Serum Folate and All-Cause Mortality is of Non-Linear Relationship Among Population with Chronic Kidney Disease: A Retrospective Cohort Study

Prevalence of anaemia, iron, and vitamin deficiencies in the health system in the Republic of Ireland: a retrospective cohort study

BACKGROUND

Anaemia is a common but treatable condition that predicts adverse clinical outcomes. However, standards of anaemia management vary considerably.

AIM

To estimate the prevalence of anaemia and extent of screening for common underlying causes in the healthcare system in the Republic of Ireland.

DESIGN & SETTING

We conducted a retrospective cohort study of 112 181 adult patients, aged ≥18 years, who had a full blood count performed in 2013, using data from the National Kidney Disease Surveillance System.

METHOD

The prevalence of anaemia was determined across demographic and clinical subgroups, according to World Health Organization (WHO) definitions. The proportion screened for iron, vitamin B12, and folate deficiency was determined within a 3-month follow-up period and the corresponding prevalence for each deficiency determined.

RESULTS

The overall prevalence of anaemia was 12.0% (95% confidence interval [CI] = 11.8% to 12.2%) and was higher in women than men (13.2% versus 10.5%, P<0.001). Anaemia increased with advancing age (33.4% for those aged >75 years) and worsening kidney function (8.2%, 10.9%, 33.2%, and 63.8% for each estimated glomerular filtration rate [eGFR] categories >90, 60-89, 30-59 and <30 ml/min/1.73 m², respectively, P<0.001). After 3-months' follow-up, the proportion screened for iron deficiency was 11.2% based on transferrin saturation and 33.7% using serum ferritin. Screening for folate and B12 deficiency was 17.6% and 19.8%, respectively. Among screened patients, the prevalence of iron deficiency, B12, and folate deficiency was 37.0%, 6.3%, and 5.8%, respectively.

CONCLUSION

The burden of anaemia in the healthcare system is substantial especially for older patients and those with advanced kidney disease. Low screening rates for iron, B12, and folate deficiency are common and warrant quality improvement initiatives.

Non-linear associations of serum and red blood cell folate with risk of cardiovascular and all-cause mortality in hypertensive adults

This study aims to assess the associations of serum and red blood cell (RBC) folate with cardiovascular and all-cause mortality in hypertensive adults. Data on serum and RBC folate from the 1999-2014 National Health and Nutrition Examination Survey were included. Through December 31, 2015, cardiovascular and all-cause mortality were identified from the National Death Index. Multiple Cox regression and restricted cubic spline analyses were used to determine the relationship between folate concentrations and outcomes. A total of 13,986 hypertensive adults were included in the analysis (mean age, 58.5 ± 16.1 years; 6898 [49.3%] men). At a median of 7.0 years of follow-up, 548 cardiovascular deaths and 2726 all-cause deaths were identified. After multivariable adjustment, the fourth quartile of serum folate was associated with cardiovascular (HR = 1.32 [1.02-1.70]) and all-cause (HR = 1.20 [1.07-1.35]) mortality compared to the second quartile, whereas the first quartile was only linked with increased all-cause (HR = 1.29 [1.15-1.46]) mortality. The inflection points for the non-linear associations of serum folate with cardiovascular and all-cause mortality were 12.3 ng/mL and 20.5 ng/mL, respectively. In addition, the highest quartile of RBC folate was associated with cardiovascular (HR = 1.68 [1.30-2.16]) and all-cause (HR = 1.30 [1.16-1.46]) mortality compared to the second quartile, but the lowest quartile was not associated with either outcome. The inflection points for the non-linear associations of RBC folate with cardiovascular and all-cause mortality were 819.7 and 760.1 ng/mL, respectively. The findings suggest non-linear associations between serum and RBC folate levels and the risk of cardiovascular and all-cause mortality in hypertensive adults.

Demand for Water-Soluble Vitamins in a Group of Patients with CKD versus Interventions and Supplementation-A Systematic Review

BACKGROUND

Increasingly, chronic kidney disease (CKD) is becoming an inevitable consequence of obesity, metabolic syndrome, and diabetes. As the disease progresses, and through dialysis, the need for and loss of water-soluble vitamins both increase. This review article looks at the benefits and possible risks of supplementing these vitamins with the treatment of CKD.

METHODS

Data in the PubMed and Embase databases were analyzed. The keywords "chronic kidney disease", in various combinations, are associated with thiamin, riboflavin, pyridoxine, pantothenic acid, folates, niacin, cobalamin, and vitamin C. This review focuses on the possible use of water-soluble vitamin supplementation to improve pharmacological responses and the overall clinical condition of patients.

RESULTS

The mechanism of supportive supplementation is based on reducing oxidative stress, covering the increased demand and losses resulting from the treatment method. In the initial period of failure (G2-G3a), it does not require intervention, but later, especially in the case of inadequate nutrition, the inclusion of supplementation with folate and cobalamin may bring benefits. Such supplementation seems to be a necessity in patients with stage G4 or G5 (uremia). Conversely, the inclusion of additional B6 supplementation to reduce CV risk may be considered. At stage 3b and beyond (stages 4-5), the inclusion of niacin at a dose of 400-1000 mg, depending on the patient's tolerance, is required to lower the phosphate level. The inclusion of supplementation with thiamine and other water-soluble vitamins, especially in peritoneal dialysis and hemodialysis patients, is necessary for reducing dialysis losses. Allowing hemodialysis patients to take low doses of oral vitamin C effectively reduces erythropoietin dose requirements and improves anemia in functional iron-deficient patients. However, it should be considered that doses of B vitamins that are several times higher than the recommended dietary allowance of consumption may exacerbate left ventricular diastolic dysfunction in CKD patients.

CONCLUSIONS

Taking into account the research conducted so far, it seems that the use of vitamin supplementation in CKD patients may have a positive impact on the treatment process and maintaining a disease-free condition.

Riboflavin Intake Inversely Associated with Cardiovascular-Disease Mortality and Interacting with Folate Intake: Findings from the National Health and Nutrition Examination Survey (NHANES) 2005-2016

The association between intakes of riboflavin and mortality has not been examined intensively in general populations. In this study, 10,480 adults in the 2005-2016 National Health and Nutrition Examination Survey (NHANES) were followed-up until 2019 for their vital status. Riboflavin and folate were assessed by two-day 24 h recall. The date and cause of death were obtained from the US Mortality Registry. The risks of all-cause mortality and cardiovascular disease (CVD) mortality were investigated using a Cox regression analysis. During a mean of 8.5 years follow-up, there were 1214 deaths registered (including 373 deaths from CVD and 302 from cancer). Compared to low level (quartile 1, Q1) of riboflavin intake, the hazard ratios (HRs) (95% confidence interval (CI)) for high level (quartile 4, Q4) were 0.53 (0.31-0.90) for CVD mortality and 0.62 (0.48-0.81) for all-cause mortality. The inverse association between riboflavin intake and CVD mortality was only significant among those with a high intake of folate (p for interaction 0.045). Those with a high folate intake (Q4) and low intake of riboflavin (Q1) had the highest risk of CVD mortality (HR 4.38, 95% CI 1.79-10.72), as compared with a high intake of both riboflavin and folate. In conclusion, riboflavin intake was inversely associated with all-cause mortality and CVD mortality, and the association was modified by folate intake.

Associations of Serum and Red Blood Cell Folate With All-Cause and Cardiovascular Mortality Among Hypertensive Patients With Elevated Homocysteine

Objectives

This study aims to explore the associations between serum and red blood cell (RBC) folate as indicators of short- and long-term folate status, respectively, and all-cause as well as CVD mortality among hypertensive patients with elevated homocysteine.

Methods

A prospective cohort study of the National Health and Nutrition Examination Survey (1999–2006) and 2015 Linked Mortality File was performed. All-cause and CVD mortality risk estimated using Cox proportional hazards models with adjusting for multiple potential covariates.

Results

A total of 1,753 hypertensive patients with elevated homocysteine [mean (SD) age, 68.5 (13.1)] were included in the analysis. During a median follow-up of 10.0 years, a total of 899 all-cause and 257 CVD deaths occurred. Compared the highest with the lowest quartile of RBC folate, the multivariable adjusted hazard ratios and 95% confidence intervals for all-cause and CVD death were 1.13 (0.92–1.39) and 1.47 (1.01–2.16) respectively. There was a significant and positive trend between RBC folate and the risk of CVD death (p for trend = 0.0196). No significant association was found between serum folate and mortality risk among the study sample.

Conclusions

High level of RBC folate is associated with an increased risk of cardiovascular mortality among hypertensive patients with elevated homocysteine while serum folate has no such effects.

Associations Between the Metabolic Score for Insulin Resistance Index and the Risk of Type 2 Diabetes Mellitus Among Non-Obese Adults: Insights from a Population-Based Cohort Study

Purpose

The metabolic score for insulin resistance (METS-IR) index is an emerging surrogate predictor of type 2 diabetes mellitus (T2DM). This study aimed to evaluate the association between the METS-IR index and the risk of T2DM in non-obese Japanese adults.

Methods

A total of 12,290 non-obese participants were selected from the NAGALA prospective cohort study conducted from 2004 to 2015. Cox proportional hazards models were used to assess the association between the baseline METS-IR index and risk of T2DM. Generalized additive models were used to identify nonlinear relationships. In addition, we performed subgroup analyses and interaction tests. Results were expressed as hazard ratios (HRs) and 95% confidence intervals (CIs).

Results

During a median follow-up of 2050 days, 176 (1.43%) incident T2DM occurred. The fully adjusted HR (95% CI) for the incidence of T2DM in non-obese adults was 1.17 (HR=1.17, 95% CI: 1.09–1.27, P<0.001) for every 1-unit increase in the METS-IR index. The risk of developing T2DM increased with the quartile of change in the METS-IR index, after adjustment for multiple potential confounding, the HRs for the Q4 group versus the Q1 group was 4.01 (95% CI, 1.39–11.57). Generalized additive models also showed a cumulative increase in the risk of T2DM with increasing the METS-IR index. Time-dependent receiver operating curve suggested helpful discriminative power of the METS-IR index for T2DM. The C-statistics by the clinical risk factors significantly improve with the addition of the METS-IR index (from 0.862 to 0.875, P = 0.035); the discriminatory power and risk reclassification also appeared to be substantially better, with the category-free NRI of 0.216, and the IDI of 0.011.

Conclusion

The METS-IR index was a significant and independent predictor for future T2DM development in non-obese adults. The METS-IR index may have clinical significance in identifying groups at high risk of T2DM.