Design and methodology of the Aging Nephropathy Study (AGNES): a prospective cohort study of elderly patients with chronic kidney disease

Older patients are less prone to fast decline of renal function: a propensity-matched study

PURPOSE

Despite CKD is common among older patients, and although factors associated with CKD progression have been explored over decades, little is known about the decline of renal function specifically in older individuals.

METHODS

We included adult patients with CKD on conservative management in a propensity-score matched study 1:1 older (> 65 year) and young (≤ 65 yr). Factors associated with the slope of the decline of eGFR such as proteinuria, initial eGFR, diabetes, sex, and use of angiotensin-converting enzyme inhibitor/angiotensin receptor block (ACEI/ARB) were analyzed. Inclusion criteria were at least two consultations in the service and an initial eGFR lower than 45 ml/min/m2, in the period between January 2012 and December 2017.

RESULTS

Crude analysis of eGFR decline shows a slower progression of older patients when compared to younger patients in both absolute change [- 2.0 (- 4.5, - 1.0) vs. -3.0 (- 7.0, - 1.0) ml/min/1.73m2, p < 0.001] and slope of eGFR reduction [- 2.2 (- 4.4, - 1.0) vs. 3.1 (- 6.7, - 1.2)) ml/min/1.73m2, p < 0.001]. Patients considered fast progressors (> 5 ml/min/1.73 m2/year decline in eGFR) were less likely to be older (35.2% young vs. 22.0% older, p < 0.001). Adjusted logistic multivariate regression confirmed that older patients had less odds ratio of eGFR decline, independently of the presence of proteinuria, diabetes, ACEI/ARB use, sex, baseline eGFR, baseline phosphate and baseline 25(OH) vitamin D.

CONCLUSION

Older patients present slower CKD progression even after multiple adjustments. This information should be taken into consideration while treating these patients on conservative management and should be kept in mind while planning dialysis start.

Long-term ozone exposure is negatively associated with estimated glomerular filtration rate in Chinese middle-aged and elderly adults

Chronic kidney disease (CKD) is an inflammatory disease characterized by the deterioration of renal function, which imposes a significant burden on the healthcare system. In the recent decades, the ageing of the population and the increase of ozone pollution have accelerated. However, epidemiological associations between long-term ozone exposure and renal function in susceptible populations are understudied. In this study, we aimed to investigate the association of 1 y ozone exposure with renal function among the older adults in Xiamen City, China. We recruited 6024 eligible participants with a median age of 65.00 years, estimated their ozone exposure data, and collected questionnaires on demographic status and lifestyle factors as well as information on healthcare access. A generalized linear model was used to assess the association. An increase of 10 μg/m3 of 1 y ozone exposure was negatively associated with the estimated glomerular filtration rate (eGFR) [-3.12 (95% CI: -4.76, -1.48)]. The associations were stronger in men, non-smokers, and those with hypertension or T2DM. Clinical indicators of high-density lipoprotein, low-density lipoprotein, triglycerides, and total cholesterol were the main mediators to regulate the ozone-renal function association. Our results suggested that long-term ozone exposure is a potential risk factor for renal function in Chinese middle-aged and elderly adults.

Ketoanalogue supplements reduce mortality in patients with pre-dialysis advanced diabetic kidney disease: A nationwide population-based study

BACKGROUND & AIMS

Metabolism dysregulation and protein energy wasting occur in patients with chronic kidney disease (CKD) and are associated with poor survival, especially in patients prior to starting dialysis. Accumulating evidence indicates that dietary supplementation with ketoanalogues (KAs, a mixture of branched-chain amino acids) exerts a variety of beneficial effects for patients with CKD. However, the role of KAs in diabetic kidney disease (DKD), one of the major causes of CKD, is still controversial. The aim of this study was to explore the impact of KA supplements on survival in patients with stage 5 DKD who have not yet started dialysis (DKD-5-ND).

METHODS

We analyzed a nationwide cohort retrieved from the National Health Insurance Research Database in Taiwan to study the long-term impact of KA supplements in patients with DKD-5-ND. We enrolled 15,782 incident pre-dialysis DKD patients between January 1, 2004 and December 31, 2007. Landmark analysis was used to eliminate immortal bias, and overlap weighting was used to balance differences between the KA users and nonusers in the beginning. The primary study endpoint was all-cause mortality, and the occurrence of permanent dialysis (presenting the end-stage renal disease, ESRD) and major adverse cardiovascular events (MACEs) was also evaluated. All patients were followed for five years or until death.

RESULTS

The prevalence of KA usage in the DKD-5-ND patients was 6.3%. The 5-year all-cause mortality rate in the KA users was lower than that in the nonusers (34.7% vs 42.7%). After adjusting for known covariates, the KA users still had a lower risk of mortality (adjusted hazard ratio [aHR]: 0.73, 95% confidence interval [CI]: 0.66-0.82). In addition, the incidence of ESRD was also slightly lower among the KA users (90.9% for users vs 91.2% for nonusers, adjusted cause-specific hazard ratio [aCSHR]: 0.65, 95% CI: 0.61-0.69), and the occurrence of MACEs was lower (adjusted incidence rate ratios [aIRR]: 0.76, 95% CI: 0.67-0.86). Although the all-cause mortality was higher among patientsolder than 70 years (60.5% for KA users vs 46.5% for nonusers) the risk reduction seemed prominent among older patients (aHR: 0.65, 95% CI: 0.56-0.76 for patients aged ≥70 years; aHR: 0.82, 95% CI: 0.71-0.96 for patients aged < 70 years). The reduction in risks of mortality was consistent in subgroup analysis and sensitivity tests.

CONCLUSIONS

The use of KA supplements seemed to be beneficial for patients with DKD-5-ND; further in-depth analysis of using KA for these patients is warranted.