Real world evaluation of kidney failure risk equations in predicting progression from chronic kidney disease to kidney failure in an Australian cohort

BACKGROUND

Chronic kidney disease progression to kidney failure is diverse, and progression may be different according to genetic aspects and settings of care. We aimed to describe kidney failure risk equation prognostic accuracy in an Australian population.

METHODS

A retrospective cohort study was undertaken in a public hospital community-based chronic kidney disease service in Brisbane, Australia, which included a cohort of 406 adult patients with chronic kidney disease Stages 3-4 followed up over 5 years (1/1/13-1/1/18). Risk of progression to kidney failure at baseline using Kidney Failure Risk Equation models with three (eGFR/age/sex), four (add urinary-ACR) and eight variables (add serum-albumin/phosphate/bicarbonate/calcium) at 5 and 2 years were compared to actual patient outcomes.

RESULTS

Of 406 patients followed up over 5 years, 71 (17.5%) developed kidney failure, while 112 died before reaching kidney failure. The overall mean difference between observed and predicted risk was 0.51% (p = 0.659), 0.93% (p = 0.602), and - 0.03% (p = 0.967) for the three-, four- and eight-variable models, respectively. There was small improvement in the receiver operating characteristic-area under the curve from three-variable to four-variable models: 0.888 (95%CI = 0.819-0.957) versus 0.916 (95%CI = 0.847-0.985). The eight-variable model showed marginal receiver operating characteristic-area under the curve improvement: 0.916 (95%CI = 0.847-0.985) versus 0.922 (95%CI = 0.853-0.991). The results were similar in predicting 2 year risk of kidney failure.

CONCLUSIONS

The kidney failure risk equation accurately predicted progression to kidney failure in an Australian chronic kidney disease population. Younger age, male sex, lower estimated glomerular filtration rate, higher albuminuria, diabetes mellitus, tobacco smoking and non-Caucasian ethnicity were associated with increased risk of kidney failure. Cause-specific cumulative incidence function for progression to kidney failure or death, stratified by chronic kidney disease stage, demonstrated differences within different chronic kidney disease stages, highlighting the interaction between comorbidity and outcome.

Hospitalizations Among Adults With CKD in Public Renal Specialty Practices: A Retrospective Study From Queensland, Australia

Rationale & Objective

Little is known about hospital admissions in nondialysis patients with chronic kidney disease (CKD) before death or starting kidney replacement therapy (KRT).

Study Design

Retrospective observational cohort study.

Setting & Participants

Hospitalizations among 7,201 patients with CKD from 10 public renal clinics in Queensland (QLD), enrolled in the CKD.QLD registry starting in May 2011, were followed for 25,496.34 person-years until they started receiving KRT or died, or until June 30, 2018.

Predictors

Demographic and clinical characteristics of patients with CKD.

Outcomes

Hospital admissions.

Analytical Approach

We evaluated the association of demographic and clinical features with hospitalizations, length of hospital stay, and cost.

Results

Approximately 81.5% of the patients were admitted at least once, with 42,283 admissions, costing Australian dollars (AUD) 231 million. The average number of admissions per person-year was 1.7, and the cost was AUD 9,060, 10 times and 2 times their Australian averages, respectively. Single (1-day) admissions constituted 59.2% of all the hospital episodes, led by neoplasms (largely chemotherapy), anemia, CKD-related conditions and eye conditions (largely cataract extractions), but only 14.8% of the total costs. Approximately 41% of admissions were >1-day admissions, constituting 85.2% of the total costs, with cardiovascular conditions, respiratory conditions, CKD-related conditions, and injuries, fractures, or poisoning being the dominant causes. Readmission within 30 days of discharge constituted >42% of the admissions and 46.8% costs. Admissions not directly related to CKD constituted 90% of the admissions and costs. More than 40% of the admissions and costs were through the emergency department. Approximately 19% of the hospitalized patients and 27% of the admissions did not have kidney disease mentioned as either principal or associate causes.

Limitations

Variable follow-up times because of different dates of consent.

Conclusions

The hospital burden of patients with CKD is mainly driven by complex multiday admissions and readmissions involving comorbid conditions, which may not be directly related to their CKD. Strategies to prevent these complex admissions and readmissions should minimize hospital costs and outcomes.

Plain-Language Summary

We analyzed primary causes, types, and costs of hospitalizations among 7,201 patients with chronic kidney disease (CKD) from renal speciality clinics across Queensland, Australia, over an average follow-up of 3.54 years. The average annual cost per person was $9,060, and was the highest in those with more advanced CKD, higher age, and with diabetes. More than 85% of costs were driven by more complex hospitalizations with longer length of stay. Cardiovascular disease was the single largest contributor for hospitalizations, length of hospital stay, and total costs. Readmission within 30 days of discharge, particularly for the same disorder, and multiday admissions should be the main targets for mitigation of hospital costs in this population.

Chronic kidney disease in public renal practices in Queensland, Australia, 2011-2018

AIM

To describe adults with (non-dialysis) chronic kidney disease (CKD) in nine public renal practice sites in the Australian state of Queensland.

METHODS

7,060 persons were recruited to a CKD Registry in May 2011 and until start of kidney replacement therapy (KRT), death without KRT or June 2018, for a median period of 3.4 years.

RESULTS

The cohort comprised 7,060 persons, 52% males, with a median age of 68 yr; 85% had CKD stages 3A to 5, 45.4% were diabetic, 24.6% had diabetic nephropathy, and 51.7% were obese. Younger persons mostly had glomerulonephritis or genetic renal disease, while older persons mostly had diabetic nephropathy, renovascular disease and multiple diagnoses. Proportions of specific renal diagnoses varied >2-fold across sites. Over the first year, eGFR fell in 24% but was stable or improved in 76%. Over follow up, 10% started KRT, at a median age of 62 yr, most with CKD stages 4 and 5 at consent, while 18.8% died without KRT, at a median age of 80 yr. Indigenous people were younger at consent and more often had diabetes and diabetic kidney disease and had higher incidence rates of KRT.

CONCLUSION

The spectrum of characteristics in CKD patients in renal practices is much broader than represented by the minority who ultimately start KRT. Variation in CKD by causes, age, site and Indigenous status, the prevalence of obesity, relative stability of kidney function in many persons over the short term, and differences between those who KRT and die without KRT are all important to explore.

Health service utilisation during the last year of life: a prospective, longitudinal study of the pathways of patients with chronic kidney disease stages 3-5

Background

Chronic kidney disease (CKD) is a growing global problem affecting around 10% of many countries’ populations. Providing appropriate palliative care services (PCS) to those with advanced kidney disease is becoming paramount. Palliative/supportive care alongside usual CKD clinical treatment is gaining acceptance in nephrology services although the collaboration with and use of PCS is not consistent.

Methods

The goal of this study was to track and quantify the health service utilisation of people with CKD stages 3-5 over the last 12 months of life. Patients were recruited from a kidney health service (Queensland, Australia) for this prospective, longitudinal study. Data were collected for 12 months (or until death, whichever was sooner) during 2015-17 from administrative health sources. Emergency department presentations (EDP) and inpatient admissions (IPA) (collectively referred to as critical events) were reviewed by two Nephrologists to gauge if the events were avoidable.

Results

Participants (n = 19) with a median age of 78 years (range 42-90), were mostly male (63%), 79% had CKD stage 5, and were heavy users of health services during the study period. Fifteen patients (79%) collectively recorded 44 EDP; 61% occurred after-hours, 91% were triaged as imminently and potentially life-threatening and 73% were admitted. Seventy-four IPA were collectively recorded across 16 patients (84%); 14% occurred on weekends or public holidays. Median length of stay was 3 days (range 1-29). The median number of EDP and IPA per patient was 1 and 2 (range 0-12 and 0-20) respectively. The most common trigger to both EDP (30%) and IPA (15%) was respiratory distress. By study end 37% of patients died, 63% were known to PCS and 11% rejected a referral to a PCS. All critical events were deemed unavoidable.

Conclusions

Few patients avoided using acute health care services in a 12 month period, highlighting the high service needs of this cohort throughout the long, slow decline of CKD. Proactive end-of-life care earlier in the disease trajectory through integrating renal and palliative care teams may avoid acute presentations to hospital through better symptom management and planned care pathways.

Tracking patients with advanced kidney disease in the last 12 months of life

BACKGROUND

There is increasing recognition of the clinical need for timely and coordinated supportive and palliative care for those with terminal organ failure.

OBJECTIVE

To describe symptoms, quality of life and supportive care needs in the anticipated 12-month period prior to death in adults with chronic kidney disease (CKD) stages 4 or 5.

METHOD

An observational, prospective, longitudinal design was used to follow 19 patients. The measures used were the Chronic Kidney Disease-Symptom Burden Index (CKD-SBI), the Australian Karnofsky Performance Scale (AKPS), the Functional Assessment of Chronic illness Therapy Palliative-14 (FACIT PAL-14), the Assessment of Quality of Life 6 Dimensions (AQoL-6D) and the Sheffield Profile for Assessment and Referral for Care (SPARC). Data were collected at study entry and three monthly until death or study end.

RESULTS

Patients' median age was 78 years (range 42-90), most were male (63%), 10 were receiving dialysis and seven died during the study. The most prevalent symptoms reported differed from those that were most troublesome. The median AKPS score did not change over time (60). Quality of life remained steady over time [FACIT-PAL median range: 43.5-46; AQoL-6D means range: 0.66 (SD 0.19) to 0.75 (SD 0.2)]. Supportive care needs were few.

CONCLUSION

We found a substantial symptom burden and slow functional decline in this group of patients. Regular assessment of both symptoms and QOL is warranted particularly if clinical experience indicates that the person is likely to be in their last year of life. Integrated supportive care programmes could assist with easing symptom burden during this time.

Spectrum (characteristics) of patients with chronic kidney disease (CKD) with increasing age in a major metropolitan renal service

Background

Aim of our study is to describe, in people with CKD, the demographic and clinical characteristics and outcomes with increasing age. The prevalence of CKD in Western populations, where longevity is the norm, is about 10–15%, but how age influence different characteristics of patients with CKD is largely not known.

Methods

One thousand two hundred sixty-five patients enrolled in the CKD.QLD registry at the Royal Brisbane and Women’s Hospital were grouped according to age at consent i.e. <35, 35–44, 45–54, 55–64, 65–74, 75–84, 85+ years age groups, and were followed till start of renal replacement therapy (RRT), death, discharge or the censor date of September 2015.

Results

Age ranged from 17.6 to 98.5 years with medians of 70.1 and 69.9 years for males and females respectively: 7% were <35 years of age, with the majority (63%) >65 years old. The leading renal diagnoses changed from genetic real disease (GRD) and glomerulonephritis (GN) in the younger patients to renovascular disease (RVD) and hypertension (HTN) in older patients. With increasing age, there were often multiple renal disease diagnoses, more advanced stages of CKD, greater number of comorbidities, more frequent and more costly hospitalizations, and higher death rates. The rates of initiation of renal replacement therapy (RRT) rose from 4.5 per 100 person years in those age < 35 years to a maximum of 5.5 per 100 person years in 45–54 years age group and were lowest, at 0.5 per 100 person years in those >85 years. Mortality rates increased by age group from 1.3 to 17.0 per 100 person years in 35–44 year and 85+ year age groups respectively. Rates of hospitalization, length of stay and cost progressively increased from the youngest to eldest groups. Patients with diabetic nephropathy had highest incidence rate of RRT and death. The proportion of patients who lost more than 5mls/min/1.73m² of eGFR during at least 12 months follow up increased from 13.3% in the youngest age group to 29.2% in the eldest.

Conclusion

This is the first comprehensive view, with no exclusions, of CKD patients seen in a public renal specialty referral practice, in Australia. The age distribution of patients encompasses the whole of adult life, with a broader range and higher median value than patients receiving RRT. Health status ranged from a single system (renal) disease in young adults through, with advancing age, renal impairment as a component of, or accompanying multisystem diseases, to demands and complexities of support of frail or elderly people approaching end of life. This great spectrum demands a broad understanding and capacity of renal health care providers, and dictates a need for a wider scope of health services provision incorporating multiple models of care.

Pharmacokinetics of Intraperitoneal Cefalothin and Cefazolin in Patients Being Treated for Peritoneal Dialysis-Associated Peritonitis

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BACKGROUND

The standard treatment of peritoneal dialysis (PD)-associated peritonitis (PD-peritonitis) is intraperitoneal (IP) administration of antibiotics. Only limited data on the pharmacokinetics and appropriateness of contemporary dose recommendations of IP cefalothin and cefazolin exist. The aim of this study was to describe the pharmacokinetics of IP cefalothin and cefazolin in patients treated for PD-peritonitis. ♦

METHODS

As per international guidelines, IP cefalothin or cefazolin 15 mg/kg once daily was dosed with gentamicin in a 6-hour dwell to patients with PD-peritonitis during routine care. Serial plasma and PD effluent samples were collected over the first 24 hours of therapy. Antibiotic concentrations were quantified using a validated chromatographic method with pharmacokinetic analysis performed using a non-compartmental approach. ♦

RESULTS

Nineteen patients were included (cefalothin n = 8, cefazolin n = 11). The median bioavailability for both antibiotics exceeded 92%, but other pharmacokinetic parameters varied markedly between antibiotics. Both antibiotics achieved high PD effluent concentrations throughout the antibiotic dwell. Cefazolin had a smaller volume of distribution compared with cefalothin (14 vs 40 L, p = 0.003). The median trough total plasma antibiotic concentration for cefazolin and cefalothin during the dwell differed (plasma 56 vs 13 mg/L, p < 0.0001) despite a similar concentration in PD effluent (37 vs 38 mg/L, p = 0.58). Lower antibiotic concentrations were noted during PD dwells not containing antibiotic, particularly cefalothin, which was frequently undetectable in plasma and PD effluent. The median duration that the unbound antibiotic concentration was above the minimum inhibitory concentration (MIC) was approximately 13% (plasma) and 25% (IP) for cefalothin, and 100% (plasma and IP) for cefazolin, of the dosing interval. ♦

CONCLUSIONS

When IP cefalothin or cefazolin is allowed to dwell for 6 hours, sufficient PD effluent concentrations are present for common pathogens during this time. However, with once-daily IP dosing, in contrast to cefazolin, there is a risk of subtherapeutic plasma and PD effluent cefalothin concentrations, so more frequent dosing may be required.

Development and validation of a dietary screening tool for high sodium consumption in Australian renal patients

OBJECTIVE

The study objective was to develop and evaluate the feasibility and validity of a self-administered Scored Sodium Questionnaire (SSQ) for use in the routine clinical care of Australian chronic kidney disease (CKD) patients.

DESIGN AND METHODS

The study took place in community-based outreach clinics using a multidisciplinary model of care. Assessment of sources of dietary sodium intake in the target population used comprehensive diet history interviews (Phase 1) to inform development of a 10-item food frequency questionnaire that was scored and validated using 24-hour urinary sodium and 2 alternative dietary intake methods (Phase 2). Subjects were adults with CKD Stages 3 to 5 (Phase 1 n = 30; Phase 2 n = 47).

INTERVENTION

On a single day, participants (n = 47) completed the SSQ, feasibility survey, 24-hour urine collection, and 24-hour food record. A diet history interview was also conducted to confirm sodium intake on the day of data collection reflected habitual intake.

MAIN OUTCOME MEASURE

Validity of the SSQ score was confirmed by correlation with 24-hour urine sodium. Validity of a cutpoint on the SSQ score to correctly identify high- versus low-sodium consumers was confirmed by receiver operating characteristic curve analysis: area under the curve, sensitivity, and specificity.

RESULTS

Total SSQ score correlated significantly with 24-hour urine sodium (r = 0.371; P = .031). Correlation between 24-hour food record and diet history sodium confirmed consumption on the data collection day reflected habitual intake (r = 0.701; P ≤ .001). A cutpoint of 65 or greater on the SSQ score was confirmed as valid to identify high-sodium consumers: area under the curve 0.713, sensitivity 61%, and specificity 82%.

CONCLUSION

The SSQ is feasible and valid to assess habitual sodium intake in the Australian CKD population and to identify high-sodium consumers for referral to individualized counseling on a low-sodium diet.

Sustained remission of systemic lupus erythematosus related calciphylaxis

Calciphylaxis continues to present a clinical challenge for patient management. As in this case, it can be associated with connective tissue disease (CTD) such as systemic lupus erythematosus (SLE). Unlike previous reported cases, long-term remission has been attained. This provides some insight into methods of therapy as well as potential pathogenic models for this disease.

Maintenance of elevated versus physiological iron indices in non-anaemic patients with chronic kidney disease: a randomized controlled trial

BACKGROUND

An optimal haemoglobin (Hb) response to erythropoietin requires elevated iron indices in dialysis patients; however, it is unknown if the same applies in chronic kidney disease (CKD).

METHODS

One hundred patients [CKD Stages 3-5, Hb >or= 110 g/L, iron replete, erythropoietin-stimulating agent (ESA)-naive, 47% diabetic, median age 69.5 years] were block-randomized in an open-label study to receive up to 200 mg intravenous iron sucrose (Group A, n = 52) bimonthly or oral iron sulphate (Group B) to maintain raised and normal iron indices (respectively) over 12 months. The primary endpoint was the change in Hb concentration at 12 months or at termination after at least 6 months of treatment.

RESULTS

Eighty-five patients reached the primary endpoint (43, Group A; 42, Group B). Initial Hb was 119 +/- 7 vs 116 +/- 12 g/L (mean +/- standard deviation); ferritin 122 (71-176), median (inter-quartile range), vs 90 microg/L (58-150); transferrin saturation (TSat) 22 (18-26) vs 21% (15-24); and creatinine 240 (195-313) vs 230 micromol/L (184-352). Ferritin and TSat differed by month 2 [157 (103-220) vs 96 microg/L (73-162), P = 0.003] and month 6 [25 (20-31) vs 21% (17-27), P = 0.02], respectively. At study end, Hb did not differ between groups (121 +/- 10 vs 117 +/- 13 g/L). Ferritin was 362 (310-458) vs 125 microg/L (84-190), P < 0.001; TSat 30 (23-34) vs 21% (18-24), P < 0.001; and creatinine 229 (188-326) vs 272 micromol/L (195-413), P = NS. For patients (Groups A and B, n = 27 in each group) whose creatinine regression slope increased (indicating worsening function), the fall in Hb over 12 months also did not differ between groups despite adequate separation in iron indices. Serious adverse events overall did not differ between groups.

CONCLUSIONS

Elevated iron indices did not increase Hb synthesis in ESA-naive, iron replete, pre-dialysis patients with Hb >110 g/L.

Day-case inguinal hernia repair in the elderly: a surgical priority

PURPOSE

To compare patients over 70 years old with those under 50 years old undergoing inguinal hernia repair.

PATIENTS AND METHODS

Fifty patients aged >70 years (group A) and 50 patients age <50 years (group B) underwent local anaesthetic mesh repair. The mean age for group A was 77.2 years (range 70-85) and for group B it was 40.2 years (range 17-49). There were 46 patients with comorbidities in group A and seven in group B. There were 30 patients with cardiac comorbidities in group A and two in group B.

RESULTS

There were no major complications, infections, haematomas or unplanned admissions in either group. Patients >70 years of age had less post-operative discomfort and recovered more quickly than patients aged <50 years. The number of days of analgesic use and time to return to normal activities was longer in the younger group, 6.0 versus 3.4 and 21 versus 13, respectively. There was no significant difference between the groups in patients having discomfort at 3 months post-operatively. More patients were satisfied in the older group, though the difference was not statistically significant.

CONCLUSION

Elective inguinal hernia repair under local anaesthetic in the elderly has a good outcome, even if there are significant comorbidities. Ambulatory surgery is feasible in this age group and age alone or co-existing disease should not be a barrier to elective day-case inguinal hernia repair.

Colchicine-induced bone marrow suppression: treatment with granulocyte colony-stimulating factor

Bone marrow aplasia is a frequent complication of colchicine poisoning. This typically occurs on day 3 to 5 postexposure, and the blood cell counts remain depressed for a week or more. Unfortunately, because patients suffering from colchicine toxicity develop multiple organ complications and sepsis, the morbidity and mortality associated with bone marrow depression is high. In this article, we present three cases of colchicine toxicity in which granulocyte colony-stimulating factor (G-CSF) was used to treat bone marrow depression. In all three cases, there was a dramatic increase in the white cell count and, to a lesser extent, the platelet count. In view of the critical nature of the bone marrow depression and multi-organ toxicity induced by colchicine, we believe that consideration of the use of G-CSF to shorten the duration of neutropenia is warranted.

Acute renal failure--10-year experience of the Johannesburg Hospital renal unit

The 10-year experience of Johannesburg Hospital's renal unit in treating acute renal failure (ARF) is described; 290 patients were treated by haemodialysis--169 drawn from the surgical disciplines, 109 from the medical disciplines and 12 from obstetrics and gynaecology, suffering 55%, 41% and 33% mortality rates, respectively. The mortality rates were found to correlate strongly with the cumulative number of acute insults to renal function accruing as a result of the particular surgical or medical illness ('precipitating event') and culminating in ARF. Age was also shown to have a powerful influence on outcome, the survival rate falling steadily with each decade of life. A plea is made to limit the potential insults to renal function actively, particularly in the elderly, in an attempt to further reduce the high mortality rate with which ARF continues to be stubbornly associated.

Detailed faecal bile acid profile: a diagnostic test for colorectal cancer?

Detailed profiles of bile acids in faeces were evaluated as a diagnostic test for colorectal cancer in rats. Twenty-seven bile acid peaks were measured using improved methods of extraction and separation followed by the sensitive and specific techniques of capillary column gas liquid chromatography and mass spectrometry. Colorectal cancer was induced in experimental animals (female Sprague-Dawley rats, n = 20) by subcutaneous injection of dimethylhydrazine (DMH) and faecal unconjugated bile acids compared with those in the control group (n = 20). The amount of total faecal unconjugated bile acids was lower in the animals administered DMH (255 mg/day vs 334 mg/day: (P = 0.04), and the excretion of seven individual bile acids was reduced when compared with those in the control group (P less than 0.01). In order to use the faecal bile acid profiles as a diagnostic test, linear discriminant analysis was performed. A discriminant score was derived which was applied to each profile, to determine to which group (control or DMH) each animal belonged retrospectively. All analyses were performed blind, and 90% of the animals were correctly assigned. In man, as in rats, the bile acid profile of faces is equally complex and the bile acid profile may be useful as a diagnostic test.

The effect of alrestatin on alanine-stimulated release of insulin and glucagon in man

Alrestatin, an aldose reductase inhibitor, was administered orally to 10 normal men. Its effect on basal plasma glucose, insulin and glucagon levels and on the response of glucose, insulin and glucagon to an oral alanine load was assessed and compared to that of a placebo. There was a significant suppression of both the mean basal insulin level and the mean insulin response to alanine in the group pretreated with alrestatin as compared to the placebo group (p less than 0.05 at 0 and 60 min). Glucagon levels rose slightly in both groups but tended to be lower in the alrestatin-treated subjects, and blood sugar levels fell slightly. There was a significant inverse correlation between the mean insulin and glucose levels in individual subjects. The possible significance and mechanisms of insulin suppression are discussed.

Adipose cell size in obese Africans: evidence against the existence of insulin resistance in some patients

Aspects of adipose tissue cellularity were examined in 15 non-diabetic premenopausal African women with simple obesity living in Johannesburg. A smaller group of six non-obese Black women served as controls. Adipose tissue was obtained by biopsy from the deltoid, gluteal, and abdominal regions, and the mean fat cell size for each site was determined. Fasting plasma glucose, insulin, and lipid levels, and the glucose and insulin responses to a 100 g oral glucose load, in these subjects provided metabolic data for correlative analyses. As expected, the overall mean and regional adipocyte sizes were significantly larger in the overweight subjects. Significant regional variations in fat cell size were also seen, the gluteal region adipocytes being larger than those of other sites in both obese and non-obese women. A significant positive correlation was found between fat cell size and the percentage of ideal body weight. There was no significant relationship between adipocyte size, however, and any of the metabolic variables measured--notably basal or stimulated plasma insulin. Nearly half of the overweight women showed large adipocytes with normal plasma insulin concentrations. A proportion of African women with hypertrophic obesity do not appear to demonstrate any classical metabolic features of insulin resistance; this may be related partly to their high carbohydrate intake and unusual degree of physical activity. Our results do not, however, indicate that hyperinsulinaemia is completely absent in obese Black women.