O70
ESTABLISHING A RENAL DATA OBSERVATORY USING HEALTHCARE DATA
LINKAGE METHODOLOGY
Black C, Marks A, Robertson L, Wilde K, Simpson WG, Prescott GJ, Smith WCS & Fluck N
Chronic Disease Research Group & Department of Renal Medicine, University of Aberdeen &
NHS Grampian
INTRODUCTION: Chronic kidney disease (CKD) affects 8-10% of the adult population, rising to
more than 50% of those over 85yrs. Understanding the epidemiology, disease progression and
burden in terms of health service needs is important for informing healthcare planning. To be able to
identify vulnerable patient groups and provide tailored care stratified by long term risks offers the
potential to target care to optimise health benefits. The aim of this work was to establish a Renal Data
Observatory enabling us to link healthcare data from various sources to study CKD.
METHODS: The Grampian Data Safe Haven (DaSH) provides a secure environment for storing,
indexing and linking and analysis of healthcare data. A 10 year extract of the NHS regional
biochemistry laboratory system for measures of renal function formed the core of the data platform.
Using the unique patient identifier assigned to all people in Scotland registered with a general
practitioner, data from a range of different sources could be linked to support bespoke study specific
data extracts. Data linkages used a mixture of deterministic and probabilistic methods to enable
linkage to hospital episode data, socioeconomic and geographical data, Scottish Renal Registry and
death registry data. The GLOMMS-II cohort (with complete capture of all individuals with a low
(<60) eGFR and a large sample of those with normal renal function) forms part of this renal
observatory.
2
100
80
60
40
20
% of population with eGFR <60ml/min/1.73m
RESULTS: After data cleaning, validation and exclusions (e.g. non-residents) there were 4,302,216
creatinine, 130,326 albumin:creatinine ratio and 31,532 protein:creatinine ratio results for 417,295
individuals from 1st July 1999 to 30th June 2009. The proportion with an estimated Glomerular
Filtration Rate (eGFR) of <60 ml/min/1.73m2 increased steeply with age (Fig 1). From this data
platform, the GLOMMS II cohort of 70,780 people was established from a baseline in 2003 and,
using record linkage, followed up for six years. GLOMMS II includes a sample of individuals with
normal renal function as well as all people with CKD (~19,000) and those on renal replacement
therapy (RRT). Using GLOMMS II, the adjusted incidence rate ratio comparing those with CKD to
normal renal function for RRT, all-cause mortality and myocardial infarction was 436.9, 1.22 and
1.95 respectively. Being male, worse kidney function and proteinuria were associated with increased
risk of poor outcomes. A simple clinical tool
Male
Female
was constructed to describe outcomes at five
years. A logistic regression prediction
model for RRT performed well (c statistic
0.9581) classifying 98% of patients
correctly. A planning tool was developed as
a simple spreadsheet.
0
CONCLUSION: Having established the
methodology and demonstrated the value for
2000
2002
2004
2006
20082000
2002
2004
2006
2008
understanding CKD, work is underway to
Year
15-24
25-34
establish ongoing updates and new linkages
35-44
45-54
to dispensing data, unique birth cohorts and
55-64
65-74
75-84
85+
maternity and neonatal data providing a rich
resource for understanding renal disease.
Figure 1- Proportion of the Grampian population with
The renal data observatory provides a
2
powerful platform for future renal research. eGFR<60 ml/min/1.73m by age-band and sex over the
years 2000 to 2008