The Danish Nephrology Registry

Incidence and clearance of cervical and anal high-risk human papillomavirus in kidney transplant recipients: Results from a Danish prospective clinical study

This study investigates the incidence and clearance of cervical and anal high-risk human papillomavirus (hrHPV) infection in kidney transplant recipients (KTRs) compared to immunocompetent controls. During 2016-2017, we enrolled 125 female KTRs and 125 female controls. Liquid-based cervical and anal cytology samples collected at enrollment and follow-up were tested for human papillomavirus (HPV) DNA using the CLART HPV2 test. All participants answered a questionnaire on lifestyle and sexual behavior at both examinations. KTRs had an increased age-adjusted risk of incident cervical hrHPV infection compared to controls (hazard ratio [HR] = 3.6, 95% CI = 1.2-11.2). Probability of cervical hrHPV clearance at 18 months was lower among KTRs (8.3%) than controls (66.7%). There was no statistically significant difference in anal hrHPV incidence between KTRs and controls (HR = 0.9, 95% CI = 0.4-2.0). Clearance of anal hrHPV was similar between KTRs and controls at 18 months. During the total follow-up, a lower anal hrHPV clearance, although not statistically significant, was observed among KTRs (HR = 0.3, 95% CI = 0.06-1.2). KTRs had higher incidence of cervical hrHPV and lower probability of clearance, especially of cervical hrHPV infections, than controls. Our findings support that KTRs are at increased risk of HPV infection and point to the need for targeted HPV prevention strategies, such as cervical cancer screening.

Anal Human Papillomavirus Infection in Kidney Transplant Recipients Compared With Immunocompetent Controls

BACKGROUND

Kidney transplant recipients (KTRs) have increased risk of human papillomavirus (HPV)-related anogenital (pre)cancers, including anal high-grade intraepithelial lesions and cancer. Previous studies on anal high-risk HPV (hrHPV) among KTRs are sparse.

METHODS

In a cross-sectional study, we included 247 KTRs and 248 controls from a dermatology department and 5 nephrology departments in Denmark during 2016-2017. All participants provided an anal cytobrush sample that was tested for HPV DNA. Participants completed a questionnaire on lifestyle and sexual habits. We used logistic regression to estimate odds ratios (ORs) of anal hrHPV in KTRs compared with controls and risk factors for anal hrHPV in KTRs.

RESULTS

The anal hrHPV prevalence was higher in female KTRs (45.5%) than in controls (27.2%). Female KTRs had almost 3-fold higher adjusted odds of anal hrHPV than controls (adjusted OR, 2.87 [95% confidence interval, 1.57-5.22]). In contrast, among men we did not observe increased prevalence or odds of anal hrHPV in KTRs compared with controls (prevalence, 19.4% vs 23.6%; adjusted OR, 0.85 [95% 95% confidence interval, .44-1.64]). Among hrHPV-positive KTRs, 63% and 52% of men and women, respectively, were infected with hrHPV types covered by the nonavalent HPV vaccine (type 16, 18, 31, 33, 45, 52, or 58). Current smoking, >10 lifetime sexual partners, history of genital warts, and among men having had receptive anal sex were risk factors for anal hrHPV in KTRs.

CONCLUSIONS

Female KTRs had an increased risk of anal hrHPV compared with immunocompetent controls. Our findings indicate that pretransplant HPV vaccination should be considered to prevent anal high-grade intraepithelial lesions and cancer caused by anal hrHPV infection in KTRs.

CLINICAL TRIALS REGISTRATION

NCT03018327.

National and international kidney failure registries: characteristics, commonalities, and contrasts

Registries are essential for health infrastructure planning, benchmarking, continuous quality improvement, hypothesis generation, and real-world trials. To date, data from these registries have predominantly been analyzed in isolated "silos," hampering efforts to analyze "big data" at the international level, an approach that provides wide-ranging benefits, including enhanced statistical power, an ability to conduct international comparisons, and greater capacity to study rare diseases. This review serves as a valuable resource to clinicians, researchers, and policymakers, by comprehensively describing kidney failure registries active in 2021, before proposing approaches for inter-registry research under current conditions, as well as solutions to enhance global capacity for data collaboration. We identified 79 kidney-failure registries spanning 77 countries worldwide. International Society of Nephrology exemplar initiatives, including the Global Kidney Health Atlas and Sharing Expertise to support the set-up of Renal Registries (SharE-RR), continue to raise awareness regarding international healthcare disparities and support the development of universal kidney-disease registries. Current barriers to inter-registry collaboration include underrepresentation of lower-income countries, poor syntactic and semantic interoperability, absence of clear consensus guidelines for healthcare data sharing, and limited researcher incentives. This review represents a call to action for international stakeholders to enact systemic change that will harmonize the current fragmented approaches to kidney-failure registry data collection and research.

Risk of Anal High-grade Squamous Intraepithelial Lesions Among Renal Transplant Recipients Compared With Immunocompetent Controls

BACKGROUND

Renal transplant recipients (RTRs) have increased risk of human papillomavirus (HPV)-related cancers, including anal cancer. We investigated the prevalence of anal high-grade intraepithelial lesions (HSILs) in RTRs compared with immunocompetent controls and risk factors for anal HSIL in RTRs.

METHODS

We included 247 RTRs and 248 controls in this cross-sectional study. We obtained anal samples for HPV testing with INNO-LiPA and performed high-resolution anoscopy on all participants. The participants completed a questionnaire on lifestyle and sexual habits. We used logistic regression to estimate odds ratios (ORs) of histologically confirmed anal HSIL in RTRs vs controls and risk factors for anal HSIL in RTRs, stratified by sex and anal high-risk (hr) HPV status, adjusting for age, smoking, lifetime sexual partners, and receptive anal sex.

RESULTS

RTRs had higher anal HSIL prevalence than controls, both among men (6.5% vs 0.8%; adjusted OR [aOR], 11.21 [95% confidence interval {CI}, 1.46-291.17]) and women (15.4% vs 4.0%; aOR, 6.41 [95% CI, 2.14-24.10]). Among those with anal hrHPV, RTRs had higher anal HSIL prevalence than controls (33.8% vs 9.5%; aOR, 6.06 [95% CI, 2.16-20.27]). Having had receptive anal sex (aOR, 6.23 [95% CI, 2.23-19.08]) or genital warts (aOR, 4.21 [95% CI, 1.53-11.48]) were risk factors for anal HSIL in RTRs. All HSIL cases occurred in individuals with anal hrHPV.

CONCLUSIONS

RTRs had increased risk of anal HSIL compared with immunocompetent controls, with particularly high prevalence in female RTRs. Receptive anal sex, previous genital warts, and anal hrHPV infection were risk factors for anal HSIL in RTRs. Screening for anal HSIL in RTRs should be considered.

CLINICAL TRIALS REGISTRATION

NCT03018927.

Present and future of kidney replacement therapy in Italy: the perspective from Italian Dialysis and Transplantation Registry (IDTR)

Incidence of kidney replacement therapy (KRT) stabilizes or declines both in Europe and in the US; however, it is predictable that global prevalence of KRT will double by 2030. In this paper, we focus on the patterns of incidence, mortality, and prevalence of KRT in Italy, and we compare, when possible, the findings with other countries. The Italian Dialysis and Transplantation Registry (IDTR) currently collects aggregate data from regional registries. In Italy, KRT yearly incidence is around 160 patients per million population (pmp). This incidence showed an increasing trend up until 2011 with an average annual percentage change (AAPC) of 1.8%, after which it stabilized. Older age is an important determinant for KRT incidence, and it is strongly associated with the variability between Italian regions. Incidence is very stable within patients less than 50 years old; however, it greatly differs between regions for patients over 75 years old, ranging from 400 to 900 pmp. Moreover, the incidence for patients over 50 years old declined from 366 pmp in 2011 to 285 in 2017. An age-period-cohort (APC) model showed a very strong cohort effect, which shows the decline in incidence seems mainly due to the better health conditions of people born after 1940. Mortality rate in KRT patients was 109 per 1000 patient-year (py) between 2011 and 2017 with great differences among treatment modalities: 162 per 1000 py in haemodialysis, 117 per 1000 py in peritoneal dialysis, and 16 per 1000 py in kidney transplantation. Premature death is better detected by the standard expected years of life lost (YLL). The distribution of YLL rate per age shows a sharp increase between 40 and 70 years old both in haemodialysis and peritoneal dialysis patients with an AAPC of 5.2% and 4.1% respectively. Transplanted patients experience a very low YLL rate at any age. KRT prevalence was 1118 pmp in 2017 and it should be close to 1175 pmp by 2025 with a projected increase of transplanted patients' prevalence to 500 pmp, and a decrease of dialysis patients from 714 to 680 pmp. The proportion of patients treated with one of the three modalities strictly depends on age, with a sharp increase of haemodialysis after the age of 50. All data suggests the necessity to improve the care of middle and older age patients who experience the higher incidence of disease and mortality.

The Danish health care system and epidemiological research: from health care contacts to database records

Denmark has a large network of population-based medical databases, which routinely collect high-quality data as a by-product of health care provision. The Danish medical databases include administrative, health, and clinical quality databases. Understanding the full research potential of these data sources requires insight into the underlying health care system. This review describes key elements of the Danish health care system from planning and delivery to record generation. First, it presents the history of the health care system, its overall organization and financing. Second, it details delivery of primary, hospital, psychiatric, and elderly care. Third, the path from a health care contact to a database record is followed. Finally, an overview of the available data sources is presented. This review discusses the data quality of each type of medical database and describes the relative technical ease and cost-effectiveness of exact individual-level linkage among them. It is shown, from an epidemiological point of view, how Denmark’s population represents an open dynamic cohort with complete long-term follow-up, censored only at emigration or death. It is concluded that Denmark’s constellation of universal health care, long-standing routine registration of most health and life events, and the possibility of exact individual-level data linkage provides unlimited possibilities for epidemiological research.

Risk of genital warts in renal transplant recipients-A registry-based, prospective cohort study

Genital warts (GWs) are a risk factor for subsequent human papillomavirus (HPV)-related anogenital cancers. In this register-based, prospective cohort study, we estimated the risk of GWs in renal transplant recipients (RTRs) compared with a nontransplanted cohort. In a nationwide database, we identified first-time RTRs in Denmark during 1996 to 2015. For each RTR, 50 age- and sex-matched nontransplanted individuals were selected from the population registry. Information on GWs, sociodemographic characteristics, HPV vaccination, and other causes of immunosuppression was retrieved from registries. We estimated the cumulative incidence of GWs and used Cox regression to estimate hazard ratios (HR) of GWs in RTRs vs non-RTRs. We included 3268 RTRs and 162 910 non-RTRs without GWs 1 year before baseline. RTRs had higher hazard of GWs than non-RTRs (HR = 3.30; 95% confidence interval, 2.76-3.93, adjusted for sex, age, education, and income). The increased hazard of GWs compared with non-RTRs was more pronounced in female than in male RTRs. Although not statistically significant, the hazard tended to be higher in RTRs with functioning grafts compared with RTRs on dialysis after graft failure. The hazard of GWs was increased <1 year after transplantation and remained increased during ≥10 years. In conclusion, RTRs had substantially higher risk of GWs than non-RTRs.

Risk of death after first-time blood stream infection in incident dialysis patients with specific consideration on vascular access and comorbidity

Background

The mortality following blood stream infection (BSI) and risk of subsequent BSI in relation to dialysis modality, vascular access, and other potential risk factors has received relatively little attention. Consequently, we assessed these matters in a retrospective cohort study, by use of the Danish nation-wide registries.

Methods

Patients more than 17 years of age, who initiated dialysis between 1.1.2010 and 1.1.2014, were grouped according to their dialysis modality and vascular access. Survival was modeled in time-dependent Cox proportional hazard analyses. Potential risk factors confined by a modified Charlson comorbidity index (MCCI), were subsequently assessed in stepwise selection models.

Results

At baseline, 764 patients received peritoneal dialysis (PD), and 434, 479, and 782 hemodialysis (HD) patients were dialyzed by use of arteriovenous fistulas (AVFs), tunneled catheters (TCs), and non-tunneled catheters (NTCs), respectively. We identified 1069 BSIs with an overall incidence rate of 17.7 episodes per 100 person years, and 216 BSIs occurred more than one time in the same patient. HRs of post BSI mortality relative to PD were 3.20 (95% CI 1.86–5.50; p < 0.001) with NTCs; whereas no associations were found for AVF and TC. The risk of subsequent BSIs was higher with NTCs [HR 2.29 (95% CI 1.09–4.82), p = 0.030], and no significant difference was found for AVF and TC, in relation to PD. There was an increased risk of both outcomes with TC relative to AVF [death: 1.57 (95% CI 1.07–2.29, P < 0.021); BSI: 1.78 (95% CI 1.13–2.83, P < 0.014], and risk of death was reduced in patients who changed to AVF after first-time BSI. The MCCI was significantly associated with the risk of subsequent BSI and post BSI death; however, only some of the variables contained in the index were found to be significant risk predictors when analyzed in the fitted model.

Conclusions

While NTC was the most predominant risk factor for subsequent BSI and post BSI mortality, AVF appeared protective.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3594-7) contains supplementary material, which is available to authorized users.