Ethnic differences in diabetes care in a multiethnic community in New Zealand

Racial differences in all-cause mortality and future complications among people with diabetes: a systematic review and meta-analysis of data from more than 2.4 million individuals

AIMS/HYPOTHESIS

The aim of this work was to quantify racial/ethnic differences in risk for future diabetic complications and all-cause mortality by performing a meta-analysis of prospective studies.

METHODS

A systematic search in PubMed and EMBASE was performed from inception to May 2021. Prospective cohort studies that reported HRs and associated 95% CIs of diabetes complications and all-cause mortality among racial/ethnic groups, with White people as the reference group, were included. Study characteristics and HR estimates were extracted from each study. Estimates were pooled using random-effects inverse-variance model with the Hartung-Knapp-Sidik-Jonkman variance estimator.

RESULTS

A total of 23 studies were included, comprising 2,416,516 individuals diagnosed with diabetes (White 59.3%, Black 11.2%, Asian 1.3%, Hispanic-American 2.4%, Native American 0.2%, East Asian 1.9%, South Asian 0.8%, Pacific Islander 2.3%, Māori 2.4% and others 18.2%). Compared with White individuals with diabetes, individuals of Māori ethnicity were at higher risk for all-cause mortality (HR 1.88 [95% CI 1.61, 2.21]; I² = 7.1%), Hispanic-American individuals had a significantly lower risk for CVD (HR 0.66 [95% CI 0.53, 0.81]; I² = 0%) and Black individuals had higher risk for end-stage renal disease (HR 1.54 [95% CI 1.05, 2.24]; I² = 95.4%). No significant higher risk for diabetes complications was found in other racial/ethnic groups relative to White people.

CONCLUSIONS/INTERPRETATION

Racial/ethnic differences exist in the risk for future diabetic complications and all-cause mortality. Our results support the use of such categories for international diabetes clinical guideline recommendations until better predictors become available. Efforts to identify high-risk groups and to better control cardiovascular risk factors across ethnically diverse populations are therefore needed.

REGISTRATION

PROSPERO registration ID CRD42021239274.

Pregnancy outcomes among multi-ethnic women with different degrees of hyperglycaemia during pregnancy in an urban New Zealand population and their association with postnatal HbA1c uptake

BACKGROUND

Adverse pregnancy outcomes are more common in women with hyperglycaemia. Many women have suboptimal uptake of HbA1c testing postdelivery.

AIMS

To compare pregnancy outcomes among multi-ethnic women with different degrees of hyperglycaemia during pregnancy, and their association with postnatal HbA1c uptake after the introduction of email reminders.

MATERIALS AND METHODS

A retrospective and prospective single-centre study was conducted in South Auckland in 2639 women with early gestational diabetes mellitus (GDM) (diagnosed < 20 weeks), late GDM (diagnosed ≥ 20 weeks), overt diabetes in pregnancy, or known type 2 diabetes (T2DM) during pregnancy. Automated email reminders were sent to general practitioners to increase postnatal HbA1c screening.

RESULTS

HbA1c during pregnancy increased across the late GDM (n = 1425), early GDM (n = 148), overt diabetes (n = 573) and T2DM (n = 493) groups (P < 0.001). Stillbirth was least common in the late GDM group (0, 0.7, 0.5, and 1.9%, respectively, P < 0.001), as were caesarean delivery (32.7, 45.1, 39.4, and 53.5%, respectively, P < 0.001), large for gestational age (LGA) (14.7, 18.2, 22.3, and 30.5%, respectively, P < 0.001), small for gestational age (8.8, 16.7, 11.0, and 11.1%, respectively, P = 0.02), and preeclampsia/eclampsia (7.7, 9.2, 13.0, and 14.8%, respectively, P < 0.001). LGA and preeclampsia/eclampsia were more common among Pacific and Māori women than European women (LGA, 30.1, 22.7, 10.3%, respectively, P < 0.001; preeclampsia/eclampsia, 13.5, 14.0, and 8.1%, respectively, P < 0.001). Postpartum HbA1c screening increased among women with GDM/overt diabetes after the introduction of the reminder emails (39.6% vs 34.0%, P = 0.03).

CONCLUSIONS

Women with late GDM are least likely to experience adverse outcomes. Email reminders to improve postpartum HbA1c screening warrant further investigation.

Low prevalence of retinopathy, but high prevalence of nephropathy among Maori with newly diagnosed diabetes-Te Wai o Rona: Diabetes Prevention Strategy

AIMS/HYPOTHESIS

To describe the prevalence of retinopathy and microalbuminuria at diagnosis of diabetes in a predominantly Maori study population.

METHODS

Biomedical assessment including photographic retinal examination was undertaken among 157 (68.9% of eligible) members of Maori families (3.3% non-Maori) diagnosed with diabetes during a community screening programme (n=5240) as part of a diabetes prevention strategy.

RESULTS

Mean HbA1c of those with newly diagnosed diabetes was 7.8+/-1.5% with 34.4% having an HbA1c >/=8.0%. Retinopathy was present in 3 (1.7%) subjects, cataracts in 3.2%, microalbuminuria in 29.6% and albuminuria in 7.7%. After adjusting for covariates, only smoking was a risk factor for microalbuminuria/proteinuria (current and former smokers: increased 3.81(1.32-11.0) and 3.67(1.30-10.4) fold, respectively).

CONCLUSIONS

The prevalence of retinopathy at diagnosis was lower than in previous studies, yet that of microalbuminuria/proteinuria remained high. The retinopathy data suggest that case detection for diabetes in the community may be improving, but that other strategies among those at risk of diabetes, including those promoting smoking cessation, will be needed to reduce the risk of renal disease among Maori with diabetes.

Ethnic differences in diabetic retinopathy

AIMS/HYPOTHESIS

To compare the prevalence of diabetic retinopathy in European, Maori and Pacific peoples with diabetes.

METHODS

Biomedical assessment and retinal examination, using photography where possible, was undertaken in 458 (67.5% of eligible) randomly selected household survey participants with known diabetes (168 Europeans, 144 Maori, 149 Pacific people). Glycaemia was measured by glycated haemoglobin, fructosamine and random glucose.

RESULTS

In those with Type 2 diabetes, the prevalence of moderate or more severe retinopathy was 4.0% in Europeans, 12.9% in Maori and 15.8% in Pacific people (P = 0.003). There was no significant ethnic difference in the prevalence of retinopathy overall or in that of macular disease. Cataracts were more common in Pacific people (19.3%, 16.4%, 36.6%, respectively, P < 0.001). After adjusting for diabetes duration and ethnicity, Type 1 diabetes was associated with 5.3(1.7-16.4)-fold increase in moderate or more severe retinopathy. Although Maori and Pacific people with Type 2 diabetes were more hyperglycaemic, with higher systolic and lower diastolic blood pressure, in the logistic regression analysis, moderate or more severe retinopathy was associated with diabetes duration, insulin therapy, ethnicity and the extent of renal disease, but not glycaemia.

CONCLUSIONS

These data demonstrate that moderate or more severe retinopathy is more common in Polynesians than Europeans. The reasons for this are unclear, but may be related to long-standing hyperglycaemia.

Comparative study on the efficacy of pioglitazone in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes

AIM

Although the pharmodynamic properties of the thiazolidinedione (TZD) insulin-sensitizing agents in the treatment of type 2 diabetes are well established, there are no studies comparing the pharmacoefficacy of these drugs in different ethnic groups. The aim of this pilot, prospective study was to examine the hypothesis that the efficacy of TZDs may vary depending on ethnicity. This aim was achieved by comparing the effects of 6-months treatment with pioglitazone (45 mg/day) on glucose control and metabolic and cardiovascular risk factors in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes.

METHODS

Ninety-seven patients (40 Caucasian and 57 Maori-Polynesian) with type 2 diabetes were selected for the study from our clinical databases if they were on the maximum tolerated dose of oral agents and had a haemoglobin A(1c) (HbA(1c)) > 8.0% for at least 2 months. All the patients received pioglitazone (45 mg/day) for 6 months in addition to their regular diabetes therapy. Clinical data and blood samples were collected at monthly intervals and the following indices measured: weight, blood pressure, oedema score, HbA(1c), plasma glucose, alanine amino transferase and adiponectin levels and plasma lipid profile, including low-density lipoprotein (LDL)-cholesterol particle size and atherogenic index of plasma (AIP). The data of the 81 patients who finished the study were analysed using analysis of variance, chi-square analysis and multiple regression methods.

RESULTS

The absolute change from baseline in mean HbA(1c) (Caucasian -1.4% vs. Maori-Polynesian -1.3%) and fasting glucose levels (Caucasian -2.1 mmol/l vs. Maori-Polynesian -2.8 mmol/l) was similar in the two groups. Pioglitazone caused an improvement in lipid profile in both ethnic groups, with a reduction in mean values of atherogenic fractions (triglyceride: Caucasian -0.5 mmol/l, p < 0.001 vs. Maori-Polynesian -0.3 mmol/l, p = 0.05; very low-density lipoprotein (VLDL)-cholesterol: Caucasian -0.11 mmol/l, p = 0.001 vs. Maori-Polynesian -0.04 mmol/l, p = 0.85; VLDL-triglyceride: Caucasian -0.36 mmol/l, p < 0.001 vs. Maori-Polynesian -0.22 mmol/l, p = 0.14; apolipoprotein B: Caucasian -0.09 mmol/l, p = 0.03 vs. Maori-Polynesian -0.08 mmol/l, p = 0.18). These changes were associated with an increase in LDL-cholesterol particle size (Caucasian +0.23 nm, p = 0.05 vs. Maori-Polynesian +0.26 nm, p = 0.04) and a decrease in AIP (Caucasian -0.14, p < 0.001 vs. Maori-Polynesian -0.08, p = 0.04). While the changes in the lipid indices tended to be greater in the Caucasian group, the difference in lipid response between the two ethnic groups was not statistically significant. Multiple regression analyses showed that the baseline value of the individual lipid fractions was the main determinant of the changes in lipid levels.

CONCLUSIONS

These results demonstrated that pioglitazone has similar beneficial effects on glucose control and plasma lipid profile in Caucasian and Maori-Polynesian patients with poorly controlled type 2 diabetes. Our data showed that while the improvement in lipid profile was more pronounced in Caucasian patients than in Maori-Polynesian patients, this difference was not statistically significant.

‘Help, educate, encourage?’: Geographical variations in the provision and utilisation of diabetes education in New Zealand

In New Zealand, as elsewhere, it is argued that a diabetes epidemic is underway. With careful management from individuals and professionals and appropriate levels of education, it is possible to prevent many complications of diabetes. The overall objective of the paper is to evaluate the role and impact of Diabetes New Zealand (DNZ), the key voluntary sector provider of diabetes education and support services, with respect to four criteria: (i) the extent to which DNZ is reaching groups most at risk of diabetes; (ii) the degree to which it has encouraged levels of member involvement; (iii) whether voluntary group provision of education is that most preferred by members; and (iv) the extent to which members see the voluntary sector model as being effective in combating the growth of diabetes. A survey of members of six of the 41 affiliated societies of DNZ suggests that such organisations, although having a high proportion of older members, have generally failed to target more deprived groups. While the societies generally score more positively in encouraging member involvement and being perceived as effective by their members, they do not always utilise the preferred form of educational provision. However, there are significant contextual variations by urban-rural location and according to the organisational structure of the societies. Rural societies and those with decentralised organisational structures generally score highest on the above criteria. The results pose a problem for DNZ which, like many other voluntary sector organisations, is facing pressures of increased corporatisation and centralisation. We see this as an important challenge that DNZ needs to address if New Zealand is going to better cope with the emerging diabetes epidemic.

Reconsidering the role of a local diabetes society: patterns of membership in Christchurch, New Zealand

OBJECTIVE

To investigate patterns of membership and barriers to service use in the Christchurch Diabetes Society.

METHODS

A socio-economic profile of the Christchurch Diabetes Society's membership was constructed by examining the residential locations of society members in Christchurch City. Rates of membership by deprivation decile were calculated by comparing the membership data to the population of people diagnosed with diabetes.

RESULTS

Persons living in deprived areas, in particular Maori and Pacific people, are under-represented in society membership. However, there is evidence that the relationship between ethnicity and membership rates is stronger in more deprived areas.

CONCLUSIONS

This study provides further insights in understanding barriers to care and the role of NGOs. Given that groups in the community most likely to be affected by diabetes are least likely to be members of the society and to have access to the society's services, the results raise questions about the most appropriate role for local diabetes societies within a decentralised health system.

A systematic review of interventions to improve diabetes care in socially disadvantaged populations

OBJECTIVE

To identify and synthesize evidence about the effectiveness of patient, provider, and health system interventions to improve diabetes care among socially disadvantaged populations.

RESEARCH DESIGN AND METHODS

Studies that were included targeted interventions toward socially disadvantaged adults with type 1 or type 2 diabetes; were conducted in industrialized countries; were measured outcomes of self-management, provider management, or clinical outcomes; and were randomized controlled trials, controlled trials, or before-and-after studies with a contemporaneous control group. Seven databases were searched for articles published in any language between January 1986 and December 2004. Twenty-six intervention features were identified and analyzed in terms of their association with successful or unsuccessful interventions.

RESULTS

Eleven of 17 studies that met inclusion criteria had positive results. Features that appeared to have the most consistent positive effects included cultural tailoring of the intervention, community educators or lay people leading the intervention, one-on-one interventions with individualized assessment and reassessment, incorporating treatment algorithms, focusing on behavior-related tasks, providing feedback, and high-intensity interventions (>10 contact times) delivered over a long duration (>or=6 months). Interventions that were consistently associated with the largest negative outcomes included those that used mainly didactic teaching or that focused only on diabetes knowledge.

CONCLUSIONS

This systematic review provides evidence for the effectiveness of interventions to improve diabetes care among socially disadvantaged populations and identifies key intervention features that may predict success. These types of interventions would require additional resources for needs assessment, leader training, community and family outreach, and follow-up.

Diabetes in New Zealand

While the ethnic make up of the New Zealand population is predominantly European, the Polynesian population, consisting of indigenous New Zealand Maori and more recent immigrants from the other Pacific Islands is increasing rapidly. The prevalence of diabetes in these Polynesians is high. There is also an increasing prevalence of obesity, and obesity is a greater problem amongst Polynesian people. The number of elderly people in the population is increasing. All of these demographic changes are increasing the incidence and prevalence of Type 2 diabetes. The incidence of Type 1 diabetes is also rising, although the reasons for this are unknown. Diabetic nephropathy is the most common cause of end stage renal failure in New Zealand. Polynesian people with diabetes, and in particular Maori, have a very high rate of diabetic nephropathy and develop renal failure at a more rapid rate than European patients with nephropathy relating to Type 1 diabetes. The propensity for Maori patients with Type 2 diabetes to develop renal failure may relate to a younger age at the onset of diabetes, a genetic susceptibility to nephropathy, and socio-economic or cultural factors leading to less adequate medical care.

Community development through partnership: promoting health in an urban indigenous community in New Zealand

Indigenous people who have been dispossessed of their lands and resources bear a disproportionate burden of health problems. Programmes aimed at improving their health status must operate within the context of colonisation history and the contemporary cultural renaissance whereby indigenous populations are asserting their rights to self-determination. Community development strategies incorporating empowerment as both means and end are consistent with the aspirations of the renaissance and reflect the principles of the Ottawa Charter for Health Promotion. This paper describes a formative and process evaluation of a community development partnership for health promotion between a health group and an urban Maori community in New Zealand. Key issues encountered related to trust, prioritisation of health, and appropriate research paradigms. Most significant among these was trust, or more specifically, distrust among Maori engendered by historical and contemporaneous experiences of contact with Europeans. Ultimately, the partnership achieved what it set out to do when the Maori partners took over the running of their own health groups and health programme. Building upon a detailed literature review and data from the evaluation, the paper offers a list of recommended procedures for the development of partnerships, applicable to health and other domains. Recommendations encompass preparatory steps, the formation of a partnership committee, programme planning and development, and the appointment of a community-based liaison worker. A conclusion of the research and premise underpinning the recommendations is that devolution of power is a key aspect of organisational process underlying successful partnerships involving professional groups and indigenous people.