Declining comorbidity-adjusted mortality rates in English patients receiving maintenance renal replacement therapy

Benjamin C Storey,Natalie Staplin,Charlie H Harper,Richard Haynes,Christopher G Winearls,Raph Goldacre,Jonathan R Emberson,Michael J Goldacre,Colin Baigent,Martin J Landray,William G Herrington

doi:10.1016/j.kint.2017.11.020

Benjamin C Storey, Natalie Staplin + Show 9 more

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https://doi.org/10.1016/j.kint.2017.11.020

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Abstract

We aimed to compare long-term mortality trends in end-stage renal disease versus general population controls after accounting for differences in age, sex and comorbidity. Cohorts of 45,000 patients starting maintenance renal replacement therapy (RRT) and 5.3 million hospital controls were identified from two large electronic hospital inpatient data sets: the Oxford Record Linkage Study (1965-1999) and all-England Hospital Episode Statistics (2000-2011). All-cause and cause-specific three-year mortality rates for both populations were calculated using Poisson regression and standardized to the age, sex, and comorbidity structure of an average 1970-2008 RRT population. The median age at initiation of RRT in 1970-1990 was 49 years, increasing to 61 years by 2006-2008. Over that period, there were increases in the prevalence of vascular disease (from 10.0 to 25.2%) and diabetes (from 6.7 to 33.9%). After accounting for age, sex and comorbidity differences, standardized three-year all-cause mortality rates in treated patients with end-stage renal disease between 1970 and 2011 fell by about one-half (relative decline 51%, 95% confidence interval 41-60%) steeper than the one-third decline (34%, 31-36%) observed in the general population. Declines in three-year mortality rates were evident among those who received a kidney transplant and those who remained on dialysis, and among those with and without diabetes. These data suggest that the full extent of mortality rate declines among RRT patients since 1970 is only apparent when changes in comorbidity over time are taken into account, and that mortality rates in RRT patients appear to have declined faster than in the general population.

Highlights

M aintenance dialysis programs for end-stage renal disease (ESRD) began in the United Kingdom in the 1960s.1–3 Until the 1980s, renal replacement therapy (RRT; i.e., dialysis or kidney transplantation) was restricted to ESRD patients who were considered the most economically active, and those with diabetes or other comorbidities were often not referred or treated.[4]
BC Storey et al.: Temporal mortality trends in RRT cohorts 1970–2010 registers, so we aimed to study mortality trends among new maintenance RRT patients and controls from the general population between 1970 and 2008 using novel approaches to ensure all cohorts could correct for changes in comorbidity over time
Indirect validation included observing closely matched numbers of kidney transplant operations recorded in Hospital Episode Statistics (HES) and the UK Transplant Registry[14] (Supplementary Table S1); closely matched cohort sizes, demographics and renal characteristics when HES data were compared with summary English data from the UK Renal Registry (Supplementary Table S2)[15,16,17,18]; and similar age- and sex-adjusted 3-year mortality rates for Oxford Record Linkage Study (ORLS)/“HES Oxford” and for Oxford Kidney Unit

Summary

Introduction

M aintenance dialysis programs for end-stage renal disease (ESRD) began in the United Kingdom in the 1960s.1–3 Until the 1980s, renal replacement therapy (RRT; i.e., dialysis or kidney transplantation) was restricted to ESRD patients who were considered the most economically active, and those with diabetes or other comorbidities were often not referred or treated.[4]. Examining long-term temporal mortality trends helps describe past and current serious health risks Interpreting these trends is difficult in RRT populations because comparisons between patients treated for ESRD and other populations need to take account of the substantial secular changes in the prevalence of comorbid illnesses that influence both mortality[6,7,8] and the likelihood of receiving RRT. The Oxford Record Linkage Study (ORLS) was established in 1963 and recorded information about all hospital inpatient admissions in Oxfordshire and surrounding counties covering about 5% of England (referred to as “Oxfordshire”).[13] Hospital Episode Statistics (HES) succeeded ORLS and established nationwide coverage from 1998 Both data sets have been linked to national mortality. We consider the effects of temporal changes in the availability of transplantation on mortality trends

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