Periodontal status and clinical outcomes in kidney transplant recipients: A systematic review

Demystifying the connection between periodontal disease and chronic kidney disease - An umbrella review

Chronic kidney disease (CKD) and poor oral health are inter-related and their significant impact on each other is well established in the literature. Many systematic reviews and meta-analyses have demonstrated a strong relationship between CKD and periodontitis, where periodontal treatment has shown potential in improving CKD outcomes. However, the quality of the studies and heterogeneity of the results show variation. The aim of this umbrella review was to review the quality of the current systematic reviews on the relationship between CKD and oral health with an emphasis on periodontal disease and to generate clinically relevant guidelines to maintain periodontal health in patients with CKD. This umbrella review was conducted and reported in alignment with the Joanna Briggs Institute and the PRISMA 2020 guidelines. The review protocol was established prior to commencing the review and registered on JBI and PROSPERO (CRD42022335209). Search strings were established for PubMed, Embase, Web of Science, Cochrane Database of Systematic Reviews, and Dentistry & Oral Science Source up to April 2022. All systematic reviews and meta-analyses that considered the relationship between CKD and periodontitis or periodontal treatment were included. Of 371 studies identified through the systematic search, 18 systematic reviews met the inclusion criteria. Ten studies assessed the relationship between oral health status and CKD with a focus on periodontitis and CKD, five reviewed the impact of periodontal treatment on CKD outcomes, two included both relationship and effectiveness of periodontal treatment and one qualitatively reviewed oral health-related quality of life in patients with kidney failure. Findings indicate there is a bidirectional relationship between CKD and periodontal disease. In view of the heterogeneity of the existing literature on CKD and periodontal disease, specific recommendations for the management of periodontitis among patients with CKD are proposed for medical professionals, dental professionals, and aged care workers based on the evidence collated in this review.

Glucose as a Risk Factor for Periodontitis in Kidney Transplantation Patients

BACKGROUND

Various factors including diabetes and oxidative stress are associated with periodontal inflammation. End-stage renal disease causes various systemic abnormalities in patients, including cardiovascular disaese, metabolic abnormalities, and infection. Even after kidney transplantation (KT), these factors are known to be associated with inflammation. Our study, therefore, aimed to study risk factors associated with periodontitis in KT patients.

METHODS

Patients who visited Dongsan Hospital, Daegu, Korea since 2018 and have undergone KT were selected. As of November 2021, 923 participants, with full data including hematologic factors were studied. Periodontitis was diagnosed based on residual bone level in panoramic views. Patients were studied by the presence of periodontitis.

RESULTS

From 923 KT patients, 30 were diagnosed with periodontal disease. Fasting glucose levels were higher in patients with periodontal disease, and total bilirubin levels were lower. When divided by fasting glucose levels, high glucose level showed increase of periodontal disease with odds ratio of 1.031 (95% confidence interval 1.004-1.060). After adjusting for confounders, the results were significant with odds ratio of 1.032 (95% CI 1.004-1.061).

CONCLUSIONS

Our study showed that KT patients, of whom uremic toxin clearance has been revolted, are yet at risk of periodontitis by other factors, such as high blood glucose levels.

Risk factors of severe periodontitis in kidney transplant recipients: A case-control study

BACKGROUND

Kidney transplant recipients (KTRs) represent a vulnerable group of patients who develop a number of comorbidities. Severe periodontitis (SP) is associated with the most common chronic systemic diseases including kidney diseases. The objective of this study was to explore the risk factors for SP in KTRs.

METHODS

In this study, KTRs were divided into those with or without periodontitis and in relation to the severity of periodontitis. A comprehensive medical and periodontal examination was performed and evaluated. Multivariate logistic regression was performed to examine possible risk factors for SP among KTRs.

RESULTS

A total of 100 KTRs were included in the analysis, of which 87% had periodontitis. Significant predictors of periodontitis were older age (OR = 1.07, 95% CI [1.01, 1.13], p = 0.016) and lower skeletal muscle mass (OR = 0.88, 95% CI [0.78, 0.99], p = 0.035). When examining periodontitis severity, predictors of SP (n = 21, 24%) were increased levels of uric acid (OR = 1.01, 95% CI [1.00, 1.02], p = 0.022) and dental plaque (OR = 1.04, 95% CI [1.01, 1.07], p = 0.013). In the subset analysis that included only KTRs with measured advanced glycation end products (AGE) (n = 47), 34% (n = 16) had SP. The predictors of SP were AGE (OR = 3.89, 95% CI [1.28, 11.82], p = 0.017) and dental plaque (OR = 1.07, 95% CI [1.01, 1.13], p = 0.028).

CONCLUSIONS

KTRs with SP had significantly higher uric acid levels and AGE, which may contribute to the systemic health status of this patient population.

Effects of periodontal pathogen-induced intestinal dysbiosis on transplant immunity in an allogenic skin graft model

Periodontal disease can induce dysbiosis, a compositional and functional alteration in the microbiota. Dysbiosis induced by periodontal disease is known to cause systemic inflammation and may affect transplant immunity. Here, we examined the effects of periodontal disease-related intestinal dysbiosis on transplant immunity using a mouse model of allogenic skin graft in which the mice were orally administered the periodontal pathogen Porphyromonas gingivalis (Pg). For 6 weeks, the Pg group orally received Pg while the control group orally received phosphate-buffered saline solution. After that, both groups received allogenic skin grafts. 16 s rRNA analysis of feces revealed that oral administration of Pg significantly increased three short chain fatty acids (SCFAs) producing genera. SCFA (acetate and propionate) levels were significantly higher in the Pg group (p = 0.040 and p = 0.005). The ratio of regulatory T cells, which are positively correlated with SCFAs, to total CD4+ T cells in the peripheral blood and spleen was significantly greater (p = 0.002 and p < 0.001) in the Pg group by flowcytometry. Finally, oral administration of Pg significantly prolonged skin graft survival (p < 0.001) and reduced pathological inflammation in transplanted skin grafts. In conclusion, periodontal pathogen-induced intestinal dysbiosis may affect transplant immunity through increased levels of SCFAs and regulatory T cells. (198 words).

Evaluation of the correlation between oral infections and systemic complications in kidney transplant patients: a retrospective pilot study

BACKGROUND

Data regarding the efficacy of the dental clearance required prior to kidney transplantation (KT) for preventing post-transplant complications is controversial. The aim of this retrospective study was to investigate a possible correlation between any untreated oral infectious foci and the onset of systemic complications in KT patients.

METHODS

Patients scheduled for regular check-ups during the post-transplant period were visited at the C.I.R. Dental School in Turin, Italy. Patients were asked to bring orthopantomography (OPT) acquired prior to transplantation to compare the possible presence of untreated infectious foci at the time of transplantation with the time of their post-transplant visit. Patients were then divided, according to the evaluation of the OPT obtained prior to the transplantation, into two groups according to their dental status prior to the transplant. "Group Infected" was comprised of patients with no dental clearance, and "Group Clear" included patients with dental clearance. The medical records were then retrospectively reviewed for the evaluation of any systemic complications that occurred after transplantation. The following medical complications were considered: fever, pneumonia, urinary tract infections, systemic infections, kidney rejection, and death. Complications were divided in two groups: early complications, which occurred within 100 days of transplantation, and late complications, which occurred more than 100 days after transplantation.

RESULTS

A total of 77 patients were enrolled in the study. Group Infected was composed of 19 subjects (25%), while Group Clear was composed of 58 patients (75%). In Group Infected, 13 (68%) patients developed complications within 100 days of transplantation, and 11 (58%) did so after 100 days. In Group Clear, 31 (53%) patients had complications within 100 days of the transplant, and 23 (40%) did after 100 days. Patients in Group Infected had a statistically significant increase in episodes of fever (p = 0.03), compared to Group Clear, with a higher relative risk (RR) of 3.66 in the first 100 days after transplantation.

CONCLUSION

Within the limitations of the present retrospective pilot study, and based on the results, a correlation between the absence of dental clearance prior to KT and a higher RR of developing a fever within the first 100 days post transplantation was highlighted. The present results encourage doctors to continue research on the topic, which remains controversial. Further prospective studies are required to confirm the results of the present study.

Interconnectedness between periodontitis stage, oral hygiene habits, adherence to the Mediterranean diet and nutritional status in Dalmatian kidney transplant recipients: a cross-sectional study

The aim of this cross-sectional study was to determine the associations between the Mediterranean diet (MeDi), nutritional status parameters, muscle strength, and periodontal status in Dalmatian kidney transplant recipients (KTRs). 89 KTRs were included in this analysis, 40 (45%) women, with a mean age of 61 years (IQR = 13) and a mean time since kidney transplantation of 5 years (IQR = 6.6). An OHIP-14 questionnaire and questionnaire-based periodontal history were obtained from all participants, a comprehensive periodontal examination was performed. Body composition data, anthropometric and clinical parameters were collected for each study participant. The Mediterranean Diet Serving Score (MDSS) was used to assess MeDi adherence, and handgrip strength was measured with a hand dynamometer. Our results showed low adherence to MeDi in KTRs (28%) and almost 50% of KTRs suffer from severe forms of periodontitis. We also found a low OHIP-14 score and poor oral hygiene habits. KTRs with a less severe form of periodontitis had higher muscle mass and handgrip strength. MDSS score was associated with a higher number of teeth, and everyday cereal intake was inversely associated with the periodontitis stage. Our results demonstrate the associations between nutritional status, muscle strength, dietary habits, and periodontal health in Dalmatian KTRs.

Number of Teeth and Nutritional Status Parameters Are Related to Intima-Media Thickness in Dalmatian Kidney Transplant Recipients

Although kidney transplantation significantly improves the quality of life of patients with end-stage renal disease (ESRD), the prevalence of cardiovascular disease (CVD) in kidney transplant recipients (KTRs) remains high. Atherosclerosis, post-transplantation metabolic changes, immunosuppressive therapy, and periodontitis contribute to elevated cardiovascular risk in this population. The aim of the study was to evaluate carotid intima-media thickness (IMT) as a surrogate marker of atherosclerosis and to analyze the possible risk factors for IMT in Dalmatian KTRs. Ninety-three KTRs were included in this study. Data on clinical and laboratory parameters, body composition, anthropometry, advanced glycation end-product (AGE) measurements, blood pressure, and arterial stiffness were collected. All participants underwent ultrasound examination of IMT and evaluation of periodontal status. KTRs with carotid IMT ≥ 0.9 were significantly older, had a lower level of total cholesterol, fat mass, end-diastolic velocity (EDV), and had fewer teeth. They also had significantly higher values of pulse wave velocity (PWV) and resistive index (RI). We found positive correlations between carotid IMT and duration of dialysis, age, PWV, AGE, RI, and average total clinical attachment level (CAL). The regression model showed that IMT in KTRs is associated with higher PWV, lower fat mass, and fewer teeth. The results of our study suggest that nutritional and periodontal status are associated with carotid IMT in KTRs.

Iguratimod Attenuates Macrophage Polarization and Antibody-Mediated Rejection After Renal Transplant by Regulating KLF4

Background: This study aimed to explore the effect and mechanism of iguratimod (IGT) on M1 macrophage polarization and antibody-mediated rejection (ABMR) after renal transplant.

Methods: Bioinformatics analysis was performed using three public databases derived from the GEO database. Sprague–Dawley (SD) rats were pre-sensitized with donors of Wistar rats in skin transplantation and a rat renal transplant ABMR model was established from the donors to skin pre-sensitized recipients. Subsequently, IGT was treated on the ABMR model. Routine staining and immunofluorescence (IF) staining were performed to observe the pathological changes in each group and flow cytometry was performed to detect the changes of DSA titers in peripheral blood. In addition, bone-marrow-derived macrophage (BMDM) was extracted and interfered with IGT to explore the effect of IGT in vivo. PCR, IF staining, and Western blot were used to detect the expression of related genes and proteins.

Results: Bioinformatics analysis revealed that several immune cells were significantly infiltrated in the ABMR allograft, while M1 macrophage was noticed with the most significance. Results of IF staining and PCR proved the findings of the bioinformatics analysis. Based on this, IGT was observed to significantly attenuate the degree of peritubular capillary vasculitis and arteriolitis in the rat renal transplant ABMR model, whereas it decreases the expression of C4d and reduces the titer of DSA. Results in vitro suggested that M1 macrophage-related transcripts and proteins were significantly reduced by the treatment of IGT in a dose- and time-dependent manner. Furthermore, IGT intervention could remarkably decrease the expression of KLF4.

Conclusion: Polarization of M1 macrophages may aggravate ABMR after renal transplant by promoting DSA-mediated endothelial cell injury, and IGT may attenuate the pathogenesis of ABMR by targeting KLF4.

A Cross-Sectional Study of the Association Between Chronic Oral Disease Burden and Serum Biomarkers in Kidney Transplant Recipients

INTRODUCTION

Poor oral health can negatively affect general health and quality of life of kidney transplant recipients. The study aimed to investigate the association between chronic oral disease burden, serum biomarkers, and comorbidities in kidney transplant recipients.

DESIGN

A cross-sectional comparative study was conducted with 44 patients after kidney transplant. The burden of chronic oral disease was composed of the following observable variables: moderate periodontitis and presence of dental caries. Serum biomarkers and comorbidities data were collected. The chi-square or Fisher's exact tests for categorical variables and Student's t-test or Mann-Whitney test for continuous variables were used. Robust Poisson regression was used to model the association.

RESULTS

Higher levels of mean uric acid (P = .01) and creatinine (P = .03) were observed in the group of patients with oral disease burden, while the highest level of high-density lipoprotein was observed in the group without oral disease. Higher values of uric acid were associated with the occurrence of chronic oral disease burden (Adjusted PR = 1.24, 95% CI: 1.03-1.48, P = .019). There was no statistical difference between the groups with and without oral disease burden in comorbidities present.

CONCLUSION

The findings suggest that chronic oral diseases burden can be associated with uric acid and creatinine levels in kidney transplant recipients.

The relationship between periodontal status and hyperglycemia after kidney transplantation

OBJECTIVES

Several factors have been associated with hyperglycemia after kidney transplantation (KTx), including systemic inflammation. This study aimed to investigate the relationship between periodontal status and hyperglycemia in KTx patients.

MATERIALS AND METHODS

Forty-four KTx patients were included in this cross-sectional study. Periodontitis severity was categorized into stage I to IV. Fasting blood glucose (FBG) was measured, and hyperglycemia was analyzed at different FBG cutoff points (100 mg/dL, 110 mg/dL, 120 mg/dL, 126 mg/dL, 140 mg/dL). Age, history of smoking, prior type 2 diabetes (T2D), and prior cardiovascular disease (CVD) were considered cofounders. Multivariable logistic regression modelling was performed with periodontitis as the exposure and hyperglycemia as the outcome. Pathway analysis was performed with FBG as a continuous outcome.

RESULTS

Periodontitis had increased odds of hyperglycemia from 120 mg/dL FBG cutoff, even after adjustment. In addition, periodontitis severity was positively associated with FBG level (β = 0.323, SE = 0.127, P = 0.011).

CONCLUSION

The findings suggest that periodontitis may be related to increase of hyperglycemia and FBG levels in KTx patients.

CLINICAL RELEVANCE

Periodontitis severity and cardiovascular disease were positively associated with FBG levels in KTx patients. Clinicians and patients should be aware of the potential benefit of periodontal care for better glycemic control management.

Analysis of Factors Influencing Kidney Function of Recipients After Renal Transplantation in Southwestern China: A Retrospective Study

Background: Factors influencing the kidney function of patients after renal transplantation include both recipient-related factors and donor-related factors. To gain a better understanding of these factors and to improve clinical decision-making, we performed a retrospective study of southwestern Chinese people receiving kidney transplantation.

Methods: In this retrospective analysis, a total of 2,462 recipients receiving allogeneic kidney transplantation in West China Hospital of Sichuan University from December 13, 2008 to January 10, 2018 were included. Data on recipient and donor characteristics were extracted from the Transplant Center Database and stratified by discrete time points after kidney transplantation. Univariate and multivariate logistic regression analyses were carried out on the study variables, and kidney function of postoperative patients was monitored using cystatin C (CysC) as the outcome indicator.

Results: From the univariate analysis, several factors showed statistically significant short-term impact on kidney function based on CysC after kidney transplantation, including age, ethnicity, body mass index (BMI), and HLA A-B-DR-DQ loci mismatch. Gender of recipients and gender-consistency between donors and recipients revealed both short-term and long-term influence. Younger donors had significantly better medium-and-long-term influence on kidney function. From the multivariate logistic regression analysis, recipient gender, ethnicity, BMI, and donor age were independent factors affecting postoperative CysC recovery at discrete time points.

Conclusion: Several factors of recipients related to renal function after kidney transplantation, such as gender, ethnicity, BMI and donor's age should be paid more attention to. Moreover, female and non-Han recipients decreased the risk of poor outcome during postoperative kidney function recovery while large BMI of recipients and higher donor age increased the risk. It is useful to predict the postoperative renal function earlier according to corresponding factors, and improve the patient's quality of life.

Association between periodontal disease and tooth loss and mortality in an elderly Chinese population

BACKGROUND

Poor oral health is a risk indicator of poor quality of life and mortality. However, whether these associations remain potent in elderly subjects after adequately considering the confounding factors is not yet clearly elucidated. The present study aimed to investigate the associations between periodontal disease and tooth loss and total mortality and cardiovascular disease (CVD) outcomes in the elderly > 75 years old.

METHODS

A total of 1385 individuals, receiving periodontal treatment in Shanghai, participated in this retrospective study. Data on oral status were obtained from radiographs to calculate the proportion of residual bone. The information about mortality was collected from the Shanghai Municipal Center for Disease Control and Prevention (SCDC). Univariate Cox proportional hazards model, multivariable-adjusted model, and competing risk hazard model were used to analyze the association between periodontal disease or tooth loss and mortality.

RESULTS

Those with severe periodontitis were associated with higher risk of total mortality than healthy individuals [hazard ratio (HR) = 1.48, 95% confidence interval (95% CI) 1.11-1.98]. Further, missing teeth increased the risk of total mortality (HR = 1.02, 95% CI 1.01-1.03). However, no significant difference was detected in the association between periodontitis or tooth loss and CVD mortality. In competing risk hazard model, an increased risk was observed for other-cause mortality, not CVD mortality, in those with severe periodontitis and missing teeth.

CONCLUSION

Periodontal diseases and tooth loss were the potential predictors of total mortality even after adjustment for confounding factors. However, these were not independent indicators for CVD mortality.

Poor oral health status and short-term outcome of kidney transplantation

AIMS

This study aims to know whether poor oral health increases the risk of acute rejection and hospitalization in kidney allograft recipients.

METHODS AND RESULTS

This is a prospective cohort study. The same dentist followed participants for 2 months after renal transplant for monitoring oral health (clinical evaluation, DTMF index, and CPITN index), signs of graft rejection, infection, and hospitalization. We compiled rates and reasons for hospital readmission or extended hospital stay. The CPITN had a mean score of 0.38 ± 0.71, increasing to 0.90 ± 0.84, 60 days after transplant (P < .001). No one rejected the graft in the period of study. Patients with older age (P = .009; OR: 1.07; CI 95% 1.01-1.12) were at higher risk of hospitalization at each year of age and patients presenting pretransplant dental focus (P = .001; OR: 7.23; CI 95% 2.13-24.56) had 7.23 times more chance to be hospitalized in the first 2 months after the transplant. One participant was hospitalized due to acute foci of dental infection.

CONCLUSION

There was an association between dental focus and hospital readmission/stay. However, our methods do not provide conclusive proof of causality. Hospitalization due to acute dental infection was rare.

Influence of Chronic Periodontitis on the Long-Term Mortality and Cardiovascular Events in Kidney Transplant Recipients

Chronic periodontitis (CP) is associated with cardiovascular disease and mortality in different populations. The aim of this study was to examine an association of CP with hard endpoints in patients after kidney transplantation during a 15-year follow-up period. Study group consist of 117 patients (77M/40F, median age 44 years) divided into two subgroups: those with initially advanced CP (CPITN 3-4) and those with no or moderate CP (CPITN 0-2). All cardiovascular events, graft losses, and re-transplantations were recorded. All deaths were noted and verified, including those occurred after the return to dialysis therapy, the causes of death were identified. Cox regression with Firth's penalized maximum likelihood models were used for data analysis. During the observation period, 49 deaths occurred. Advanced CP (n = 35) was not associated with overall mortality but was associated with increased risk of death with functioning graft (DWFG) [HR 3.54 (1.20-10.45); p < 0.05]. Risk of graft loss was not associated with CP status. In conclusion, an advanced CP was independently associated with increased risk of DWFG, but not all-cause or cardiovascular mortality after renal transplantation.

Pathological Characteristics of Periodontal Disease in Patients with Chronic Kidney Disease and Kidney Transplantation

Chronic kidney disease (CKD) is recognized as an irreversible reduction of functional nephrons and leads to an increased risk of various pathological conditions, including cardiovascular disease and neurological disorders, such as coronary artery calcification, hypertension, and stroke. In addition, CKD patients have impaired immunity against bacteria and viruses. Conversely, kidney transplantation (KT) is performed for patients with end-stage renal disease as a renal replacement therapy. Although kidney function is almost normalized by KT, immunosuppressive therapy is essential to maintain kidney allograft function and to prevent rejection. However, these patients are more susceptible to infection due to the immunosuppressive therapy required to maintain kidney allograft function. Thus, both CKD and KT present disadvantages in terms of suppression of immune function. Periodontal disease is defined as a chronic infection and inflammation of oral and periodontal tissues. Periodontal disease is characterized by the destruction of connective tissues of the periodontium and alveolar bone, which may lead to not only local symptoms but also systemic diseases, such as cardiovascular diseases, diabetes, liver disease, chronic obstructive pulmonary disease, and several types of cancer. In addition, the prevalence and severity of periodontal disease are significantly associated with mortality. Many researchers pay special attention to the pathological roles and clinical impact of periodontal disease in patients with CKD or KT. In this review, we provide information regarding important modulators of periodontal disease to better understand the relationship between periodontal disease and CKD and/or KT. Furthermore; we evaluate the impact of periodontal disease on various pathological conditions in patients with CKD and KT. Moreover, pathogens of periodontal disease common to CKD and KT are also discussed. Finally, we examine the importance of periodontal care in these patients. Thus, this review provides a comprehensive overview of the pathological roles and clinical significance of periodontal disease in patients with CKD and KT.