title: Mapping end-stage renal disease (ESRD): spatial variations on small area level in northern France, and association with deprivation.
abstract: BACKGROUND
  Strong geographic variations in the incidence of end-stage renal disease (ESRD) are observed in developed countries. The reasons for these variations are unknown. They may reflect regional inequalities in the population's sociodemographic characteristics, related diseases, or medical practice patterns. In France, at the district level, the highest incidence rates have been found in the Nord-Pas-de-Calais region. This area, with a high population density and homogeneous healthcare provision, represents a geographic situation which is quite suitable for the study, over small areas, of spatial disparities in the incidence of ESRD, together with their correlation with a deprivation index and other risk factors.
  
  
  METHODS
  The Renal Epidemiology and Information Network is a national registry, which lists all ESRD patients in France. All cases included in the Nord-Pas-de-Calais registry between 2005 and 2011 were extracted. Adjusted and smoothed standardized incidence ratio (SIR) was calculated for each of the 170 cantons, thanks to a hierarchical Bayesian model. The correlation between ESRD incidence and deprivation was assessed using the quintiles of Townsend index. Relative risk (RR) and credible intervals (CI) were estimated for each quintile.
  
  
  RESULTS
  Significant spatial disparities in ESRD incidence were found within the Nord-Pas-de-Calais region. The sex- and age-adjusted, smoothed SIRs varied from 0.66 to 1.64. Although no correlation is found with diabetic or vascular nephropathy, the smoothed SIRs are correlated with the Townsend index (RR: 1.18, 95% CI [1.00-1.34] for Q2; 1.28, 95% CI [1.11-1.47] for Q3; 1.30, 95% CI [1.14-1.51] for Q4; 1.44, 95% CI [1.32-1.74] for Q5).
  
  
  CONCLUSIONS
  For the first time at this aggregation level in France, this study reveals significant geographic differences in ESRD incidence. Unlike the time of renal replacement care, deprivation is certainly a determinant in this phenomenon. This association is probably independent of the patients' financial ability to gain access to healthcare.
authors.affiliation: EA 4483, Université Lille Nord de France, Faculté de Pharmacie de Lille, Lille, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Occelli
authors.affiliation: EA 4483, Université Lille Nord de France, Faculté de Pharmacie de Lille, Lille, France; Faculté Ingénierie et Management de la Santé (ILIS), Loos, France.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Deram
authors.affiliation: EA 2694, Université Lille Nord de France, Faculté de Médecine pôle Recherche, Lille, France.
authors.forename: Michaël
authors.initials: M
authors.lastname: Génin
authors.affiliation: Service de Néphrologie, Hopital Huriez, CHRU de Lille, Lille, France; Réseau Néphronor, Hôpital Huriez, CHRU de Lille, Lille, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Noël
authors.affiliation: EA 4483, Université Lille Nord de France, Faculté de Pharmacie de Lille, Lille, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Cuny
authors.affiliation: EA 4483, Université Lille Nord de France, Faculté de Pharmacie de Lille, Lille, France; Service de Néphrologie, Hopital Huriez, CHRU de Lille, Lille, France; Réseau Néphronor, Hôpital Huriez, CHRU de Lille, Lille, France.
authors.forename: François
authors.initials: F
authors.lastname: Glowacki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007676:Kidney Failure, Chronic / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D062206:Spatial Analysis; D019371:Topography, Medical; D055815:Young Adult