Comparative Effectiveness of High-Dose Versus Standard-Dose Influenza Vaccine Among Patients Receiving Maintenance Hemodialysis

Rationale & Objective: Studies of patients on maintenance dialysis therapy suggest that standard-dose influenza vaccine (SDV) may not prevent influenza-related outcomes. Little is known about the comparative effectiveness of SDV versus high-dose influenza vaccine (HDV) in this population. Study Design: Cohort study using data from the US Renal Data System. Setting & Participants: 507,552 adults undergoing in-center maintenance hemodialysis between the 2010 to 2011 and 2014 to 2015 influenza seasons. Exposures: SDV and HDV. Outcomes: All-cause mortality, hospitalization due to influenza or pneumonia, and influenza-like illness during the influenza season. Analytic Approach: Patients were eligible for inclusion in multiple yearly cohorts; thus, our unit of analysis was the influenza patient-season. To examine the relationship between vaccine dose and effectiveness outcomes, we estimated risk differences and risk ratios using propensity score weighting of Kaplan-Meier functions, accounting for a wide range of patient- and facility-level characteristics. For nonmortality outcomes, we used competing-risk methods to account for the high mortality rate in the dialysis population. Results: Within 225,215 influenza patient-seasons among adults 65 years and older, 97.4% received SDV and 2.6% received HDV. We observed similar risk estimates for HDV and SDV recipients for mortality (risk difference, −0.08%; 95% CI, −0.85% to 0.80%), hospitalization due to influenza or pneumonia (risk difference, 0.15%; 95% CI, −0.69% to 0.93%), and influenza-like illness (risk difference, 0.00%; 95% CI, −1.50% to 1.08%). Our findings were similar among adults younger than 65 years, as well as within other subgroups defined by influenza season, age group, dialysis vintage, month of influenza vaccination, and vaccine valence. Limitations: Residual confounding and outcome misclassification. Conclusions: The HDV does not appear to provide additional protection beyond the SDV against all-cause mortality or influenza-related outcomes for adults undergoing hemodialysis. The additional cost and side effects associated with HDV should be considered when offering this vaccine. Future studies of HDV and other influenza vaccine strategies are warranted

Supplementary Material for: Understanding Medical Care of Transplant Recipients through Integrated Registry and Pharmacy Claims Data

<b><i>Background:</i></b> Limited data exist on medication use aside from immunosuppression among large samples of kidney transplant recipients. <b><i>Methods:</i></b> We examined a novel database wherein Organ Procurement and Transplantation Network (OPTN) registry data were linked to records from a US pharmaceutical claims clearinghouse (2005-2010 claims) to examine pharmaceutical care at the first transplant anniversary (n = 16,157). We quantified the use of the following medication types within ±60 days of the first-year OPTN report according to estimated glomerular filtration rate (eGFR): antihypertensives, lipid-lowering, bone and mineral, and anemia treatments. Adjusted associations of medication use with eGFR and other clinical factors were quantified by multivariate logistic regression. <b><i>Results:</i></b> Requirements for multiple antihypertensive agents rose with lower eGFR, with β-blockers comprising the most commonly used antihypertensive agent. The adjusted likelihood of vitamin D (adjusted odds ratio (aOR) 2.07, 95% CI 1.19-3.59) and especially erythrocyte-stimulating agents (aOR 19.94, 95% CI 7.01-56.00) rose in a graded manner to peak with eGFR <15 versus >90, whereas statin use was most common with eGFR 30-59 ml/min/1.73 m². Black race was independently associated with increased use of all classes of antihypertensives and vitamin D, but lower adjusted statin use. Rapamycin-based immunosuppression was associated with increased use of statins and erythrocyte-stimulating agents. <b><i>Conclusions:</i></b> Integrated registry and pharmacy fill data provide a novel tool for pharmacoepidemiologic investigations of delivered post-transplant care. Transplant recipients with reduced renal function have increased requirements for pharmaceutical care of comorbidities. Causes of racial variation in medication fills warrant further investigation

Supplementary Material for: Associations of Pre-Transplant Prescription Narcotic Use with Clinical Complications after Kidney Transplantation

<b><i>Background:</i></b> The impact of narcotic use before kidney transplantation on post-transplant clinical outcomes is not well described. <b><i>Methods:</i></b> We examined integrated national transplant registry, pharmacy records, and Medicare billing claims to follow 16,322 kidney transplant recipients, of whom 28.3% filled a narcotic prescription in the year before transplantation. Opioid analgesic fills were normalized to morphine equivalents (ME) and expressed as mg/kg exposures (approximate quartiles: 0.1-1.7, 1.8-5.4, 5.5-23.7, and ≥23.8 mg/kg, respectively). Post-transplant cardiovascular, respiratory, neurological, accidents, substance abuse, and noncompliance events were identified using diagnosis codes on Medicare billing claims. Adjusted associations of ME level with post-transplant complications were quantified by multivariate Cox regression. <b><i>Results:</i></b> The incidence of complications at 3 years post-transplant among those with the highest pre-transplant ME exposure compared to no use included: ventricular arrhythmias, 1.1 vs. 0.2% (p < 0.001); cardiac arrest, 4.7 vs. 2.7% (p < 0.05); hypotension, 14 vs. 8% (p < 0.0001); hypercapnia, 1.6 vs. 0.9% (p < 0.05); mental status changes, 5.3 vs. 2.7% (p < 0.001); drug abuse/dependence, 7.0 vs. 1.7% (p < 0.0001); alcohol abuse, 1.8 vs. 0.6% (p = 0.0001); accidents, 0.9 vs. 0.3% (p < 0.05); and noncompliance, 3.5 vs. 2.3% (p < 0.05). In multivariate analyses, transplant recipients with the highest level of pre-transplant narcotic use had approximately 2 to 4 times the risks of post-transplant ventricular arrhythmias, mental status changes, drug abuse, alcohol abuse, and accidents compared with non-users, and 35-45% higher risks of cardiac arrest and hypotension. <b><i>Conclusion:</i></b> Although associations may reflect underlying conditions or behaviors, high-level prescription narcotic use before kidney transplantation predicts increased risk of clinical complications after transplantation

Glomerular filtration rate estimates decrease during high altitude expedition but increase with Lake Louise acute mountain sickness scores

AIM: Acute mountain sickness (AMS) can result in pulmonary and cerebral oedema with overperfusion of microvascular beds, elevated hydrostatic capillary pressure, capillary leakage and consequent oedema as pathogenetic mechanisms. Data on changes in glomerular filtration rate (GFR) at altitudes above 5000 m are very limited. METHODS: Thirty-four healthy mountaineers, who were randomized to two acclimatization protocols, undertook an expedition on Muztagh Ata Mountain (7549 m) in China. Tests were performed at five altitudes: Zurich pre-expedition (PE, 450 m), base camp (BC, 4497 m), Camp 1 (C1, 5533 m), Camp 2 (C2, 6265 m) and Camp 3 (C3, 6865 m). Cystatin C- and creatinine-based (Mayo Clinic quadratic equation) GFR estimates (eGFR) were assessed together with Lake Louise AMS score and other tests. RESULTS: eGFR significantly decreased from PE to BC (P < 0.01). However, when analysing at changes between BC and C3, only cystatin C-based estimates indicated a significant decrease in GFR (P = 0.02). There was a linear decrease in eGFR from PE to C3, with a decrease of approx. 3.1 mL min(-1) 1.73 m(-2) per 1000 m increase in altitude. No differences between eGFR of the two groups with different acclimatization protocols could be observed. There was a significant association between eGFR and haematocrit (P = 0.01), whereas no significant association between eGFR and aldosterone, renin and brain natriuretic peptide could be observed. Finally, higher AMS scores were significantly associated with higher eGFR (P = 0.01). CONCLUSIONS: Renal function declines when ascending from low to high altitude. Cystatin C-based eGFR decreases during ascent in high altitude expedition but increases with AMS scores. For individuals with eGFR <40 mL min(-1) 1.73 m(-2), caution may be necessary when planning trips to high altitude above 4500 m above sea level