Medicine (St Vincent's) - Research Publications

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    Cross-sectional associations of albuminuria among Aboriginal and Torres Strait Islander adults: the eGFR Study
    Hughes, JT ; Maple-Brown, LJ ; Thomas, M ; Lawton, PD ; Sinha, A ; Cass, A ; Barzi, F ; Jones, GRD ; Jerums, G ; MacIsaac, RJ ; O'Dea, K ; Hoy, WE (WILEY, 2018-01)
    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.
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    The threat among us: significance and scale of diabetic chronic kidney disease in Australia
    Lecamwasam, A ; Ekinci, EI ; MacIsaac, RJ ; Saffery, R ; Dwyer, KM (WILEY, 2017-12)
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    Relationship between urinary sodium-to-potassium ratio and ambulatory blood pressure in patients with diabetes mellitus
    Libianto, R ; Moran, J ; O'Callaghan, C ; Baqar, S ; Chen, AX ; Baker, ST ; Clarke, M ; MacIsaac, RJ ; Jerums, G ; Ekinci, EI (WILEY, 2018-01)
    Previous studies investigating the relationship between sodium intake and blood pressure have mostly relied on dietary recall and clinic blood pressure measurement. In this cross-sectional study, we aimed to investigate the relationship between 24 hour urinary sodium and potassium excretion, and their ratio, with 24 hour ambulatory blood pressure parameters including nocturnal blood pressure dipping in patients with type 1 and 2 diabetes. We report that in 116 patients with diabetes, systolic blood pressure was significantly predicted by the time of day, age, the interaction between dipping status with time, and 24 hour urinary sodium-to-potassium ratio (R2  = 0.83) with a relative contribution of 53%, 21%, 20% and 6%, respectively. However, there was no interaction between urinary sodium-to-potassium ratio and dipping status.
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    Asymmetric changes in circulating insulin levels after an increase compared with a reduction in insulin pump basal rate in people with Type 1 diabetes
    McAuley, SA ; Ward, GM ; Horsburgh, JC ; Gooley, JL ; Jenkins, AJ ; MacIsaac, RJ ; O'Neal, DN (WILEY, 2017-08)
    AIMS: To investigate circulating insulin profiles after a clinically relevant insulin pump basal rate increase vs a reduction, and the associated glucose responses. METHODS: A cohort of 12 adults with Type 1 diabetes undertook this two-stage university hospital study using Accu-Chek pumps (Roche Diagnostics, Mannheim, Germany) and insulin aspart. An insulin basal rate change of 0.2 unit/h (increase in first stage, reduction in second stage) was implemented at ~09:30 h, after a single overnight basal rate (without bolus insulin), while fasting participants rested. Frequent venous samples for the assessment of plasma free insulin, glucose and cortisol were collected from 60 min before until 300 min after rate change. The primary outcome was time to steady-state insulin. RESULTS: The 0.2-unit/h rate change represented a mean ± sd alteration of 23 ± 6%. After the rate increase, the median (interquartile range) times to 80% and 90% steady-state insulin were 170 (45) min and 197 (87) min, respectively. By contrast, after rate reduction, 80% steady-state insulin was not achieved. After the rate increase, mean ± se insulin levels increased by 4.3 ± 3.1%, 12.0 ± 2.9% and 25.6 ± 2.6% at 60, 120 and 300 min, respectively (with no significant difference until 180 min). After the rate reduction, insulin decreased by 8.3 ± 3.0% at 300 min (with no significant difference until 300 min). After rate reduction, glucose levels paradoxically declined by 17.4 ± 3.7% after 300 min; cortisol levels also fell during observation (P = 0.0003). CONCLUSIONS: The time to circulating insulin change after a 0.2-unit/h basal rate change was substantial, and was greater after a reduction than after an increase. Counter-regulatory hormone circadian variation may affect glycaemia when implementing minor changes at low basal rates. Both direction of basal rate change, and time of day, warrant consideration when anticipating the clinical effects of basal rate changes.
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    Aceruloplasminaemia: a disorder of diabetes and neurodegeneration
    Calder, GL ; Lee, MH ; Sachithanandan, N ; Bell, S ; Zeimer, H ; MacIsaac, RJ (WILEY-BLACKWELL, 2017-01)
    Aceruloplasminaemia is an autosomal recessive disorder of iron metabolism which is characterised by diabetes, neurodegeneration and anaemia. It should be considered in the differential diagnosis of adult onset, antibody-negative diabetes associated with persistent mild anaemia and hyperferritinaemia and/or progressive neuropsychiatric impairments.
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    Higher risk of phaeochromocytoma/ paraganglioma (Phaeo-Pgl) in SDHD than SDHB carriers: an Australian cohort study
    Hong, A ; Shanahan, M ; Schenberg, T ; Inder, W ; MacIsaac, R ; James, P ; Sachithanandan, N (WILEY, 2019-04)
    Carriers of succinate dehydrogenase (SDHx) mutations are at risk of developing phaeochromocytomas, catecholamine secreting extra-adrenal paragangliomas and non-secretory head and neck paragangliomas and require lifelong surveillance. There is no current consensus on the optimal surveillance strategy. This study describes the outcomes of a cohort of 50 SDHx mutation carriers followed at a tertiary Australian hospital using a surveillance protocol involving annual clinical review with plasma/urine metanephrines and biennial magnetic resonance imaging from skull base to pelvis.
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    Bone health in chronic kidney disease-mineral and bone disorder: a clinical case seminar and update
    Aleksova, J ; Ng, KW ; Jung, C ; Zeimer, H ; Dwyer, KM ; Milat, F ; MacIsaac, RJ (WILEY, 2018-12)
    The metabolic abnormalities affecting bone in the setting of chronic kidney disease (CKD) are complex with overlapping and interacting aetiologies and have challenging diagnostic and management strategies. Disturbances in calcium, phosphate, fibroblast growth factor 23, parathyroid hormone concentrations and vitamin D deficiency are commonly encountered and contribute to the clinical syndromes of bone disorders in CKD, including hyperparathyroidism, osteomalacia, osteoporosis and adynamic bone disease. Mineral and bone abnormalities may also persist or arise de novo post-renal transplantation. The Kidney Disease Improving Global Outcomes organisation describes these mineral metabolism derangements and skeletal abnormalities as 'CKD Mineral and Bone Disorder'. Patients with this disorder have an increased risk of fracture, cardiovascular events and overall increased mortality. In light of the recently updated 2017 guidelines from the Kidney Disease Improving Global Outcomes, we present a clinical case-based discussion to highlight the complexities of investigating and managing the bone health of patients with CKD with a focus on these updates.
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    Suboptimal behaviour and knowledge regarding overnight glycaemia in adults with type 1 diabetes is common
    Larsson, CR ; Januszewski, AS ; McGrath, RT ; Ludvigsson, J ; Keech, AC ; MacIsaac, RJ ; Ward, GM ; O'Neal, DN ; Fulcher, GR ; Jenkins, AJ (WILEY, 2018-09)
    BACKGROUND: In people with type 1 diabetes (T1D), nocturnal hypoglycaemia (NH) can be slept through and can cause seizures, arrhythmias and death. Hypoglycaemia avoidance can induce hyperglycaemia and ketosis. Patient behaviour impacts clinical outcomes and may be changed by education. AIM: To develop and utilise a survey to evaluate patient self-management of overnight glycaemia in adults with T1D. METHODS: Adults with T1D attending two Australian tertiary referral diabetes clinics completed a survey about their diabetes self-management and glycaemic control, including responses to hypothetical pre-bed blood glucose (BG) levels (4-20 mmol/L). Statistical analyses included t-tests, Chi square tests and ANOVA with significance considered at P < 0.05. RESULTS: There were 205 participants (103 females), with a mean (SD) age of 41 (17) years, T1D duration of 20 (16) years, HbA1c of 7.8(1.4)%, (61.3(8.2) mmol/mol), 38% on insulin pump therapy (CSII) and 36% with impaired hypoglycaemia awareness (IHA). Mean (SD) number of BG tests/day was 5.4 (2.7). Patients set higher BG target levels at bedtime and overnight: 7.5(1.4) and 7.1(1.3) mmol/L, respectively, compared to daytime (6.9(1.0); P < 0.0001 and P = 0.002 respectively). Only 36% of participants reported treating nocturnal hypoglycaemia (NH) with the recommended refined, then complex, carbohydrate. Only 28% of patients made safe choices in all bedtime BG scenarios, with higher rates for CSII users, P = 0.0005. Further education was desired by 32% of respondents, with higher rates in those with (44%) versus without IHA (25%), P = 0.006. CONCLUSIONS: Many adults with T1D have suboptimal knowledge and behaviour regarding overnight BG self-management. A survey, piloted herein, may facilitate the identification of patients who could benefit from further education.
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    Lipid-lowering therapy use and achievement of cholesterol targets in an Australian diabetes clinic
    Kiburg, KV ; Ward, GM ; O'Neal, DN ; MacIsaac, RJ (WILEY, 2018-02)
    We documented temporal changes in the use of lipid-lowering medications and achievement of cholesterol targets in an Australian diabetes clinic. The number of patients using lipid-lowering therapy for primary or secondary cardiovascular prevention increased from 6 to 69% between 1993-1995 and 2014-2016, which corresponded to a decrease in low-density lipoprotein cholesterol levels from 3.7 to 2.4 mmol/L (P < 0.01).
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    Diabetic ketoacidosis in adult patients: an audit of factors influencing time to normalisation of metabolic parameters
    Lee, MH ; Calder, GL ; Santamaria, JD ; MacIsaac, RJ (WILEY, 2018-05)
    BACKGROUND: Diabetic ketoacidosis (DKA) is an acute life-threatening metabolic complication of diabetes that imposes substantial burden on our healthcare system. There is a paucity of published data in Australia assessing factors influencing time to resolution of DKA and length of stay (LOS). AIMS: To identify factors that predict a slower time to resolution of DKA in adults with diabetes. METHODS: Retrospective audit of patients admitted to St Vincent's Hospital Melbourne between 2010 to 2014 coded with a diagnosis of 'Diabetic Ketoacidosis'. The primary outcome was time to resolution of DKA based on normalisation of biochemical markers. Episodes of DKA within the wider Victorian hospital network were also explored. RESULTS: Seventy-one patients met biochemical criteria for DKA; median age 31 years (26-45 years), 59% were male and 23% had newly diagnosed diabetes. Insulin omission was the most common precipitant (42%). Median time to resolution of DKA was 11 h (6.5-16.5 h). Individual factors associated with slower resolution of DKA were lower admission pH (P < 0.001) and higher admission serum potassium level (P = 0.03). Median LOS was 3 days (2-5 days), compared to a Victorian state-wide LOS of 2 days. Higher comorbidity scores were associated with longer LOS (P < 0.001). CONCLUSIONS: Lower admission pH levels and higher admission serum potassium levels are independent predictors of slower time to resolution of DKA. This may assist to stratify patients with DKA using markers of severity to determine who may benefit from closer monitoring and to predict LOS.