Clinical implications and outcome prediction in chronic hemodialysis patients with lower serum potassium×uric acid product.

BACKGROUND: The aims of this study were to evaluate correlations between serum potassium (S[K]) and uric acid (S[UA]) in hemodialysis patients and to determine whether lower levels of both S[K] and S[UA] were associated with poor long-term prognoses in these patients. METHODS: A cohort of 424 maintenance hemodialysis patients (58±13 years of age; 47% male; 39% with diabetes) from a single center were divided into tertiles based on the product of S[K]×S[UA] (K×UA): Group 1: low K×UA: n=141; Group 2: median K×UA: n=141; and Group 3: high K×UA: n=142. The longest observation period was 60 months. RESULTS: S[K] showed a positive linear correlation with S[UA] (r=0.33; p<0.001). In multivariate logistic regression analysis, Group 1 was characterized by hypoalbuminemia (odds ratio [OR]=0.20, 95% confidence interval (CI)=0.11-0.35) and lower levels of normalized protein catabolism [nPCR] (OR=0.10, 95%CI=0.05-0.22) and phosphate levels (OR=0.41, 95%CI=0.33-0.51). In contrast, Group 3 was associated with higher nPCR (OR=6.07, 95%CI=2.93-12.50) and albumin levels (OR=2.12, 95% CI=2.12-7.00). Compared to the reference (Group 1), the hazard ratio (HR) for long-term mortality was significantly lower in Groups 2 (HR=0.65, 95%CI=0.43-0.99) and 3 (HR=0.56, 95%CI=0.36-0.89). In multivariate Cox proportional analysis, the risk of mortality decreased by 2% (HR=0.98; 95%CI=0.96-0.99) per 1 unit increase in K×UA product. CONCLUSION: Hemodialysis patients with lower S[K] and [UA] levels were characterized by hypoalbuminemia and lower nPCR, and they were associated with a long-term mortality risk.

Precedent fluctuation of serum hs-CRP to albumin ratios and mortality risk of clinically stable hemodialysis patients.

BACKGROUND: A high sensitivity C-reactive protein to albumin ratio (hs-CRP/Alb) predicts mortality risk in patients with acute kidney injury. However, it varies dynamically. This study was conducted to evaluate whether a variation of this marker was associated with long-term outcome in clinically stable hemodialysis (HD) patients. METHODS: hs-CRP/Alb was checked bimonthly in 284 clinically stable HD outpatients throughout all of 2008. Based on the "slope" of trend equation derived from 5-6 hs-CRP/alb ratios for each patient, the total number of patients was divided into quartiles--Group 1: ß≦ -0.13, n = 71; group 2: ß>-0.13≦0.003; n = 71, group 3: ß>0.003≦0.20; and group 4: ß>0.20, n = 71. The observation period was from January 1, 2009 to August 31, 2012. RESULTS: Group 1+4 showed a worse long-term survival (p = 0.04) and a longer 5-year hospitalization stay than Group 2+3 (38.7±44.4 vs. 16.7±22.4 days, p<0.001). Group 1+4 were associated with older age (OR = 1.03, 95% CI = 1.01-1.05) and a high prevalence of congestive heart failure (OR = 2.02, 95% CI = 1.00-4.11). Standard deviation (SD) of hs-CRP/Alb was associated with male sex (ß = 0.17, p = 0.003), higher Davies co-morbidity score (ß = 0.16, p = 0.03), and baseline hs-CRP (ß = 0.39, p<0.001). Patients with lower baseline and stable trend of hs-CRP/Alb had a better prognosis. By multivariate Cox proportional methods, SD of hs-CRP/alb (HR: 1.05, 95% CI: 1.01-1.08) rather than baseline hs-CRP/Alb was an independent predictive factor for long-term mortality after adjusting for sex and HD vintage. CONCLUSION: Clinically stable HD patients with a fluctuating variation of hs-CRP/Alb are characterized by old age, and more co-morbidity, and they tend to have longer subsequent hospitalization stay and higher mortality risk.

Comparison of the impact of "fast decline" in residual renal function and "initial anuria" on long-term outcomes in CAPD patients.

BACKGROUND: Residual renal function (RRF) is pivotal to long-term outcomes, while rapid RRF decline (RRFD) is associated with mortality risk for continuous ambulatory peritoneal dialysis (CAPD) patients. This study was conducted to compare the impact of "initial anuria" and rapid RRFD on the long-term prognosis of CAPD patients. METHOD: According to the timing of anuria and the slope of RRFD, a total of 255 incident CAPD patients were divided into 3 groups. For the "anuria" group, anuria was detected from CAPD initiation and persisted for > 6 months (n = 27). Based on the median of the RRFD slope, the other 228 non-anuric patients were divided into a "slow decliner" group (n = 114), and a "rapid decliner" group (n = 114). The maximal observation period was 120 months. RESULTS: Logistic regression tests indicated that the "anuria" group was associated with previous hemodialysis > 3 months (odds ratio [OR]: 8.52, 95% confidence interval [CI]: 3.12 - 23.28), and female (OR: 0.29, 95% CI: 0.09 - 0.90), while the "fast decliner" group with higher Davies co-morbidity scores (DCS) (OR: 1.52; 95% CI: 1.08 - 2.14), body mass index (BMI) (OR: 1.12; 95% CI: 1.04 - 1.21), and male (OR: 1.12; 95% CI: 1.04 - 1.21). After adjusting for DCS, the "fast decliner" group (hazard ratio [HR]: 0.37; 95% CI: 0.17 - 0.80) showed a better outcome than that of the "anuria" group (reference = 1). Both baseline RRF (ß = -0.24; p < 0.001) and DCS (ß = -3.76; p < 0.001) showed inverse linear correlations to the slope of RRFD. From the Cox proportional analyses, higher baseline RRF (HR: 0.92; 95% CI: 0.88 -.97) and higher slope of RRFD (slower decline in RRF) (HR: 0.90; 95% CI: 0.85 - 0.96) were independent factors for less mortality risk in patients with DCS = 0. However, only a higher slope of RRFD (HR: 0.97; 95% CI: 0.94 - 0.99) was significant for better survival in CAPD patients with DCS > 0. CONCLUSION: Compared to the baseline RRF, CAPD patients with co-morbidities that rapidly deteriorate RRFD are more crucially associated with long-term mortality risk.

Lower serum potassium combined with lower sodium concentrations predict long-term mortality risk in hemodialysis patients.

BACKGROUND: The purpose of this study was to evaluate the combined effect of different pre-hemodialysis (HD) serum sodium (S[Na]) and potassium (S[K]) concentrations on the long-term prognosis of HD patients. METHODS: A cohort of 424 maintenance HD patients (age: 58 ± 13 years, male: 47%, diabetes: 39%) from a single center were divided into four groups based on both medians of S[Na] (138.4 mmol/L) and S[K] (4.4 mmol/L): Group 1: lower S[Na] & lower S[K]: n = 92; Group 2: lower S[Na] & higher S[K]: n =113; Group 3: higher S[Na] & lower S[K]: n =123; Group 4: higher S[Na] & higher S[K]: n =96. The median observation period was 21 months. RESULT: By multivariate logistic regression analysis, Group 1 was characterized by hypoalbuminemia (OR = 0.37, 95%CI = 0.20-0.67), and lower normalized protein catabolism rate (nPCR) (OR = 0.37, 95% CI = 0.16-0.83). In contrast, Group 4 was characterized by higher nPCR (OR = 2.26, 95% CI = 1.05-4.86) and albumin level (OR = 2.26, 95% CI = 1.17-4.39). As compared to the reference (group 1), the HR for long-term mortality was significantly lower in Groups 3 (HR = 0.54, 95% CI = 0.34- 0.86) and 4 (HR = 0.49, 95% CI = 0.28-0.84). By multivariate Cox proportional analysis, Group 1 was an independent factor (HR = 1.74, 95% CI = 1.18-2.58) associated with long-term mortality. CONCLUSION: HD patients combined with lower S[K] and lower S[Na] were characterized by hypoalbuminemia, lower nPCR and a high prevalence of co-morbidity. They were associated with long-term mortality risk. On the other hand, those patients with higher levels of S[Na] and S[K] tended to have better clinical outcomes.

Hypokalemia is associated with increased mortality rate in chronic hemodialysis patients.

BACKGROUND: Both hypokalemia (hypoK) and hyperkalemia (hyperK) are life-threatening to hemodialysis (HD) patients. This study was conducted to compare their clinical characteristics and long-term survival. METHODS: Patients were divided into three groups according to the last mid-week predialysis serum potassium concentrations: hypoK (<3.5 mEq/l), normoK (between 3.5 and 5.5 mEq/l), and hyperK (>5.5 mEq/l). The maximal duration of the follow-up period was 54 months. RESULTS: Compared with the hyperK group,patients in the hypoK group were older (p <0.05), had a higher incidence of comorbidity factors, less body weight gain prior to HD (p < 0.05), lower body mass index (BMI, p < 0.05), and higher BUN to creatinine ratio and hs-CRP (p < 0.05). The serum albumin and prealbumin concentrations were also lowest in the hypoK group, compared with the normoK and hyperK groups, respectively (all p < 0.001). A similar finding was also obtained for the normalized protein catabolism rate (nPCR, p < 0.001) among the three groups. Positive linear correlations between serum albumin and potassium concentration were only found in the hypoK and normoK groups (p < 0.001). Multiple logistic regression analysis showed that hypoalbuminemia, low BUN, and phosphate concentrations were significantly correlated with hypoK. HypoK patients also had a lower cumulative survival rate than hyperK patients. CONCLUSION: HypoK HD patients, with lower serum levels of albumin, prealbumin, nPCR, and BMI, but higher level of hs-CRP, showed a malnutritional and inflammatory status, and caused increased mortality rate.

High water evaporation rate is associated with low blood pressure in chronic peritoneal dialysis patients.

BACKGROUND: The relationship between water evaporation rate (WER) and blood pressure (BP) in continuous ambulatory peritoneal dialysis (CAPD) patients has not been addressed before. This study was undertaken to evaluate the effects of WER on the BP and body weight (BW) of end-stage renal disease patients treated with CAPD. METHODS: Based on mean WER of each month, the year 2005 was divided into "high WER" and "low WER" stages. This study enrolled 66 CAPD patients at our center during 2005. The BP and BW of each patient were collected monthly. WER was measured with a class A evaporation pan. RESULTS: Compared to the high WER stage, CAPD patients had higher BP (systolic: 142 ± 29 vs 134 ± 27 mmHg, p < 0.001; diastolic: 86 ± 17 vs 84 ± 16 mmHg, p < 0.001) and BW (56.8 ± 10.2 vs 56.1 ± 10.2 kg, p < 0.001) in the low WER stage. Ambient temperature was significantly higher in the high WER stage (p = 0.004) and it was also positively correlated with WER (r = 0.82, p = 0.0012). Both mean BP (r = -0.72, p = 0.0089) and BW (r = -0.79, p = 0.002) showed inverse relationships to the WER. Moreover, both mean BP (r = -0.95, p < 0.001) and BW (r = -0.90, p < 0.001) also showed negative linear regressions to ambient temperature. There was a positive linear regression between mean BP and BW (r = 0.85, p = 0.0004). Multiple linear regression analysis found that WER (ß = -0.672, p = 0.026) was an independent factor correlated to patients' mean BP. CONCLUSIONS: CAPD patients had lower BP and BW in the high WER stage. These decreases were associated with higher ambient temperature and WER. We hypothesize that increased insensible salt and fluid loss secondary to high WER during hot seasons, especially in subtropical areas, ameliorates the hypervolemia and hypertension in CAPD patients.

Long-term effect of different dialysate calcium concentrations on parathyroid hormone levels in hemodialysis patients.

The appropriate dialysate calcium concentration (D[Ca]) for hemodialysis (HD) therapy has not yet reached a consensus. We have conducted a prospective control study for five years on the effects of different D[Ca] on serum intact parathyroid hormone (iPTH) levels. Patients were divided into three groups receiving different D[Ca] therapies: the low-Ca (D[Ca] = 2.5 mEq/L; N = 96), mid-Ca (D[Ca] = 3.0 mEq/L; N = 121), and high-Ca (D[Ca] = 3.5 mEq/L; N = 82) groups. After five years' study, only 41 patients in the low-Ca group, 34 in the mid-Ca group, and 32 in the high-Ca group completed the study. The results demonstrated that serum corrected calcium concentrations were significantly lower in the low-Ca group compared with other groups in years 3 and 4, although the products of corrected calcium time phosphate did not show difference between each group.(Delta)serum alkaline phosphatase ((Delta)Alk-p) to baseline levels increased significantly after the fourth year in all three groups (p < 0.05). Serum (Delta) iPTH only increased significantly after the fourth year in the low-Ca group (p < 0.05) but not in the other groups. There were no significant differences in the extent of (Delta)Alk-p and (Delta)iPTH between the groups. Cox proportional methods also showed no difference in cumulative survival between the groups. In conclusion, our results demonstrate that compared with the other two groups of D[Ca], long-term use of D[Ca] of 2.5 mEq/L was associated with relatively lower serum calcium concentration. Perhaps this was related to a greater extent of iPTH concentration elevation after five years.

Effect of climatic temperature on fluid gain in hemodialysis patients with different degrees of overhydration.

BACKGROUND: To assess the effect of seasonal temperature on the interdialytic body weight gain (deltaBW), %deltaBW/dry weight (DW), and pre-dialysis blood pressure in chronic hemodialysis (HD) patients with different degrees of overhydration. METHOD: Year 2005 was divided into two seasons: 'cold' (the coolest 5 months) and 'hot' (the hottest 5 months). A total of 221 end-stage renal disease patients treated with HD at our center throughout the year 2005 were enrolled. RESULTS: DeltaBW showed a reversed trend to the water evaporation rate, which paralleled temperature change. Increases of deltaBW and %deltaBW/DW in cold weather were more significant in non-diabetes mellitus than diabetes mellitus. Only patients in the bottom two quartiles for %deltaBW/DW in hot weather (i.e., <5%) showed a cold weather-induced increase in %deltaBW/DW. CONCLUSION: A cold weather-induced increase in fluid accumulation occurs in only those patients with less hypervolemia during the hot season.

Comparison of peritoneal equilibrium test with icodextrin and 2.5% glucose dialysis solutions.

BACKGROUND: Icodextrin provides a different ultrafiltration mechanism than glucose-based dialysate. METHODS: To evaluate the difference in the peritoneal equilibrium test (PET) with regard to using icodextrin (Ico-PET) and glucose dialysate we designed a prospective study using Ico-PET and 2 cross-over conventional 2.5% glucose-based dialysate PETs (Gluco 1-PET and Gluco 2-PET) administered 3 months before and after the Ico-PET in 58 chronic peritoneal dialysis patients. RESULTS: More patients demonstrated higher transport types with the Ico-PET than the Gluco 1-PET and Gluco 2-PET (p<0.001). After a dwell time of 4 hours, the Ico-PET did not show an ultrafiltration benefit compared with the Gluco-PET (272.8 +/- 137.1 mL vs. 348.3 +/- 215.2 mL, p<0.001). The Ico-PET not only showed significantly higher values in the 0-hour, 2-hour and 4-hour dialysate to plasma creatinine concentration ratio (D/P Cr) than those of the Gluco 1-PET (p=0.029 and p<0.001, respectively), but also showed higher values in the 0-hour and 4-hour D/P Cr than those of the Gluco 2-PET (both p<0.001). The total ultrafiltration volume was positively correlated with the 4-hour D/P Cr with the Ico-PET (r=0.41, p=0.001), but the correlation was negative with the Gluco 1-PET (r=-0.33, p=0.012) and Gluco 2-PET (r=-0.51, p<0.001). The ratio of the glucose concentration in the outflow dialysate compared with baseline level (D/Do glucose), was also significantly higher with the Ico-PET than with the Gluco 1-PET and Gluco 2-PET after both 2 and 4 hours (both p<0.001). CONCLUSIONS: The Ico-PET showed a completely different result from the conventional Gluco-PET. The Ico-PET provi-des a superior solute transport and inferior ultrafiltration rates, and the prevalence of high transporters was also increased with the Ico-PET.