Re-evaluating the predictive roles of metabolic complications and clinical outcome according to eGFR levels--a four-years prospective cohort study in Taiwan

Serum Uric Acid and Mortality in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Existing studies suggested conflicting relationships between serum uric acid (SUA) and mortality in CKD patients. The present meta-analysis aimed to determine whether SUA can be a predictor for mortality in CKD cohorts.

METHOD

A systematical search was conducted on PubMed, EMBASE, and The Cochrane Library to identify studies reporting the relationship between SUA level and all-cause and cardiovascular mortality in CKD populations. In addition, random-effects models were adopted to calculate the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs).

RESULTS

On the whole, 29 studies were involved. In the present meta-analysis, patients exhibiting the maximum SUA level showed an association with a significantly higher risk for all-cause mortality (HR, 1.30; 95% CI, 1.06-1.59) compared with patients exhibiting the minimum SUA level. As revealed from the meta-analysis of 8 studies, low level of SUA was another predictor for all-cause mortality in patients with CKD (HR, 1.36; 95% CI, 1.20-1.54). No significant relationship was identified between SUA and cardiovascular mortality.

CONCLUSIONS

Higher and lower SUA levels are both associated with significantly increased risk of all-cause mortality in patients with CKD. A appreciate dose of treatment of lowering SUA agents should be confirmed.

The Impact of CKD Anaemia on Patients: Incidence, Risk Factors, and Clinical Outcomes-A Systematic Literature Review

Anaemia is a common consequence of chronic kidney disease (CKD); however, the risk factors for its development and its impact on outcomes have not been well synthesised. Therefore, we undertook a systematic review to fully characterise the risk factors associated with the presence of anaemia in patients with CKD and a contemporary synthesis of the risks of adverse outcomes in patients with CKD and anaemia. We searched MEDLINE, EMBASE, and the Cochrane Library from 2002 until 2018 for studies reporting the incidence or prevalence of anaemia and associated risk factors and/or associations between haemoglobin (Hb) or anaemia and mortality, major adverse cardiac events (MACE), hospitalisation, or CKD progression in adult patients with CKD. Extracted data were summarised as risk factors related to the incidence or prevalence of anaemia or the risk (hazard ratio (HR)) of outcome by Hb level (<10, 10-12, >12 g/dL) in patients not on dialysis and in those receiving dialysis. 191 studies met the predefined inclusion criteria. The risk factor most associated with the prevalence of anaemia was CKD stage, followed by age and sex. Mean HRs (95% CI) for all-cause mortality in patients with CKD on dialysis with Hb <10, 10-12, and >12 g/dL were 1.56 (1.43-1.71), 1.17 (1.09-1.26), and 0.91 (0.87-0.96), respectively. Similar patterns were observed for nondialysis patients and for the risks of hospitalisation, MACE, and CKD progression. This is the first known systematic review to quantify the risk of adverse clinical outcomes based on Hb level in patients with CKD. Anaemia was consistently associated with greater mortality, hospitalisation, MACE, and CKD progression in patients with CKD, and risk increased with anaemia severity. Effective treatments that not only treat the anaemia but also reduce the risk of adverse clinical outcomes are essential to help reduce the burden of anaemia and its management in CKD.

Association between Parathyroid Hormone, 25 (OH) Vitamin D, and Chronic Kidney Disease: A Population-Based Study

Identification of the accurate risk factor for CKD remains mandatory to combat the high prevalence of diseases. Growing evidence suggests the association of serum vitamin D with diverse health conditions. However, the relationship between vitamin D, intact parathyroid hormone (PTH), and calcium-phosphate metabolism and development of CKD remains controversial. We conduct this cross-sectional observational study to investigate the association between serum 25 (OH) vitamin D, intact PTH, and calcium and phosphate levels with eGFR and albuminuria, as a surrogate marker of CKD, in a community population. A total of 4080 participants were recruited. The mean age was 58.4 ± 13.3 years and 1480 (36.3%) were men. The mean eGFR was 94.1 ± 26.3 mL/min/1.73 m². The prevalence of CKD was 19.8%. Serum 25 (OH) vitamin D and log intact PTH levels were inversely correlated with eGFR but positively correlated with log albuminuria. Logistic regression analysis identified the log intact PTH as an independent factor associated with eGFR ≤ 60 mL/min/1.73 m² and proteinuria. This association was consistent when serum intact PTH was analyzed as continuous as well as categorical variables (as hyperparathyroidism). The relationship remains significant using resampling subset analysis with comparable baseline characteristics and adjustment for 25 (OH) vitamin D, calcium, and phosphate levels. This finding warranted further research to clarify the causal relationship of PTH/25 (OH) vitamin D with the risk of CKD in the general population.

Serum uric acid and mortality in chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

Studies have shown inconsistent results about the association between serum uric acid levels and mortality in patients with chronic kidney disease (CKD).

METHODS

A systematic literature search in MEDLINE, Web of Science and bibliographies of retrieved articles was performed to identify studies investigating the association between serum uric acid and mortality in patients with CKD. Pooled hazard ratios (HR) and corresponding 95% confidence intervals (CIs) were calculated using random-effects models.

RESULTS

A total of 24 studies with 25,453 patients with CKD were included. By meta-analysis, patients with the highest serum uric acid level were associated with a significantly higher risk for mortality (14 studies; HR, 1.52; 95% CI, 1.33-1.73) compared with patients with the lowest serum uric acid level. For dose-response analysis, a linear relationship (8 studies; Pfor non-linearity=0.14) between serum uric acid levels and risk of mortality was found. Overall, an increase of 1mg/dl in serum uric acid level was associated with an 8% increased risk of mortality (21 studies; HR, 1.08; 95% CI, 1.04-1.11).

CONCLUSIONS

Elevated serum uric acid levels are significantly associated with risk of mortality in patients with CKD. Further randomized controlled trials should attempt to determine whether it improves survival to target serum uric acid in patients with CKD.

Malnutrition in pre-dialysis chronic kidney disease patients in a teaching hospital in Southern Nigeria

BACKGROUND

Malnutrition is a complication in chronic kidney disease (CKD) known to affect quality of life and prognosis although not often diagnosed. It is associated with rapid progression to end stage renal disease (ESRD) and mortality. Early identification and treatment will slow down progression to ESRD and mortality.

OBJECTIVE

To determine the prevalence and pattern of malnutrition in pre-dialysis CKD patients in Southern Nigeria.

METHODS

One hundred and twenty consecutive pre-dialysis CKD and 40 control subjects without CKD were studied. Data obtained from participants were demographics, body mass index (BMI), and aetiology of CKD. Indices used to assess presence of malnutrition were low BMI, hypocholesterolaemia and hypoalbuminaemia. Statistical significance was taken at 0.05 level.

RESULTS

The mean age of the CKD subjects was 48.8±16.6years with a male: female ratio of 1.7:1. Prevalence of malnutrition in the CKD subjects was 46.7%, higher than 27.5% observed in the controls (p=0.033). Prevalence of malnutrition increased significantly across CKD stages 2 to 5 (p=0.020). It was significantly commoner in elderly patients (p=0.047) but not significantly different between males and females(p=0.188).

CONCLUSION

Malnutrition is common in pre-dialysis CKD patients even in early CKD stages. Prevalence of malnutrition increases with worsening kidney function and increasing age.

Association between human leucocyte antigen subtypes and risk of end stage renal disease in Taiwanese: a retrospective study

Background

End stage renal disease (ESRD) is prevalent in Taiwan. Human leukocyte antigens (HLA) have been found to be associated with the pathogenesis of autoimmune diseases, allergies and inflammatory bowel diseases, and there are emerging evidences of correlations between HLA genotypes and renal diseases such as diabetic nephropathy, IgA nephropathy, and glomerulonephritis. The aim of this study is to investigate detailed HLA subtypes in a case-control study of Taiwanese individuals.

Methods

The polymorphisms of HLA class I and II antigens in ESRD patients and a healthy control group were retrospectively analyzed. The information of 141 ESRD patients was obtained from the medical record of the Keelung branch of Chang Gung Memorial Hospital and was compared to the HLA type of a control group comprized of 190 healthy unrelated Taiwanese from one of our previous studies. In order to standardize the HLA designation of prior low-resolution typings with the more advanced DNA based typings, all HLA-A, −B and -DR were analyzed using a low resolution serologic equivalent.

Results

The current work suggests that HLA-DR3 (odds ratio = 1.91, 95 % CI = 1.098–3.324, P = 0.024, Pc = 0.312) and HLA-DR11 (odds ratio = 2.06, 95 % CI = 1.133–3.761, P = 0.021, Pc = 0.273) may represent susceptibility risk factors for the development of ESRD in Taiwanese individuals. On the other hand, HLA-DR8 (odds ratio = 0.47, 95 % CI = 0.236–0.920, p = 0.027. Pc = 0.351) may be a protective factor. HLA-A and -B antigens did not show any contribution of progression to ESRD. However, we note that the significance of all these findings is lost when the results are corrected for multiple comparisons according to Bonferroni. Further investigation with a larger group of patients and control is needed to resolve this issue.

Conclusions

HLA typing might be a useful clinical method for screening patients with high risk of progression to ESRD.

Risk prediction for chronic kidney disease progression using heterogeneous electronic health record data and time series analysis

BACKGROUND

As adoption of electronic health records continues to increase, there is an opportunity to incorporate clinical documentation as well as laboratory values and demographics into risk prediction modeling.

OBJECTIVE

The authors develop a risk prediction model for chronic kidney disease (CKD) progression from stage III to stage IV that includes longitudinal data and features drawn from clinical documentation.

METHODS

The study cohort consisted of 2908 primary-care clinic patients who had at least three visits prior to January 1, 2013 and developed CKD stage III during their documented history. Development and validation cohorts were randomly selected from this cohort and the study datasets included longitudinal inpatient and outpatient data from these populations. Time series analysis (Kalman filter) and survival analysis (Cox proportional hazards) were combined to produce a range of risk models. These models were evaluated using concordance, a discriminatory statistic.

RESULTS

A risk model incorporating longitudinal data on clinical documentation and laboratory test results (concordance 0.849) predicts progression from state III CKD to stage IV CKD more accurately when compared to a similar model without laboratory test results (concordance 0.733, P<.001), a model that only considers the most recent laboratory test results (concordance 0.819, P < .031) and a model based on estimated glomerular filtration rate (concordance 0.779, P < .001).

CONCLUSIONS

A risk prediction model that takes longitudinal laboratory test results and clinical documentation into consideration can predict CKD progression from stage III to stage IV more accurately than three models that do not take all of these variables into consideration.

Presence of early CKD-related metabolic complications predict progression of stage 3 CKD: a case-controlled study

BACKGROUND

Only a subset of patients who enter stage 3 chronic kidney disease (CKD) progress to stage 4. Identifying which patients entering stage 3 are most likely to progress could improve outcomes, by allowing more appropriate referrals for specialist care, and spare those unlikely to progress the adverse effects and costliness of an unnecessarily aggressive approach. We hypothesized that compared to non-progressors, patients who enter stage 3 CKD and ultimately progress have experienced greater loss of renal function, manifested by impairment of metabolic function (anemia, worsening acidosis and mineral abnormalities), than is reflected in the eGFR at entry to stage 3. The purpose of this case-controlled study was to design a prediction model for CKD progression using laboratory values reflecting metabolic status.

METHODS

Using data extracted from the electronic health record (EHR), two cohorts of patients in stage 3 were identified: progressors (eGFR declined >3 ml/min/1.73 m2/year; n=117) and non-progressors (eGFR declined <1 ml/min/1.713 m2; n=364). Initial laboratory values recorded a year before to a year after the time of entry to stage 3, reflecting metabolic complications (hemoglobin, bicarbonate, calcium, phosphorous, and albumin) were obtained. Average values in progressors and non-progressors were compared. Classification algorithms (Naïve Bayes and Logistic Regression) were used to develop prediction models of progression based on the initial lab data.

RESULTS

At the entry to stage 3 CKD, hemoglobin, bicarbonate, calcium, and albumin values were significantly lower and phosphate values significantly higher in progressors compared to non-progressors even though initial eGFR values were similar. The differences were sufficiently large that a prediction model of progression could be developed based on these values. Post-test probability of progression in patients classified as progressors or non-progressors were 81% (73% - 86%) and 17% (13% - 23%), respectively.

CONCLUSIONS

Our studies demonstrate that patients who enter stage 3 and ultimately progress to stage 4 manifest a greater degree of metabolic complications than those who remain stable at the onset of stage 3 when eGFR values are equivalent. Lab values (hemoglobin, bicarbonate, phosphorous, calcium and albumin) are sufficiently different between the two cohorts that a reasonably accurate predictive model can be developed.