Deprivation and dialysis: pathways to kidney failure in Australian Aborigines

Glomerular hyperfiltration

Circulating blood is filtered across the glomerular barrier to form an ultrafiltrate of plasma in the Bowman's space. The volume of glomerular filtration adjusted by time is defined as the glomerular filtration rate (GFR), and the total GFR is the sum of all single-nephron GFRs. Thus, when the single-nephron GFR is increased in the context of a normal number of functioning nephrons, single glomerular hyperfiltration results in 'absolute' hyperfiltration in the kidney. 'Absolute' hyperfiltration can occur in healthy people after high protein intake, during pregnancy and in patients with diabetes, obesity or autosomal-dominant polycystic kidney disease. When the number of functioning nephrons is reduced, single-nephron glomerular hyperfiltration can result in a GFR that is within or below the normal range. This 'relative' hyperfiltration can occur in patients with a congenitally reduced nephron number or with an acquired reduction in nephron mass consequent to surgery or kidney disease. Improved understanding of the mechanisms that underlie 'absolute' and 'relative' glomerular hyperfiltration in different clinical settings, and of whether and how the single-nephron haemodynamic and related biomechanical forces that underlie glomerular hyperfiltration promote glomerular injury, will pave the way toward the development of novel therapeutic interventions that attenuate glomerular hyperfiltration and potentially prevent or limit consequent progressive kidney injury and loss of function.

Frequent use of hospital inpatient services during a nine year period: a retrospective cohort study

Background

Frequent use (FU) of hospital services impacts on patients and health service expenditure. Studies examining FU in emergency departments and inpatient settings have found heterogeneity and the need to differentiate between potentially preventable FU and that associated with ongoing management of complex conditions. Psychosocial factors have often been reported as underpinning or exacerbating the phenomena.

Most FU studies have been limited by time, to a single study site, or restricted to specific diagnoses or patient groups. This study provides a comprehensive description of adult patient characteristics, conditions and risk factors associated with FU, based on admissions to the five public hospitals in the Northern Territory (NT) of Australia over a nine year period. The study population is distinctive comprising both Aboriginal and non-Aboriginal patients.

Methods

Data on all inpatient episodes in NT public hospitals between 2005 and 2013 was analysed to identify patients with any FU (four or more episodes within any 12-month period) and measure FU duration (number of FU years) and intensity (mean number of episodes per FU year). Pregnancy, alcohol-related and mental health condition flags were assigned to patients with any episode with relevant diagnoses during the study period. Multivariate analysis was used to assess factors associated with any FU, FU duration and FU intensity, separately for Aboriginal and non-Aboriginal patients.

Results

Of people with any inpatient episodes during the study period, 13.6% were frequent users (Aboriginal 22%, non-Aboriginal 10%) accounting for 46.6% of all episodes. 73% of frequent users had only one FU year. Any FU and increased FU duration were more common among individuals who were: Aboriginal; older; female; and those with a pregnancy, alcohol or mental health flag. Having two or more alcohol-related episodes in the nine-year period was strongly associated with any FU for both Aboriginal (odds ratio 8.9, 95% CI. 8.20–9.66) and non-Aboriginal patients (11.5, 9.92–13.26).

Conclusion

For many people, frequent inpatient treatment is necessary and unavoidable. This study suggests that damage arising from excessive alcohol consumption (either personal or by others) is the single most avoidable factor associated with FU, particularly for Aboriginal people.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2285-1) contains supplementary material, which is available to authorized users.

Racial disparities in health care-emergency department management of minor head injury

Background/aim

International research has demonstrated disparities in the Emergency Department care of patients of certain racial or ethnic backgrounds. The management of minor head injuries requires a careful clinical assessment to determine the requirement of a CT scan of the head. The aim of this study was to determine if there was any disparity, based on race, in the management of minor head injury.

Methods

This was a retrospective, structured, medical record review of patients presenting to The Townsville Hospital Emergency Department, between September 2004 and April 2007, with minor head injury. The main outcome measure was whether or not patients received a CT head scan when clinically indicated. The Canadian CT Head Rule was considered the standard for clinical indication for a CT head scan. Secondary outcome measures included triage category, waiting time, level of care provider, disposition and serum ethanol.

Results

A total of 270 patients (73 indigenous and 196 non-indigenous) were enrolled. There was no statistically significant difference in ordering CT head scans when clinically indicated between indigenous and non-indigenous patients. However, a trend indicating that indigenous patients were less likely to receive a CT head scan when clinically indicated (OR 0.35; 95% CI = 0.07 to 1.77) was noted. Indigenous patients had a mean waiting time of 44.6 min (SD 49.6) compared to non-indigenous with 31.1 min (SD 36.4; p = 0.02).

Conclusion

This study concluded that there was no statistically significant disparity based upon race in the management of minor head injuries with regard to decision to perform a CT head scan. There is some evidence that indigenous patients waited longer to be seen. A multi-centre prospective study is necessary to confirm these findings.

Retinoic acid enhances nephron endowment in rats exposed to maternal protein restriction

A reduced nephron complement at birth renders the kidney susceptible to renal disease in adulthood. Retinoic acid (RA; the active metabolite of vitamin A) is linked to nephrogenesis in vitro and in vivo. The aim of this study was to determine the effect of administration of retinoic acid in midgestation in rats on nephron endowment in offspring exposed to maternal protein restriction. Rats were fed either a normal-protein diet (NPD) or a low-protein diet (LPD) during pregnancy and lactation. Half of the dams in the LPD group were injected intraperitoneally with retinoic acid (20 mg/kg) during gestation at embryonic day 11.5. At 4 weeks of age, the offspring were anesthetized and perfusion-fixed, and nephron number estimated using unbiased stereological techniques. Body weight and kidney volume was significantly reduced in all LPD offspring. There was a significant 29% reduction in nephron number in the LPD group compared with the NPD offspring, whereas the number of nephrons in kidneys from the LPD + RA offspring was not significantly different compared with controls. In conclusion, administration of a single bolus dose of retinoic acid during midgestation restored nephron endowment to normal in offspring exposed to maternal protein restriction.

The management of diabetes in indigenous Australians from primary care

Background

Indigenous Australians have high rates of diabetes and its complications. This study examines ethnic differences in the management of patients with type 2 diabetes in Australian primary care.

Methods

Diabetes management and outcomes in Indigenous patients enrolled in the NEFRON study (n = 144) was systematically compared with that in non-Indigenous patients presenting consecutively to the same practitioner (n = 449), and the NEFRON cohort as a whole (n = 3893).

Results

Indigenous Australians with diabetes had high rates of micro- and macrovascular disease. 60% of Indigenous patients had an abnormal albumin to creatinine ratio compared to 33% of non-Indigenous patients (p < 0.01). When compared to non-Indigenous patients, Indigenous patients were more likely to have established macrovascular disease ((adjusted Odds ratio 2.7). This excess in complications was associated with poor glycemic control, with an HbA_1c ≥ 8.0%, observed in 55% of all Indigenous patients, despite the similar frequency use of oral antidiabetic agents and insulin. Smoking was also more common in Indigenous patients (38%vs 10%, p < 0.01). However, the achievement of LDL and blood pressure targets was the same or better in Indigenous patients.

Conclusion

Although seeing the same doctors and receiving the same medications, glycaemic and smoking cessation targets remain unfulfilled in Indigenous patients. This cross-sectional study confirms Aboriginal ethnicity as a powerful risk factor for microvascular and macrovascular disease, which practitioners should use to identify candidates for intensive multifactorial intervention.

Renal ultrasound findings in an Australian Aboriginal population with high rates of renal disease

BACKGROUND

Rates of albuminuria and haematuria are extremely high with haematuria prevalence as high as 30-50% in adults of some Aboriginal groups. Dipstick testing of urine is routinely carried out in Aboriginal communities and as part of school screening programmes. Evaluation of the many affected individuals has traditionally included renal ultrasound examination, which involves considerable expense and logistic problems in remote communities. The present study was conducted to evaluate the usefulness of ultrasound in this setting.

METHODS

A population survey was conducted in a remote community. Urine dipstick analysis and the albumin:creatinine ratio (ACR; g/mol) were measured in 1440 people over 5 years of age (89% of the eligible population), and a detailed renal ultrasound examination was performed in a random subset of 647 people (41.1% of the whole group), 276 aged 5-19 years and 371 over 20 years of age.

RESULTS

Urine dipstick proteinuria (>1+) was present in 8.5% (23/271) of those aged 5-19 years and 37.9% (132/348) in those aged over 20 years; pathological albuminuria (ACR>3.4) was present in 7.6% (21/276) and 54.7% (203/371), respectively, and isolated haematuria was present in 7.7% (21/273) and 11.5% (40/347), respectively. Eight ultrasound abnormalities were found. Ultrasound findings did not change the management of any individual.

CONCLUSION

Renal ultrasound added little to the evaluation of people with asymptomatic proteinuria or haematuria in this setting. In this scenario, ultrasound examination could be reserved for the cases with an unusual presentation where findings are likely to influence the prognosis or treatment, or in preparation for a renal biopsy.