REIN: a tool to highlight inequalities in health / REIN : un outil au service de l'éclairage des inégalités en santé

On the occasion of the 20th anniversary of the REIN (French Renal Epidemiology and Information Network), a summary work on the contributions of the national French ESKD register was carried out. On the issue of Social Inequalities in Health, the following key messages were retained. Social inequalities in health exist throughout the journey of a patient with chronic kidney disease and manifest as territorial inequalities in access to home-based or independent dialysis treatment and to transplant, whether preemptive or otherwise. SIH are observed in adults as well as in the paediatric population. The female gender appears to be associated with a disparity in access to kidney transplant.

À l'occasion des 20 ans du REIN (Réseau Epidémiologie et Information en Néphrologie), un travail de synthèse sur les apports du registre a été mené. Sur la question des inégalités sociales de santé, les messages clés suivants ont été retenus. Les inégalités sociales de santé existent tout au long du parcours du patient atteint d'une maladie rénale chronique et se traduisent par des inégalités territoriales d'accès au traitement par dialyse au domicile ou autonome, à la greffe qu'elle soit préemptive ou non. Les ISS sont retrouvées chez l'adulte mais aussi dans la population pédiatrique. Le genre féminin semble associé à une disparité d'accès à la greffe rénale.

Gender differences in the association between socioeconomic status and hypertension in France: A cross-sectional analysis of the CONSTANCES cohort.

BACKGROUND: Hypertension prevalence increases when socioeconomic status decreases but gender differences in the relationship between socioeconomic status and hypertension have been less studied. This work aimed to explore the pattern of associations between three indicators of socioeconomic status at individual, household, and municipal levels with hypertension across genders in a large sample of French adults from the CONSTANCES cohort. METHODS: Using data at inclusion from 59 805 participants (52% women) aged 25-69 years and recruited between 2012 and 2015, multilevel log-Poisson regressions with robust variance estimates were used to assess the associations of Relative Index of Inequality in education, monthly income per consumption unit and residential deprivation with hypertension. Modifying effects of gender and age in those associations were tested. RESULTS: Hypertension prevalence was higher in men than in women. Steep socioeconomic gradients of hypertension were observed for the three socioeconomic indicators in both genders and from the youngest to the oldest age class. Socioeconomic inequalities, especially educational inequalities, were larger among women than men: Relative Index of Inequality for highest versus lowest education among the 25-34 years were 0.43 [95%-confidence interval = 0.28-0.67] in women and 0.70 [95%-confidence interval = 0.53-0.92] in men. With increasing age, socioeconomic gradients of hypertension eased in men and even more in women so that gender differences decreased. CONCLUSIONS: In this cross-sectional analysis of a large sample of adults, prevalence of hypertension was higher in men than in women. Moreover, socioeconomic status and especially education displayed a stronger association with hypertension prevalence in women compared to men. Reducing inequalities in hypertension may require gender-specific approaches.

Geographical variations in the prevalence of hypertension in France: Cross-sectional analysis of the CONSTANCES cohort.

AIMS: While international variations in the prevalence of hypertension are well described, less is known about intra-national disparities and their determinants. We wanted to describe the variations in hypertension prevalence within France and to determine how much lifestyle and socioeconomic factors contributed to explain these regional variations. METHODS: Participants (62,247 French adults aged 18 to 69 years) were recruited in the 16 centres of the CONSTANCES study between 2012 and 2015. Hypertension was defined as blood pressure higher than 140/90 mmHg and/or taking antihypertensive medications. The contribution of lifestyle and socioeconomic factors to hypertension prevalence variations among centres was examined using sequential hierarchical logistic models. RESULTS: Hypertension prevalence was 37.3% (95% confidence interval (CI) = 36.6-38.0) in men and 23.2% (95% CI = 22.7-23.8) in women. Hypertension prevalence rates varied by almost two-fold among centres (1.9 in men, 1.6 in women) with the highest prevalence in the north and the east of France. Body mass index was strongly associated with hypertension in women (odds ratio (OR)1-unit increase = 1.11 (95% CI = 1.11-1.12)) and was the highest contributor to between-centre variations (27% in women), followed by socioeconomic characteristics (e.g. ORhigh versus low education = 0.85 (95% CI = 0.83-0.87), contributing to 14% of variations in women). Together, family history of hypertension, body mass index, education, occupation and residential area socioeconomic level explained about 30% and 40% of between-centre variations in men and women, respectively. CONCLUSION: Hypertension prevalence greatly varies among French regions and this is partly explained by known lifestyle and socioeconomic factors. Nevertheless, these variations and all the hypertension determinants have not been fully deciphered yet.

Outcome-dependent geographic and individual variations in the access to renal transplantation in incident dialysed patients: a French nationwide cohort study.

This study investigated geographical variations of access to renal transplantation using three outcomes (access to the transplant waiting list, access to renal transplantation after waitlisting and access to renal transplantation after dialysis start). Associations of patient-related and regional variables with the studied outcomes were assessed using a Cox shared frailty model and a Fine and Gray model. At the study endpoint (December 31, 2015), 26.3% of all 18-90-year-old patients who started dialysis in the 22 mainland and four overseas French regions in 2012 (n = 9312) were waitlisted and 15.1% received a kidney transplant. The geographical disparities of access to renal transplantation varied according to the studied outcome. Patients from the Ile-de-France region had the highest probability of being waitlisted, but were less likely to receive a kidney transplant. Two regional factors were associated with the access to the waiting list and to renal transplantation from dialysis start: the incidence of preemptive kidney transplantation and of ESRD. The use of different outcomes to evaluate access to kidney transplantation could help healthcare policy-makers to select the most appropriate interventions for each region in order to reduce treatment disparities.

Sex differences in adherence to antihypertensive treatment in patients aged above 55: The French League Against Hypertension Survey (FLAHS).

Despite the availability of efficient therapies to reduce the risk of cardiovascular complications, poor adherence to antihypertensive (anti-HTN) drugs is frequent, especially during the first year of treatment and among uncontrolled/resistant hypertensive patients. The aim of the study was to identify factors associated with adherence to anti-HTN treatment and to examine whether they differ across sex. A total of 2743 treated hypertensive participants to the cross-sectional Metascope survey (France, 2015) aged 55 years or more were included. The authors measured adherence to anti-HTN treatment using the 6-item Girerd compliance test. Variations in adherence were examined using the Rao-Scott statistics and Poisson regression. Overall, 63.6% of participants were adherent to anti-HTN treatment. Adherence was more frequent among women than men (69% vs 58%, P < 10-4 ). For both sexes, level of adherence was positively associated with age (P < 10-4 ), but inversely associated with number of anti-HTN tablets, number of tablets taken for metabolic diseases, history of cardiovascular diseases, number of other chronic diseases (all P < 10-4 ). The inverse relationship between adherence and the number of anti-HTN tablets significantly differed between sexes (P < 10-4 ): Adherence decreased sharply when taking two or more anti-HTN tablets in men, whereas the decrease in women was only observed when taking three or more anti-HTN tablets. This study suggests that adherence to anti-HTN treatment is higher among women, decreases with the number of tablets prescribed, and differentially so across sex. Reducing the number of tablets for anti-HTN treatment may improve adherence, especially among men and patients with multiple comorbidities.

Influence of Socio-Economic Inequalities on Access to Renal Transplantation and Survival of Patients with End-Stage Renal Disease.

BACKGROUND: Public and scientific concerns about the social gradient of end-stage renal disease and access to renal replacement therapies are increasing. This study investigated the influence of social inequalities on the (i) access to renal transplant waiting list, (ii) access to renal transplantation and (iii) patients' survival. METHODS: All incident adult patients with end-stage renal disease who lived in Bretagne, a French region, and started dialysis during the 2004-2009 period were geocoded in census-blocks. To each census-block was assigned a level of neighborhood deprivation and a degree of urbanization. Cox proportional hazards models were used to identify factors associated with each study outcome. RESULTS: Patients living in neighborhoods with low level of deprivation had more chance to be placed on the waiting list and less risk of death (HR = 1.40 95%CI: [1.1-1.7]; HR = 0.82 95%CI: [0.7-0.98]), but this association did not remain after adjustment for the patients' clinical features. The likelihood of receiving renal transplantation after being waitlisted was not associated with neighborhood deprivation in univariate and multivariate analyses. CONCLUSIONS: In a mixed rural and urban French region, patients living in deprived or advantaged neighborhoods had the same chance to be placed on the waiting list and to undergo renal transplantation. They also showed the same mortality risk, when their clinical features were taken into account.

Mining care trajectories using health administrative information systems: the use of state sequence analysis to assess disparities in prenatal care consumption.

BACKGROUND: Pregnant women are a vulnerable population. Although regular follow-ups are recommended during pregnancy, not all pregnant women seek care. This pilot study wanted to assess whether the integration of data from administrative health information systems and socio-economic features allows identifying disparities in prenatal care trajectories. METHODS: Prenatal care trajectories were extracted from the permanent sample of the French health insurance information system linked to the hospital discharge information system. The records of 2518 women who gave birth without complications in France in 2009 were analyzed. State sequence data analysis was performed to identify homogeneous groups of prenatal care trajectories. Socio-economic data were used to characterize their living environment. RESULTS: We identified three groups of homogeneous prenatal care trajectories: (i) women with relatively high prenatal care consumption (~11%), (ii) women with no prenatal care (~21%), and (iii) women with an intermediate level of prenatal care (~66%). Analysis of the socio-economic data demonstrated the association between disparities in prenatal care trajectories and the women's living environment. Women with relatively high care consumption generally lived in socio-economically privileged areas (better education levels, employment status and housing conditions) compared with women with few or no prenatal care. CONCLUSIONS: Although ecological, our approach demonstrates that data from health administrative information systems could be used to describe prenatal care. However, more individual variables and an improvement of the data quality are needed to efficiently monitor the content and timing of prenatal care. Moreover, state sequence analysis, which was used in this context for the first time, proves to be an interesting approach to explore care trajectories. Finally, the integration of heterogeneous sources of data, including contextual information, might help identifying areas that require health promotion actions toward vulnerable populations, such as pregnant women.

Spatial distribution of end-stage renal disease (ESRD) and social inequalities in mixed urban and rural areas: a study in the Bretagne administrative region of France.

BACKGROUND: Several studies have investigated the implication of biological and environmental factors on geographic variations of end-stage renal disease (ESRD) incidence at large area scales, but none of them assessed the implication of neighbourhood characteristics (healthcare supply, socio-economic level and urbanization degree) on spatial repartition of ESRD. We evaluated the spatial implications of adjustment for neighbourhood characteristics on the spatial distribution of ESRD incidence at the smallest geographic unit in France. METHODS: All adult patients living in Bretagne and beginning renal replacement therapy during the 2004-09 period were included. Their residential address was geocoded at the census block level. Each census block was characterized by socio-economic deprivation index, healthcare supply and rural/urban typology. Using a spatial scan statistic, we examined whether there were significant clusters of high risk of ESRD incidence. RESULTS: The ESRD incidence was non-randomly spatially distributed, with a cluster of high risk in the western Bretagne region (relative risk, RR = 1.28, P-value = 0.0003). Adjustment for sex, age and neighbourhood characteristics induced cluster shifts. After these adjustments, a significant cluster (P = 0.013) persisted. CONCLUSIONS: Our spatial analysis of ESRD incidence at a fine scale, across a mixed rural/urban area, indicated that, beyond age and sex, neighbourhood characteristics explained a great part of spatial distribution of ESRD incidence. However, to better understand spatial variation of ESRD incidence, it would be necessary to research and adjust for other determinants of ESRD.

Comparison of Bayesian network and decision tree methods for predicting access to the renal transplant waiting list.

The study compares the effectiveness of Bayesian networks versus Decision Trees for predicting access to renal transplant waiting list in a French healthcare network. The data set consisted in 809 patients starting renal replacement therapy. The data were randomly divided into a training set (90%) and a validation set (10%). Bayesian network and CART decision tree were built on the training set. Their predictive performances were compared on the validation set. The age variable was found to be the most important factor in both models. Both models were highly sensitive and specific: sensitivity 90.0% (95%CI: 76.8-100), specificity 96.7% (95%CI: 92.2-100). Moreover, the models were complementary since the Bayesian network provided a global view of the variables' associations while the decision tree was more easily interpretable by physicians. These approaches provide insights on the current care process. This knowledge could be used for optimizing the healthcare process.