PREVALENCE AND INCIDENCE OF DIABETIC RETINOPATHY IN THE UK

Rohini MathurLSHTM

RNIB Research Day 2015

Improving health worldwide www.lshtm.ac.uk

Background

• Diabetic Retinopathy (DR) is caused by the presence of diabetes which results in damage to the retina.

• Within 20 years of diabetes diagnosis nearly all people with type 1 and almost two thirds of people with type 2 diabetes have some degree of retinopathy.

• In the UK, the risk of developing type two diabetes has been shown to be 2-6 times higher in South Asian communities compared to the White British population.

• If untreated, diabetic retinopathy leads to blindness, and is one of the most common causes of sight loss in people of working age.

Aims

Though diabetic retinopathy is thought to be one of the leading causes of visual impairment and blindness in the UK, population-

wide measures of incidence and prevalence have not been determined

The aims of this study were to: 1. Generate nationally representative estimates of the incidence and

prevalence of diabetic retinopathy in the United Kingdom 2. Examine trends according to age, sex, ethnicity, socio-economic

deprivation, calendar period, and region.

Methods

• A prospective cohort study was conducted to examine the prevalence and incidence of diabetic retinopathy in all patients aged 12 and over between January 2004 and December 2014.

• The study used data from the Clinical Practice Research Datalink:– A database containing the anonymised medical records of 5.5 million

patients– From 601 general practices across the UK – The CPRD is representative of the UK population with respect to age, gender

and ethnic group.

• Retinopathy Screening was introduced as a payment indicator in 2004 as part of the Quality and Outcomes Framework, thus coding is likely to be complete and accurate over the study period

Results

7,707,475 patients in the CPRD aged

12+

4% with type 1 diabetes

(338,390)

28% with diabetic retinopathy

(95,807)

0.4% with type 1 diabetes(30,657)

48% with diabetic retinopathy

(18,846)

Prevalence in CPRD over time

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

% T1DM

0.0034676391027037

0.0035649534518935

0.0036764106553135

0.0037769876094363

0.0038454947274578

0.003920502094066

0.0039829543634888

0.0040554291086471

0.0041241876696631

0.0042170881779291

0.0042981577275502

% T2DM

0.0293606367324538

0.0322723393727695

0.0355830809197207

0.0383759793089895

0.0403455626018718

0.0422896310367903

0.0442466820733561

0.0462749906049184

0.0477007411502337

0.0488262518722859

0.0500064528477633

% DR

0.0088093239060409

0.009787730031536

0.0108637813209628

0.0121722129749758

0.0137833198386803

0.0156976662955338

0.017538005163759

0.0193864543523886

0.0208109049498922

0.0214860292453745

0.022954992789644

0.5%

1.5%

2.5%

3.5%

4.5%

5.5%

% T1DM % T2DM % DR

N=7,707,475

North East

North W

est

Yorkshire

& The H

umber

East M

idlands

West

Midlands

East of E

ngland

South W

est

South Centra

l

London

South East

Norther I

reland

Scotla

ndW

ales0.00%

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

2.26%

1.91%

1.59%1.82%

2.12%

1.45%

2.22%

1.73%1.55% 1.63%

1.15%

2.37%2.52%

Prevalence in CPRD by Region

N=7,707,475

Trends by gender

T1DM T2DM0

10

20

30

40

50

60

48.3

29

48.6

29.7

Prevalence of Retinopathy in Type 1 and Type 2 diabetes

Male Female

%

Hazard Ratio CI 95% p.val

T1DM Male (ref) 1

Female 1.05 (1.01-1.11) 0.030

T2DM Male (ref) 1

Female 0.92 (0.91-0.93) <0.001

Relative risk of incident Retinopathy

The prevalence of retinopathy is comparable between males and females

The risk of incident retinopathy is lower in females relative to males

Trends by ethnic group

T1DM T2DM0

10

20

30

40

50

6050.2

29.6

40.6

29.933.2

28.9

Prevalence of Retinopathy in Type 1 and Type 2 diabetes

White South Asian Black

%

Hazard Ratio

CI 95% p.val

T1DM White (ref) 1

South Asian 0.87 (0.68-1.10) 0.237

Black 0.79 (0.59-1.04) 0.091

T2DM White (ref) 1

South Asian 1.14 (1.10-1.19) <0.001

Black 1.08 (1.02-1.15) 0.014

Relative risk of incident Retinopathy

Large ethnic differences in prevalence for patients with T1DM

Risk of retinopathy is raised for South Asian and Black groups with type 2 diabetes relative to White groups

Trends by deprivation quintile

T1DM T2DM0

5

10

15

20

25

30

18.415.5

19.5 18.521.1 20.2

22.324.1

18.821.8

Prevalence of Retinopathy in Type 1 and Type 2 diabetes

Most affluent Q2 Q3Q4 Least affluent

%

Hazard Ratio

CI 95% p.val

T1DM Most affluent 1

Least affluent 0.94 (0.87-1.02) 0.128

T2DM Most affluent 1

Least affluent 1.08 (1.05-1.11) <0.001

Relative risk of incident Retinopathy

Prevalence of retinopathy increases with deprivation till Q4

Risk of retinopathy is higher for the least affluent compared to most affluent in patients with type 2 diabetes

Conclusions

• The study has shown that the overall prevalence of retinopathy has been increasing steadily over the last 10 years in parallel to that of type 2 diabetes.

• Increases in prevalence of retinopathy are likely to be related to increasing prevalence of T2DM and potentially increased ascertainment through national screening programs.

• Prevalence of retinopathy is similar between males and females, but incidence is lower for females with T2DM.

• Increasing levels of deprivation are associated with higher prevalence of retinopathy in all diabetics, and with higher incidence amongst T2DM only.

• Amongst patients with type 2 diabetes, prevalence and incidence of retinopathy is highest in the South Asian group relative to the White group.

Strengths

• This study constitutes the largest ever sample size to examine trends in the burden of diabetes and diabetic retinopathy in the UK.

• Currently, this is the only national study to examine ethnicity and deprivation in relation to the prevalence and incidence of diabetic retinopathy.

• The advantage of routine electronic health databases is that they are regularly updated and can be used to provide timely information on the demographic makeup of the general population and on areas of growing healthcare need.

Policy implications

• Given that the CPRD is representative of the UK population structure, we estimate that the absolute number of people with any form of diabetic retinopathy in the UK is approximately 1.5 million.

• In 2014, attendance at diabetic retinopathy screening was removed from the Quality and Outcomes Framework. Not only will this impact on future research into retinopathy, it is likely to have serious negative implications on service planning for diabetic patients unless the indicator is reinstated.

• The national diabetic retinopathy screening programme needs to improve access to screening and support around self-management of diabetes for deprived and ethnic minority populations to avoid increasing inequalities.

Thank you!

I’d like to thank the team at LSHTM: Ian Douglas, Krishnan Bhaskaran, Nish Chaturvedi, Liam Smeeth

And at the RNIBEmma Edwards, Helen Lee, John Slade

Any Questions?

(Full Results will be published on the RNIB website in 2016)

PREVALENCE AND INCIDENCE OF DIABETIC RETINOPATHY IN THE UK

Rohini MathurLSHTM

RNIB Research Day 2015

Improving health worldwide www.lshtm.ac.uk