Kidney Function

Background: The Centers for Disease Control and Prevention recommend immunizing susceptible high-risk groups, such as hemodialysis patients, against hepatitis B virus. However, hemodialysis patients may not develop seroprotective antibodies despite receiving high doses of the vaccine. Recent reports indicate that combined vaccination against hepatitis B and hepatitis A viruses may improve the immunogenicity of hepatitis B vaccine in healthy individuals, but the effectiveness of this strategy in hemodialysis patients is unknown.Study Design: Prospective randomized controlled trial.Setting & Participants: Hepatitis B virus–seronegative hemodialysis patients with undetectable antibody levels at baseline.Intervention: Intramuscular administration of Twinrix (inactivated hepatitis A virus [720 ELISA units] and purified hepatitis B virus surface antigen [20 μg]; GlaxoSmithKline) and Engerix-B (purified hepatitis B virus surface antigen [20 μg]) at 0, 1, and 6 months plus Engerix-B, 40 μg, at month 2 (intervention arm) or Engerix-B, 40 μg, at 0, 1, 2, and 6 months (control arm). Both groups received a total dose of 160 μg of hepatitis B antigen.Outcomes: The primary outcome was the difference in seroprotection rates at 7 months, defined by antibody titers >10 mIU/mL. The secondary outcome was frequency of adverse events.Measurements: Antibody response at months 3 and 7.Results: 96 patients were enrolled, and 73 completed the investigation. At 3 months, there was no difference in the groups' seroprotection rates (25% vs 27%; P = 0.4). At the completion of the vaccination series, using per-protocol analysis, 27 of 40 (68%) and 16 of 33 (49%) had antibody titers >10 mIU/mL in the treatment and control groups, respectively (P = 0.05; RR, 1.4; absolute abatement, 19%). Intention-to-treat analysis showed 58% and 38% seroprotection rates in the treatment and control groups, respectively (P = 0.02; RR, 1.5; absolute abatement, 20%). There was no difference in adverse events.Limitations: Lack of evidence of long-term protection.Conclusion: Vaccination of hemodialysis patients with a combined hepatitis A and hepatitis B regimen resulted in a statistically significant and clinically important improvement in seroprotection against hepatitis B virus compared with hepatitis B monovalent vaccine.

Background: Acute kidney injury (AKI) requiring renal replacement therapy (RRT) in patients undergoing cardiac surgery is associated strongly with adverse patient outcomes. Recently, 3 predictive risk models for RRT have been developed. The aims of our study are to validate the predictive scoring models for patients requiring postoperative RRT and test applicability to the broader spectrum of patients with postoperative severe AKI.Study Design: Diagnostic test study.Setting & Participants: 12,096 patients undergoing cardiac surgery with cardiopulmonary bypass at Mayo Clinic, Rochester, MN, from 2000 through 2007.Index Test: Cleveland Clinic score, Mehta score, and Simplified Renal Index (SRI) score.Reference Test or Outcome: Incidence of postoperative RRT or composite outcome of severe AKI, defined as serum creatinine level >2.0 mg/dL, and a 2-fold increase compared with the preoperative baseline creatinine level or RRT.Results: RRT was used in 254 (2.1%) patients, whereas severe AKI was present in 467 (3.9%). Discrimination for the prediction of RRT and severe AKI was good for all scoring models measured using areas under the receiver operating characteristic curve (AUROCs): 0.86 (95% CI, 0.84-0.88) for RRT and 0.81 (95% CI, 0.79-0.83) for severe AKI using the Cleveland score, 0.81 (95% CI, 0.78-0.86) and 0.76 (95% CI, 0.73-0.80) using the Mehta score, and 0.79 (95% CI, 0.77-0.82) and 0.75 (95% CI, 0.72-0.77) using the SRI score. The Cleveland score and Mehta score consistently showed significantly better discrimination compared with the SRI score (P < 0.001). Despite lower AUROCs for the prediction of severe AKI, the Cleveland score AUROC was still >0.80. The Mehta score is applicable in only a subgroup of patients.Limitations: Single-center retrospective cohort study.Conclusions: The Cleveland scoring system offers the best discriminative value to predict postoperative RRT and covers most patients undergoing cardiac surgery. It also can be used for prediction of the composite end point of severe AKI, which enables broader application to patients at risk of postoperative kidney dysfunction.

Background: Infection is an important cause of hospitalization and death in patients receiving dialysis. Few studies have examined the full range of infections experienced by dialysis patients. The purpose of this study is to examine types, rates, and risk factors for infection in older persons starting dialysis therapy.Study Design: Retrospective observational cohort study.Setting & Participants: The cohort was assembled from the US Renal Data System and included patients aged 65-100 years who initiated dialysis therapy between January 1, 2000, and December 31, 2002. Exclusions included prior kidney transplant, unknown dialysis modality, or death, loss to follow-up, or transplant during the first 90 days of dialysis therapy. Patients were followed up until death, transplant, or study end on December 31, 2004.Predictors: Baseline demographics, comorbid conditions, and serum albumin and hemoglobin levels.Outcomes & Measurements: Infection-related hospitalizations were ascertained using discharge International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Hospitalization rates were calculated for each type of infection. The Wei-Lin-Weissfeld model was used to examine risk factors for up to 4 infection-related events.Results: 119,858 patients were included, 7,401 of whom were on peritoneal dialysis therapy. During a median follow-up of 1.9 years, infection-related diagnoses were observed in approximately 35% of all hospitalizations. Approximately 50% of patients had at least 1 infection-related hospitalization. Rates (per 100 person-years) of pulmonary, soft-tissue, and genitourinary infections ranged from 8.3-10.3 in patients on peritoneal dialysis therapy and 10.2-15.3 in patients on hemodialysis therapy. Risk factors for infection included older age, female sex, diabetes, heart failure, pulmonary disease, and low serum albumin level.Limitations: Use of ICD-9-CM codes, reliance on Medicare claims to capture hospitalizations, use of the Medical Evidence Form to ascertain comorbid conditions, and absence of data for dialysis access.Conclusion: Infection-related hospitalization is frequent in older patients on dialysis therapy. A broad range of infections, many unrelated to dialysis access, result in hospitalization in this population.