Trend patterns of HBsAg kinetics in chronic hepatitis B patients during nucleos(t)ide analogue therapy based on ARMA models.

BACKGROUND: Trend pattern analysis are lacking for hepatitis B surface antigen (HBsAg) kinetics in chronic hepatitis B (CHB) patients during nucleos(t)ide analogue (Nuc) therapy. We evaluated the trend patterns of HBsAg kinetics by time series analysis and forecasting times to HBsAg seroclearance accordingly. METHODS: A total of 116 CHB patients with documented three-month HBsAg levels during the previous more than five years of Nuc therapy were included. The piecewise linear trends of the autoregressive-moving average (ARMA) model were used for time series analysis of HBsAg kinetics trends. Best fitted models were created for each patient using HBsAg datasets with backtracking capability. Predicted time to HBsAg seroclearance was calculated accordingly. RESULTS: Four trend patterns of HBsAg kinetics were found: no trend (n = 22, 19.0%), single trend (n = 16, 13.8%), biphasic trend with rapid-slow decline (n = 56, 48.2%) and biphasic trend with rise-decline (n = 22, 19.0%). Except for no-trend patients, the trend became slow reduction as HBsAg declined. Only 6.1% of patients continued rapid decline when the initial HBsAg of the last trend reached <100 IU/mL. Last trend slopes < -10 and rise-decline patterns indicate greater chances of achieving HBsAg seroclearance within two years. CONCLUSION: Best fitted ARMA models of HBsAg kinetics can be created individually for patients during Nuc therapy. About 67.2% patients have biphasic trend patterns, suggesting the dynamic nature of HBsAg kinetics over time. Trend patterns and last trend slopes predict individual times to HBsAg seroclearance.

A quality and cost-benefit analysis of dialyzer reuse in hemodialysis patients.

BACKGROUND: To evaluate the benefits of dialyzer reuse for hemodialysis (HD) patients, including the cost of HD treatment and patient's survival, a comparison was made regarding the standard practice of single-use dialysis. METHODS: From January 1, 2005, to December 31, 2005, a total of 128,232 successive HD treatments in 822 patients in Chang Gung Memorial Hospital-Kaohsiung Medical Center were included in this study. RESULTS: Approximately 54.25% (446/822) of patients reused dialyzers. The average times of dialyzer reuse was 2.54. The annual hollow fiber cost is reduced by $241,054.08 U.S. dollars (NT $7,834,257.60). The annual cost of hollow fiber was reduced by $540.48 U.S. dollars (NT $17,565.60) in one patient with dialyzer reuse. The mortality rates in dialyzer reuse and single use groups were 3.1% and 10.9% within one year (p < 0.0001). Multiple logistic regressions showed that single use compared with reuse was associated with higher mortality after adjusting co-morbid conditions including age, diabetes mellitus, etc. CONCLUSIONS. We concluded that the benefits of dialyzer reuse included safety in our center and reduction in cost during a 12-month period. Dialyzer reuse may be a safe alternative.

Hyperhomocystinemia and the prevalence of symptomatic atherosclerotic vascular disease in Taiwanese chronic hemodialysis patients: a retrospective study.

AIM: Hyperhomocystinemia is now recognized as an independent risk factor for atherosclerotic cardiovascular disease in patients with normal renal function. Hyperhomocystinemia is common in patients with chronic renal failure. This aim of this study was designed to look for associations between hyperhomocystinemia and clinically symptomatic atherosclerotic vascular disease (ASVD) in Taiwanese chronic hemodialysis patients. METHODS: Two hundred patients undergoing hemodialysis were enrolled in the study. They had predialysis blood work performed for total homocysteine, serum folate, and vitamin B12 levels. A history of clinically significant ASVD was elicited using information from the patients' questionnaires and verified by careful inpatient and outpatient chart review. RESULTS: Mean homocysteine concentration was 29.0 micromol/L overall. A total of 196 patients had hyperhomocystinemia and were enrolled in this study. ASVD was present in 24.5% of patients. The mean homocysteine concentration was 31.9 micromol/L and 28.7 micromol/L in patients with (n = 48) and without (n = 148) ASVD, respectively (P = 0.04). There was association hyperhomocystinemia between chronic hemodialysis patients with ASVD and without ASVD. There were significant differences including age, homocysteine level, vitamin B12 level and glucose intolerance in the two groups (P < 0.05). Plasma homocysteine concentrations showed significant positive correlations with serum folate or vitamin B12 in majority patients. No patient had serum folate or vitamin B12 deficiency. The adjusted odds ratio for atherosclerotic disease was 2.8 (95% CI, 1.109-7.467) for those subjects with a homocysteine level in the highest quartile compared with the lowest 3 quartiles. CONCLUSIONS: The prevalence of hyperhomocystinemia is 98% among hemodialysis patients. There is a significant association between hyperhomocystinemia and ASVD in Taiwanese chronic hemodialysis patients. There are also associations between homocysteine levels and serum folate/vitamin B12 levels in the majority of the patients. Clinical trials are needed to determine the optimal therapy of folic acid dose for hyperhomocystinemia in Taiwanese chronic hemodialysis patients in the future.