Birth outcomes in women with gestational diabetes managed by lifestyle modification alone: The PANDORA study

AIMS

To assess outcomes of women in the Pregnancy and Neonatal Diabetes Outcomes in Remote Australia (PANDORA) cohort with gestational diabetes mellitus (GDM) managed by lifestyle modification compared with women without hyperglycaemia in pregnancy.

METHODS

Indigenous (n = 97) and Europid (n = 113) women managed by lifestyle modification were compared to women without hyperglycaemia (n = 235). Multivariate linear and logistic regressions assessed whether GDM-lifestyle women had poorer outcomes compared to women without hyperglycaemia.

RESULTS

Women with GDM-lifestyle had higher body mass index and lower gestational weight gain than women without hyperglycaemia. On univariate analysis, gestational age at delivery was lower and induction rates were higher in women with GDM-lifestyle than without hyperglycaemia. On multivariable regression, GDM-lifestyle was associated with lower gestational age at delivery (by 0.73 weeks), lower birthweight z-score (by 0.26, p = 0.007), lower likelihood of large for gestational age (LGA) [OR (95% CI): 0.55 (0.28, 1.02), p = 0.059], and greater likelihood of labour induction [2.34 (1.49, 3.66), p < 0.001] than women without hyperglycaemia.

CONCLUSION

Women with GDM managed by lifestyle modification had higher induction rates and their offspring had lower birthweight z-scores, with a trend to lower LGA than those without hyperglycaemia in pregnancy. Further studies are indicated to explore reasons for higher induction rates.

Cross-sectional associations of albuminuria among Aboriginal and Torres Strait Islander adults: the eGFR Study

OBJECTIVE

To describe the detailed associations of albuminuria among a contemporary cohort of Aboriginal and Torres Strait Islander people to inform strategies for chronic kidney disease prevention and management.

METHODS

A cross-sectional analysis of Indigenous participants of the eGFR Study.

MEASURES

Clinical, biochemical and anthropometric measures were collected (including body-circumferences, blood pressure (BP); triglycerides, HbA1c, liver function tests, creatinine; urine- microscopic-haem, albumin: creatinine ratio (ACR), prescriptions- angiotensin converting enzyme inhibitor or angiotensin receptor II antagonist (ACEI/ARB). Albuminuria and diabetes were defined by an ACR>3.0 mg/mmol, and HbA1c≥48 mmol/mol or prior history respectively. Waist: hip ratio (WHR), and estimated glomerular filtration rate (eGFR) were calculated. ACR was non-normally distributed; a logarithmic transformation was applied (in base 2), with each unit increase in log2-albuminuria representing a doubling of ACR.

RESULTS

591 participants were assessed (71% Aboriginal, 61.6% female, mean age 45.1 years, BMI 30.2 kg/m² , WHR 0.94, eGFR 99.2 ml/min/1.73m² ). The overall prevalence of albuminuria, diabetes, microscopic-haem and ACEI/ARB use was 41.5%, 41.5%, 17.8% and 34.7% respectively; 69.3% of adults with albuminuria and diabetes received an ACEI/ARB. Using multivariable linear regression modelling, the potentially modifiable factors independently associated with log2-albuminuria were microscopic-haem, diabetes, WHR, systolic BP, alkaline phosphatase (all positive) and eGFR (inverse).

CONCLUSION

Albuminuria is associated with diabetes, central obesity and haematuria. High ACEI/ARB prescribing for adults with diabetes and albuminuria was observed. Further understanding of the links between fat deposition, haematuria and albuminuria is required.

Bilirubin concentration is positively associated with haemoglobin concentration and inversely associated with albumin to creatinine ratio among Indigenous Australians: eGFR Study

Low serum bilirubin concentrations are reported to be strongly associated with cardio-metabolic disease, but this relationship has not been reported among Indigenous Australian people who are known to be at high risk for diabetes and chronic kidney disease (CKD).

HYPOTHESIS

serum bilirubin will be negatively associated with markers of chronic disease, including CKD and anaemia among Indigenous Australians.

METHOD

A cross-sectional analysis of 594 adult Aboriginal and Torres Strait Islander (TSI) people in good health or with diabetes and markers of CKD. Measures included urine albumin: creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), haemoglobin (Hb) and glycated haemoglobin (HbA1c). Diabetes was defined by medical history, medications or HbA1c≥6.5% or ≥48mmol/mol. Anaemia was defined as Hb<130g/L or <120g/L in males and females respectively. A multivariate regression analysis examining factors independently associated with log-bilirubin was performed.

RESULTS

Participants mean (SD) age was 45.1 (14.5) years, and included 62.5% females, 71.7% Aboriginal, 41.1% with diabetes, 16.7% with anaemia, 41% with ACR>3mg/mmol and 18.2% with eGFR<60mL/min/1.73m². Median bilirubin concentration was lower in females than males (6 v 8μmol/L, p<0.001) and in Aboriginal than TSI participants (6 v 9.5μmol/L, p<0.001). Six factors explained 35% of the variance of log-bilirubin; Hb and cholesterol (both positively related) and ACR, triglycerides, Aboriginal ethnicity and female gender (all inversely related).

CONCLUSION

Serum bilirubin concentrations were positively associated with Hb and total cholesterol, and inversely associated with ACR. Further research to determine reasons explaining lower bilirubin concentrations among Aboriginal compared with TSI participants are needed.

Preconception care for women with type 2 diabetes mellitus: A mixed-methods study of provider knowledge and practice

AIMS

Preconception care may decrease adverse pregnancy outcomes associated with pre-existing diabetes mellitus. Aboriginal Australians are at high risk of type 2 diabetes mellitus (T2DM), with earlier onset. We explored practitioner views on preconception care delivery for women with T2DM in the Northern Territory, where 31% of births are to Aboriginal women.

METHODS

Mixed-methods study including cross-sectional survey of 156 health practitioners and 11 semi-structured interviews.

RESULTS

Practitioners reported low attendance for preconception care however, 51% provided counselling on an opportunistic basis. Rural/remote practitioners were most likely to find counselling feasible. The majority (69%) utilised appropriate guidelines and addressed lifestyle modifications including smoking (81%), weight management (79%), and change medications appropriately such as ceasing ACE inhibitors (69%). Fewer (40%) prescribed the recommended dose of folate (5mg) or felt comfortable recommending delaying pregnancy to achieve optimal preconception glucose control (42%). Themes identified as barriers to care included the complexity of care setting and infrequent preconception consultations. There was a focus on motivation of women to make informed choices about conception, including birth spacing, timing and contraception. Preconception care enablers included cross-cultural communication, a multi-disciplinary care team and strong client-based relationships.

CONCLUSIONS

Health practitioners are keen to provide preconception counselling and reported knowledge of evidence-based guidelines. Improvements are needed in recommending high dose folate and optimising glucose control. Cross-cultural communication and team-based care were reported as fundamental to successful preconception care in women with T2DM. Continued education and policy changes are required to support practitioners in opportunities to enhance pregnancy planning.

Associations of mortality and cardiovascular disease risks with diabetes and albuminuria in urban Indigenous Australians: the DRUID follow-up study

AIM

To assess the relationships of diabetes and albuminuria with all-cause mortality and cardiovascular disease outcomes in a population without prior cardiovascular disease using data from the Darwin Region Urban Indigenous Diabetes (DRUID) study.

METHODS

We conducted a prospective cohort study of 706 participants (aged 15-81 years, 68% women) without prior cardiovascular disease who underwent a 75-g oral glucose tolerance test. Deaths and fatal or non-fatal cardiovascular disease were determined over 7 years, and hazard ratios with 95% CIs and population attributable risks were estimated for baseline glycaemia and albuminuria.

RESULTS

Compared with normoglycaemia and after adjustment for age, sex, hypertension, dyslipidaemia and smoking, known diabetes was associated with an adjusted hazard ratio of 4.8 (95% CI 1.5-14.7) for all-cause mortality and 5.6 (95% CI 2.1-15.2) for cardiovascular disease. Compared with normoalbuminuria, the respective adjusted risks for macroalbuminuria were 10.9 (95% CI 3.7-32.1) and 3.9 (95% CI 1.4-10.8). The Adjusted all-cause mortality and cardiovascular disease estimated population attributable risks for diabetes were 27% and 32%, and for albuminuria they were 32% and 21%, respectively.

CONCLUSIONS

In our study population, the burden of mortality and cardiovascular disease was largely driven by diabetes and albuminuria. This finding on the influence of diabetes and albuminuria is consistent with reports in other high-risk Indigenous populations and should be better reflected in risk scores and intervention programmes.

Periodontal therapy and glycaemic control among individuals with type 2 diabetes: reflections from the PerioCardio study

OBJECTIVES

Diabetes mellitus and periodontal disease are highly prevalent among Indigenous Australian adults. Untreated periodontitis impacts glycaemic control in people with diabetes. The aim of this study was to report on the effect of periodontal therapy on glycaemic control among people with obesity.

METHODS

This subgroup analysis is limited to 62 participants with diabetes from the original 273 Aboriginal Australian adults enrolled into the PerioCardio study. Intervention participants received full-mouth non-surgical periodontal scaling during a single, untimed session while controls were untreated. Endpoints of interest included change in glycated haemoglobin (HbA1c), C-reactive protein (CRP) and periodontal status at 3 months post-intervention.

RESULTS

There were more females randomized to the treatment group (n = 17) than control (n = 10) while the control group had a higher overall body mass index (BMI) [mean (SD)] 33.1 (9.7 kg m^-2 ) versus 29.9 (6.0 kg m^-2 ). A greater proportion of males were followed up at 3 months compared to females, P = 0.05. Periodontal therapy did not significantly reduce HbA1c: ancova difference in means 0.22 mmol mol^-1 (95% CI -6.25 to 6.69), CRP: ancova difference in means 0.64 (95% CI -1.08, 2.37) or periodontal status at 3 months.

CONCLUSIONS

Non-surgical periodontal therapy did not significantly reduce glycated haemoglobin in participants with type 2 diabetes. Reasons are likely to be multifactorial and may be influenced by persistent periodontal inflammation at the follow-up appointments. Alternatively, the BMI of study participants may impact glycaemic control via alternative mechanisms involving the interplay between inflammation and adiposity meaning HbA1c may not be amenable to periodontal therapy in these individuals.

Associations of serum adiponectin with markers of cardio-metabolic disease risk in Indigenous Australian adults with good health, diabetes and chronic kidney disease

The higher serum adiponectin concentrations observed in females are often attributed to differences in adiposity or sex hormones. There is little data describing adiponectin in Indigenous Australians, and no studies examining its association with cardio-metabolic disease risk markers and chronic kidney disease (CKD).

AIM

To describe the relationship of serum adiponectin with cardio-metabolic disease risk markers and kidney function in a community-based sample of Indigenous Australian adults, with particular reference to sex-specific differences.

METHODS

A cross-sectional analysis of a community-based volunteer sample of 548 Indigenous Australian adults (62% female), stratified into five cardio-metabolic risk groups ranging from good health (strata-1) to high cardio-metabolic risk and low measured glomerular filtration rate (mGFR, <60ml/min/1.73m²) (strata-5). We examined serum adiponectin concentrations with cardio-metabolic risk markers, albuminuria and mGFR.

RESULTS

Indigenous Australian females had a lower than expected adiponectin concentration (3.5μg/ml), which was higher than males in strata 1-4 (as in other populations), but not in strata-5 (mGFR<60, p=0.19), and higher leptin: adiponectin ratio than other populations (7.8ng/μg - strata-1, healthy females; 12.2ng/μg - strata-3, females with diabetes and mGFR≥90). Female-gender, HDL-cholesterol (positive), mGFR and waist: hip ratio (WHR) (inverse) were independently associated with log-adiponectin when mGFR≥60; when mGFR<60, female-gender was associated with 0.27 units lower log-adiponectin.

CONCLUSION

Female-gender was not associated with higher adiponectin concentrations in Indigenous Australians with mGFR<60ml/min/1.73m². High WHR was frequent in both genders, and inversely associated with adiponectin. Longitudinal studies are needed to examine relationships of serum adiponectin, obesity and cardiovascular disease events in Indigenous Australians.

Performance of formulas for estimating glomerular filtration rate in Indigenous Australians with and without Type 2 diabetes: the eGFR Study

AIMS

It has been proposed that the Chronic Kidney Disease Epidemiology Collaboration formula estimates glomerular filtration rate more accurately than the Modification of Diet in Renal Disease formula. With the very high incidence of diabetes and end-stage kidney disease in Indigenous Australians, accurate estimation of glomerular filtration rate is vital in early detection of kidney disease. We aimed to assess the performance of the Chronic Kidney Disease Epidemiology Collaboration, Modification of Diet in Renal Disease and Cockcroft-Gault formulas in Indigenous Australians with and without diabetes.

METHODS

Indigenous Australians with (n = 224) or without (n = 340) Type 2 diabetes had a reference glomerular filtration rate measure using plasma disappearance of iohexol (measured glomerular filtration rate) over 4 h. Serum creatinine was measured by an enzymatic method. Performance was assessed by bias (measured glomerular filtration rate - estimated glomerular filtration rate) and accuracy (percentage of estimated glomerular filtration rate within 30% of measured glomerular filtration rate).

RESULTS

The median measured glomerular filtration rate (interquartile range) in participants with or without diabetes was 97 (68-119) and 108 (90-122) ml min(-1)  1.73 m(-2) , respectively. The Chronic Kidney Disease Epidemiology Collaboration formula had smaller bias and greater accuracy than the Modification of Diet in Renal Disease and Cockcroft-Gault formulas overall, for participants both with and without diabetes. However, for estimated glomerular filtration rate > 90 ml min(-1)  1.73 m(-2) , the Chronic Kidney Disease Epidemiology Collaboration formula had greater bias in participants with diabetes, underestimating measured glomerular filtration rate by 7.4 vs. 1.0 ml min(-1)  1.73 m(-2) in those without diabetes. The Chronic Kidney Disease Epidemiology Collaboration formula was less accurate across the whole range of estimated glomerular filtration rates in participants with vs. those without diabetes (87.1% vs. 93.3%).

CONCLUSIONS

The Chronic Kidney Disease Epidemiology Collaboration formula outperforms the Modification of Diet in Renal Disease and Cockcroft-Gault formulas overall in Indigenous Australians with and without diabetes. However, the Chronic Kidney Disease Epidemiology Collaboration formula has greater bias in people with diabetes compared with those without diabetes, especially in those with normal renal function.

Area-under-the-HbA1c-curve above the normal range and the prediction of microvascular outcomes: an analysis of data from the Diabetes Control and Complications Trial

AIMS

In the Diabetes Control and Complications Trial, mean updated HbA(1c) accounted for most of the differential risk of microvascular complications between intensive and conventional insulin therapy. We hypothesized, however, that a more precise measure of chronic hyperglycaemic exposure may be the incremental area-under-the-HbA(1c)-curve above the Diabetes Control and Complications Trial-standardized normal range for HbA(1c) (iAUC(HbA1c>norm)).

METHODS

Using the Principal Diabetes Control and Complications Trial data set, we compared the following three measures of chronic glycaemic exposure for their capacity to predict retinopathy, nephropathy and neuropathy during the Diabetes Control and Complications Trial: mean updated HbA(1c), iAUC(HbA1c>norm), and total area-under-the-HbA(1c)-curve (tAUC(HbA1c)). For each outcome, models using each of these three glycaemic measures were compared in the following three ways: hazard or odds ratio, χ(2) statistic, and Akaike information criterion.

RESULTS

The three glycaemic measures did not differ in their prediction of neuropathy. iAUC(HbA1c>norm) was modestly superior to mean updated HbA(1c) for predicting nephropathy (χ(2) P = 0.017, Akaike P = 0.032). In contrast, for predicting retinopathy, both iAUC(HbA1c>norm) (χ(2) P = 0.0005, Akaike P = 0.0005) and tAUC(HbA1c) (χ(2) P = 0.004, Akaike P = 0.004) were significantly better than mean updated HbA(1c). Varying its HbA(1c) threshold incrementally between 37 and 53 mmol/mol (5.5-7.0%), inclusive, did not improve the prediction of retinopathy by iAUC(HbA1c>threshold) beyond that of tAUC(HbA1c,) consistent with the concept of a continuous relationship between glycaemia and retinopathy, with no glycaemic threshold.

CONCLUSIONS

Both iAUC(HbA1c>norm) and tAUC(HbA1c) were superior to mean updated HbA(1c) for predicting retinopathy. Optimal assessment of chronic glycaemic exposure as a determinant of retinopathic risk may require consideration of both the degree of hyperglycaemia and its duration.

Increased bone mineral density in Aboriginal and Torres Strait Islander Australians: impact of body composition differences

Bone mineral density (BMD) has been reported to be both higher and lower in Indigenous women from different populations. Body composition data have been reported for Indigenous Australians, but there are few published BMD data in this population. We assessed BMD in 161 Indigenous Australians, identified as Aboriginal (n=70), Torres Strait Islander (n=68) or both (n=23). BMD measurements were made on Norland-XR46 (n=107) and Hologic (n=90) dual-energy X-ray absorptiometry (DXA) machines. Norland BMD and body composition measurements in these individuals, and also in 36 Caucasian Australians, were converted to equivalent Hologic BMD (BMD(H)) and body composition measurements for comparison. Femoral neck (FN) and lumbar spine Z-scores were high in Indigenous participants (mean FN Z-score: Indigenous men +0.98, p<0.0001 vs. mean zero; Indigenous women +0.82, p<0.0001 vs. mean zero). FN BMD(H) was higher in Aboriginal and/or Torres Strait Islander than Caucasian participants, after adjusting for age, gender, diabetes and height and remained higher in men after addition of lean mass to the model. We conclude that FN BMD is higher in Aboriginal and/or Torres Strait Islander Australians than Caucasian Australian reference ranges and these differences still remained significant in men after adjustment for lean mass. It remains to be seen whether these BMD differences translate to differences in fracture rates.

Diabetes care and complications in a remote primary health care setting

Prevalence of complications of type 2 diabetes in a remote Australian Indigenous community was measured as part of a population survey of risk factors for diabetes and cardiovascular disease. Information was obtained from history, clinical examination, blood sample and medical records. Forty-three diabetic participants (six newly diagnosed) were assessed from a sample of 339 (12% diabetes prevalence); mean age 50 (range 31-67), duration of diabetes 5.6 (0-15) years, 40% male. Risk factors/complications: 70% with >/= 25, 50% cigarette smokers, HbA1c 8.5 (S.D. 2.9)%, cholesterol 4.8 (0.8)mmol/l, triglycerides 2.7 (1.6)mmol/l, HDL 0.83 (0.2)mmol/l; 60% had albuminuria (micro 38%, macro 22%), 47% were hypertensive, 7% (n = 2) had retinopathy, 24% had peripheral neuropathy, none had peripheral vascular disease, 14% had documented coronary vascular and one participant cerebrovascular disease. Of 37 with previously diagnosed diabetes: 43% were on aspirin, 65% on metformin, 80% with albuminuria on ACE inhibitors. Four additional diabetic participants (not studied) were receiving renal dialysis elsewhere. The results demonstrate on the one hand, very high indices of cardiovascular risk (smoking, hypertension, dyslipidaemia and albuminuria) and on the other, good quality primary health care providing good detection and follow up management of type 2 diabetic patients.