♦ Objective The aim of this study was to prospectively evaluate the risk factors for decline of residual renal function (RRF) in an incident peritoneal dialysis (PD) population. ♦ Design Prospective observational study of an incident PD cohort at a single center. ♦ Setting Tertiary-care institutional dialysis center. ♦ Participants The study included 146 consecutive patients commencing PD at the Princess Alexandra Hospital between 1 August 1995 and 1 July 2001 (mean age 54.8 ± 1.4 years, 42% male, 34% diabetic). Patients with failed renal transplants ( n = 26) were excluded. ♦ Main Measurements Timed urine collections ( n = 642) were performed initially and at 6-month intervals thereafter to measure RRF. The development of anuria was also prospectively recorded. ♦ Results The mean (±SD) follow-up period was 20.5 ± 14.8 months. The median slope of RRF decline was –0.05 mL/minute/month/1.73 m2. Using binary logistic regression, it was shown that the 50% of patients with more rapid RRF loss (< –0.05 mL/min/month/1.73 m2) were more likely to have had a higher initial RRF at commencement of PD [adjusted odds ratio (AOR) 1.83, 95% confidence interval (CI) 1.39 – 2.40] and a higher baseline dialysate/plasma creatinine ratio at 4 hours (D/P creat; AOR 44.6, 95% CI 1.05 – 1900). On multivariate Cox proportional hazards model analysis, time from commencement of PD to development of anuria was independently predicted by baseline RRF [adjusted hazard ratio (HR) 0.81, 95% CI 0.60 – 0.81], D/P creat (HR 2.87, 95% CI 2.06 – 82.3), body surface area (HR 6.23, 95% CI 1.53 – 25.5), dietary protein intake (HR 2.87, 95% CI 1.06 – 7.78), and diabetes mellitus (HR 1.65, 95% CI 1.00 – 2.72). Decline of RRF was independent of age, gender, dialysis modality, urgency of initiation of dialysis, smoking, vascular disease, blood pressure, medications (including angiotensin-converting enzyme inhibitors), duration of follow-up, and peritonitis rate. ♦ Conclusions The results of this study suggest that high baseline RRF and high D/P creat ratio are risk factors for rapid loss of RRF. Moreover, a shorter time to the onset of anuria is independently predicted by low baseline RRF, increased body surface area, high dietary protein intake, and diabetes mellitus. Such at-risk patients should be closely monitored for early signs of inadequate dialysis.

Lymphoproliferative disease is an increasingly common problem after renal transplantation, and the outcome is poor. Measures to reduce its incidence might include reduction of long-term immunosuppression exposure. Established disease has a high short-term mortality, and new treatment options, such as anti-B-lymphocyte monoclonal antibodies, should be aggressively pursued.

Background. Serum creatinine concentration is an unreliable and insensitive marker of chronic kidney disease (CKD). To improve CKD detection, the Australasian Creatinine Consensus Working Committee recommended reporting of estimated glomerular filtration rate (eGFR) using the four-variable Modification of Diet in Renal Disease (MDRD) formula with every request for serum creatinine concentration. The aim of this study was to evaluate the impact of automated laboratory reporting of eGFR on the quantity and quality of referrals to nephrology services in Southeast Queensland, Australia.Methods. Outpatient referrals to a tertiary and regional renal service, and a single private practice were prospectively audited over 3–12 months prior to and 12 months following the introduction of automated eGFR reporting and concomitant clinician education. The appropriateness of referrals to a nephrologist was assessed according to the Kidney Check Australia Taskforce (KCAT) criteria. Significant changes in the quantity and/or quality of referrals over time were analysed by exponentially weighed moving average (EWMA) charts with control limits based on ±3 standard deviations.Results. A total of 1019 patients were referred to the centres during the study period. Monthly referrals overall increased by 40% following the introduction of eGFR reporting, and this was most marked for the tertiary renal service (52% above baseline). The appropriateness of nephrologist referrals, as adjudicated by the KCAT criteria, fell significantly from 74.3% in the 3 months pre-eGFR reporting to 65.2% in the 12 months thereafter (P < 0.05). Nevertheless, a greater absolute number of CKD patients were appropriately being referred for nephrologist review in the post-eGFR period (24 versus 15 per month). Patients referred following the introduction of eGFR were significantly more likely to be older (median 63.2 versus 59.3 years, P < 0.05), diabetic (25 versus 18%, P = 0.05) and have stage 3 CKD (48% versus 36%, P < 0.01).Conclusion. The introduction of automated eGFR calculation has led to an overall increase in referrals with a small but significant decrease in referral quality. The increase in referrals was seen predominantly in older and diabetic patients with stage 3 CKD and appeared to result in net benefit.

Background and objectivesThe cytokine midkine (MK) is pathologically implicated in progressive chronic kidney disease (CKD) and its systemic consequences and has potential as both a biomarker and therapeutic target. To date, there are no published data on MK levels in patients with different stages of CKD. This study aims to quantify MK levels in patients with CKD and to identify any correlation with CKD stage, cause, progression, comorbid disease or prescribed medication.MethodsIn this observational, single-centre study, demographic data were collected, and serum and urine assayed from 197 patients with CKD and 19 healthy volunteers in an outpatient setting.ResultsThe median serum and urine MK level in volunteers was 754 pg/mL (IQR: 554–1025) and 239 pg/mL (IQR: 154–568), respectively. Compared with serum MK in stage 1 CKD (660 pg/mL, IQR: 417–893), serum MK increased in stage 3 (1878 pg/mL, IQR: 1188–2756; p<0.001), 4 (2768 pg/mL, IQR: 2065–4735; p<0.001) and 5 (4816 pg/mL, IQ: 37477807; p<0.001). Urine MK levels increased from stage 1 CKD (343 pg/mL, IQR: 147–437) to stage 3 (1007 pg/mL, IQR: 465–2766; p=0.07), 4 (2961 pg/mL, IQR: 1368–5686; p=0.005) and 5 (6722 pg/mL, IQR: 3796–10 060; p=0.001). Fractional MK excretion (FeMK) increased from stage 1 CKD (0.159, IQR: 0.145–0.299) to stage 3 (1.024, IQR: 0.451–1.886, p=0.047), 4 (3.39, IQR: 2.10–5.82, p=0.004) and 5 (11.95, IQR: 5.36–24.41, p<0.001). When adjusted for estimated glomerular filtration rate, neither serum nor urine MK correlated with primary CKD diagnosis or CKD progression (small sample). There was a positive correlation between protein:creatinine ratio and FeMK (p=0.003). Angiotensin blockade (adjusted for proteinuria) was associated with lower urine MK (p=0.018) and FeMK (p=0.025).ConclusionMK levels sequentially rise with CKD stage beyond stage 2, and our data support existing animal evidence for an MK/renin angiotensin-system/proteinuria relationship. To what extent this is related to renal clearance versus pathology, or the consequences of chronically elevated MK levels requires further exploration.