-Visual Analogue Scale (EQ-VAS). The association between CKD (eGFR < 60, < 45 ml or < 30 ml/min/1.73m²) and low EQoL-VAS was investigated by multivariable logistic regression models.

Results

CKD was found to be significantly associated with low EQoL-VAS in crude analysis (OR = 1.47, 95%CI = 1.16–1.85 for eGFR< 60; OR = 1.38, 95%CI = 1.08–1.77 for eGFR< 45; OR = 1.57, 95%CI = 1.01–2.44). Such association was no longer significant only when adjusting for SPPB (OR = 1.20, 95%CI = 0.93–1.56 for eGFR< 60; OR = 0.87, 95%CI = 0.64–1.18 for eGFR< 45; OR = 0.84, 95%CI = 0.50–1.42), CIRS and polypharmacy (OR = 1.16, 95%CI = 0.90–1.50 for eGFR< 60; OR = 0.86, 95%CI = 0.64–1.16 for eGFR< 45; OR = 1.11, 95%CI = 0.69–1.80) or diabetes, hypertension and chronic obstructive pulmonary disease (OR = 1.28, 95%CI = 0.99–1.64 for eGFR< 60; OR = 1.16, 95%CI = 0.88–1.52 for eGFR< 45; OR = 1.47, 95%CI = 0.92–2.34). The association between CKD and low EQoL-VAS was confirmed in all remaining multivariable models.

Conclusions

CKD may significantly affect QoL in community-dwelling older adults. Physical performance, polypharmacy, diabetes, hypertension and COPD may affect such association, which suggests that the impact of CKD on QoL is likely multifactorial and partly mediated by co-occurrent conditions/risk factors.

To Compare the Level of Cystatin C in Type 2 Diabetes Mellitus with Obesity

BACKGROUND

Cystatin C is a non-glycosylated basic protein that is produced and secreted at a constant rate by all nucleated cells. Cystatin C is a more reliable marker than the serum creatinine because it is less affected by external factors such as gender, race and muscle mass. However, the comparison of serum cystatin C level in type 2 diabetes mellitus is not well known in people with obesity.

OBJECTIVES

To estimate the level of cystatin C in type 2 diabetes and that can be explained by the change in obesity. Thus, this current study aimed to determine and compare the level of cystatin C in type 2 DM with obesity and also correlate the cystatin C level with the quality of life in type 2 DM and obesity.

MATERIAL AND METHODS

We have taken three groups: Group A containing type 2 DM, Group B containing obesity, and Group C containing type 2 DM with obesity. In all, 25 patients in each group were selected and analyzed for cystatin C.

RESULTS

Cystatin C level was very high in type 2 DM with obesity group. The P value was 0.008 in type 2 DM with the obesity group and it has shown a highly significant correlation with BMI. In our study, we have also seen the positive correlation of cystatin C with BMI in Group B plain obese and Group C diabetes obese than Group A diabetes non-obese. We have seen in our study and found a poor correlation between HbA1c, RBS and cystatin C.

CONCLUSION

The level of cystatin C is much higher in type 2 DM with obese patient as compared with type 2 DM and obese patients.

Shrunken pore syndrome - a common kidney disorder with high mortality. Diagnosis, prevalence, pathophysiology and treatment options

Invasive studies show that the glomerular sieving coefficients for 5-30 kDa plasma proteins in the human kidney may be selectively reduced compared to those for small molecules < 0.9 kDa, commonly used to measure glomerular filtration rate (GFR). Identification of this pathophysiological state, called shrunken pore syndrome (SPS), can easily and non-invasively be done by comparing estimations of GFR using cystatin C (13.3 kDa) and creatinine (0.113 kDa). SPS is present if the estimate of GFR using cystatin C is lower than 60 or 70% of the estimate using creatinine in the absence of non-renal influences on cystatin C or creatinine. All studies of SPS show that the 3- or 5-year mortality is strongly increased and high hazard ratios for mortality associated with SPS have been observed for many different patient cohorts, including cohorts with normal measured GFR, no albuminuria and no diagnosis. The prevalence of SPS in the cohorts so far investigated is between 0.2 and 36%. Proteome studies of SPS demonstrate that the high mortality associated with the syndrome might be caused by the accumulation of 10-30 kDa signalling proteins promoting development of atherosclerosis and thus suggesting use of monoclonal antibodies to reduce the levels of the most detrimental signalling proteins as a treatment option. The KDIGO recommendations for classification of chronic kidney disease (CKD) comprise determination, or estimation, of GFR and analysis of albuminuria and therefore cannot identify a large fraction of the patients with SPS. The high prevalence and mortality of SPS and the possible treatment options strongly suggest that the KDIGO recommendations should be expanded to include determination of cystatin C to be able to identify all patients with SPS.