Complications of diabetes in urban Indigenous Australians: The DRUID study

https://doi.org/10.1016/j.diabres.2008.01.011Get rights and content

Abstract

Aims

To accurately assess the management and complications of type 2 diabetes in urban Indigenous Australians and compare the risk of complications with a general Australian population (AusDiab Study).

Methods

The Darwin Region Urban Indigenous Diabetes (DRUID) Study included 1004 volunteers aged ≥15 years; diabetes status was classifiable for 866. The assessment of diabetic complications and metabolic control was performed in participants with known diabetes (KDM) and diabetes newly diagnosed by the study (NDM) using an interviewer-administered questionnaire and clinical examination.

Results

Among 172 DRUID participants eligible for complications assessment, 135 were assessed, including 99 KDM (mean age 53 years) and 36 NDM (mean age 47 years). Percentages of KDM participants meeting therapeutic targets were: HbA1c < 7%, 29%; blood pressure < 130/80 mmHg, 45%; total cholesterol < 5.5mmol/L, 65%. Among KDM, 39% had albuminuria, 21% retinopathy, 12% peripheral vascular disease (PVD), 9% neuropathy. Factors independently associated with diabetic complications were: albuminuria–HbA1c, systolic blood pressure; retinopathy–diabetes duration; PVD–age. Compared to AusDiab participants after adjusting for other risk factors, DRUID participants had 2–3-fold increased risk of albuminuria and PVD and a non-significant increased risk of neuropathy, but no increased risk of retinopathy.

Conclusions

Urban Indigenous Australians with diabetes are relatively young and have poor glycaemic control. Compared to the general Australian population with type 2 diabetes, they have greater adjusted risk of albuminuria and PVD but not retinopathy. Urgent action is required to prevent diabetes at a population level and improve diabetes management in this high-risk population.

Introduction

Relative to the overall Australian population, Indigenous Australians have a 15–20 year shorter life-expectancy and a 10-fold higher prevalence of diabetes (in those aged 20–50 years) [1], [2]. Complications of diabetes are significant contributors to premature mortality of Indigenous Australians [3], however this population is inadequately represented in relevant recent Australian studies (AusDiab [4], [5], [6], [7] and ANDIAB, National Association of Diabetes Centres [8]). It is also problematic to compare Indigenous and non-Indigenous groups with diabetes due to differences in age profiles (the age of onset of diabetes and its complications is much younger in Indigenous Australians).

There have been few studies involving complete assessment of complications of diabetes in Indigenous Australians [9], however high rates of nephropathy [10], [11], retinopathy [12], [13] and diabetic foot complications [14], [15] have been described in this population. Audits of Aboriginal people with diabetes have consistently reported poor glycaemic control despite adequate monitoring [16], [17], [18], [19], [20], [21] with better monitoring and control of blood pressure than glycaemia [20].

Of note, most Indigenous Australian studies concerned those living in rural and remote regions, while little is known about diabetes care and complications in the urban setting, where the majority of Indigenous Australians live [1]. The Darwin Region Urban Indigenous Diabetes (DRUID) Study was designed to address this knowledge gap. Compared to the rural/remote setting, health services are more likely to exist in urban Australia. However, there may still be important barriers for Indigenous Australians accessing these services, as evident by reported delays for Indigenous Australians accessing thrombolysis to a similar extent in both urban and remote settings (compared to non-Indigenous Australians) [22].

The aim of this study was to accurately assess metabolic control of type 2 diabetes and diabetes-related complications (micro- and macro-vascular) in an urban Indigenous cohort and to compare the risk of complications for DRUID participants with that of participants in the AusDiab Study of the general Australian population.

Section snippets

Participants

Participants were a subset of the DRUID Study, a cross-sectional study of approximately 1000 urban Indigenous people from Darwin, Australia, undertaken from September 2003 to March 2005. The population, methods and response rates of the DRUID Study have been previously described [23]. In summary, DRUID participants met the following eligibility criteria: identified as Aboriginal or Torres Strait Islander; aged  15 years; had resided within a specified geographical region around Darwin for at

Results

Diabetes status could be classified for 866 DRUID participants (Fig. 1). Of these, 172 (19.9%) had diabetes and were eligible for complications assessment, including 48 newly diagnosed by the study (28% of those with diabetes). The majority of participants with diabetes were women (74%). The proportions of females with diabetes were similar to proportions in the whole study sample for the age groups 45–54 years (70.8% female) and 55–64 years (71.2% female) but are not representative of the

Discussion

We report a minimum 2-fold independent increased risk of PVD and albuminuria in urban Indigenous Australians with diabetes compared to the general Australian population with diabetes. By contrast, we found no increase in relative odds of retinopathy in DRUID participants. Health care of DRUID participants was predominantly by primary health care providers, with moderate rates of meeting therapeutic targets.

Diabetes was common in this urban Indigenous cohort (19% of those with fasting bloods).

Conflict of interest

PZ has received fees for speaking and consulting from GlaxoSmithKline, Lilly Pharmaceuticals, Novartis, Bayer Schering Pharma AG, Merk, Sharp and Dohme, MerckAG, BMS, Solvay/Fournier and Sanofi Aventis. JES has received fees for speaking and for consulting from GlaxoSmithKline, Lilly Pharmaceuticals, Novo Nordisk, Bayer Schering Pharma AG, Merk, Sharp and Dohme, and Sanofi Aventis.

Acknowledgements

The authors gratefully acknowledge the support of DRUID study participants, study staff, members of the Indigenous Steering Group, and partner organisations. The DRUID Study was funded by the National Health and Medical Research Council (NHMRC Project Grant #236207), with additional support from the Australian Government Department of Employment and Workplace Relations, the Clive and Vera Ramaciotti Foundation, the Vincent Fairfax Family Foundation, the International Diabetes Institute (AusDiab

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