How much of the regional variation in RRT incidence rates within the UK is explained by the health needs of the general population?

Background. Variation in end-stage renal disease treatment rates in the UK persist after adjustment for socio-demographic factors. Methods. UK-wide ecological study using population socio-demographic factors, health status characteristics and access to health services factor in to explain the incidence of renal replacement therapy (RRT). Results. There was a 6% higher incidence rate of RRT per standard deviation (SD) increase in area diabetes prevalence after adjustment for area level socio-economic deprivation status and the proportion of non-white residents [incidence rate ratio adjusted (IRR adjusted) 1.06 (95% confidence interval 1.03,1.09), P < 0.001]. A 3% lower-adjusted RRT incidence rate was seen with each SD higher proportion of diabetics achieving an HbA1c of <7.5% [IRR 0.97 (0.94, 1.00), P = 0.03]. Hypertension prevalence was independently associated with an 8% higher RRT incidence rate per SD increase [IRR adjusted 1.08 (1.04, 1.11), P < 0.001] and an SD increase in life expectancy in an area was independently associated with 7% lower RRT incidence rate [IRR adjusted 0.93 (0.91, 0.96), P < 0.001]. An SD increase in premature cardiovascular (CV) mortality rate in an area was also independently associated with RRT incidence rates [IRR adjusted 1.06 (1.03, 1.09), P < 0.001]. Rates of coronary artery bypass grafting (CABG)/angioplasty and knee replacement were positively associated with RRT incidence, but mammography uptake was not associated. In total, 31% of the regional variation in RRT incidence could be explained by these factors. Conclusions. Diabetes prevalence, the proportion of diabetics achieving good glycaemic control, hypertension prevalence, life expectancy, premature CV mortality, CABG/angioplasty and knee replacement rates were all associated with RRT incidence. A third of the regional variation in RRT incidence between areas can be explained by these demographic, health and access to health services factors.