Competing risks of death and kidney failure in a cohort of Australian adults with severe chronic kidney disease

OBJECTIVES

To examine the competing risks of death (any cause) and of kidney failure in a cohort of Australian adults with severe chronic kidney disease.

DESIGN

Population-based cohort study; analysis of linked data from the Tasmanian Chronic Kidney Disease study (CKD.TASlink), 1 January 2004 - 31 December 2017.

PARTICIPANTS

All adults in Tasmania with incident stage 4 chronic kidney disease (estimated glomerular filtration rate [eGFR], 15-29 mL/min/1.73 m² ).

MAIN OUTCOME MEASURES

Death or kidney failure (defined as eGFR below 10 mL/min/1.73 m² or initiation of dialysis or kidney transplantation) within five years of diagnosis of stage 4 chronic kidney disease.

RESULTS

We included data for 6825 adults with incident stage 4 chronic kidney disease (mean age, 79.3 years; SD, 11.1 years), including 3816 women (55.9%). The risk of death increased with age - under 65 years: 0.18 (95% CI, 0.15-0.22); 65-74 years: 0.39 (95% CI, 0.36-0.42); 75-84 years, 0.56 (95% CI, 0.54-0.58); 85 years or older: 0.78 (95% CI, 0.77-0.80) - while that of kidney failure declined - under 65 years: 0.39 (95% CI, 0.35-0.43); 65-74 years: 0.12 (95% CI, 0.10-0.14); 75-84 years: 0.05 (95% CI, 0.04-0.06); 85 years or older: 0.01 (95% CI, 0.01-0.02). The risk of kidney failure was greater for people with macroalbuminuria and those whose albumin status had not recently been assessed. The risks of kidney failure and death were greater for men than women in all age groups (except similar risks of death for men and women under 65 years of age).

CONCLUSIONS

For older Australians with incident stage 4 chronic kidney disease, the risk of death is higher than that of kidney failure, and the latter risk declines with age. Clinical guidelines should recognise these competing risks and include recommendations about holistic supportive care, not just on preparation for dialysis or transplantation.

Island medicine: using data linkage to establish the kidney health of the population of Tasmania, Australia

Objective

To report (using linked laboratory data) the incidence, prevalence and geographic variation of chronic kidney disease (CKD) across the whole island population of Tasmania, Australia.

Methods

A retrospective cohort study (the Tasmanian Chronic Kidney Disease study (CKD.TASlink)) using linked data from five health and two pathology datasets from the island state of Tasmania, Australia between 1/1/2004 and 31/12/2017. We used data on 460,737 Tasmanian adults (aged 18 years and older, representing 86.8% of the state's population) who had a serum creatinine measured during the study period. We defined CKD as per Kidney Disease Outcomes Quality Initiative, requiring two measures of estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m², at least three months apart. Kidney replacement therapy (KRT) included dialysis or kidney transplantation.

Results

We identified 56,438 Tasmanians with CKD during the study period, equating to an age-standardised annual incidence of 1.0% and a prevalence of 6.5%. These figures were higher in women, older Tasmanians and people living in the North-West region of Tasmania. Testing for urinary albumin:creatinine ratio is increasing, with 28.5% of women and 30.8% of men with stage 3 CKD having both an eGFR and uACR in 2017. Use of KRT was consistently seen in >65% of Tasmanians with eGFR <15 mL/min/1.73m².

Conclusion

There is geographic and gender variation in the incidence and prevalence of CKD, but it is reassuring to see that the majority of people with end-stage kidney failure are actually receiving treatment with dialysis or transplantation.

Chronic Kidney Disease in Tasmania: Protocol for a Data Linkage Study

Background

Chronic kidney disease (CKD) is a significant and growing health burden globally. Tasmania has the highest state prevalence for non-Indigenous Australians and it has consistently had the lowest incidence and prevalence of dialysis in Australia.

Objective

To examine the gap between the high community prevalence of CKD in Tasmania and the low use of dialysis.

Methods

This is a retrospective cohort study using linked data from 5 health and 2 pathology data sets from the island state of Tasmania, Australia. The study population consists of any person (all ages including children) who had a blood measurement of creatinine with the included pathology providers between January 1, 2004, and December 31, 2017. This study population (N=460,737) includes within it a CKD cohort, which was detected via pathology or documentation of kidney replacement therapy (KRT; dialysis or kidney transplant). Kidney function (estimated glomerular filtration rate [eGFR]) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. Individuals with 2 measures of eGFR<60 mL/min/1.73 m², at least 90 days apart, were identified as having CKD and were included in the CKD cohort. Individuals treated with dialysis or transplant were identified from the Australia and New Zealand Dialysis and Transplant Registry.

Results

The study population consisted of 460,737 people (n=245,573 [53.30%] female, mean age 47.4 years) who were Tasmanian residents aged 18 years and older and were followed for a median of 7.8 years. During the later 5 years of the study period, 86.79% (355,622/409,729) of Tasmanian adults were represented. The CKD cohort consisted of 56,438 people (ie, 12.25% of the study population; 53.87% (30,405/56,438) female, mean age 69.9 years) followed for a median of 10.4 years with 56,039 detected via eGFR and 399 people detected via documentation of KRT. Approximately half (227,433/460,737, 49.36%) of the study population and the majority of the CKD cohort (41,448/56,438, 73.44%) had an admission episode. Of the 55,366 deaths recorded in the study population, 45.10% (24,970/55,366) had CKD.

Conclusions

Whole-of-population approaches to examine CKD in the community can be achieved by data linkage. Over this 14-year period, CKD affected 12.25% (56,438/460,737) of Tasmanian adult residents and was present in 45.10% (24,970/55,366) of deaths.

International Registered Report Identifier (IRRID)

DERR1-10.2196/20160

Medication Adherence, Burden and Health-Related Quality of Life in Adults with Predialysis Chronic Kidney Disease: A Prospective Cohort Study

This study examines the associations between medication adherence and burden, and health-related quality of life (HRQOL) in predialysis chronic kidney disease (CKD). A prospective study targeting adults with advanced CKD (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m²) and not receiving renal replacement therapy was conducted in Tasmania, Australia. The actual medication burden was assessed using the 65-item Medication Regimen Complexity Index, whereas perceived burden was self-reported using a brief validated questionnaire. Medication adherence was assessed using a four-item Morisky-Green-Levine Scale (MGLS) and the Tool for Adherence Behaviour Screening (TABS). The Kidney Disease and Quality of Life Short-Form was used to assess HRQOL. Of 464 eligible adults, 101 participated in the baseline interview and 63 completed a follow-up interview at around 14 months. Participants were predominantly men (67%), with a mean age of 72 (SD 11) years and eGFR of 21 (SD 6) mL/min/1.73 m². Overall, 43% and 60% of participants reported medication nonadherence based on MGLS and TABS, respectively. Higher perceived medication burden and desire for decision-making were associated with nonadherent behaviour. Poorer HRQOL was associated with higher regimen complexity, whereas nonadherence was associated with a decline in physical HRQOL over time. Medication nonadherence, driven by perceived medication burden, was prevalent in this cohort, and was associated with a decline in physical HRQOL over time.

The effect of hospitalization on potentially inappropriate medication use in older adults with chronic kidney disease

OBJECTIVES

Potentially inappropriate medication (PIM) use is associated with increased morbidity and mortality in chronic kidney disease (CKD). However, there is a paucity of data on how hospitalization affects PIM use in older adults with CKD. Therefore, we aimed to measure the impact of hospitalization on PIM use in older CKD patients, and identify factors predicting PIM use.

METHODS

A retrospective cohort study was conducted in older adults (≥65 years) with CKD admitted to an Australian tertiary care hospital over a 6 month period. PIM use was measured, upon admission and at discharge, using the Medication Appropriateness Index (MAI) and Beers criteria (2015 version) for medications recommended to be avoided in older adults and under certain conditions.

RESULTS

The median age of the 204 patients was 83 years (interquartile range (IQR): 76-87 years) and most were men (61%). Overall, the level of PIM use (MAI) decreased from admission to discharge (median [IQR]: 6 [3-12] to 5 [2-9]; p < .01]). More than half of the participants (55%) had at least one PIM per Beers criterion on admission, which was reduced by discharge (48%; p < .01). People admitted with a higher number of medications (β 0.72, 95% CI 0.56-0.88) and lower eGFR values (β - 0.11, 95% CI -0.18 to -0.04) had higher MAI scores after adjusting for age, sex and Charlson's comorbidity index.

CONCLUSIONS

PIMs were commonly used in older CKD patients. Hospitalization was associated with a reduction in PIM use, but there was considerable scope for improvement in these susceptible individuals.

Medication-Related Factors and Hospital Readmission in Older Adults with Chronic Kidney Disease

This study aimed to examine the association between medication-related factors and risk of hospital readmission in older patients with chronic kidney disease (CKD). A retrospective analysis was conducted targeting older CKD (n = 204) patients admitted to an Australian hospital. Medication appropriateness (Medication Appropriateness Index; MAI), medication regimen complexity (number of medications and Medication Regimen Complexity Index; MRCI) and use of selected medication classes were exposure variables. Outcomes were occurrence of readmission within 30 and 90 days, and time to readmission within 90 days. Logistic and Cox hazards regression were used to identify factors associated with readmission. Overall, 50 patients (24%) were readmitted within 30 days, while 81 (40%) were readmitted within 90 days. Mean time to readmission within 90 days was 66 (SD 34) days. Medication appropriateness and regimen complexity were not independently associated with 30- or 90-day hospital readmissions in older adults with CKD, whereas use of renin‒angiotensin blockers was associated with reduced occurrence of 30-day (adjusted OR 0.39; 95% CI 0.19⁻0.79) and 90-day readmissions (adjusted OR 0.45; 95% CI 0.24⁻0.84) and longer time to readmission within 90 days (adjusted HR 0.52; 95% CI 0.33⁻0.83). This finding highlights the importance of considering the potential benefits of individual medications during medication review in older CKD patients.

Medication Regimen Complexity and Hospital Readmission in Older Adults With Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is characterized by high rates of hospital admissions and readmissions. However, there is a scarcity of research into medication-related factors predicting such outcomes in this patient group.

OBJECTIVE

To evaluate the effect of medication regimen complexity at hospital discharge on subsequent readmissions and their timing in older adults with CKD.

METHODS

This was a 12-month retrospective cohort study of 204 older (⩾65 years) CKD patients in an Australian tertiary care hospital. Medication regimen complexity was quantified using the 65-item medication regimen complexity index (MRCI). The outcomes were the occurrence of readmission in 30 days and time to readmission within 12 months. Logistic regression was used to identify factors predicting 30-day readmission, and a competing risks proportional subdistribution hazard model, accounting for deaths, was used for factors predicting time to readmission.

RESULTS

Overall, 50 (24%) patients, predominantly men (72%), were readmitted within 30 days of follow-up. MRCI was not significantly associated with 30-day readmission (odds ratio [OR] = 1.27; 95% CI = 0.94-1.73). The median (interquartile range) time to readmission within 12 months was 145 (31-365) days. On a multivariate analysis, a 10-unit increase in MRCI was associated with a shorter time to readmission within 12 months (subdistribution HR = 1.18; 95% CI = 1.01-1.36). Conclusion and Relevance: Medication regimen complexity was not significantly associated with 30-day readmission; however, it was associated with a significantly shorter time to 12-month readmission in older CKD patients. This finding highlights the importance of medication regimen complexity as a potential target for medical interventions to reduce readmission risks.

Gender differences in the dialysis treatment of Indigenous and non-Indigenous Australians

OBJECTIVE

Access to dialysis treatment and the types of treatments employed in Australia differs by Indigenous status. We examined whether dialysis treatment utilisation in Indigenous and non-Indigenous Australians also differs by gender.

METHODS

Using registry data we evaluated 21,832 incident patients (aged ≥18 years) commencing dialysis, 2001-2013. Incidence rates were calculated and multivariate regression modelling used to examine differences in dialysis treatment (modality, location and vascular access creation) by race and gender.

RESULTS

Dialysis incidence was consistently higher in Indigenous women compared to all other groups. Compared to Indigenous women, both non-Indigenous women and men were more likely to receive peritoneal dialysis as their initial treatment (non-Indigenous women RR=1.91, 95%CI 1.55-2.35; non-Indigenous men RR=1.73, 1.40-2.14) and were more likely to commence initial treatment at home (non-Indigenous women RR=2.07, 1.66-2.59; non-Indigenous men RR=1.95, 1.56-2.45). All groups were significantly more likely than Indigenous women to receive their final treatment at home.

CONCLUSIONS

Contemporary dialysis treatment in Australia continues to benefit the dominant non-Indigenous population over the Indigenous population, with non-Indigenous men being particularly advantaged. Implications for Public Health: Treatment guidelines that incorporate a recognition of gender-based preferences and dialysis treatment options specific to Indigenous Australians may assist in addressing this disparity.

Tryptophan metabolism, its relation to inflammation and stress markers and association with psychological and cognitive functioning: Tasmanian Chronic Kidney Disease pilot study

Background

Adults with chronic kidney disease (CKD) exhibit alterations in tryptophan metabolism, mainly via the kynurenine pathway, due to higher enzymatic activity induced mainly by inflammation. Indoles produced by gut-microflora are another group of tryptophan metabolites related to inflammation and conditions accompanying CKD. Disruptions in tryptophan metabolism have been associated with various neurological and psychological disorders. A high proportion of CKD patients self-report symptoms of depression and/or anxiety and decline in cognitive functioning. This pilot study examines tryptophan metabolism in CKD and explores associations with psychological and cognitive functioning.

Methods

Twenty-seven adults with CKD were part of 49 patients recruited to participate in a prospective pilot study, initially with an eGFR of 15–29 mL/min/1.73 m². Only participants with viable blood samples and complete psychological/cognitive data at a 2-year follow-up were included in the reported cross-sectional study. Serum samples were analysed by Liquid Chromatography coupled to Mass Spectrometry, for tryptophan, ten of its metabolites, the inflammation marker neopterin and the hypothalamic–pituitary–adrenal (HPA) axis marker cortisol.

Results

The tryptophan breakdown index (kynurenine / tryptophan) correlated with neopterin (Pearson R = 0.51 P = 0.006) but not with cortisol. Neopterin levels also correlated with indoxyl sulfate (R = 0.68, P < 0.0001) and 5 metabolites of tryptophan (R range 0.5–0.7, all P ≤ 0.01), which were all negatively related to eGFR (P < 0.05). Higher levels of kynurenic acid were associated with lower cognitive functioning (Spearman R = −0.39, P < 0.05), while indole-3 acetic acid (IAA) was correlated with anxiety and depression (R = 0.52 and P = 0.005, R = 0.39 and P < 0.05, respectively).

Conclusions

The results of this preliminary study suggest the involvement of inflammation in tryptophan breakdown via the kynurenine pathway, yet without sparing tryptophan metabolism through the 5-HT (serotonin) pathway in CKD patients. The multiple moderate associations between indole-3 acetic acid and psychological measures were a novel finding. The presented pilot data necessitate further exploration of these associations within a large prospective cohort to assess the broader significance of these findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0387-3) contains supplementary material, which is available to authorized users.

Associations of fish oil and vitamin B and E supplementation with cardiovascular outcomes and mortality in people receiving haemodialysis: a review

Background

Cardiovascular complications are the leading cause of mortality in patients with end-stage kidney disease. Research indicates that the Mediterranean diet is protective of cardiovascular disease in the general population. Components of this diet have been trialled in haemodialysis patients with the aim of reducing the risk of cardiovascular disease and improving associated risk factors. Components include fish, fruit and vegetables in the form of fish oil supplements and vitamin and antioxidant supplements. This narrative review provides an overview of observational studies, and interventional and randomised controlled trials examining the association of these supplements with cardiovascular outcomes in haemodialysis patients.

Methods

We reviewed the relevant literature by searching English-language publications in Web of Science and references from relevant articles published since 1992. Eight-seven abstracts were reviewed and 38 relevant articles were included.

Results

The extant literature suggests that risk of mortality is reduced in patients with a higher fish intake and those with higher serum omega-3 fatty acid levels. However, the pathways by which risk of mortality is reduced have not been fully extrapolated. While only a few studies have examined the effect of vitamin B supplementation in haemodialysis patients, these studies suggest that supplementation alone does not reduce the risk of mortality. Finally, studies examining vitamin E supplementation have drawn inconsistent conclusions regarding its pro-oxidant or antioxidant effects. Differences between studies are likely due to methodological variations in regards to dose, route of administration and treatment duration.

Conclusions

Nutritional and dietary supplementation in haemodialysis patients is an area which requires larger, more methodologically robust randomised controlled trials to determine if risk of cardiovascular outcomes can be improved.

Physical activity patterns and risk of depression in young adulthood: a 20-year cohort study since childhood

PURPOSE

Little is known about how physical activity patterns during childhood and adolescence are associated with risk of subsequent depression. We examined prospective and retrospective associations between leisure physical activity patterns from childhood to adulthood and risk of clinical depression in young adulthood.

METHODS

Participants (759 males, 871 females) in a national survey, aged 9-15 years, were re-interviewed approximately 20 years later. Leisure physical activity was self-reported at baseline (1985) and follow-up (2004-2006). To bridge the interval between the two time-points, historical leisure activity from age 15 years to adulthood was self-reported retrospectively at follow-up. Physical activity was categorized into groups that, from a public health perspective, compared patterns that were least beneficial (persistently inactive) with those increasingly beneficial (decreasing, increasing and persistently active). Depression (major depressive or dysthymic disorder) was assessed using the Composite International Diagnostic Interview.

RESULTS

Compared with those persistently inactive, males who were increasingly and persistently active had a 69 and 65 % reduced risk of depression in adulthood, respectively (all p < 0.05). In retrospective analyses, females who were persistently active had a 51 % reduced risk of depression in adulthood (p = 0.01). Similar but non-significant trends were observed for leisure physical activity in females and historical leisure activity in males. Results excluded those with childhood onset of depression and were adjusted for various sociodemographic and health covariates.

CONCLUSIONS

Findings from both prospective and retrospective analyses indicate a beneficial effect of habitual discretionary physical activity since childhood on risk of depression in young adulthood.

Psychosocial factors in people with chronic kidney disease prior to renal replacement therapy

Increasing evidence implicates psychosocial factors including depression, anxiety, perceived social support and health-related quality of life in the pathophysiology of various chronic diseases. Research examining the psychosocial aspects of kidney disease has focussed predominantly on depressive disorders in dialysis patients where they are independently associated with increased risk of mortality and poor health-related quality of life. In contrast, studies examining the influence of psychosocial factors in people with chronic kidney disease (CKD) prior to the initiation of renal replacement therapy are sparse. Limited data indicate that clinical depression and depressive symptoms are common and may independently predict progression to dialysis, hospitalization and death. In contrast, the influence of anxiety disorders, lower perceived social support and impaired health-related quality of life on the clinical course of CKD have received little attention. Large-scale prospective cohort studies are needed to clarify the burden and prognostic impact of these factors in this vulnerable population. Given the escalating burden of CKD worldwide examining the role of these potentially modifiable risk factors is crucial. Identifying and implementing targeted interventions in order to prevent or delay the progression of CKD and improve quality of life will be a major challenge.

Childhood and adolescent predictors of leisure time physical activity during the transition from adolescence to adulthood: a population based cohort study

BACKGROUND

Few studies have investigated factors that influence physical activity behavior during the transition from adolescence to adulthood. This study explores the associations of sociodemographic, behavioral, sociocultural, attitudinal and physical factors measured in childhood and adolescence with physical activity behavior during the transition from adolescence to adulthood.

METHODS

Childhood and adolescent data (at ages 7-15 years) were collected as part of the 1985 Australian Health and Fitness Survey and subdivided into sociodemographics (socioeconomic status, parental education), behavioral (smoking, alcohol, sports diversity, outside school sports), sociocultural (active father, active mother, any older siblings, any younger siblings, language spoken at home), attitudinal (sports/recreational competency, self-rated health, enjoyment physical education/physical activity, not enjoying school sports) and physical (BMI, time taken to run 1.6 km, long jump) factors. Physical activity between the ages 15 and 29 years was reported retrospectively using the Historical Leisure Activity Questionnaire at follow-up in 2004-2006 by 2,048 participants in the Childhood Determinants of Adult Health Study (CDAH). Australia's physical activity recommendations for children and adults were used to categorize participants as persistently active, variably active or persistently inactive during the transition from adolescence to adulthood.

RESULTS

For females, perceived sports competency in childhood and adolescence was significantly associated with being persistently active (RR=1.88, 95% CI=1.39, 2.55). Smoking (RR=0.31 CI=0.12, 0.82) and having younger siblings (RR=0.69 CI=0.52, 0.93) were inversely associated with being persistently active after taking physical and attitudinal factors into account. For males, playing sport outside school (RR=1.47 CI=1.05, 2.08), having active fathers (RR=1.25 CI=1.01, 1.54) and not enjoying school sport (RR=4.07 CI=2.31, 7.17) were associated with being persistently active into adulthood. Time taken to complete the 1.6 km run was inversely associated with being persistently active into adulthood (RR=0.85 CI=0.78, 0.93) after adjusting for recreational competency.

CONCLUSIONS

Perceived sports competency (females) and cardiorespiratory fitness, playing sport outside school and having active fathers (males) in childhood and adolescence were positively associated with being persistently active during the transition from adolescence to adulthood.

Overweight and obesity in childhood and risk of mental disorder: a 20-year cohort study

OBJECTIVE

Very little is known about whether overweight and obese children have long-term risk for mental health problems. This study examined the association between overweight and obesity in childhood and DSM-IV mood, anxiety, and substance use disorders in young adulthood.

METHOD

Participants in a national Australian school survey when aged 7-15 years in 1985 were re-interviewed 20 years later as young adults aged 26-36 years (1135 women, 1108 men). Body mass index (BMI) was calculated from measured height and weight in childhood and adulthood. Children were classified as overweight or obese based on a BMI ≥85th centile for age and sex-specific height and weight. Obesity in adulthood was defined as BMI of ≥30. Twelve-month DSM-IV diagnoses of mood, anxiety and substance use disorders were obtained from the Composite International Diagnostic Interview. The relative risk (RR) for each class of mental disorder was estimated for childhood overweight/obesity versus non-overweight, and for four weight trajectories: non-overweight in childhood and non-obese in adulthood; overweight in childhood and non-obese in adulthood; non-overweight in childhood and obese in adulthood; and overweight in childhood and obese in adulthood.

RESULTS

Childhood overweight and obesity was associated with an increased risk of mood disorder in adulthood (RR = 1.54, 95%CI 1.06-2.23, p = 0.03), with a similar risk observed among girls and boys. When weight in adulthood was taken into consideration, increased risk of mood disorder was observed only among overweight girls who were obese in adulthood (adjusted RR = 2.03, 95%CI 1.22-3.66, p = 0.006), with childhood overweight or obesity in non-obese adults not associated with any mental disorder.

CONCLUSIONS

Childhood overweight may increase risk for mood disorder in adulthood, especially among overweight girls who become obese women. These results suggest that prevention of childhood overweight is equally important in both sexes for reducing risk of diagnosed mood disorder in adulthood.