Analysis of IL1 gene polymorphisms and transcript levels in periodontal and chronic kidney disease

The Role of Inflammation in CKD

Chronic kidney disease (CKD) affects many adults worldwide. Persistent low-grade inflammation is a substantial factor in its development and progression and has correlated with increased mortality and cardiovascular problems. This low-grade inflammation is a product of dysregulation of the normal balance between pro- and anti-inflammatory markers. Various factors such as increased innate immune system activation, reactive oxygen species production, periodontal disease, dysregulation of anti-inflammatory systems and intestinal dysbiosis result in the dysregulation of this balance. Furthermore, this low-grade inflammation has down-effects such as hypertension, renal fibrosis and acceleration of renal function decline. Moreover, low-grade inflammation over time has been linked to malignancy in CKD. As CKD progresses, many patients require dialysis, which has a negative bidirectional relationship with persistent inflammation. Treatment options for inflammation in CKD are vast, including cytokine inhibitors, statins and diets. However, more research is needed to create a standardized management plan. In this review, we will examine the normal physiology of the kidney and its relationship with the immune system. We will then delve into the pathology behind persistent inflammation, the various causes of inflammation, the downstream effects of inflammation, dialysis and potential treatments for inflammation in CKD.

A Systematic Review and Meta-Analysis on Multiple Cytokine Gene Polymorphisms in the Pathogenesis of Periodontitis

Aim

Periodontitis is an inflammatory disease that destroys both soft and hard periodontal tissues. However, a complex periodontal cytokine network remains unclear. This systematic review explored multiple cytokine gene polymorphisms in the pathogenesis of periodontitis.

Material and Methods

A systematic search was performed using the databases from previous publications, which indicated the association between cytokine polymorphisms and periodontitis pathogenesis. Meta-analysis was conducted using fixed or randomized models to calculate the significance of multiple cytokine polymorphisms. A total of 147 articles were analyzed with polymorphisms in 12 interleukins [Th1 (IL-2, IFN-γ, and TNF-α), Th2 (IL-4 and IL-13), Th17 (IL-1α, IL-1β, IL-6, and IL-17), and Treg cytokines (IL-10 and TGF-β)]. Doi plot was used to probe the occurrence of publication bias.

Results

The polymorphisms of IL-2 and TNF-α of Th1 cytokine family may be associated with the pathogenesis or the prevention of periodontitis risk, while the polymorphism of IFN-γ is not related to periodontitis risk. The polymorphisms for IL-4 and IL-13 of Th2 cytokine family are not found to be associated with the pathogenesis of periodontitis. For the polymorphisms of the members of Th17 cytokine family, different IL-1α polymorphisms may have inverse actions in the pathogenesis of periodontitis. IL-1β is a noteworthy cytokine biomarker in periodontitis development and progression. IL-6 may have a protective function in the inflammatory responses of periodontitis, and IL-17 has a weak relationship the inflammatory responses. The polymorphisms for the members of Treg cell cytokines may have a protective function against periodontitis risk. LFK indexes show the major asymmetry due to publication bias.

Conclusion

IL-1β is a notable cytokine biomarker in periodontitis risk. Treg cytokines favor an anti-inflammatory and protective environment. Further data are needed to confirm the present conclusion due to publication bias.

Periodontitis Exacerbates and Promotes the Progression of Chronic Kidney Disease Through Oral Flora, Cytokines, and Oxidative Stress

Periodontitis is a type of systemic immune inflammation that is caused by the complex infection of a variety of microorganisms in the subgingival plaque and the imbalance of the microbial ecological environment in the mouth. Periodontitis and chronic kidney disease (CKD) share many risk factors, such as obesity, smoking, and age. A growing body of data supports a strong correlation between periodontitis and kidney disease. Evidence supports the role of periodontal inflammation and elevated serum inflammatory mediators in renal atherosclerosis, renal deterioration, and end-stage renal disease (ESRD) development. Periodontitis is a risk factor for kidney disease. However, to our knowledge, there are few studies detailing the possible link between periodontitis and CKD. This review summarizes the possible mechanisms underlying periodontitis and CKD. More importantly, it highlights novel and potential pathogenic factors for CKD, including bacteria, pro-inflammatory mediators and oxidative stress. However, most research on the relationship between periodontitis and systemic disease has not determined causality, and these diseases are largely linked by bidirectional associations. Future research will focus on exploring these links to contribute to new treatments for CKD.

Formononetin ameliorates muscle atrophy by regulating myostatin-mediated PI3K/Akt/FoxO3a pathway and satellite cell function in chronic kidney disease

Muscle atrophy is a common complication in chronic kidney disease (CKD). Inflammation and myostatin play important roles in CKD muscle atrophy. Formononetin (FMN), which is a major bioactive isoflavone compound in Astragalus membranaceus, exerts anti‐inflammatory effects and the promotion of myogenic differentiation. Our study is based on myostatin to explore the effects and mechanisms of FMN in relation to CKD muscle atrophy. In this study, CKD rats and tumour necrosis factor α (TNF‐α)‐induced C2C12 myotubes were used for in vivo and in vitro models of muscle atrophy. The results showed that FMN significantly improved the renal function, nutritional status and inflammatory markers in CKD rats. Values for bodyweight, weight of tibialis anterior and gastrocnemius muscles, and cross‐sectional area (CSA) of skeletal muscles were significantly larger in the FMN treatment rats. Furthermore, FMN significantly suppressed the expressions of MuRF‐1, MAFbx and myostatin in the muscles of CKD rats and the TNF‐α‐induced C2C12 myotubes. Importantly, FMN significantly increased the phosphorylation of PI3K, Akt, and FoxO3a and the expressions of the myogenic proliferation and differentiation markers, myogenic differentiation factor D (MyoD) and myogenin in muscles of CKD rats and the C2C12 myotubes. Similar results were observed in TNF‐α‐induced C2C12 myotubes transfected with myostatin‐small interfering RNA (si‐myostatin). Notably, myostatin overexpression plasmid (myostatin OE) abolished the effect of FMN on the phosphorylation of the PI3K/Akt/FoxO3a pathway and the expressions of MyoD and myogenin. Our findings suggest that FMN ameliorates muscle atrophy related to myostatin‐mediated PI3K/Akt/FoxO3a pathway and satellite cell function.

Polymorphisms in the interleukin genes and chronic periodontitis: A field synopsis and revaluation by Bayesian approaches

Periodontitis is a high prevalent disease into the clinical dentistry. Genetic variations in interleukins (IL) genes were associated with chronic periodontitis (CP) and were focus of several meta-analyses. This study aimed to assess the noteworthiness in the meta-analyses by means of a Bayesian approach to determinate possible false report associations. A systematic search was performed for meta-analyses with associations between gene polymorphisms in interleukins and CP. The calculations for the False-Positive Rate Probability (FPRP) and the Bayesian False Discovery Probability (BFDP) were performed to assess the noteworthiness with a statistical power of 1.2 and 1.5 of Odds Ratio at a prior probability of 10^-3 and 10^-6. As results, eight meta-analyses approaching the IL1A/rs1800587, IL1B/rs1143634, IL1RN/rs2234663, IL4/rs2243250, IL6/rs1800795/rs1800796, IL17A/rs2275913 and IL18/rs1946518/rs187238 polymorphisms have been identified. Twenty-two from 270 calculations (8.15%) were noteworthy. Herein, we have identified the IL1A and IL1B polymorphisms as noteworthy biomarkers for CP susceptibility.

Interleukin 1α and 1β gene variations are associated with tuberculosis in silica exposed subjects

INTRODUCTION

Silicosis is a fibrotic lung disease resulting from the inhalation of crystalline silica and can be classified as simple or complicated according to the International Labour Organization criteria. Furthermore, individuals exposed to crystalline silica also have a higher risk for the development of tuberculosis (Tb). The contribution of inflammatory cytokines to the risk of silicosis and Tb in different populations has previously been reported. Since genetic background might be related to susceptibility to silicosis and Tb, the study of polymorphisms within IL-1α, IL-1β, and tumor necrosis factor protein-coding genes may contribute to elucidating the genetic basis of these diseases.

METHODS

Single nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction using restriction fragment length polymorphism or by Taqman methodology, in a sample of 102 silica-exposed patients from Brazil.

RESULTS

No significant associations were observed between the SNPs studied and the severity of silicosis. However, significant associations were found between Tb and the C allele (odds ratio [OR] = 1.93, 95% confidence interval [CI], 1.01-3.73) and the CC genotype (OR = 2.34, 95% CI, 1.04-5.31) of IL1A -899C>T. The IL1B +3954C>T polymorphism also showed an association with Tb (T allele dominant model OR = 2.38, 95% CI, 1.04-5.41).

CONCLUSION

These preliminary results demonstrate that the IL1A and IL1B gene variations may contribute to some extent to susceptibility to Tb, but not silicosis. However, additional studies are still needed to confirm these results.

Association between Monocyte Chemoattractant Protein-1 -2518 (A/G) Single Nucleotide Polymorphism and Chronic Periodontitis in End-stage Renal Disease Patients - A Case-control Study

Monocyte chemoattractant protein 1 (MCP-1) plays an important role in the development of periodontitis. The purpose of this investigation was to evaluate association of the  MCP-1 gene polymorphism with chronic periodontitis in patients with end-stage renal disease (ESRD). One hundred fifty ESRD patients with chronic periodontitis (CP), 100 without CP and 190 healthy controls were included in this study. Genomic DNA from all participants was genotyped for the -2518 (A/G) polymorphism by a polymerase chain reaction - restriction fragment length polymorphism (PCR--RFLP) assay. Significant differences were observed in the genotype and allele frequencies between patients with ESRD and CP and controls.  The G allele frequency was significantly higher in patients than in control subjects, with odds ratio 1.77 (95 % CI 1.2-2.5), p = 0.0014. For the GG genotype the OR was 3.63 (95 % CI 1.5-8.76), p = 0.041.  No significant differences in the polymorphism distribution were observed between ESRD patients  without CP and control subjects. Comparison of the MCP-1 gene polymorphism distribution in ESRD patients with various primary diseases leading to ESRD did not show any significant differences. The mean MCP-1 serum levels were compared between subgroups. They were significantly higher in ESRD patients with CP (582 ± 112 pg/ml) than in patients without CP (309 ± 103 pg/ml) and controls (265 ± 85 pg/ml). Our results suggest that the MCP-1-2518 A/G  polymorphism might be a novel risk factor for developing chronic periodontitis in patients with ESRD.

Quality of methods and reporting in association studies of chronic periodontitis and IL1A -889 and IL1B +3953/4 SNPs: A systematic review

OBJECTIVE

The aim of this systematic review was to evaluate the quality of reporting and methodology in genetic association studies between IL1A -889 and IL1B +3954 polymorphisms and chronic periodontitis.

BACKGROUND

Evidence provided by periodontal research on genetic risk factors is of uttermost importance in clinical practice as a possible diagnostic and prognostic tool for periodontitis. Inadequate reporting of results as well as high risk of bias due to methodological inconsistency hampers the integration of evidence in terms of clinical applicability.

METHODS

This review includes case-control studies in humans published between 1997 and July 2017. Searching was conducted through MEDLINE, EMBASE, and search handing. Specific scoring systems have been developed to evaluate the quality of methods and reporting. Each article was scored according to its adequacy, and then, the total number and the percentage of items positively qualified for both methods and reporting were calculated. The quality of methods in studies scoring 0-6, 7-12, and 13-16 was, respectively, considered poor, moderate, and good. For reporting, scores of 0-9, 10-18, and 19-26 were deemed of poor, moderate, and good quality, respectively. Pearson's correlation coefficient was calculated to explore the correlation between the year of publication and the quality in terms of methods and reporting.

RESULTS

From the 531 screened studies, 52 met the inclusion criteria and were thus included in the study. The quality of methods and reporting of published genetic association papers on IL1 and chronic periodontitis is moderate. On a scale from 0 to 16, the mean score for methods of the reviewed studies was 8.19 ± 1.93. The items more frequently considered inadequate concerned the handling of confounders in statistical analysis, especially oral hygiene habits, socioeconomic status, subgingival colonization of specific periodontal pathogens, and stress. A significant positive correlation was found between the year of publication and the quality scores in terms of method (r = 0.401, P = 0.003). In terms of reporting, the mean score was 14.83 ± 3.04 on a scale from 0 to 26 and it was considered overall moderate. No statistically significant correlation was found between the year of publication and the quality of reporting (P = 0.266).

CONCLUSIONS

The association between IL1A -889 and IL1B +3954 polymorphisms and chronic periodontitis is questionable due to methodological inconsistency. Evidence arising from meta-analysis is unreliable due to high risk of bias and moderate quality in terms of reporting.

Lack of Association between Interleukin-1β Gene Polymorphism (rs16944) and Chronic Periodontitis: From a Case-Control Studies to an Updated Meta-Analysis

Background

Interleukin-1β (IL-1β) plays an important role as a mediator of various inflammatory responses in chronic periodontitis. Several studies have investigated the potential relationship between IL-1β polymorphism (rs16944) and susceptibility to chronic periodontitis; inflammatory process is involved, but conclusions is still controversial.

Objective

The aim of this study was to determine whether the IL-1β polymorphism (rs16944) is associated with susceptibility to chronic periodontitis.

Material and Methods

For the case-control study, 51 patients with chronic periodontitis and 33 healthy control patients were recruited in the study. Genotyping was conducted by direct sequencing. SNPStats and SPSS 18.0 were used for the analysis of genetic data and to evaluate odds ratios, 95% confidence intervals, and P values; logistic regression models were used. And to perform meta-analysis, studies about IL-1β polymorphism (rs16944) and chronic periodontitis were searched in PubMed, Embase, Google Scholar, and Korean Studies Information Service System (KISS) electronic databases until July 2017.

Results

In our case-control study, no significant relationship was revealed between IL-1β polymorphism (rs16944) and chronic periodontitis (P > 0.05 in each model). When combined with the previous studies in the meta-analysis, the result was not associated with chronic periodontitis in any of the models (CC vs. CT + TT: OR = 0.97, 95% CI = 0.762–1.246; CC + CT vs. TT: OR = 0.90, 95% CI = 0.658–1.232; and C vs. T: OR = 0.93, 95% CI = 0.774–1.128). The subgroup analysis stratified by ethnicity showed a weak association between the IL-1β polymorphism (rs16944) and chronic periodontitis in the Caucasian population (recessive model, OR = 1.34, 95% CI = 1.017–1.758, P = 0.037).

Conclusion

Evidences from a case-control study and the meta-analysis suggest that IL-1β polymorphism (rs16944) is not associated with susceptibility to chronic periodontitis.

IL4 gene VNTR polymorphism in chronic periodontitis in end-stage renal disease patients

OBJECTIVE

Interleukin-4 gene polymorphisms were found to be associated with periodontitis. The purpose of this case-control study was to evaluate association of IL4 VNTR polymorphism with periodontitis in patients with end-stage renal disease (ESRD).

SUBJECTS AND METHODS

We examined 180 ESRD patients with chronic periodontitis, 82 without CP and 180 healthy controls. Genomic DNA from all subjects was genotyped for the IL4 VNTR polymorphism by polymerase chain reaction (PCR).

RESULTS

Genotype distribution in all groups followed Hardy-Weinberg equilibrium. Significant differences in genotype and allele frequencies were observed between groups. The patient group had higher frequency of P1 allele than controls, with odds ratio for P1 allele 1.6 (95% CI 1.1-2.3) and P1P1 genotype 2.73 (95% CI 1.06-7.5). There were no differences in polymorphism distribution between ESRD patients without CP and controls. Periodontal disease was more severe in older patients (≥50 years). Similarly, patients with T2DM had more severe manifestation of CP than patients without diabetes (p = 0.01 for plaque index, p = 0.004 for bleeding index and p = 0.03 for gingival index).

CONCLUSION

Our findings suggest that VNTR polymorphism in IL4 gene might be a risk factor for chronic periodontitis in patients with ESRD.

The Roles of Genetic Factors in Kawasaki Disease: A Systematic Review and Meta-analysis of Genetic Association Studies

This systematic review and meta-analysis aimed to better elucidate the roles of genetic factors in Kawasaki disease (KD), and determine the potential genetic biomarkers of KD. The systematic literature search of PubMed, Medline, Embase, Web of Science and CNKI identified 164 eligible studies. The qualitative synthesis revealed that 62 genes may be correlated with the susceptibility to KD, and 47 genes may be associated with the incidence of coronary artery lesions (CALs) in KD. A total of 53 polymorphisms in 34 genes were investigated in further quantitative synthesis. Of these, 23 gene polymorphisms were found to be significantly correlated with KD susceptibility, and 10 gene polymorphisms were found to be significantly associated with the incidence of CALs in KD. In conclusion, our findings indicate that gene polymorphisms of ACE, BLK, CASP3, CD40, FCGR2A, FGβ, HLA-E, IL1A, IL6, ITPKC, LTA, MPO, PD1, SMAD3, CCL17 and TNF may affect KD susceptibility. Besides, genetic variations in BTNL2, CASP3, FCGR2A, FGF23, FGβ, GRIN3A, HLA-E, IL10, ITPKC and TGFBR2 may serve as biomarkers of CALs in KD.

Advanced cancer pain: the search for genetic factors correlated with interindividual variability in opioid requirement

AIM

To assess association between genetic variants and opioid requirement in cancer patients.

MATERIALS & METHODS

A prospective observational trial of 243 advanced cancer patients with inadequate analgesia treated by the palliative care team was analyzed for ABCB1, ARRB2, COMT, GCH1, IL1RN, KCNJ6, OPRM1, RHBDF2, SCN9A and Stat6 polymorphisms.

RESULTS

For patients carrying OPRM1 118AG/GG and COMT 472GG (Val158Val) or these genotypes alone, a significant higher median percentage dose increase was observed (95.2% [32.8-345]) compared with OPRM1 118AA and COMT 472GA/AA (158Met allele carriers; 48.5% [0-98.8]; p = 0.0016). No associations were found with morphine equivalent dose after consultation palliative care team or ketamine use.

CONCLUSION

Patients with the combined OPRM1 118AG/GG and COMT 472GG genotype required 50% higher dose increase for sufficient analgesia.

Relationship between -889 C/T polymorphism in interleukin-1A gene and risk of chronic periodontitis: Evidence from a meta-analysis with new published findings

Background

Periodontitis results from an inflammatory response caused by accumulative microorganisms in periodontal sites. Several factors are involved in pathogenesis of periodontitis, for example the -889 C/T polymorphism in interleukin-1A gene. This study aimed to evaluate the relationship between this polymorphism and risk of development of chronic periodontitis by a meta-analysis based in new published findings.

Material and Methods

Thereunto a review in literature was performed in the electronic biomedical and education databases (Cochrane Library, Google Scholar, MEDLINE and PubMed) to studies published before August 2, 2015, the abstracts were evaluated and the data extraction performed by two calibrated examiners. The calculations of the meta-analysis were obtained through statistical software Review Manager version 5.2 with calculation of Odds Ratio (OR), heterogeneity (I²) and Funnel plots with P <0.05.

Results

In overall, twenty-one case/control studies were selected with 2,174 patients with chronic periodontitis and 1, 756 controls. The meta-analysis showed T allele was associated with chronic periodontitis (OR = 1.22, 95% CI: 1.09, 1.36, P = 0.0004) with decreased value to heterogeneity (I² = 15%, P = 0.28). TT genotype was associated to patients with chronic periodontitis (OR = 1.40, 95% CI: 1.07, 1.83, P = 0.01). No publication bias was found in this meta-analysis by asymmetry in Funnel plots.

Conclusions

This meta-analysis with 2,174 patients with chronic periodontitis and 1, 756 controls evidenced the -889 C/T polymorphism is associated to risk of development of chronic periodontitis with no significant value to heterogeneity to allelic evaluation.

Key words:Alleles, odds ratio, periodontal disease, cytokines.

Interaction of IL1B and IL1RN polymorphisms, smoking habit, gender, and ethnicity with aggressive and chronic periodontitis susceptibility

Background:

Although the interleukin-1 (IL-1) plays a critical role in the pathogenesis of periodontitis, associations between IL1 gene cluster polymorphisms and the disease remains unclear.

Aims:

To investigate the importance of IL1B-511C>T (rs16944), IL1B +3954C>T (rs1143634), and IL1RN intron 2 variable number tandem repeat (VNTR) (rs2234663) polymorphisms, individually or in combination, as the risk factors of periodontitis in a Southeastern Brazilian population with a high degree of miscegenation.

Subjects and Methods:

A total of 145 individuals, with aggressive (aggressive periodontitis [AgP], n = 43) and chronic (chronic periodontitis [CP], n = 52) periodontitis, and controls (n = 50) were genotyped by polymerase chain reaction (PCR) (IL1RN intron 2 VNTR) or PCR-restriction fragment length polymorphism (PCR-RFLP) (IL1B-511 C>T and IL1B + 3954C>T) techniques.

Statistical Analysis:

The independent t-test, Chi-square, and Fisher's exact tests were used. The SNPStats program was used for haplotype estimation and multiplicative interaction analyses.

Results:

The IL1B +3954T allele represented risk for CP (odds ratio [OR] = 2.84), particularly in smokers (OR = 4.43) and females (OR = 6.00). The minor alleles IL1RN*2 and *3 increased the risk of AgP (OR = 2.18), especially the IL1RN*2*2 genotype among  white Brazilians (OR = 7.80). Individuals with the combinations of the IL1B + 3954T and IL1RN*2 or *3-containing genotypes were at increased risk of developing CP (OR = 4.50). Considering the three polymorphisms (rs16944, rs1143634, and rs2234663), the haplotypes TC2 and CT1 represented risk for AgP (OR = 3.41) and CP (OR = 6.39), respectively.

Conclusions:

Our data suggest that the IL1B +3954C>T and IL1RN intron 2 VNTR polymorphisms are potential candidates for genetic biomarkers of periodontitis, particularly in specific groups of individuals.

Regulatory elements and genetic variations in periodontal diseases

OBJECTIVE

Current evidence suggests that many GWAS and IL1 SNPs are associated with periodontal diseases but their functional role remains ambiguous. Therefore, it is imperative to elucidate the molecular pathways through which these SNPs might act on the development of the disease. The purpose of this review was to highlight the regulatory elements of noncoding regions of the genome and provide insights on the functional role of periodontitis-associated GWAS and IL1 SNPs.

DESIGN

A search was performed using ENCODE data available on different browsers.

RESULTS

GWAS and IL1 SNPs overlap DNase I hypersensitivity sites, histone modifications and transcription binding sites. Some of these noncoding variants influenced the transcription activity of inflammatory genes.

CONCLUSION

SNPs associated with periodontal diseases may contribute to the development of the disorder through their functional roles. Unraveling the character of genetic components might explain the diversity of clinical phenotypes among population groups as well as disease susceptibility.

Inflammation and nutrition in children with chronic kidney disease

Chronic inflammation and nutritional imbalance are important comorbid conditions that correlate with poor clinical outcomes in children with chronic kidney disease (CKD). Nutritional disorders such as cachexia/protein energy wasting, obesity and growth retardation negatively impact the quality of life and disease progression in children with CKD. Inadequate nutrition has been associated with growth disturbances in children with CKD. On the other hand, over-nutrition and obesity are associated with poor outcomes in children with CKD. The exact mechanisms leading to these unfavorable conditions are not fully elucidated and are most likely multifactorial. In this review, we focus on the pathophysiology of nutrition disorders and inflammation and their impact on clinical outcomes in children with CKD.

Association among oral health parameters, periodontitis, and its treatment and mortality in patients undergoing hemodialysis

BACKGROUND

Chronic periodontitis (CP) is a continuous, reversible source of inflammation with a potential impact on mortality in patients undergoing hemodialysis (HD). This study investigates the impact of oral health indicators, CP, and its treatment on survival rates in a group of patients undergoing HD.

METHODS

Clinically stable patients undergoing HD were referred for a dental examination. All patients were prospectively followed in the dialysis clinic, and all-cause mortality was recorded. Three groups of patients were analyzed: those who received CP treatment, those who did not, and patients without CP as a control group.

RESULTS

A total of 122 patients (79 males and 43 females, aged 23 to 77 years; mean age: 50 years; range: 23 to 77 years) were enrolled. Forty percent reported having rarely been evaluated by a dentist, and 59% had CP. There were 34 fatal events during a mean follow-up time of 64.1 ± 11.2 months. Oral factors associated with death in the univariate analysis were decreased frequency of dental visits; non-use of dental floss; increased decayed, missing, and filled teeth index; presence of CP; and absence of CP treatment. Patients with CP had a higher risk of death from all causes compared with patients without CP in the univariate analysis for untreated patients (hazard ratio 2.65 [95% confidence interval 1.06 to 6.59]; P = 0.036) and to a lesser extent for treated patients (2.36 [1.01 to 5.59]; P = 0.047). These significant differences were not maintained after adjustments for confounders in the multivariate model.

CONCLUSIONS

These results suggest that poor oral health, including CP, is a common finding in patients undergoing HD. The results of this study call for intervention trials to test the hypothesis that treatment of CP improves survival in maintenance of patients undergoing HD.