The prevalence of diabetes complications andassociated risk factors in Pacific Islands countries

Si Thu Win Tin a,*, Geoffrey Kenilorea b, Eva Gadabu c, John Tasserei d,Ruth Colagiuri e

aHealth and Sustainability Unit, The Boden Institute of Obesity, Nutrition, Exercise & Eating Disorders, G82 Medical

Foundation Building K25, The University of Sydney, NSW 2006, AustraliabNon Communicable Diseases Unit, Ministry of Health and Medical Services, The Solomon IslandscPublic Health Centre, Ministry of Health and Medical Services, Republic of NaurudHealth Promotion Unit, Public Health Department, VanuatueHealth and Sustainability Unit, Menzies Centre for Health Policy, Victor Coppleson Building DO2, The University of

Sydney, NSW 2006, Australia

d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 3 ( 2 0 1 4 ) 1 1 4 – 1 1 8

a r t i c l e i n f o

Article history:

Received 5 July 2013

Accepted 12 September 2013

Available online 9 November 2013

Keywords:

Type 2 diabetes

Complications

Risk factors

Pacific Island countries (PICs)

Diabetes care

a b s t r a c t

Aim: To determine the prevalence of diabetes complications and associated risk factors

among people with type 2 diabetes in three Pacific Island countries, Nauru, Solomon Islands

and Vanuatu.

Methods: This cross-sectional study was carried out on a sample of 459 people with diabetes.

Subjects were screened for complications using a standardised protocol which gathered

information on demographics, physical and biochemical parameters.

Results: Of the 459 subjects, 47% were female, mean age was 54 years and mean duration of

diabetes was eight years. The prevalence of diabetes complications was significantly higher

in Nauru compared with the Solomon Islands and Vanuatu – microalbuminuria 71%, 36%

and 51% respectively (P < 0.001), retinopathy 69%, 40% and 42% respectively (P < 0.001), and

abnormal foot sensation 30%, 23% and 19% respectively (P = 0.036). The prevalences of

hypertension, overweight/obesity and poor glycaemic control were high. The percentages of

subjects achieving recommended clinical targets were low. Microalbuminuria was signifi-

cantly associated with duration of diabetes, hypertension and glycaemic control. Diabetic

retinopathy was significantly associated with duration of diabetes whereas abnormal foot

sensation was significantly associated with duration of diabetes and glycaemic control.

Conclusions: This study found a high prevalence of diabetes complications and associated

risk factors, which indicate the need to improve diabetes care and strengthen preventive

efforts to reduce complications.

# 2013 Elsevier Ireland Ltd. All rights reserved.

Contents available at ScienceDirect

Diabetes Researchand Clinical Practice

journal homepage: www.elsevier .com/locate/diabres

1. Introduction

The magnitude of the global health burden of diabetes [1,2]

and its negative implications for human development and

* Corresponding author. Tel.: +61 424993595; fax: +61 290363176.E-mail addresses: si.wintin@sydney.edu.au, sithuwintin@gmail.co

evagadbu@gmail.com (E. Gadabu), jtasserei@vanuatu.gov.vu (J. Tasse

0168-8227/$ – see front matter # 2013 Elsevier Ireland Ltd. All rights

http://dx.doi.org/10.1016/j.diabres.2013.09.017

achievement of global development goals [3,4] is well docu-

mented. The vast majority of this burden is due to compli-

cations of diabetes and accounts for substantial costs [5,6].

Many studies from a range of countries have reported the

prevalence of complications and related risk factors among

m (S.T. Win Tin), gkenilorea@moh.gov.sb (G. Kenilorea),rei), ruth.colagiuri@sydney.edu.au (R. Colagiuri).

reserved.

d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 3 ( 2 0 1 4 ) 1 1 4 – 1 1 8 115

people with diabetes. Diabetes complications can be pre-

vented through proven cost effective interventions [7,8].

Multi-risk factor interventions which include lifestyle changes

and pharmacological therapy have been shown to reduce the

risk of diabetes complications by up to 50% [9,10].

The risk of microvascular complications is reduced by

intensive glycaemic control [11] and tight blood pressure

control [12]. Regular risk factor assessment in the primary care

setting minimises hospitalisation due to diabetes complica-

tions [13], and improvements in systems of diabetes care,

screening and treatment programmes for diabetes improve

diabetes clinical outcomes [14,15].

Pacific Island countries (PICs) have a limited capacity to

deliver effective diabetes prevention and care [16,17] and the

proportion of people with diabetes who practice self care is

low [18]. Despite anecdotal reports of high rates of diabetes

complications in PICs, a formal literature search yielded no

recent peer-reviewed literature on the prevalence of diabetes

complications in these countries. Consequently, as part of a

larger capacity building project, we aimed to (i) determine the

prevalence of diabetes complications and associated risk

factors in people with diabetes in three PICs: Nauru, the

Solomon Islands and Vanuatu, and (ii) assess the control of

risk factors against recommended clinical targets.

2. Subjects, materials and methods

This cross-sectional study was carried out on a convenience

sample of 459 people with known diabetes (100 from Nauru,

160 from the Solomon Islands, and 199 from Vanuatu) to

determine the prevalence of diabetes complications and

associated risk factors. Subjects attending the diabetes clinics

in each country during a one week period, which co-incided

with a visit by an Australian diabetes team, were screened

using a standardised protocol. Data were collected on age,

gender, age at diagnosis, duration of diabetes and diabetes

treatment. Physical assessment included measurement of

weight and height and calculation of BMI with overweight

defined as a BMI � 25 and obese as a BMI � 30. The Omron

digital automatic blood pressure monitor was used to measure

resting blood pressure. Blood pressure was measured three

times and mean was used in the analysis. Hypertension was

defined as a systolic blood pressure �140 mmHg and/or

diastolic blood pressure �90 mmHg or taking blood pressure

lowering medications. Visual acuity was assessed and fundus

examination through dilated pupils was performed by an

experienced optometrist. Foot sensation was assessed using a

10 g monofilament by trained foot care nurses and loss of the

ability to detect this pressure (abnormal foot sensation) at one

or more anatomic sites on the plantar surface of the foot was

defined as neuropathy. Biochemical assessment included

measurement of HbA1c using a DCA Analyser; urinary

albumin/creatinine ratio (ACR) using a DCA Analyser and

microalbuminuria was defined as an ACR > 2.5 mg/mmol for

men or >3.5 mg/mmol for women; blood lipids (total choles-

terol, HDL cholesterol, LDL cholesterol and triglycerides) were

measured by Cholestech LDX analyser.

The clinical targets agreed for the overarching diabetes

project in the three PICs and specifically for this study were:

(i) HbA1c <7.0% (53 mmol/mol)

(ii) Blood pressure <130/85 mmHg

(iii) Total cholesterol <5.0 mmol/L

HDL cholesterol >1.0 mmol/L

LDL cholesterol <2.5 mmol/L

Triglycerides <2.0 mmol/L

The data were compiled and analysed using IBM SPSS

statistical package version 21. Country data are reported as

means � SEM and percentages, and compared using one way

ANOVA test and logistic regression model adjusted for age, sex

and duration of diabetes. Associations between diabetes

related complications and risk factors for complications were

assessed using logistic regression model adjusted for country.

Statistical significance was defined as P < 0.05.

This research was approved by the Human Research Ethics

Committee, the University of Sydney and the Research Ethics

Committees of the Nauru, Solomon Islands and Vanuatu.

3. Results

Table 1 shows the demographic details of the 459 people

(mean age 54 years, mean age at diagnosis 46 years, and mean

duration of diabetes eight years) screened for complications

and associated risk factors by country. Overall there were 244

(53%) males (mean age 53.9 years) and 215 (47%) females (mean

age 54.1 years). Subjects in Nauru were younger than those in

the Solomon Islands and Vanuatu but had the longest duration

of diabetes. The percentage treated with diet alone in Nauru,

Solomon Islands and Vanuatu was 41%, 13% and 11%

respectively, oral anti-diabetic agents 49%, 82% and 83%

respectively, and insulin 10%, 5% and 6% respectively.

Risk factors for diabetes complications were common but

the risk factor profile differed between the PICs. Nauru had the

highest mean BMI, HbA1c, ACR and LDL cholesterol while

Vanuatu had the highest mean blood pressure and triglycer-

ides. The percentage of people in Nauru, Solomon Islands and

Vanuatu achieving targets were 50%, 31% and 15% respectively

for blood pressure, 20%, 17% and 28% respectively for HbA1c,

47%, 55% and 49% respectively for total cholesterol, 29%, 29%,

and 11% respectively for HDL cholesterol, 16%, 24% and 42%

respectively for LDL cholesterol, and 54%, 50%, 45% respec-

tively for triglycerides.

Diabetes complications were common and the prevalence

also varied in the three PICs. The prevalence of microalbu-

minuria in Nauru, Solomon Island and Vanuatu was 71%, 36%

and 51% respectively, retinopathy 69%, 40% and 42% respec-

tively, and abnormal foot sensation 30%, 23% and 19%

respectively (Table 2).

The association between diabetes complications and risk

factors for complications was assessed using logistic regres-

sion models. Microalbuminuria was significantly associated

with longer duration of diabetes, hypertension and poorer

glycaemic control, abnormal foot sensation with longer

duration of diabetes and poor glycaemic control and diabetic

retinopathy with longer duration of diabetes. Although higher

rates of retinopathy were found in people with poor glycaemic

control and hypertension, the association was not statistically

significant.

Table 1 – Demographic details and risk factors for diabetes complications in the three Pacific Island countries.

Nauru (n = 100) Solomon Islands (n = 160) Vanuatu (n = 199) P value

Age (years)a 51.2 � 1.3 54.2 � 0.8 55.5 � 0.1 0.006

Genderb 0.340*

Male 41% 57% 42%

Female 59% 43% 58%

Age at diagnosis (years)c 39.5 � 1.3 44.9 � 0.8 50.2 � 0.6 <0.001

Duration of diabetes (years)d 11.8 � 0.9 9.2 � 0.7 5.2 � 0.4 <0.001

Diabetes treatmente <0.001*

Diet alone 41% 13% 11%

Oral anti-diabetic agents 49% 82% 83%

Insulin 10% 5% 6%

BMI (kg/m2) 31.1 � 0.6 28.6 � 0.4 28.8 � 0.4 <0.001

Overweight 90% 79% 78% 0.040*

Obese 53% 33% 38% 0.004*

Blood Pressure (mmHg) 127/74 141/81 151/85 <0.001

Hypertension 42% 55% 72% <0.001*

<130/85 mmHg 50% 31% 15% <0.001*

HbA1c (%) 10.0 � 0.3 9.5 � 0.2 8.0 � 0.1 <0.001

HbA1c (mmol/mol) 86 80 64

Glycemic control <0.001*

HbA1c <7.0 (<53 mmol/mol) 20% 17% 28%

HbA1c 7–7.9 (53–63 mmol/mol) 14% 11% 26%

HbA1c 8–8.9 (64–74 mmol/mol) 6% 20% 20%

HbA1c 9–9.9 (75–85 mmol/mol) 12% 11% 11%

HbA1c �10 (�86 mmol/mol) 48% 41% 15%

ACR (mg/mmol) 23.7 � 2.9 7.9 � 0.7 10.3 � 1.2 <0.001

Total cholesterol (mmol/L) 5.0 � 0.1 4.9 � 0.1 5.0 � 0.1 0.520

Total cholesterol <5.0 mmol/L 47% 55% 49% 0.783*

HDL cholesterol (mmol/L) 0.8 � 0.1 0.9 � 0.1 0.8 � 0.1 0.060

HDL >1.0 mmol/L 29% 29% 11% <0.001*

LDL cholesterol (mmol/L) 3.3 � 0.1 3.1 � 0.1 2.7 � 0.1 <0.001

LDL <2.5 mmol/L 16% 24% 42% 0.001*

Triglycerides (mmol/L) 2.0 � 0.1 2.0 � 0.1 2.8 � 0.1 <0.001

Triglycerides <2.0 mmol/L 54% 50% 45% 0.021*

Data are shown as mean � SEM or percentage. P values are derived from one way ANOVA test.a Overall mean = 54 years.b Overall male = 53%, female = 47%.c Overall mean = 46 years.d Overall mean = 8 years.e Overall diet alone = 18%, oral anti-diabetic agents = 76%, insulin = 6%.* P values are derived from logistic regression model adjusted for age, sex and duration of diabetes.

d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 3 ( 2 0 1 4 ) 1 1 4 – 1 1 8116

4. Discussion

This study found a high prevalence of diabetes complications

and associated risk factors among people with diabetes, and a

low rate of subjects achieving standardised clinical targets in

all three PICs.

The prevalence of microalbuminuria, an indicator of future

nephropathy, found in this study was 71%, 36% and 51% in

Nauru, Solomon Islands and Vanuatu respectively which

overall was higher than in previous studies in PICs (23.4% in

Samoa [19], 33.3% in Pacific Islanders in South Auckland [20]

and 42.1% in Nauru [21]). These rates are also higher than in

western countries (24.9% in the UK [22] and 17.2% in the

Netherlands [23]). The prevalence of diabetic retinopathy was

also high. The highest rates were observed in Nauru (69%)

which are higher than previously reported in other PICs [19,24–

26] and western countries [23]. Similarly neuropathy and foot

problems were common, with Nauru again having the highest

prevalence of neuropathy (30%). These complications could

potentially be reduced or prevented with improved quality of

diabetes care in people with diabetes in PICs.

In this study microalbuminuria was significantly associat-

ed with duration of diabetes, hypertension and glycaemic

control, diabetic retinopathy with duration of diabetes, and

abnormal foot sensation with duration of diabetes and

glycaemic control. These findings are consistent with previous

studies [19,27]. Subjects in Nauru had longer duration of

diabetes and poorer glycaemic control and this finding may

explain why the Nauruan subjects had the highest prevalence

of diabetes complications. These factors together with the

highest prevalence of overweight/obesity in Nauru may

Table 2 – Prevalence of diabetes complications in the three Pacific Island countries.

Nauru N (%)(n = 100)

Solomon Islands N(%) (n = 160)

Vanuatu N (%)(n = 199)

P value

Microalbuminuria 71 (71%) 58 (36%) 102 (51%) <0.001

Diabetic retinopathy 69 (69%) 64 (40%) 83 (42%) <0.001

Abnormal foot sensation 30 (30%) 36 (23%) 38 (19%) 0.036

Abnormal digital foot pulse 24 (24%) 28 (18%) 3 (1.5%) <0.001

Foot ulcer 8 (8%) 13 (8%) 10 (5%) 0.870

Diabetes-related amputation 11 (11%) 17 (11%) 21 (11%) 0.520

P values are derived from logistic regression model adjusted for age, sex and duration of diabetes.

d i a b e t e s r e s e a r c h a n d c l i n i c a l p r a c t i c e 1 0 3 ( 2 0 1 4 ) 1 1 4 – 1 1 8 117

account for it having the highest prevalence of complications

of the three PICs. With regard to glycaemic control, Nauruan

subjects had the highest use of diet alone and the lowest use of

oral anti-diabetic agents. There is no evidence to explain this

and our study did not attempt to explore reasons for

differences in therapy.

Evidence from several studies has shown that diabetes

complications can be reduced by multi-risk factor interven-

tions [9,10], intensive glycaemic control [11] and tight blood

pressure control [12]. However this study found that the

percentage of subjects achieving the agreed clinical targets

in the three PICs was generally low. The glycaemic target

was achieved in 17–28% of individuals, blood pressure target

in 15–50% and LDL cholesterol target in 16–42%. Conse-

quently, this study confirms the need for better control of

risk factors which can prevent and minimise diabetes

complications.

Although our study has identified several key important

clinical findings, it has certain limitations. Cardiovascular

complications were not included in the analysis because this

information was poorly recorded in medical records and

appropriate diagnostic investigations were not available. The

potential causality of the associations observed between risk

factors and complications are limited by the cross-sectional

nature of this study. Although we used a standardised

protocol for biochemical assessment, methods and equip-

ment for assessing risk factors and complications, the

methods differed from previous studies and may have

impacted on direct comparisons. Notwithstanding these

limitations, our study has certain strengths including

comparable sample size for each country and use of a

standardised protocol to assess physical and biochemical

measures by experienced medical personnel. The findings in

PICs support current theories about complications of diabetes

and their associated risk factors.

In conclusion, this study found a high prevalence of

diabetes complications and associated risk factors in PICs,

and a low percentage of subjects achieving agreed standar-

dised clinical targets. This indicates the need to improve the

quality and accessibility of diabetes care and strengthen

preventive efforts to reduce diabetes complications. This will

require system changes to ensure the availability of essential

medicines, diagnostic and monitoring technologies, aware-

ness programmes and patient education services which still

remain a challenge in PICs. Further research is needed on

models and systems for reducing the diabetes burden in these

small developing Pacific nations.

Conflict of interest

None known or perceived.

Acknowledgements

The World Diabetes Foundation funded the overarching

diabetes capacity building projects in Nauru, Vanuatu and

the Solomon Islands under which this study was under-

taken. These projects were conducted in partnership with

the Ministries of Health of the Solomon Islands, Nauru

and Vanuatu, the International Centre for Eyecare Educa-

tion at the University of New South Wales, the Australia

and New Zealand Society of Nephrologists. Additional

support was provided by University of Sydney’s Medical

School Foundation.

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