Association of Longitudinal Urinary Metabolic Biomarkers With ADPKD Severity and Response to Metformin in TAME-PKD Clinical Trial Participants.

Introduction: Dysregulated cellular metabolism contributes to autosomal dominant polycystic kidney disease (ADPKD) pathogenesis. The Trial of Administration of Metformin in Polycystic Kidney Disease (TAME-PKD) tested the effects of metformin treatment over 2 years in adult ADPKD patients with mild-moderate disease severity. Metformin was found to be safe and tolerable with an insignificant trend toward reduced estimated glomerular filtration rate (eGFR) decline compared to placebo. Here we tested whether targeted urinary metabolic biomarkers measured in TAME-PKD participants correlated with disease progression, severity, and metformin treatment in cross-sectional and longitudinal analyses. Methods: Concentrations of total protein, targeted metabolites (lactate, pyruvate, and succinate), and glycolytic enzymes (pyruvate kinase-M2, lactate dehydrogenase-A, and pyruvate dehydrogenase kinase-1) were measured and normalized by creatinine or osmolality in urine specimens and compared with height-adjusted total kidney volume (htTKV) and eGFR at the different study timepoints. Results: In cross-sectional analyses utilizing placebo group data, urinary succinate normalized by creatinine negatively correlated with ln (htTKV), whereas protein excretion strongly positively correlated with ln (htTKV), and negatively correlated with eGFR. Significant time-varying negative associations occurred with eGFR and the lactate/pyruvate ratio and with urine protein normalized by osmolality, indicating correlations of these biomarkers with disease progression. In secondary analyses, urinary pyruvate normalized by osmolality was preserved in metformin-treated participants but declined in placebo over the 2-year study period with a significant between-arm difference, suggesting time-dependent urinary pyruvate changes may serve as a discriminator for metformin treatment effects in this study population. Conclusion: Proteinuria with enhanced glycolytic and reduced oxidative metabolic markers generally correlated with disease severity and risk of progression in the TAME-PKD study population.

Seroresponse to Inactivated and Recombinant Influenza Vaccines Among Maintenance Hemodialysis Patients.

RATIONALE & OBJECTIVE: High-dose influenza vaccine provides better protection against influenza infection in older adults than standard-dose vaccine. We compared vaccine seroresponse among hemodialysis patients over a period of 4 months after administration of high-dose trivalent inactivated (HD-IIV3), standard-dose quadrivalent inactivated (SD-IIV4), or quadrivalent recombinant quadrivalent (RIV4) influenza vaccine. STUDY DESIGN: Prospective observational study. SETTING & PARTICIPANTS: Patients at 4 hemodialysis clinics who received influenza vaccine. EXPOSURE: Type of influenza vaccine. OUTCOME: Hemagglutination inhibition (HI) titers were measured at baseline and at 1, 2, 3, and 4 months after vaccination. The primary outcome was seroprotection rates at HI titers of at least 1:40 and at least 1:160 (antibody levels providing protection from infection in approximately 50% and 95% of immunocompetent individuals, respectively) at 1, 2, 3, and 4 months after vaccination. ANALYTICAL APPROACH: We calculated geometric mean titer as well as seroprotection and seroconversion rates. Adjusted generalized linear models with additional trend analyses were performed to evaluate the association between vaccine type and outcomes. RESULTS: 254 hemodialysis patients were vaccinated against influenza with HD-IIV3 (n = 141), SD-IIV4 (n = 36), or RIV4 (n = 77). A robust initial seroresponse to influenza A strains was observed after all 3 vaccines. Geometric mean titer and seroprotection (HI titer ≥1:160) rates against influenza A strains were higher and more sustained with HD-IIV3 than SD-IIV4 or RIV4. More than 80% of patients vaccinated with HD-IIV3 were seroprotected (HI titer ≥1:160) at month 4 (P < 0.001), whereas, among patients vaccinated with SD-IIV4 or RIV4, seroprotection rates were similar to those at baseline. Seroprotection rates were lower against B strains for all vaccines. LIMITATIONS: Because of the use of observational data, bias from unmeasured confounders may exist. Some age subgroups were small in number. Clinical outcome data were not available. CONCLUSIONS: Hemodialysis patients exhibited high seroprotection rates after all 3 influenza vaccines. The seroresponse waned more slowly with HD-IIV3 compared with SD-IIV4 and RIV4 vaccines.

Association of Baseline Urinary Metabolic Biomarkers with ADPKD Severity in TAME-PKD Clinical Trial Participants.

BACKGROUND: Recent work suggests that dysregulated cellular metabolism may play a key role in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). The TAME-PKD clinical trial is testing the safety, tolerability, and efficacy of metformin, a regulator of cell metabolism, in patients with ADPKD. This study investigates the cross-sectional association of urinary metabolic biomarkers with ADPKD severity among TAME-PKD trial participants at baseline. METHODS: Concentrations of total protein, targeted metabolites (lactate, pyruvate, succinate, and cAMP), and key glycolytic enzymes (pyruvate kinase M2 [PKM2], lactate dehydrogenase A [LDHA], and pyruvate dehydrogenase kinase 1 [PDK1]) were measured by ELISA, enzymatic assays, and immunoblotting in baseline urine specimens of 95 TAME-PKD participants. These analytes, normalized by urinary creatinine or osmolality to estimate excretion, were correlated with patients' baseline height-adjusted total kidney volumes (htTKVs) by MRI and eGFR. Additional analyses were performed, adjusting for participants' age and sex, using multivariable linear regression. RESULTS: Greater htTKV correlated with lower eGFR (r=-0.39; P=0.0001). Urinary protein excretion modestly correlated with eGFR (negatively) and htTKV (positively). Urinary cAMP normalized to creatinine positively correlated with eGFR. Among glycolytic enzymes, PKM2 and LDHA excretion positively correlated with htTKV, whereas PKM2 excretion negatively correlated with eGFR. These associations remained significant after adjustments for age and sex. Moreover, in adjusted models, succinate excretion was positively associated with eGFR, and protein excretion was more strongly associated with both eGFR and htTKV in patients <43 years old. CONCLUSIONS: Proteinuria correlated with ADPKD severity, and urinary excretion of PKM2 and LDHA correlated with ADPKD severity at baseline in the TAME-PKD study population. These findings are the first to provide evidence in human urine samples that upregulated glycolytic flux is a feature of ADPKD severity. Future analysis may reveal if metformin treatment affects both disease progression and the various urinary metabolic biomarkers in patients throughout the study.

Comparison of Dialysis Unit and Home Blood Pressures: An Observational Cohort Study.

RATIONALE & OBJECTIVE: Prior studies of patients receiving maintenance hemodialysis have shown that, on average, blood pressure (BP) measured predialysis is higher than BP measured at home. We hypothesized that a subset of hemodialysis patients has BP that is higher when measured at home than when measured predialysis and this subgroup of patients has a higher prevalence of left ventricular hypertrophy. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 97 hypertensive hemodialysis patients enrolled in the Blood Pressure in Dialysis Study (BID), a randomized trial of comparing target predialysis BP ≤140/90 to 155-165/90 mm Hg. EXPOSURE: Differences between predialysis and next-day home systolic BP measured ≥6 times over 1 year. OUTCOME: Left ventricular mass index (LVMI) by cardiac magnetic resonance imaging. ANALYTICAL APPROACH: A hierarchical clustering analysis divided patients into 3 clusters based on the average and variability of differences in systolic predialysis and home BP. Clusters were compared with respect to clinical factors and LVMI. RESULTS: Mean differences between predialysis and home systolic BP were 19.1 (95% CI, 17.0 to 21.1) mm Hg for cluster 1 ("home lower"), 3.7 (95% CI, 1.6 to 5.8) mm Hg for cluster 2 ("home and predialysis similar"), and -9.7 (95% CI, -12.0 to -7.4) mm Hg for cluster 3 ("home higher"). Systolic BP declined during dialysis in clusters 1 and 2 but increased in cluster 3. Interdialytic weight gains did not differ. After adjusting for sex and treatment arm, LVMI was higher in cluster 3 than in clusters 1 and 2: differences in means of 10.6 ± 4.96 (SE) g/m2 (P = 0.04) and 12.0 ± 5.08 g/m2 (P = 0.02), respectively. LIMITATIONS: Limited statistical power. CONCLUSIONS: Nearly one-third of participants had home BPs higher than predialysis BPs. These patients had LVMI higher than those with similar or lower BPs at home, indicating that their BP may have been undertreated.

Primary results of the randomized trial of metformin administration in polycystic kidney disease (TAME PKD).

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by growth of kidney cysts and glomerular filtration rate (GFR) decline. Metformin was found to impact cystogenesis in preclinical models of polycystic disease, is generally considered safe and may be a promising candidate for clinical investigation in ADPKD. In this phase 2 two-year trial, we randomly assigned 97 patients, 18-60 years of age, with ADPKD and estimated GFR over 50 ml/min/1.73 m2, in a 1:1 ratio to receive metformin or placebo twice daily. Primary outcomes were medication safety and tolerability. Secondary outcomes included estimated GFR decline, and total kidney volume growth. Thirty-eight metformin and 39 placebo participants still received study product at 24-months. Twenty-one participants in the metformin arm reduced drug dose due to inability to tolerate, compared with 14 in the placebo arm (not significant). Proportions of participants experiencing serious adverse events was similar between the groups. The Gastrointestinal Symptoms Rating Scale score was low at baseline and did not significantly change over time. The annual change for estimated GFR was -1.71 with metformin and -3.07 ml/min/1.73m2 per year with placebo (mean difference 1.37 {-0.70, 3.44} ml/min/1.73m2), while mean annual percent change in height-adjusted total kidney volume was 3.87% in metformin and 2.16% per year in placebo, (mean difference 1.68% {-2.11, 5.62}). Thus, metformin in adults with ADPKD was found to be safe and tolerable while slightly reducing estimated GFR decline but not to a significant degree. Hence, evaluation of efficacy requires a larger trial, with sufficient power to detect differences in endpoints.

COVID-19 Among US Dialysis Patients: Risk Factors and Outcomes From a National Dialysis Provider.

RATIONALE & OBJECTIVE: During the coronavirus disease 2019 (COVID-19) pandemic, patients receiving maintenance dialysis are a highly vulnerable population due to their comorbidities and circumstances that limit physical distancing during treatment. This study sought to characterize the risk factors for and outcomes following COVID-19 in this population. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Maintenance dialysis patients in clinics of a midsize national dialysis provider that had at least 1 patient who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from February to June 2020. PREDICTORS: Demographics, dialysis characteristics, residence in a congregated setting, comorbid conditions, measurements of frailty, and use of selected medications. OUTCOMES: COVID-19, defined as having a positive SARS-CoV-2 test result, and all-cause mortality among those with COVID-19. ANALYTICAL APPROACH: Logistic regression analyses conducted to identify clinical characteristics associated with COVID-19 and risk factors associated with mortality among patients following COVID-19. RESULTS: 438 of 7948 (5.5%) maintenance dialysis patients developed COVID-19. Male sex, Black race, in-center dialysis (vs home dialysis), treatment at an urban clinic, residence in a congregate setting, and greater comorbidity were associated with contracting COVID-19. Odds of COVID-19 were 17-fold higher for those residing in a congregated setting (odds ratio [OR], 17.10 [95% CI, 13.51-21.54]). Of the 438 maintenance dialysis patients with COVID-19, 109 (24.9%) died. Older age, heart disease, and markers of frailty were associated with mortality. LIMITATIONS: No distinction was detected between symptomatic and asymptomatic SARS-CoV-2 positivity, with asymptomatic screening limited by testing capacity during this initial COVID-19 surge period. CONCLUSIONS: COVID-19 is common among patients receiving maintenance dialysis, particularly those residing in congregate settings. Among maintenance dialysis patients with COVID-19, mortality is high, exceeding 20%.

Multidisciplinary Medication Therapy Management and Hospital Readmission in Patients Undergoing Maintenance Dialysis: A Retrospective Cohort Study.

RATIONALE & OBJECTIVES: Dialysis patients frequently experience medication-related problems. We studied the association of a multidisciplinary medication therapy management (MTM) with 30-day readmission rates. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Maintenance dialysis patients discharged home from acute-care hospitals between May 2016 and April 2017 who returned to End-Stage Renal Disease Seamless Care Organization dialysis clinics after discharge were eligible. Patients who were readmitted within 3 days, died, or entered hospice within 30 days were excluded. EXPOSURE: MTM consisting of nurse medication reconciliation, pharmacist medication review, and nephrologist oversight was categorized into 3 levels of intensity: no MTM, partial MTM (defined as an incomplete MTM process), or full MTM (defined as a complete MTM process). OUTCOME: The primary outcome was 30-day readmission. ANALYTICAL APPROACH: Time-varying Prentice, Williams, and Peterson total time hazards models explored associations between MTM and time to readmission after adjusting for age, race, sex, diabetes comorbidity, albumin level, vascular access type, kidney failure cause, dialysis vintage and modality, marital status, home medications, frequent prior hospitalizations, length of stay, discharge diagnoses, hierarchical condition category, and facility standardized hospitalization rates. Propensity score matching was performed to examine the robustness of the associations in a comparison between the full- and no-MTM exposure groups on time to readmission. RESULTS: Among 1,452 discharges, 586 received no MTM, 704 received partial MTM, and 162 received full MTM; 30-day readmission rates were 29%, 19%, and 11%, respectively (P < 0.001). Compared with no MTM, discharges with full MTM had the lowest time-varying risk for readmission within 30 days (HR, 0.26; 95% CI, 0.15-0.45); discharges with partial MTM also had lower readmission risk (HR, 0.50; 95% CI, 0.37-0.68). In propensity score-matched sensitivity analysis, full MTM was associated with lower 30-day readmission risk (HR, 0.20; 95% CI, 0.06-0.69). LIMITATIONS: Reliance on observational data. Residual bias and confounding. CONCLUSIONS: MTM services following hospital discharge were associated with fewer 30-day readmissions in dialysis patients. Randomized controlled studies evaluating different MTM delivery models and cost-effectiveness in dialysis populations are warranted.

Baseline Characteristics and Patient-Reported Outcomes of ADPKD Patients in the Multicenter TAME-PKD Clinical Trial.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) has been associated with metabolic disturbances characterized by downregulation of AMP-activated protein kinase (AMPK), a critical sensor of the cellular energy status. Therapeutic activation of AMPK by metformin could inhibit cyst enlargement by inhibition of both the mammalian target of rapamycin pathway and fluid secretion via the CFTR chloride channel. METHODS: We designed a phase-2, randomized, placebo-controlled, clinical trial to assess the safety, tolerability, and efficacy of metformin on total kidney volume in adults without diabetes (age 18-60 years) with ADPKD and eGFR of ≥50 ml/min per 1.73 m2. There were no eligibility criteria relating to kidney volume. In addition to demographics and clinical/family history, baseline parameters included eGFR, total kidney and liver volumes measured by MRI, and patient-reported outcomes were ascertained by the Medical Outcomes Study Short Form-36, the Gastrointestinal Safety Rating Scale, and the HALT-PKD pain questionnaire. RESULTS: We successfully randomized 97 participants recruited from two university-based clinical sites in Baltimore and Boston. The mean age of participants was 41.9 years, 72% were female, and 94% of participants were White. The majority of study participants had early stage disease, with a mean eGFR of 86.8±19.0 ml/min per 1.73 m2. Approximately half of the study participants (48%) were classified as high risk for progression (Mayo imaging classes 1C, 1D, or 1E). There was no correlation between kidney and/or liver size and health-related quality of life (HRQoL) or gastrointestinal symptom severity. CONCLUSIONS: We report successful recruitment in this ongoing, novel, clinical trial of metformin in ADPKD, with a study sample comprising patients with early stage disease and nearly a half of participants considered at high estimated risk for progression. Participants reported a low gastrointestinal symptom burden at baseline, and HRQoL similar to that of the general population, with no differences in symptoms or HRQoL related to organomegaly. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Metformin as a Novel Therapy for Autosomal Dominant Polycystic Kidney Disease (TAME), NCT02656017.

Chronic disease burdens of incident U.S. dialysis patients, 1996 - 2015
.

INTRODUCTION: The United States Renal Data System has collected data on incident hemodialysis (HD) and peritoneal dialysis (PD) patients since 1995, allowing prevalence of chronic diseases over the past 20 years to be measured. MATERIALS AND METHODS: All first-time HD/PD patients 1996 - 2015 were analyzed. Diabetes and cardiovascular diseases were grouped into single variables. Prevalence of each condition was evaluated with logistic regression. Odds ratios (OR) for a 5-year difference in year of dialysis initiation were calculated. Models were adjusted for age, sex, and race, with interactions between modality and year. One- and 5-year mortality were calculated. RESULTS: Age increased among 1,847,212 HD and 156,965 PD patients; PD patients were younger. First-year mortality fell from 24.4 to 21.1% in HD patients and from 17.1 to 8.5% in PD. 5-year mortality fell from 65.9 to 58.6% in HD patients and from 56.3 to 40.4% in PD. Hypertension increased (OR = 1.34 for HD, 1.35 for PD), as did diabetes (OR = 1.16 for HD, 1.06 for PD) and cancer (OR = 1.09 for HD, 1.10 for PD). Cardiovascular disease decreased in PD (OR = 0.87) only. Stroke decreased (OR = 0.98 for HD, 0.90 for PD), as did peripheral vascular disease (OR = 0.91 for HD, 0.82 for PD). Lung disease increased in HD (OR = 1.10) but decreased in PD (OR = 0.97). DISCUSSION: Mortality and cardiovascular disease burden have declined for dialysis patients in the United States despite an aging population that is increasingly hypertensive and diabetic. Comorbid disease burdens among HD and PD patients have diverged over time, with PD patients having fewer comorbid conditions.

Influenza in dialysis patients: an opportunity to decrease mortality?

PURPOSE OF REVIEW: Influenza is a major cause of morbidity in dialysis patients. RECENT FINDINGS: A recent meta-analysis finds reduced influenza infections, hospitalizations and deaths with use of high dose as compared with standard-dose vaccine in the elderly. There remain no randomized clinical trials of vaccine efficacy in dialysis patients. One observational study finds reduced all-cause hospitalization with high-dose as compared with standard-dose vaccine but another study finds no difference in influenza related events. A simulation study, in which the timing of vaccination and antibody waning rates are varied, finds vaccine efficacy among populations prone to premature waning, to be greater if the vaccine is administered later, as long as the opportunity to vaccinate does not decline. In a phase 3 trial involving low-risk patients with uncomplicated influenza, baloxavir (which is of a novel class of antiinfluenza treatment), was associated with a faster decline in virus titers and no difference in resolution of symptoms as compared with oseltamivir. SUMMARY: By extension of high-quality evidence in the elderly, we recommend using the high dose vaccine in all dialysis patients. Vaccine efficacy may be enhanced in dialysis patients if vaccination is delayed until late October to mid-November. It is premature to use baloxavir over oseltamivir or the combination to treat influenza in dialysis patients though trials are forthcoming.

Transfers to Hemodialysis Among US Patients Initiating Renal Replacement Therapy With Peritoneal Dialysis.

RATIONALE & OBJECTIVE: Identifying patients who are likely to transfer from peritoneal dialysis (PD) to hemodialysis (HD) before transition could improve their subsequent care. This study developed a prediction tool for transition from PD to HD. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Adults initiating PD between January 2008 and December 2011, followed up through June 2015, for whom data were available in the US Renal Data System (USRDS). PREDICTORS: Clinical characteristics at PD initiation and peritonitis claims. OUTCOMES: Transfer to HD, with the competing outcomes of death and kidney transplantation. ANALYTICAL APPROACH: Outcomes were ascertained from USRDS treatment history files. Subdistribution hazards (competing-risk) models were fit using clinical characteristics at PD initiation. A nomogram was developed to classify patient risk at 1, 2, 3, and 4 years. These data were used to generate quartiles of HD transfer risk; this quartile score was incorporated into a cause-specific hazards model that additionally included a time-dependent variable for peritonitis. RESULTS: 29,573 incident PD patients were followed up for a median of 21.6 (interquartile range, 9.0-42.3) months, during which 41.2% transferred to HD, 25.9% died, 17.1% underwent kidney transplantation, and the rest were followed up to the study end in June 2015. Claims for peritonitis were present in 11,733 (40.2%) patients. The proportion of patients still receiving PD decreased to <50% at 22.6 months and 14.2% at 5 years. Peritonitis was associated with a higher rate of HD transfer (HR, 1.82; 95% CI, 1.76-1.89; P < 0.001), as were higher quartile scores of HD transfer risk (HRs of 1.31 [95% CI, 1.25-1.37), 1.51 [95% CI, 1.45-1.58], and 1.78 [95% CI, 1.71-1.86] for quartiles 2, 3, and 4 compared to quartile 1 [P < 0.001 for all]). LIMITATIONS: Observational data, reliant on the Medical Evidence Report and Medicare claims. CONCLUSIONS: A large majority of the patients who initiated renal replacement therapy with PD discontinued this modality within 5 years. Transfer to HD was the most common outcome. Patient characteristics and comorbid diseases influenced the probability of HD transfer, death, and transplantation, as did episodes of peritonitis.

The TiME Trial: A Fully Embedded, Cluster-Randomized, Pragmatic Trial of Hemodialysis Session Duration.

BACKGROUND: Data from clinical trials to inform practice in maintenance hemodialysis are limited. Incorporating randomized trials into dialysis clinical care delivery should help generate practice-guiding evidence, but the feasibility of this approach has not been established. METHODS: To develop approaches for embedding trials into routine delivery of maintenance hemodialysis, we performed a cluster-randomized, pragmatic trial demonstration project, the Time to Reduce Mortality in ESRD (TiME) trial, evaluating effects of session duration on mortality (primary outcome) and hospitalization rate. Dialysis facilities randomized to the intervention adopted a default session duration ≥4.25 hours (255 minutes) for incident patients; those randomized to usual care had no trial-driven approach to session duration. Implementation was highly centralized, with no on-site research personnel and complete reliance on clinically acquired data. We used multiple strategies to engage facility personnel and participating patients. RESULTS: The trial enrolled 7035 incident patients from 266 dialysis units. We discontinued the trial at a median follow-up of 1.1 years because of an inadequate between-group difference in session duration. For the primary analysis population (participants with estimated body water ≤42.5 L), mean session duration was 216 minutes for the intervention group and 207 minutes for the usual care group. We found no reduction in mortality or hospitalization rate for the intervention versus usual care. CONCLUSIONS: Although a highly pragmatic design allowed efficient enrollment, data acquisition, and monitoring, intervention uptake was insufficient to determine whether longer hemodialysis sessions improve outcomes. More effective strategies for engaging clinical personnel and patients are likely required to evaluate clinical trial interventions that are fully embedded in care delivery.

Evaluation of non-response to the In-Center Hemodialysis Consumer Assessment of Healthcare Providers and Systems (ICH CAHPS) survey.

BACKGROUND: The In-Center Hemodialysis Consumer Assessment of Healthcare Providers and Systems (ICH CAHPS) Survey is the first patient reported outcome measure included in the U.S. Medicare End Stage Renal Disease Quality Incentive Program. Administered twice yearly, it assesses in-center dialysis experience and survey responses are tied to dialysis facility payments. Low response rates, currently approximately 35%, raise concern for possible underrepresentation of patient groups. METHODS: Cross-sectional analysis of survey administration in 2012 to all in-center hemodialysis patients in Dialysis Clinic, Inc. (DCI) facilities nationally over 18 years old who received hemodialysis at their facility for at least 3 months. Patient-level covariates included demographic, clinical, laboratory, and functional characteristics. Random effects multivariable logistic regression was used to assess survey non-response. RESULTS: Among 11,055 eligible patients 6541 (59%) were non-responders. Of the remaining 4514 responders, 549 (14%) surveys were not usable due to presence of proxy help or incomplete responses. Non-responders were more likely to be men, non-white, younger, single, dual Medicare/Medicaid eligible, less educated, non-English speaking, and not active on the transplant list; non-responders had longer ESRD vintage, lower body mass index, lower serum albumin, worse functional status, and more hospitalizations, missed treatments, and shortened treatments. Similar associations were found using more parsimonious multivariable analyses and after imputing missing data. CONCLUSIONS: Non-responders to the ICH CAHPS significantly differed from responders, broadly spanning individuals with fewer socioeconomic advantages and greater illness burden, raising limitations in interpreting facility survey results. Future research should assess reasons for non-response to improve ICH CAHPS generalizability and utility.

High-Dose Seasonal Influenza Vaccine in Patients Undergoing Dialysis.

BACKGROUND AND OBJECTIVES: High-dose influenza vaccine, which contains fourfold more antigen than standard dose, is associated with fewer cases of influenza and less influenza-related morbidity in the elderly general population. Whether the high-dose influenza vaccine benefits patients on dialysis, whose immune response to vaccination is less robust than that of healthy patients, is uncertain. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We compared hospitalizations and deaths during the 2015-2016 and 2016-2017 influenza seasons by vaccine type (standard trivalent, standard quadrivalent, and high-dose trivalent influenza vaccine) administered within a national dialysis organization. The association of vaccine type with outcomes was estimated using Cox proportional hazards regression with adjustment for patient factors and "center effect." Analyses were stratified by age and dialysis modality. RESULTS: Between September 1 and December 31, 2015, standard dose trivalent, standard dose quadrivalent, and high-dose trivalent influenza vaccines were administered to 3057 (31%), 5981 (61%), and 805 (8%) patients, respectively. The adjusted rates of first hospitalizations by vaccine type during the influenza season were 8.43, 7.88, and 7.99 per 100 patient-months, respectively, and the adjusted rates of death were 1.00, 0.97, and 1.04, respectively. These differences were not significant. In 2016, 3614 (39%) received quadrivalent vaccine, and 5700 (61%) received high-dose trivalent vaccine. The adjusted rates of first hospitalization by vaccine type were 8.71 and 8.04 per 100 patient-months, respectively, and the adjusted rates of death were 0.98 and 1.02, respectively. Receipt of high dose was associated with a significant reduction in hospitalization (hazard ratio, 0.93; 95% confidence interval, 0.86 to 1.00; P=0.04); there was no significant association with death. There was no significant heterogeneity of either association by age group or dialysis modality. CONCLUSIONS: Receipt of high-dose compared with standard dose influenza vaccine in 2016-2017 was associated with lower rates of hospitalization in patients on dialysis, although that was not seen in 2015-2016.