Age of Onset and Disease Course in Biopsy-Proven Minimal Change Disease: An Analysis From the Cure Glomerulonephropathy Network.

RATIONALE & OBJECTIVE: Adolescent- and adult-onset minimal change disease (MCD) may have a clinical course distinct from childhood-onset disease. We characterized the course of children and adults with MCD in the Cure Glomerulonephropathy Network (CureGN) and assessed predictors of rituximab response. STUDY DESIGN: Prospective, multicenter, observational study. STUDY PARTICIPANTS: CureGN participants with proven MCD on biopsy. EXPOSURE: Age at disease onset, initiation of renin-angiotensin-aldosterone system (RAAS) blockade, and immunosuppression including rituximab during the study period. OUTCOME: Relapse and remission, change in estimated glomerular filtration rate (eGFR), and kidney failure. ANALYTICAL APPROACH: Remission and relapse probabilities were estimated using Kaplan-Meier curves and gap time recurrent event models. Linear regression models were used for the outcome of change in eGFR. Cox proportional hazards models were used to estimate the association between rituximab administration and remission. RESULTS: The study included 304 childhood- (≤12 years old), 49 adolescent- (13-17 years old), and 201 adult- (≥18 years) onset participants with 2.7-3.2 years of follow-up after enrollment. Children had a longer time to biopsy (238 vs 23 and 36 days in adolescent- and adult-onset participants, respectively; P<0.001) and were more likely to have received therapy before biopsy. Children were more likely to be treated with immunosuppression but not RAAS blockade. The rate of relapse was higher in childhood- versus adult-onset participants (HR, 1.69 [95% CI, 1.29-2.21]). The probability of remission was also higher in childhood-onset disease (HR, 1.33 [95%CI, 1.02-1.72]). In all groups eGFR loss was minimal. Children were more likely to remit after rituximab than those with adolescent- or adult-onset disease (adjusted HR, 2.1; P=0.003). Across all groups, glucocorticoid sensitivity was associated with a greater likelihood of achieving complete remission after rituximab (adjusted HR, 2.62; P=0.002). LIMITATIONS: CureGN was limited to biopsy-proven disease. Comparisons of childhood to nonchildhood cases of MCD may be subject to selection bias, given that childhood cases who undergo a biopsy may be limited to patients who are least responsive to initial therapy. CONCLUSIONS: Among patients with MCD who underwent kidney biopsy, there were differences in the course (relapse and remission) of childhood-onset compared with adolescent- and adult-onset disease, as well as rituximab response. PLAIN-LANGUAGE SUMMARY: Minimal change disease is a biopsy diagnosis for nephrotic syndrome. It is diagnosed in childhood, adolescence, or adulthood. Patients and clinicians often have questions about what to expect in the disease course and how to plan therapies. We analyzed a group of patients followed longitudinally as part of the Cure Glomerulonephropathy Network (CureGN) and describe the differences in disease (relapse and remission) based on the age of onset. We also analyzed rituximab response. We found that those with childhood-onset disease had a higher rate of relapse but also have a higher probability of reaching remission when compared with adolescent- or adult-onset disease. Children and all steroid-responsive patients are more likely to achieve remission after rituximab.

Total fluid intake, caffeine, and other bladder irritant avoidance among adults having urinary urgency with and without urgency incontinence: The Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN).

INTRODUCTION: Caffeine has long been vilified as a cause for urinary urgency incontinence (UUI) along with other potential bladder irritants such as carbonation, alcohol, and acidic juices. The objective of this study was to assess the fluid intake behavior of people with urgency, UUI, and those with lower urinary tract symptoms (LUTS) without UUI or urgency to assess if they avoided certain potential bladder irritants or had different fluid intake. We hypothesized that patients with UUI would avoid caffeine as a self-management method more so than these other two groups. METHODS: Treatment-seeking men and women with LUTS in the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) Observational Cohort study completed a baseline 3-day voiding and intake diary. "Complete" diaries had 3 days of data and no missing intake or voided volumes. Beverages with any caffeine, alcohol, carbonation, or acidic juice were identified and the total volume was recorded as well as the type of beverage containing caffeine to calculate the daily caffeine dose. RESULTS: Four hundred and ninety-one participants (277 men and 214 women) with a median age of 63 had complete diaries. Urinary urgency was more prevalent in women than men (79% vs. 55%, p < 0.0001) as was UUI (84% vs. 47%, p < 0.0001). Total fluid intake over 3 days was lower among the urgency group versus the nonurgency group (median [interquartile range] 5.2 [4.0-6.8] L vs. 5.7 [4.3-7.0] L, p = 0.028) and the UUI group compared to the urgency without incontinence group were less likely to consume alcohol (26% vs. 37%, p = 0.04). After adjusting for sex, BMI, age, and total intake volume, UUI participants had 54% lower odds of consuming any caffeine (odds ratio = 0.46, 95% confidence interval = 0.22-0.96, p = 0.04) than those without incontinence, but among those that did consume caffeine, no difference in the volume of caffeinated beverages or milligrams of caffeine consumed was detected between those with UUI and those with urgency without incontinence. No difference in carbonation or acidic juice intake was detected between groups. CONCLUSIONS: Individuals with urgency consume a lower volume of fluid than those without urgency. UUI participants more often abstain from caffeine, but among those that consume caffeine, the dose is similar to those without UUI. One explanation for these results is that only a subset of individuals with urgency or UUI are caffeine sensitive.

Kidney Biopsy Features Most Predictive of Clinical Outcomes in the Spectrum of Minimal Change Disease and Focal Segmental Glomerulosclerosis.

BACKGROUND: Heterogeneity in disease course and treatment response among patients with MCD/FSGS necessitates a granular evaluation of kidney tissue features. This study aimed to identify histologic and ultrastructural descriptors of structural changes most predictive of clinical outcomes in the Nephrotic Syndrome Study Network (NEPTUNE). METHODS: Forty-eight histologic (37 glomerular, 9 tubulointerstitial, 2 vascular) and 20 ultrastructural descriptors were quantified by applying the NEPTUNE Digital Pathology Scoring System to NEPTUNE kidney biopsies. Outcomes included time from biopsy to disease progression, first complete remission of proteinuria, and treatment response. Relative importance of pathology and clinical predictors was obtained from random forest models, and predictive discrimination was assessed. RESULTS: Among 224 participants (34% Black, 24% Hispanic), model performance was excellent, with predictive discrimination of 0.9 for disease progression, 0.85 for complete remission, and 0.81 for treatment response. The most predictive descriptors of outcomes included both conventional-e.g., global sclerosis or segmental sclerosis and interstitial fibrosis/tubular atrophy-and novel features, including adhesion, interstitial foam cells, deflation, periglomerular fibrosis, mononuclear white blood cells, endothelial cell abnormalities, microvillous transformation, and acute tubular injury. CONCLUSIONS: The most predictive descriptors of clinical outcomes among MCD/FSGS patients reflected structural changes in multiple renal compartments. Reporting these descriptors should be standardized to guide prognostication of proteinuric glomerular diseases.

Experimental Pain and Auditory Sensitivity in Overactive Bladder Syndrome: A Symptoms of the Lower Urinary Tract Dysfunction Research Network (LURN) Study.

PURPOSE: The objective of this study was to investigate the presence of nonbladder sensory abnormalities in participants with overactive bladder syndrome (OAB). MATERIALS AND METHODS: Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN) study participants with OAB symptoms and controls were recruited from 6 U.S. tertiary referral centers. Quantitative sensory testing (QST) was performed to determine pressure pain sensitivity at the thumbnail bed and auditory sensitivity. Fixed and mixed effect multivariable linear regressions and Weibull models were used to compare QST responses between groups. Pearson correlations were used to assess the relationship between QST measures. Associations between QST and self-reported symptoms were explored with linear regression. RESULTS: A total of 297 participants were analyzed (191 OAB, 106 controls; 76% white, 51% male). OAB cases were older than controls (57.4 vs 52.2 years, p=0.015). No significant differences in experimental thumbnail (nonbladder) pain or auditory sensitivity were detected between OAB cases and controls. Correlations between pressure and auditory derived metrics were weak to moderate overall for both groups, with some significantly stronger correlations for cases. Exploratory analyses indicated increased pressure pain and auditory sensitivity were modestly associated with greater self-reported bladder pain and pain interference with physical function. CONCLUSIONS: As a group, no significant differences between OAB cases and controls were observed in experimental nonbladder pain or auditory sensitivity during QST. Associations between QST outcomes and clinical pain raise the possibility of centrally mediated sensory amplification in some individuals with OAB.

Quantification of Glomerular Structural Lesions: Associations With Clinical Outcomes and Transcriptomic Profiles in Nephrotic Syndrome.

RATIONALE & OBJECTIVE: The current classification system for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) does not fully capture the complex structural changes in kidney biopsies nor the clinical and molecular heterogeneity of these diseases. STUDY DESIGN: Prospective observational cohort study. SETTING & PARTICIPANTS: 221 MCD and FSGS patients enrolled in the Nephrotic Syndrome Study Network (NEPTUNE). EXPOSURE: The NEPTUNE Digital Pathology Scoring System (NDPSS) was applied to generate scores for 37 glomerular descriptors. OUTCOME: Time from biopsy to complete proteinuria remission, time from biopsy to kidney disease progression (40% estimated glomerular filtration rate [eGFR] decline or kidney failure), and eGFR over time. ANALYTICAL APPROACH: Cluster analysis was used to group patients with similar morphologic characteristics. Glomerular descriptors and patient clusters were assessed for associations with outcomes using adjusted Cox models and linear mixed models. Messenger RNA from glomerular tissue was used to assess differentially expressed genes between clusters and identify genes associated with individual descriptors driving cluster membership. RESULTS: Three clusters were identified: X (n = 56), Y (n = 68), and Z (n = 97). Clusters Y and Z had higher probabilities of proteinuria remission (HRs of 1.95 [95% CI, 0.99-3.85] and 3.29 [95% CI, 1.52-7.13], respectively), lower hazards of disease progression (HRs of 0.22 [95% CI, 0.08-0.57] and 0.11 [95% CI, 0.03-0.45], respectively), and lower loss of eGFR over time compared with X. Cluster X had 1,920 genes that were differentially expressed compared with Y+Z; these reflected activation of pathways of immune response and inflammation. Six descriptors driving the clusters individually correlated with clinical outcomes and gene expression. LIMITATIONS: Low prevalence of some descriptors and biopsy at a single time point. CONCLUSIONS: The NDPSS allows for categorization of FSGS/MCD patients into clinically and biologically relevant subgroups, and uncovers histologic parameters associated with clinical outcomes and molecular signatures not included in current classification systems.

Burden and Cost of Caring for US Veterans With CKD: Initial Findings From the VA Renal Information System (VA-REINS).

Kidney disease is a common, complex, costly, and life-limiting condition. Most kidney disease registries or information systems have been limited to single institutions or regions. A national US Department of Veterans Affairs (VA) Renal Information System (VA-REINS) was recently developed. We describe its creation and present key initial findings related to chronic kidney disease (CKD) without kidney replacement therapy (KRT). Data from the VA's Corporate Data Warehouse were processed and linked with national Medicare data for patients with CKD receiving KRT. Operational definitions for VA user, CKD, acute kidney injury, and kidney failure were developed. Among 7 million VA users in fiscal year 2014, CKD was identified using either a strict or liberal operational definition in 1.1 million (16.4%) and 2.5 million (36.3%) veterans, respectively. Most were identified using an estimated glomerular filtration rate laboratory phenotype, some through proteinuria assessment, and very few through International Classification of Diseases, Ninth Revision coding. The VA spent ∼$18 billion for the care of patients with CKD without KRT, most of which was for CKD stage 3, with higher per-patient costs by CKD stage. VA-REINS can be leveraged for disease surveillance, population health management, and improving the quality and value of care, thereby enhancing VA's capacity as a patient-centered learning health system for US veterans.

The Utility of Routine Fundus Photography Screening for Posterior Segment Disease: A Stepped-wedge, Cluster-randomized Trial in South India.

PURPOSE: To assess whether routine fundus photography (RFP) to screen for posterior segment disease at community eye clinics (vision centers [VCs]) in India increases referral to centralized ophthalmolic care. DESIGN: Stepped-wedge, cluster-randomized trial. PARTICIPANTS: Patients aged 40 to 75 years and those aged 20 to 40 years with a known history of hypertension or diabetes mellitus presenting to 4 technician-run VCs associated with the Aravind Eye Care System in India. METHODS: VCs (clusters) were randomized to standard care or RFP across five 2-week study periods (steps). Patients in each cluster received standard care initially. At the start of each subsequent step, a randomly chosen cluster crossed over to providing RFP to eligible patients. All clusters took part in RFP during the last step. Standard care involved technician eye exams, optional fundus photography, and teleconsultation with an ophthalmologist. RFP involved eye exams, dilation and 40-degree fundus photography, and teleconsultation with an ophthalmologist. MAIN OUTCOME MEASURES: Standard care and RFP clusters were compared by the proportion of patients referred for in-person evaluation by an ophthalmologist because of fundus photography findings and urgency of referral (urgently in ≤ 2 weeks vs. nonurgently in > 2 weeks). Generalized linear mixed models adjusting for cluster and step were used to estimate the odds of referral due to fundus photography findings compared with standard care. RESULTS: A total of 1447 patients were enrolled across the VCs, including 737 in the standard care group and 710 in the RFP group. Compared with standard care, the RFP group had a higher proportion of referrals due to fundus photography findings (11.3% vs. 4.4%), nonurgent referrals due to fundus photography (9.3% vs. 3.3%), and urgent referrals due to fundus photography (1.8% vs. 1.1%). The RFP intervention was associated with a 2-fold increased odds of being referred because of photography findings compared with standard care (odds ratio, 2.07; 95% confidence interval, 0.98-4.40; P = 0.058). CONCLUSIONS: Adding RFP to community eye clinics was associated with an increased odds of referral compared with standard care. This increase in referral was mostly due to nonurgent posterior segment disease.

Ultrastructural Characterization of Proteinuric Patients Predicts Clinical Outcomes.

BACKGROUND: The analysis and reporting of glomerular features ascertained by electron microscopy are limited to few parameters with minimal predictive value, despite some contributions to disease diagnoses. METHODS: We investigated the prognostic value of 12 electron microscopy histologic and ultrastructural changes (descriptors) from the Nephrotic Syndrome Study Network (NEPTUNE) Digital Pathology Scoring System. Study pathologists scored 12 descriptors in NEPTUNE renal biopsies from 242 patients with minimal change disease or FSGS, with duplicate readings to evaluate reproducibility. We performed consensus clustering of patients to identify unique electron microscopy profiles. For both individual descriptors and clusters, we used Cox regression models to assess associations with time from biopsy to proteinuria remission and time to a composite progression outcome (≥40% decline in eGFR, with eGFR<60 ml/min per 1.73 m2, or ESKD), and linear mixed models for longitudinal eGFR measures. RESULTS: Intrarater and interrater reproducibility was >0.60 for 12 out of 12 and seven out of 12 descriptors, respectively. Individual podocyte descriptors such as effacement and microvillous transformation were associated with complete remission, whereas endothelial cell and glomerular basement membrane abnormalities were associated with progression. We identified six descriptor-based clusters with distinct electron microscopy profiles and clinical outcomes. Patients in a cluster with more prominent foot process effacement and microvillous transformation had the highest rates of complete proteinuria remission, whereas patients in clusters with extensive loss of primary processes and endothelial cell damage had the highest rates of the composite progression outcome. CONCLUSIONS: Systematic analysis of electron microscopic findings reveals clusters of findings associated with either proteinuria remission or disease progression.

A New Brief Clinical Assessment of Lower Urinary Tract Symptoms for Women and Men: LURN SI-10.

PURPOSE: Lower urinary tract symptoms are common in men and women. Members of the LURN (Lower Urinary Tract Dysfunction Research Network) sought to create a brief, clinically relevant tool to improve existing measurements of lower urinary tract symptoms in men and women. MATERIALS AND METHODS: Using a modified Delphi methodology during an expert consensus meeting we reduced the LURN CASUS (Comprehensive Assessment of Self-Reported Urinary Symptoms) questionnaire to a brief set of clinically relevant items measuring lower urinary tract symptoms. The sum score of these items was evaluated by comparing it to the AUA SI (American Urological Association Symptom Index), the UDI-6 (Urinary Distress Inventory Short Form) in women only and the CASUS lower urinary tract symptoms screening questions using the Pearson correlation, regression analysis and ROC curves. RESULTS: The LURN SI-10 (10-Item LURN Symptom Index) assesses urinary frequency, nocturia, urgency, incontinence, bladder pain, voiding and post-micturition symptoms (score range 0 to 38). The correlation between LURN SI-10 and AUA SI scores was 0.77 in men and 0.70 in women. The UDI-6 and the LURN SI-10 correlated highly in women (r=0.76). The LURN SI-10 showed good accuracy to predict moderate and severe lower urinary tract symptoms as defined by the AUA SI (ROC AUC range 0.82-0.90). Similar accuracy was shown in predicting different levels of symptom status using the UDI-6 (AUC range 0.84-0.86). CONCLUSIONS: The LURN SI-10 correlates well with the AUA SI and the UDI-6. It includes items related to a broader spectrum of lower urinary tract symptoms, particularly incontinence, bladder pain and post-micturition symptoms, and it applies to men and women.

CKD Awareness Among US Adults by Future Risk of Kidney Failure.

RATIONALE & OBJECTIVE: Persons with chronic kidney disease (CKD) are often unaware of their disease status. Efforts to improve CKD awareness may be most effective if focused on persons at highest risk for progression to kidney failure. STUDY DESIGN: Serial cross-sectional surveys. SETTING & PARTICIPANTS: Nonpregnant adults (aged≥20 years) with CKD glomerular filtration rate categories 3-4 (G3-G4) who participated in the National Health and Nutrition Examination Survey from 1999 to 2016 (n = 3,713). PREDICTOR: 5-year kidney failure risk, estimated using the Kidney Failure Risk Equation. Predicted risk was categorized as minimal (<2%), low (2%-<5%), intermediate (5%-<15%), or high (≥15%). OUTCOME: CKD awareness, defined by answering "yes" to the question "Have you ever been told by a doctor or other health professional that you had weak or failing kidneys?" ANALYTICAL APPROACH: Prevalence of CKD awareness was estimated within each risk group using complex sample survey methods. Associations between Kidney Failure Risk Equation risk and CKD awareness were assessed using multivariable logistic regression. CKD awareness was compared with awareness of hypertension and diabetes during the same period. RESULTS: In 2011 to 2016, unadjusted CKD awareness was 9.6%, 22.6%, 44.7%, and 49.0% in the minimal-, low-, intermediate-, and high-risk groups, respectively. In adjusted analyses, these proportions did not change over time. Awareness of CKD, including among the highest risk group, remains consistently below that of hypertension and diabetes and awareness of these conditions increased over time. LIMITATIONS: Imperfect sensitivity of the "weak or failing kidneys" question for ascertaining CKD awareness. CONCLUSIONS: Among adults with CKD G3-G4 who have 5-year estimated risks for kidney failure of 5%-<15% and≥15%, approximately half were unaware of their kidney disease, a gap that has persisted nearly 2 decades.

The Association between Medication Adherence and Visual Field Progression in the Collaborative Initial Glaucoma Treatment Study.

PURPOSE: To evaluate the relationship between medication adherence and visual field progression in participants randomized to the medication arm of the Collaborative Initial Glaucoma Treatment Study (CIGTS). DESIGN: The CIGTS was a randomized, multicenter clinical trial comparing initial treatment with topical medications to trabeculectomy for 607 participants with newly diagnosed glaucoma. PARTICIPANTS: Three hundred seven participants randomized to the medication arm of the CIGTS. METHODS: Participants were followed up at 6-month intervals for up to 10 years. Self-reported medication adherence and visual fields were measured. Medication adherence was assessed by telephone from responses to the question, "Did you happen to miss any dose of your medication yesterday?" The impact of medication adherence on mean deviation (MD) over time was assessed with a linear mixed regression model adjusting for the effects of baseline MD and age, cataract extraction, interactions, and time (through year 8, excluding time after crossover to surgery). Medication adherence was modeled as a cumulative sum of the number of prior visits where a missed dose of medication was reported. MAIN OUTCOME MEASURE: Mean deviation over time. RESULTS: Three hundred seven subjects (306 with adherence data) were randomized to treatment with topical medications and followed up for an average of 7.3 years (standard deviation, 2.3 years). One hundred forty-two subjects (46%) reported never missing a dose of medication over all available follow-up, 112 patients (37%) reported missing medication at up to one third of visits, 31 patients (10%) reported missing medication at one third to two thirds of visits, and 21 patients (7%) reported missing medication at more than two thirds of visits. Worse medication adherence was associated with loss of MD over time (P = 0.005). For subjects who reported never missing a dose of medication, the average predicted MD loss over 8 years was 0.62 dB, consistent with age-related loss (95% confidence interval [CI], 0.17-1.06; P = 0.007); subjects who reported missing medication doses at one third of visits had a loss of 1.42 dB (95% CI, 0.86-1.98; P < 0.0001); and subjects who reported missing medication doses at two thirds of visits showed a loss of 2.23 dB (95% CI, 1.19-3.26; P < 0.0001). CONCLUSIONS: This longitudinal assessment demonstrated a statistically and clinically significant association between medication nonadherence and glaucomatous vision loss.

Patient demographic and psychosocial characteristics associated with 30-day recall of self-reported lower urinary tract symptoms.

AIMS: Measurement of self-reported lower urinary tract symptoms (LUTS) typically uses a recall period, for example, "In the past 30 days…." Compared to averaged daily reports, 30-day recall is generally unbiased, but recall bias varies by item. We examined the associations between personal characteristics (eg, age, symptom bother) and 30-day recall of LUTS using items from the Symptoms of Lower Urinary Tract Dysfunction Research Network Comprehensive Assessment of Self-reported Urinary Symptoms questionnaire. METHODS: Participants (127 women and 127 men) were recruited from 6 US tertiary care sites. They completed daily assessments for 30 days and a 30-day recall assessment at the end of the study month. For each of the 18 tested items, representing 10 LUTS, the average of the participant's daily responses was modeled as a function of their 30-day recall, the personal characteristic, and the interaction between the 30-day recall and the characteristic in separate general linear regression models, adjusted for sex. RESULTS: Nine items representing 7 LUTS exhibited under- or overreporting (recall bias) for at least 25% of participants. Bias was associated with personal characteristics for six LUTS. Underreporting of incontinence was associated with older age, lower anxiety, and negative affect; overreporting of other LUTS was associated with, symptom bother, symptom variability, anxiety, and depression. CONCLUSIONS: We identified under- or overreporting that was associated with personal characteristics for six common LUTS. Some cues (eg, less bother and lower anxiety) were related to recall bias in an unexpected direction. Thus, providers should exercise caution when making judgments about the accuracy of a patient's symptom recall based on patient demographic and psychosocial characteristics.

Cramping, crashing, cannulating, and clotting: a qualitative study of patients' definitions of a "bad run" on hemodialysis.

BACKGROUND: Hemodialysis sessions frequently become unstable from complications such as intradialytic hypotension and untoward symptoms. Previous patient safety initiatives promote prevention of treatment complications; yet, they have placed little specific focus on avoidable session instability. A patient-centered definition of session instability grounded in patient experiences, and an understanding of patient perceptions of causes and solutions to instability, may enable such efforts. METHODS: Twenty-five participants participated in three focus groups and/or a survey. They were purposively sampled for variation in region of residence, and sensitivity to patient well-being. Focus group recordings were analyzed using descriptive coding, in vivo coding, and thematic analysis. RESULTS: Patients define unstable sessions ("bad runs") as those in which they experience severe discomfort or unanticipated events that interfere with their ability to receive therapy. Bad runs were characterized primarily by cramping, low blood pressure ("crashing"), cannulation-related difficulties ("bad sticks"), and clotting of the dialysis circuit or vascular access. Patients believed that cramping and crashing could be explained by both patient and clinician behavior: patient fluid consumption and providers' fluid removal goals. Patients felt that the responsibility for cannulation-related problems lay with dialysis staff, and they asked for different staff or self-cannulated as solutions. Clotting was viewed as an idiosyncratic issue with one's body, and perceived solutions were clinician-driven. Patients expressed concern about "bad runs" on their ability to achieve fluid balance. CONCLUSIONS: Findings point to novel priorities for efforts to enhance hemodialysis session stability, and areas in which patients can be supported to become involved in such efforts.

Elevated serum anion gap in adults with moderate chronic kidney disease increases risk for progression to end-stage renal disease.

Acid retention associated with reduced glomerular filtration rate (GFR) exacerbates nephropathy progression in partial nephrectomy models of chronic kidney disease (CKD) and might be reflected in patients with CKD with reduced estimated GFR (eGFR) by increased anion gap (AG). We explored the presence of AG and its association with CKD in 14,924 adults aged ≥20 yr with eGFR ≥ 15 ml·min-1·1.73 m-2 enrolled in the National Health and Nutrition Examination Survey III, 1988-1994, using multivariable regression analysis. The model was adjusted for sociodemographic characteristics, diabetes, and hypertension. We further examined the association between AG and incident end-stage renal disease (ESRD) using frailty models, adjusting for demographics, clinical factors, body mass index, serum albumin, bicarbonate, eGFR, and urinary albumin-to-creatinine ratio by following 558 adults with moderate CKD for 12 yr via the United States Renal Data System. Laboratory measures determined AG using the traditional, albumin-corrected, and full AG definitions. Individuals with moderate CKD (eGFR: 30-59 ml·min-1·1.73 m-2) had a greater AG than those with eGFR ≥ 60 ml·min-1·1.73 m-2 in multivariable regression analysis with adjustment for covariates. We found a graded relationship between the adjusted mean for all three definitions of AG and eGFR categories (P trend < 0.0001). During followup, 9.2% of adults with moderate CKD developed ESRD. Those with AG in the highest tertile had a higher risk of ESRD after adjusting for covariates in a frailty model [relative hazard (95% confidence interval) for traditional AG: 1.76 (1.16-2.32)] compared with those in the middle tertile. The data suggest that high AG, even after adjusting for serum bicarbonate, is a contributing acid-base mechanism to CKD progression in adults with moderate chronic kidney disease.

Health-related quality of life in glomerular disease.

There is scant literature describing the effect of glomerular disease on health-related quality of life (HRQOL). The Cure Glomerulonephropathy study (CureGN) is an international longitudinal cohort study of children and adults with four primary glomerular diseases (minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and IgA nephropathy). HRQOL is systematically assessed using items from the Patient-Reported Outcomes Measurement Informative System (PROMIS). We assessed the relationship between HRQOL and demographic and clinical variables in 478 children and 1115 adults at the time of enrollment into CureGN. Domains measured by PROMIS items included global assessments of health, mobility, anxiety, fatigue, and sleep impairment, as well as a derived composite measure incorporating all measured domains. Multivariable models were created that explained 7 to 32% of variance in HRQOL. Patient-reported edema consistently had the strongest and most robust association with each measured domain of HRQOL in multivariable analysis (adjusted ß [95% CI] for composite PROMIS score in children, -5.2 [-7.1 to -3.4]; for composite PROMIS score in adults, -6.1 [-7.4 to -4.9]). Female sex, weight (particularly obesity), and estimated glomerular filtration rate were also associated with some, but not all, domains of HRQOL. Primary diagnosis, disease duration, and exposure to immunosuppression were not associated with HRQOL after adjustment. Sensitivity analyses and interaction testing demonstrated no significant association between disease duration or immunosuppression and any measured domain of HRQOL. Thus, patient-reported edema has a consistent negative association with HRQOL in patients with primary glomerular diseases, with substantially greater impact than other demographic and clinical variables.

Can 7 or 30-Day Recall Questions Capture Self-Reported Lower Urinary Tract Symptoms Accurately?

PURPOSE: Self-reported measurement tools often provide a recall period, eg "In the past 7 days…" For lower urinary tract symptoms the concordance of end of day (daily) reports with 7 and 30-day recalled reports is unknown to our knowledge. We evaluated how accurately 7 or 30-day recall questions capture lower urinary tract symptoms. MATERIALS AND METHODS: The 261 female and 254 male participants were recruited from a total of 6 United States tertiary care sites. We evaluated 18 items representing 7 symptoms covering storage, voiding and post-micturition symptoms. Item responses on the daily forms were averaged for a 7 or a 30-day period and compared to the corresponding 7 or 30-day recall version of the item. Analyses were item and gender specific. Within person concordance was assessed using the Pearson correlation. Bias (systematic overreporting or underreporting) was calculated as the difference between the recalled item and the averaged daily item score, and reported as a percent of the item scale. RESULTS: All correlations exceeded 0.60. Correlations between averaged daily reports and recalled reports ranged from 0.72 to 0.89 for 7 days and from 0.71 to 0.91 for 30 days among women, and from 0.68 to 0.90 and 0.68 to 0.95, respectively, among men. Most items did not show systematic bias and the median percent bias did not exceed 10% for any item. However, bias exceeding ±10% for some items was observed in a subset of individuals. CONCLUSIONS: Recalled reports during the 7 and 30 days tracked well with averaged daily reports for men and women. Systematic bias was minimal, suggesting that 7 and 30-day recall periods for self-reported lower urinary tract symptoms are reasonable.

Using All Longitudinal Data to Define Time to Specified Percentages of Estimated GFR Decline: A Simulation Study.

RATIONALE & OBJECTIVE: The standard method to calculate time to the event of a specified percentage decline in estimated glomerular filtration rate (eGFR) uses 2 eGFR assessments, 1 at baseline and 1 at the event time. However, event times may be inaccurate due to eGFR variability and restriction of events to study visit times. We propose a novel method for calculating time to a specified percentage decline in eGFR that uses all available longitudinal eGFR assessments. STUDY DESIGN: Simulation study and comparison of methods in 2 observational cohorts. SETTINGS & PARTICIPANTS: Simulation data and study participants in the Nephrotic Syndrome Study Network (NEPTUNE) and Clinical Phenotyping and Resource Biobank Core (C-PROBE). EXPOSURE: Analytical method for calculating time to a specified percentage decline in eGFR: standard 2-point method versus a regression method incorporating all available longitudinally assessed eGFR assessments. OUTCOME: Time to percentage decline in eGFR. ANALYTIC APPROACH: A 2-point method used only the baseline eGFR and first eGFR below the decline threshold. The comparison method used ordinary linear regression incorporating all longitudinal eGFR assessments to define the baseline measure and 40% decline threshold. Time to a 40% decline in eGFR was defined as the time when the regression line crossed the decline threshold. The 2 outcome calculation methods were compared using simulations to assess the accuracy of estimated event times and power to detect event time differences between groups. Comparison of event times calculated using each method was also implemented using data from NEPTUNE and C-PROBE. RESULTS: The regression method incorporating all eGFR assessments was more accurate than the 2-point method in estimating event times in simulation analyses, particularly when eGFR variability was high, there was a greater correlation among successive eGFR values, or there were more missing data. This method was also more powerful in detecting differences between groups. Using NEPTUNE and C-PROBE data, the standard method estimated a more rapid rate of events, some likely representing transient reductions in kidney function, and was less likely to give accurate estimates in the presence of nonlinear eGFR trajectories. LIMITATIONS: Computations required for our proposed method currently limit its use to research rather than clinical applications. CONCLUSIONS: A regression method using all longitudinal eGFR values to estimate time to a percentage decline in eGFR increases accuracy and power over traditional methods, representing a potential improvement in the ability to discover treatment or biomarker effects on kidney disease progression.

Outcomes of the First and Second Hemodialysis Fistula: A Cohort Study.

RATIONALE & OBJECTIVE: Fistulas are the preferred form of hemodialysis access; however, many fistulas fail to mature into usable accesses after creation. Data for outcomes after placement of a second fistula are limited. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: People who initiated hemodialysis therapy in any of 5 Canadian dialysis programs (2004-2012) and had at least 1 hemodialysis fistula placed. PREDICTOR: Second versus initial fistula; receipt of 2 versus 1 fistula; second versus first fistula in recipients of 2 fistulas. OUTCOMES: Catheter-free fistula use during 1 year following initiation of hemodialysis therapy or following fistula creation, if created after hemodialysis therapy start; proportion of time with catheter-free use; time to catheter free use; time of functional patency. ANALYTICAL APPROACH: Logistic regression; fractional regression. RESULTS: Among the 1,091 study participants (mean age, 64±15 [SD] years; 63% men; 59% with diabetes), 901 received 1 and 190 received 2 fistulas. 38% of second fistulas versus 46% of first fistulas were used catheter free at least once. Average percentages of time that second and initial fistulas were used catheter free were 34% and 42%, respectively (OR, 0.72; 95% CI, 0.54-0.94). Compared with people who received 1 fistula, those who received 2 fistulas were less likely to achieve catheter-free use (26% vs 56%) and remain catheter free (23% vs 49% of time; OR, 0.30, 95% CI, 0.24-0.39). Among people who received 2 fistulas, the proportion of time that the second fistula was used catheter free was 11% higher with each 10% greater proportion of time that the first fistula was used catheter free (95% CI, 1%-22%). Model discrimination was modest (C index, 0.69). LIMITATIONS: Unknown criteria for patient selection for 1 or 2 fistulas; unknown reasons for prolonged catheter use. CONCLUSIONS: Outcomes of a second fistula may be inferior to outcomes of the initial fistula. First and second fistula outcomes are weakly correlated and difficult to predict based on clinical characteristics.

CureGN Study Rationale, Design, and Methods: Establishing a Large Prospective Observational Study of Glomerular Disease.

RATIONALE & OBJECTIVES: Glomerular diseases, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and immunoglobulin A (IgA) nephropathy, share clinical presentations, yet result from multiple biological mechanisms. Challenges to identifying underlying mechanisms, biomarkers, and new therapies include the rarity of each diagnosis and slow progression, often requiring decades to measure the effectiveness of interventions to prevent end-stage kidney disease (ESKD) or death. STUDY DESIGN: Multicenter prospective cohort study. SETTING & PARTICIPANTS: Cure Glomerulonephropathy (CureGN) will enroll 2,400 children and adults with minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, or IgA nephropathy (including IgA vasculitis) and a first diagnostic kidney biopsy within 5 years. Patients with ESKD and those with secondary causes of glomerular disease are excluded. EXPOSURES: Clinical data, including medical history, medications, family history, and patient-reported outcomes, are obtained, along with a digital archive of kidney biopsy images and blood and urine specimens at study visits aligned with clinical care 1 to 4 times per year. OUTCOMES: Patients are followed up for changes in estimated glomerular filtration rate, disease activity, ESKD, and death and for nonrenal complications of disease and treatment, including infection, malignancy, cardiovascular, and thromboembolic events. ANALYTICAL APPROACH: The study design supports multiple longitudinal analyses leveraging the diverse data domains of CureGN and its ancillary program. At 2,400 patients and an average of 2 years' initial follow-up, CureGN has 80% power to detect an HR of 1.4 to 1.9 for proteinuria remission and a mean difference of 2.1 to 3.0mL/min/1.73m2 in estimated glomerular filtration rate per year. LIMITATIONS: Current follow-up can only detect large differences in ESKD and death outcomes. CONCLUSIONS: Study infrastructure will support a broad range of scientific approaches to identify mechanistically distinct subgroups, identify accurate biomarkers of disease activity and progression, delineate disease-specific treatment targets, and inform future therapeutic trials. CureGN is expected to be among the largest prospective studies of children and adults with glomerular disease, with a broad goal to lessen disease burden and improve outcomes.

Does One Size Fit All With the Effects of Payment Reform? Dialysis Facility Payer Mix and Anemia Management Under the Expanded Medicare Prospective Payment System.

BACKGROUND: The effects of Medicare payment reforms aiming to improve the efficiency and quality of care by establishing greater financial accountability for providers may vary based on the extent and types of other coverage for their patient populations. Providers who are more resource constrained due to a less favorable payer mix face greater financial risks under such reforms. The impact of the expanded Medicare dialysis prospective payment system (PPS) on quality of care in independent dialysis facilities may vary based on the extent of higher payments from private insurers available for managing increased risks. OBJECTIVES: To evaluate whether anemia outcomes for dialysis patients in independent facilities differ under the Medicare PPS based on facility payer mix. DESIGN: We examined changes in anemia outcomes for 122,641 Medicare dialysis patients in 921 independent facilities during 2009-2014 among facilities with differing levels of employer insurance (EI). We performed similar analyses of facilities affiliated with large dialysis organizations, whose practices were not expected to change based on facility-specific payer mix. RESULTS: Among independent facilities, similar modeled trends in low hemoglobin for all 3 facility EI groups in 2009-2010 were followed by increased low hemoglobin during 2012-2014 for facilities with lower EI (P<0.01). Post-PPS standardized blood transfusion ratios were 9% higher for lower EI versus higher EI independent facilities (P<0.01). Among large dialysis organizations facilities, there was no divergence in low hemoglobin by payer mix under the PPS. CONCLUSIONS: There is evidence of poorer quality of care for anemia under the PPS in independent facilities with lower versus higher EI. Provider responses to payment reform may vary based on attributes such as payer mix that could have implications for health disparities.