Relationship between sodium removal, hydration and outcomes in peritoneal dialysis patients.

BACKGROUND: Fluid overload (FO) in peritoneal dialysis (PD) patients is associated with mortality. We explore if low daily sodium removal is an independent risk factor for mortality. We examined severely FO PD patients established for >1 year in expectation that PD prescription would have been optimized for solute clearance and ultrafiltration. We also wish to determine the relationship between kt/v and sodium removal. METHODS: Retrospective analysis of 231 PD patients with FO ≥2.0 L and compared with 218 PD patients who were euvolaemic throughout their PD treatment. Patients were followed up until death censored for transplantation. RESULTS: Mean daily sodium removal in overhydrated patients was only 75 mmoles (=1.7 g). CAPD usage was more common in patients with the highest sodium removal. Achievement of UK guidelines for solute clearance and daily fluid removal were not independent predictors of mortality. Markers of sarcopenia (low serum albumin and high CRP) were associated with increased mortality, but these parameters were not independent predictors in a model that included functional assessment (Karnofsky score). Daily sodium removal was not predictive of mortality but the imprecision of clinically used sodium assay should be noted. The correlation between Na and kt/v is statistically significant but R2 was weak at .07. CONCLUSION: While diabetic males were more likely to become overhydrated, these factors did not increase mortality further. Traditional targets of 'dialysis adequacy' did not predict survival. Kt/v is not a good indicator of sodium removal which can be surprisingly low. Measuring sodium clearance may help clinicians optimize PD modality (CAPD vs. APD).

Long-term follow-up of patients randomized to biocompatible or conventional peritoneal dialysis solutions show no difference in peritonitis or technique survival.

Peritonitis remains a common clinical problem for patients on peritoneal dialysis (PD). There are, however, retrospective studies with historical controls that suggest that biocompatible PD solutions may reduce the rates of peritonitis. We conducted a randomized controlled study comparing the use of biocompatible and conventional solutions, accumulating over 7000 patient-months experience. We included peritonitis episodes from patients who discontinued PD during the follow-up period. The study was powered to detect a reduction in the peritonitis rate of over half in the 267 randomized patients in demographically similar groups. There were no intergroup differences in PD technique survival irrespective of whether the outcome was censored for death. Peritonitis-free survival was 26.7 months using conventional compared to 23.1 months using biocompatible PD solutions. The peritonitis rates were also not statistically different when measured in patient-months. Thus, despite the finding of non-randomized studies suggesting benefits of the biocompatible PD solutions, we could not detect any clinically significant advantages in terms of technique survival or peritonitis. Although our study is the largest randomized study comparing different PD solutions to date, we do not exclude the possibility that our results are a consequence of the lack of statistical power. Meta-analysis of randomized control trials in this field is essential.

Comparing automated peritoneal dialysis with continuous ambulatory peritoneal dialysis: survival and quality of life differences?

BACKGROUND: There is a wide disparity in the use of automated peritoneal dialysis (APD) or continuous ambulatory peritoneal dialysis (CAPD) in the UK. This may be due to a perceived quality of life and technique survival advantage with APD, although evidence is lacking. METHODS: We conducted a single-centre retrospective study of incident end-stage renal disease initiating APD and CAPD with data collected prospectively over 5 years. PD modality was based on patient preference. Health status was assessed using SF-36 questionnaires at initial and 1-year follow-up appointments. RESULTS: Three hundred and seventy-two patients were included: 194 patients chose APD, and 178 patients chose CAPD. CAPD patients were generally older and more dependent than APD patients. Univariate analysis for technique survival was inferior for CAPD (relative risk for failure 1.46, 95% CI 1.08-1.97). But on multivariate analysis when comorbidity was added into the model, PD modality was no longer a significant predictor of technique survival. There was no difference in decline in residual renal function. Baseline CAPD patients had worse health status (HS); mean (SEM) physical and social composite scores were 32.3 (0.9) vs 36.5 (0.9) and 33.3 (1.2) vs 40.3 (1.2). After 1 year, HS scores for CAPD and APD patients were similar, but the improvement in HS scores correlated with baseline scores (PD modality was not an independent predictor of the change in HS). CONCLUSIONS: This study did not show any advantages of APD over CAPD in terms of technique survival or HS. There is no evidence to support physician bias towards one PD modality, and both should be available to allow patient choice.

Accelerated decline of GFR in diabetic nephropathy predicted by interferon release assay to tuberculosis antigens.

BACKGROUND: The QuantiFERON® test (QFT) is a diagnostic tool for active and latent tuberculosis (TB) infections. High rates of positivity to QuantiFERON® have been demonstrated in patients with chronic kidney disease (CKD) and diabetic patients. We performed a pilot study to investigate if QFT positivity in diabetic CKD patients predicted the rate of renal function decline. METHODS: QFT was performed in 38 diabetic patients with CKD 4-5 not on dialysis. The rate of decline in estimated glomerular filtration rate (eGFR) was calculated. RESULTS: 18/38 patients had a positive QFT. Patients with a positive QFT had a steeper decline in eGFR, compared with patients with a negative QFT. Ethnicity (a marker of risk of previous TB exposure), urine protein/creatinine ratio, use of ACE inhibitors/angiotensin II receptor blockers and statins, serum C-reactive protein, vitamin D levels, HbA1c concentration and presenting GFR did not differ significantly. CONCLUSIONS: The finding in this small cohort needs to be replicated in a larger study because our study is susceptible to both type I and type II statistical error. We found that QFT positivity was associated with a more rapid rate of decline in GFR, but this association may be coincidental (with the difference in decline attributed to differences in the blood pressure or proteinuria of the two groups). Moreover, an association does not necessarily mean causality, although it would be interesting to speculate if we are identifying patients with latent TB who have an active interstitial nephritis. Another intriguing possibility is that this assay identifies patients with an immunological phenotype that predisposes to eGFR loss.

Do oral aluminium phosphate binders cause accumulation of aluminium to toxic levels?

BACKGROUND: Aluminium (Al) toxicity was frequent in the 1980s in patients ingesting Al containing phosphate binders (Alucaps) whilst having HD using water potentially contaminated with Al. The aim of this study was to determine the risk of Al toxicity in HD patients receiving Alucaps but never exposed to contaminated dialysate water. METHODS: HD patients only treated with Reverse Osmosis(RO) treated dialysis water with either current or past exposure to Alucaps were given standardised DFO tests. Post-DFO serum Al level > 3.0 µmol/L was defined to indicate toxic loads based on previous bone biopsy studies. RESULTS: 39 patients (34 anuric) were studied. Mean dose of Alucap was 3.5 capsules/d over 23.0 months. Pre-DFO Al levels were > 1.0 µmol/L in only 2 patients and none were > 3.0 µmol/L. No patients had a post DFO Al levels > 3.0 µmol/L. There were no correlations between the serum Al concentrations (pre-, post- or the incremental rise after DFO administration) and the total amount of Al ingested.No patients had unexplained EPO resistance or biochemical evidence of adynamic bone. CONCLUSIONS: Although this is a small study, oral aluminium exposure was considerable. Yet no patients undergoing HD with RO treated water had evidence of Al toxicity despite doses equivalent to 3.5 capsules of Alucap for 2 years. The relationship between the DFO-Al results and the total amount of Al ingested was weak (R² = 0.07) and not statistically significant. In an era of financial prudence, and in view of the recognised risk of excess calcium loading in dialysis patients, perhaps we should re-evaluate the risk of using Al-based phosphate binders in HD patients who remain uric.

Tackling Dialysis Burden around the World: A Global Challenge.

CKD is a global problem that causes significant burden to the healthcare system and the economy in addition to its impact on morbidity and mortality of patients. Around the world, in both developing and developed economies, the nephrologists and governments face the challenges of the need to provide a quality and cost-effective kidney replacement therapy for CKD patients when their kidneys fail. In December 2019, the 3rd International Congress of Chinese Nephrologists was held in Nanjing, China, and in the meeting, a symposium and roundtable discussion on how to deal with this CKD burden was held with opinion leaders from countries and regions around the world, including Australia, Canada, China, Hong Kong, Singapore, Taiwan, the UK, and the USA. The participants concluded that an integrated approach with early detection of CKD, prompt treatment to slow down progression, promotion of home-based dialysis therapy like peritoneal dialysis and home HD, together with promotion of kidney transplantation, are possible effective ways to combat this ongoing worldwide challenge.

The Pan-Thames EPS study: treatment and outcomes of encapsulating peritoneal sclerosis.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is a disease process that can occur as a complication of peritoneal dialysis (PD). The aim of this study was to make a general assessment of the clinical features, diagnosis, management and outcome of PD-related EPS cases from London and South-East England. METHODS: Questionnaires were sent to 11 PD units in March 2007; cases were identified retrospectively. Outcome data on surviving patients were collected in March 2008. RESULTS: A total of 111 patients were identified; the mean time on PD was 82 months (range 8-247). Mortality increased with length of time on PD, being 42% at <3 years (n = 12), 32% at 3-4 years (n = 19), 61% at 5-6 years (n = 31), 54% at 7-8 years (n = 24), 75% at 9-10 years (n = 8) and 59% at >10 years (n = 17). Twelve patients had no previous peritonitis episodes, 28 had one previous episode, 30 had two previous episodes and 33 had three or more previous episodes. Of the patients with PD details available, 41/63 were high (>0.81) transporters and 44/71 had ultrafiltration <1 l/24 h, but 7/63 were low average transporters (0.5-<0.65) and 27/71 had ultrafiltration >1 l/24 h and a few had significant residual renal function. Sixty-five (59%) patients had their PD discontinued prior to diagnosis (51 HD; 14 transplanted). CT scans were performed on 91 patients and laparotomy on 47 patients. Drug treatment consisted of tamoxifen, immunosuppression or both. The median survival was 15 months in patients treated with tamoxifen (n = 17), 12 months in patients treated with immunosuppression (n = 24) and 21 months in patients who received both (n = 13), against 13 months (n = 46) in patients who received no specific treatment. Adhesionolysis was performed in 5 patients, and 39 patients were given parenteral nutrition. The overall mortality was 53% with a median survival of 14 months and a median time to death of 7 months. Conclusion. This is one of the largest cohorts of patients with EPS in the literature. Long-term survival occurred in over 50%, regardless of the various treatments strategies undertaken by the centres.

Long term outcome of patients with autosomal dominant polycystic kidney diseases receiving peritoneal dialysis.

There is a general perception that patients with polycystic kidney disease on peritoneal dialysis have poor long-term technique survival. In order to test this opinion, we performed a retrospective analysis comparing results of 56 consecutive patients with polycystic kidney disease to 56 non-diabetic patients with bilateral small kidneys. The patient groups were all initiated on peritoneal dialysis over a 12 year period and matched for age, gender and years of end stage renal failure. After a mean follow-up period of 37 months the two groups were statistically indistinguishable in terms of mortality, kidney transplantation-censored technique survival, median death-censored technique survival, the number of patients switched permanently to hemodialysis due to technique failure and the rate of peritonitis. On Cox regression (multivariate) analysis, only the baseline serum albumin level was a significant and independent risk factor of death-censored technique failure. Our study found no difference in long term outcome of peritoneal dialysis therapy in patients with polycystic kidney disease compared to a non-diabetic matched control group.

Anti-inflammatory effects of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors (statins) in peritoneal dialysis patients.

OBJECTIVE: Elevated C-reactive protein (CRP) level is an independent predictor of all-cause and cardiovascular mortality in peritoneal dialysis (PD) patients. Statins have been demonstrated to have anti-inflammatory properties by virtue of their CRP lowering effects in hemodialysis patients. However, whether statins have an anti-inflammatory effect in PD patients is unknown. DESIGN: All prevalent PD patients at our center were reviewed. Eligible (257) patients were categorized into 2 groups: those on statin therapy (n = 137) and those not on statins (n = 120). Data were abstracted for hemoglobin, albumin, phosphates, cholesterol, CRP, Kt/V, and erythropoietin dose, along with relevant clinical data. RESULTS: The two groups had similar concentrations of hemoglobin, albumin, and phosphates. They were also matched for dialysis adequacy and duration of dialysis but the statin group patients were older (57 +/- 13 vs 52 +/- 17 years, p = 0.01). Serum cholesterol was lower in the statin group (4.74 +/- 1.05 vs 5.02 +/- 1.17 mmol/L, p < 0.05). Single-point (14 +/- 13 vs 19 +/- 18 mg/L, p < 0.02) and serially measured CRP (9 +/- 7.4 vs 12 +/- 10 mg/L, p < 0.02) levels were significantly lower in the statin group despite increased comorbidity (0.84 vs 0.54, p < 0.02) and greater incidence of diabetes mellitus (52% vs 25%, p < 0.01). CONCLUSION: Statin therapy is associated with low single-point and serially measured CRP levels in PD patients, thereby suggesting that their anti-inflammatory properties persist in PD. These data have implications for considering statin therapy in PD patients as an anti-inflammatory agent in addition to a cholesterol lowering drug.

Predictors of survival and technique success after reinsertion of peritoneal dialysis catheter following severe peritonitis.

BACKGROUND: Peritonitis remains the most important complication of peritoneal dialysis (PD). The success rate of restarting PD after severe peritonitis (peritonitis unresolved despite treatment with appropriate antibiotics for 3 days, or fungal or pseudomonas infections) is unclear. We wished to determine PD technique survival and overall mortality when PD is offered to these patients and to identify predictors of successful reinitiation. METHOD: We conducted a retrospective single-center study of 556 patients undergoing PD between January 2000 and December 2001. We collected demographic information from the 106 patients who had their PD catheter removed for peritonitis, details about their dialysis history and peritonitis, and whether they successfully restarted PD and if not, the reason. RESULTS: We divided patients into groups as follows: group 1 (n = 42) underwent catheter reinsertion, group 2 (n = 16) had no medical contraindication to restarting PD but the patients elected to remain on hemodialysis, group 3 (n = 35) were deemed medically unsuitable to return to PD, and group 4 (n = 13) were those that died within 4 weeks of presenting with peritonitis. If there were no medical contraindications, Indo-Asians were more likely to retry PD. In group 1, after a mean follow-up of 20 +/- 7.3 months, 23 of 42 patients restarted PD successfully. Technique survival for group 1 as a whole was 69% at 3 months and 55% at the end of follow-up. Patients of greater dialysis vintage were more likely to develop PD technique failure after restarting. Of those judged suitable for PD, there was no statistically significant difference in the mortality of patients who wished to either restart PD or remain on hemodialysis (group 1 vs group 2). Significant numbers of patients returned successfully to PD after pseudomonas and fungal peritonitis. CONCLUSION: Restarting PD after severe peritonitis was possible and safe. Ethnicity was an important predictor for wanting to retry PD, but not for technique failure: given the choice, Indo-Asians preferred PD and had a higher failure rate after restarting, but this did not reach statistical significance. Only dialysis vintage predicted technique failure. We conclude that, after severe peritonitis, patients should be given the choice to return to PD but risk stratification based on dialysis vintage is important. Patient retraining and creating a backup arteriovenous fistula might minimize morbidity in these high-risk patients.

Comparative study of diagnosis of PD peritonitis by quantitative polymerase chain reaction for bacterial DNA vs culture methods.

INTRODUCTION: Peritonitis remains one of the main complications that afflict peritoneal dialysis patients. We conducted a pilot study to determine the feasibility and potential advantages of quantitative PCR (qPCR) assays for the presence of bacterial DNA in this clinical scenario. METHODS: 14 patients attending with 'cloudy bags' had PD fluid analyzed in accordance with Renal Association Standards. In addition, quantitative bacterial DNA analysis was performed on 50 mL samples of PD fluid. DNA was extracted using a Qiagen kit. Quantitative PCR assays using primers and probes targeted at 16S rDNA were used to measure the levels of bacterial DNA. Samples from 13 patients attending the department for other reasons served as negative controls. Laboratory staff were blinded to clinical details at the time of analysis. RESULTS: We determined a threshold of bacterial DNA whereby 11 of 13 negative controls were 'negative'. Significant bacterial DNA was found in 6 of 9 culture positive' peritonitis cases (p < 0.05 by chi(2). The 3 cases of 'no growth' peritonitis had 'insignificant' bacterial DNA. Serial DNA analysis was performed in 8 patients. Of the 6 patients who were 'cured' with standard antibiotic therapy, only 1 showed a rise in bacterial DNA from Day 1 to 5. But the 2 patients who relapsed after antibiotics had marked rises in bacterial DNA (p < 0.05 by chi(2). DISCUSSION: We showed that results from quantitative bacterial DNA PCR assays correlate with current microbiological tests despite the small size of this study. We also suggest that this technology might be clinically useful as an adjunct for cases of 'no growth' peritonitis and to identify those patients likely to relapse despite apparent clinical improvement with standard antibiotic therapy.

Are we underestimating the problem of ultrafiltration in peritoneal dialysis patients?

BACKGROUND: Accurate measurement of ultrafiltration (UF) is important to improve the morbidity and mortality of peritoneal dialysis (PD) patients. The introduction of "flush-before-fill" PD systems has led to improved peritonitis rates. Partly to compensate for dialysate lost during flush-before-fill, extra dialysate was added to each PD bag. A 2-L PD bag now contains a mean volume of 2.225 L. That overfill volume might be erroneously measured as UF. We previously studied how this confounding factor might be affecting the diagnosis of UF failure and found that almost all units were overestimating daily UF by 900 mL. We now repeat the study to determine if the accuracy of UF estimation has improved. METHODS: We conducted a telephone survey of PD units in the UK to determine how drain bags are weighed and how UF is calculated during formal assessment of adequacy and the peritoneal equilibrium test (PET). We also retrospectively analyzed our last 100, 24-hour dialysate collections and PET results to determine the potential clinical impact of overestimating UF. RESULTS: There has been an improvement since our last study, but 70% of PD units in the UK are still overestimating daily UF in patients on continuous ambulatory PD (CAPD). Half the surveyed units also inaccurately calculate UF during the PET, and 85% were reporting results of PET and 24-hour dialysate collections through the software provided by Baxter Healthcare. By including the overfill volume, 73% of patients with daily UF <750 mL would not be diagnosed as having inadequate daily UF (assuming that all were fluid overloaded and anuric). Similarly, 73% with potential UF failure during the PET (4-hour UF <100 mL) would be missed if overfill volume was misrepresented as UF. CONCLUSION: For patients undergoing CAPD, there requires standardization on when drain bags are weighed. Awareness that calculation of UF must exclude overfill volumes has improved but remains poor. The PD Adequest software (Baxter Healthcare, Compton, UK) is widely adopted in the UK and perhaps it could draw attention of users to the potential of UF overestimation in CAPD patients.

New prospects for the management of renal bone disease.

The last decade has been a remarkably productive one in the field of bone biology. New insights into the maintenance of a normal bone microenvironment have led to significant advances in our understanding of many important skeletal disorders, including renal osteodystrophy. Novel targets for therapeutic manipulation have been exposed and encouraging progress made towards new treatments. In addition, just as clinical studies have alerted us to the potential hazards of vascular calcification, basic science has unearthed the intimate nature of the relationship between the previously separate disciplines of bone and vascular biology. The clinical nephrologist, however, may be forgiven a little cynicism at this point. If such progress has been made, why do the same proverbial difficulties confront us in day-to-day practice? Control of phosphate remains inadequate, despite a literature which constantly reaffirms its crucial importance, and parathyroid hyperplasia seems inevitable in many patients. Furthermore, even the satisfaction of successful control of serum parathyroid hormone concentration must now be tempered by disquiet regarding the skeletal and cardiovascular consequences of oversuppression. This review aims to provide an update of the latest developments in relevant skeletal research and to assess how recently acquired knowledge may improve clinical nephrological practice over the next five years.

Intraperitoneal vancomycin concentrations during peritoneal dialysis-associated peritonitis: correlation with serum levels.

BACKGROUND: For the treatment of peritoneal dialysis-associated peritonitis (PDP), it has been suggested that serum concentrations of vancomycin be kept above 12 mg/L-15 mg/L. However, studies correlating vancomycin concentrations in serum and peritoneal dialysate effluent (PDE) during active infection are sparse. We undertook the present study to investigate this issue and to determine whether achieving the recommended serum level of vancomycin results in therapeutic levels intraperitoneally. METHODS: We studied patients treated with intraperitoneal (i.p.) vancomycin for non-gram-negative PDP. We gave a single dose (approximately 30 mg/kg) at presentation, and we subsequently measured vancomycin levels in PDE on day 5; we wanted to determine if efflux of vancomycin from serum to PDE during a 4-hour dwell was consistent and resulted in therapeutic levels. RESULTS: Of the 48 episodes of PDP studied, serum vancomycin concentrations exceeding 12 mg/L were achieved in 98% of patients, but in 11 patients (23%), a PDE vancomycin level below 4 mg/L--the minimal inhibitory concentration (MIC) of many gram-positive organisms--was observed at the end of a 4-hour dwell on day 5. The correlation between the concentrations of vancomycin in serum and PDE (from efflux of antibiotic over 4 hours) was statistically significant, but poor (R(2) = 0.18). CONCLUSIONS: Our data support the International Society for Peritoneal Dialysis statement that adequate serum vancomycin concentrations can be achieved with intermittent dosing (single dose every 5 days), but cannot guarantee therapeutic PDE levels in the treatment of PDP. Intermittent dosing of vancomycin may not consistently result in PDE concentrations markedly greater than MIC of many important pathogens. Although the clinical significance of this finding remains to be determined, it may be preferable to give smaller but more frequent doses of PDE vancomycin (continuous dosing) for adults with PDP (as is currently recommended for children).

Single UK centre experience on the treatment of PD peritonitis--antibiotic levels and outcomes.

BACKGROUND: There are few studies of the pharmacokinetics of vancomycin and gentamicin in peritoneal dialysis (PD) patients and the influence of antibiotic concentrations on treatment outcome. Concerns about resistance to ceftazidime and potential of aminoglycoside toxicity make the choice of empiric antibiotic difficult. METHODS: We retrospectively collected data from 613 patients on PD between 1 June 2002 and 31 December 2005. During this time, we adopted a protocol that minimized aminoglycoside exposure to patients with residual renal function and carefully monitored serum antibiotic concentrations. RESULTS: There were no statistical differences in mean day-5 vancomycin concentrations for continuous ambulatory peritoneal dialysis (CAPD) vs automated peritoneal dialysis (APD) and for anuric vs not-anuric patients. However, low levels (<12 mg/l) were recorded for 12.8% CAPD and 15% APD patients. These remained low at day 10 in 16% patients (25% if not anuric) despite incremental dosing. Vancomycin concentration did not predict cure or relapse of Gram-positive or culture-negative peritonitis. Gentamicin concentration (>2 mg/l in >50% patients) did not predict outcome of Gram-negative and culture-negative peritonitis. Moreover, cure rates were the same irrespective of whether gentamicin was continued for 14 days or was switched to ceftazidime after 5 days. CONCLUSION: We have confirmed that the International Society for Peritoneal Dialysis (ISPD) dosing guideline for vancomycin in CAPD and APD patients produces adequate serum concentrations of the antibiotics in the vast majority. However, large incremental dosing of vancomycin is needed if day-5 levels are low; especially for not-anuric patients. Whilst evidence of gentamicin toxicity in PD remains controversial, ISPD dosing regimen resulted in high levels for >50% patients. High gentamicin concentrations did not correlate with treatment success, but switching gentamicin to ceftazidime at day 5 appeared safe and limited aminoglycoside exposure. Increasing vancomycin and gentamicin concentrations do not appear to improve cure rates and alternative strategies (such as combination treatment) should be considered for future research.

Race and sex: predictors of the severity of hyperparathyroidism in peritoneal dialysis patients.

BACKGROUND: Uraemic hyperparathyroidism remains a common clinical problem. Conversely, oversuppression of parathyroid hormone (PTH), particularly in diabetic patients on peritoneal dialysis, has been implicated in low bone turnover disease. Race may also be an important factor determining susceptibility to hyperparathyroidism and the different forms of renal osteodystrophy. These compounding factors that might influence the severity of hyperparathyroidism have been studied in US dialysis and predialysis populations. Dialysis-dependant Africans and Afro-Caribbeans (AC) are known to have higher circulating PTH concentrations than comparable Caucasians (C) but Indo-Asians (IA) living in temperate climates have not been studied. METHODS: We performed a cross-sectional study of all patients undergoing peritoneal dialysis at St Bartholomew's and The Royal London Hospital on 1 May 2000. The highest historical recorded PTH was recorded with concurrent biochemical and demographic details. Regression models were used for the analysis of covariance and separate manova was performed incorporating the factors that were shown on univariate analysis to be significant. RESULTS: The current study confirmed that in 50 AC patients on peritoneal dialysis, the mean (+/- SEM) peak PTH concentration (93.9 +/- 9.3 pmol/L) was higher than in 148 C (56.7 +/- 4.3 pmol/L) and 67 IA (60.2 +/- 5.7 pmol/L), P < 0.0001 and P < 0.002, respectively. This is despite there being no significant difference in serum calcium concentrations and AC having a lower serum phosphate concentration at the time of peak hyperparathyroidism. There was no significant difference in mean peak PTH concentration between C and IA. Females were also found to have higher peak PTH concentrations, but the presence of diabetes did not influence the peak PTH concentration in this study. CONCLUSION: Although we have demonstrated that patients of African (but not Asian) descent undergoing peritoneal dialysis have more severe hyperparathyroidism than Caucasians, other studies suggest that Afro-Americans develop low bone turnover at higher PTH. This would suggest that PTH values should be interpreted with care and that bone biopsies to determine histology remain important. It may emerge that there are different optimal PTH concentrations according to race.