Kidney Outcomes with Sodium-Glucose Cotransporter-2 Inhibitor Initiation after AKI among Veterans with Diabetic Kidney Disease

Key Points

Post-AKI sodium–glucose cotransporter-2 inhibitor use was associated with a reduced risk for progression of CKD and for recurrent AKI among veterans with diabetic kidney disease even after accounting for recovery from the index AKI. A minority of Veterans with diabetic kidney disease received a sodium–glucose cotransporter-2 inhibitor after having had AKI during the study period.

Background

The effect of sodium–glucose cotransporter-2 inhibitor (SGLT2i) on kidney function after AKI is unknown.

Methods

The study population was drawn from a retrospective cohort of Veterans with diabetes mellitus type 2 (DM2) and proteinuria. The study exposure was time-varying use of SGLT2i after an index AKI hospitalization. The two study outcomes were time to (1 ) a sustained decrease in eGFR over at least 3 months to <60 ml/min per 1.73 m2 and ≥30% below a post-AKI–updated eGFR and (2 ) recurrent hospitalization with AKI. AKI was defined as a rise in serum creatinine concentration to ≥50% above a moving outpatient creatinine baseline. DM2 was defined by ≥2 billing codes related to DM2 before the index AKI; proteinuria was defined by the most recent albuminuria, proteinuria, or urinalysis test. Veterans were required to have a baseline eGFR and an eGFR 3–12 months after the index AKI hospitalization ≥30 ml/min per 1.73 m2.

Results

Ten thousand thirty-six Veterans met study inclusion criteria. Two thousand seven hundred and ninety-four (28%) received a SGLT2i. Seven hundred and seventy-five (8%) had CKD progression, and 1816 (18%) had recurrent AKI over a median follow-up of 1.8 and 1.7 years, respectively, which began 1 year after the index AKI hospitalization. SGLT2i use was associated with lower risk for CKD progression (adjusted hazard ratio 0.72 [95% confidence interval, 0.57 to 0.91]) and for recurrent AKI (adjusted hazard ratio 0.75 [95% confidence interval, 0.65 to 0.88]).

Conclusions

SGLT2i use was associated with a lower risk for CKD progression and for recurrent AKI among those with diabetic kidney disease and recent AKI.

Strategies for secondary use of real-world clinical and administrative data for outcome ascertainment in pragmatic clinical trials

BACKGROUND

Pragmatic trials are gaining popularity as a cost-effective way to examine treatment effectiveness and generate timely comparative evidence. Incorporating supplementary real-world data is recommended for robust outcome monitoring. However, detailed operational guidelines are needed to inform effective use and integration of heterogeneous databases.

OBJECTIVE

Lessons learned from the Veterans Affairs (VA) Diuretic Comparison Project (DCP) are reviewed, providing adaptable recommendations to capture clinical outcomes from real-world data.

METHODS

Non-cancer deaths and major cardiovascular (CV) outcomes were determined using VA, Medicare, and National Death Index (NDI) data. Multiple ascertainment strategies were applied, including claims-based algorithms, natural language processing, and systematic chart review.

RESULTS

During a mean follow-up of 2.4 (SD = 1.4) years, 907 CV events were identified within the VA healthcare system. Slight delays (∼1 year) were expected in obtaining Medicare data. An additional 298 patients were found having a CV event outside of the VA in 2016 - 2021, increasing the CV event rate from 3.5 % to 5.7 % (770 of 13,523 randomized). NDI data required ∼2 years waiting period. Such inclusion did not increase the number of deaths identified (all 894 deaths were captured by VA data) but enhanced the accuracy in determining cause of death.

CONCLUSION

Our experience supports the recommendation of integrating multiple data sources to improve clinical outcome ascertainment. While this approach is promising, hierarchical data aggregation is required when facing different acquisition timelines, information availability/completeness, coding practice, and system configurations. It may not be feasible to implement comparable applications and solutions to studies conducted under different constraints and practice. The recommendations provide guidance and possible action plans for researchers who are interested in applying cross-source data to ascertain all study outcomes.

Pharmacist-driven outreach initiative to increase prescribing of sodium-glucose cotransporter-2 inhibitors in eligible VHA patients with chronic kidney disease: a study protocol

BACKGROUND

Patients with chronic kidney disease (CKD) are at increased risk for multiple adverse events, several of which have been proven to be less likely with the use of sodium-glucose cotransporter-2 inhibitors (SGLT2i). As a result, guidelines now recommend SGLT2i be given to those with mild to moderate CKD and type 2 diabetes. The objective of this study is to evaluate if a pharmacist-driven SGLT2i prescribing initiative among eligible patients with CKD and diabetes within the VA could more rapidly improve the adoption of SGLT2i via a pragmatic approach aligned with learning health systems.

METHODS

Eligible patients will be identified through an established VA diabetes dashboard. Veterans with an odd social security number (SSN), which is effectively a random number, will be the intervention group. Those with even SSNs will serve as the control while awaiting a second iteration of the same interventional program. The intervention will be implemented in a rolling fashion across one Veterans Integrated Service Network. Our primary outcome is initiation of an SGLT2i. Secondary outcomes will include medication adherence and safety-related outcomes.

DISCUSSION

This project tests the impact of a pharmacist-driven medication outreach initiative as a strategy to accelerate initiation of SGLT2i. The results of this work will not only illustrate the effectiveness of this strategy for SGLT2is but may also have implications for increasing other guideline-concordant care. Furthermore, the utilization of SSNs to select Veterans for the first wave of this program has created a pseudo-randomized interventional trial supporting a pragmatic learning health system approach.

TRIAL REGISTRATION

ISRCTN12374636.

Effect of Intensive Blood Pressure Control on Kidney Outcomes: Long-Term Electronic Health Record-Based Post-Trial Follow-Up of SPRINT

BACKGROUND

Intensive BP lowering in the Systolic Blood Pressure Intervention Trial (SPRINT) produced acute decreases in kidney function and higher risk for AKI. We evaluated the effect of intensive BP lowering on long-term changes in kidney function using trial and outpatient electronic health record (EHR) creatinine values.

METHODS

SPRINT data were linked with EHR data from 49 (of 102) study sites. The primary outcome was the total slope of decline in eGFR for the intervention phase and the post-trial slope of decline during the observation phase using trial and outpatient EHR values. Secondary outcomes included a ≥30% decline in eGFR to <60 ml/min per 1.73 m 2 and a ≥50% decline in eGFR or kidney failure among participants with baseline eGFR ≥60 and <60 ml/min per 1.73 m 2 , respectively.

RESULTS

EHR creatinine values were available for a median of 8.3 years for 3041 participants. The total slope of decline in eGFR during the intervention phase was -0.67 ml/min per 1.73 m 2 per year (95% confidence interval [CI], -0.79 to -0.56) in the standard treatment group and -0.96 ml/min per 1.73 m 2 per year (95% CI, -1.08 to -0.85) in the intensive treatment group ( P < 0.001). The slopes were not significantly different during the observation phase: -1.02 ml/min per 1.73 m 2 per year (95% CI, -1.24 to -0.81) in the standard group and -0.85 ml/min per 1.73 m 2 per year (95% CI, -1.07 to -0.64) in the intensive group. Among participants without CKD at baseline, intensive treatment was associated with higher risk of a ≥30% decline in eGFR during the intervention (hazard ratio, 3.27; 95% CI, 2.43 to 4.40), but not during the postintervention observation phase. In those with CKD at baseline, intensive treatment was associated with a higher hazard of eGFR decline only during the intervention phase (hazard ratio, 1.95; 95% CI, 1.03 to 3.70).

CONCLUSIONS

Intensive BP lowering was associated with a steeper total slope of decline in eGFR and higher risk for kidney events during the intervention phase of the trial, but not during the postintervention observation phase.

Renin-Angiotensin-Aldosterone System Blockade after AKI with or without Recovery among US Veterans with Diabetic Kidney Disease

SIGNIFICANCE STATEMENT

Among patients with CKD, optimal use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers after AKI is uncertain. Despite these medications' ability to reduce risk of mortality and other adverse outcomes, there is concern that ACEi/ARB use may delay recovery of kidney function or precipitate recurrent AKI. Prior studies have provided conflicting data regarding the optimal timing of these medications after AKI and have not addressed the role of kidney recovery in determining appropriate timing. This study in US Veterans with diabetes mellitus and proteinuria demonstrated an association between ACEi/ARB use and lower mortality. This association was more pronounced with earlier post-AKI ACEi/ARB use and was not meaningfully affected by initiating ACEis/ARBs before versus after recovery from AKI.

BACKGROUND

Optimal use of angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) after AKI is uncertain.

METHODS

Using data derived from electronic medical records, we sought to estimate the association between ACEi/ARB use after AKI and mortality in US military Veterans with indications for such treatment (diabetes and proteinuria) while accounting for AKI recovery. We used ACEi/ARB treatment after hospitalization with AKI (defined as serum creatinine ≥50% above baseline concentration) as a time-varying exposure in Cox models. The outcome was all-cause mortality. Recovery was defined as return to ≤110% of baseline creatinine. A secondary analysis focused on ACEi/ARB use relative to AKI recovery (before versus after).

RESULTS

Among 54,735 Veterans with AKI, 31,146 deaths occurred over a median follow-up period of 2.3 years. Approximately 57% received an ACEi/ARB <3 months after hospitalization. In multivariate analysis with time-varying recovery, post-AKI ACEi/ARB use was associated with lower risk of mortality (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.72 to 0.77). The association between ACEi/ARB use and mortality varied over time, with lower mortality risk associated with earlier initiation ( P for interaction with time <0.001). In secondary analysis, compared with those with neither recovery nor ACEi/ARB use, risk of mortality was lower in those with recovery without ACEi/ARB use (aHR, 0.90; 95% CI, 0.87 to 0.94), those without recovery with ACEi/ARB use (aHR, 0.69; 95% CI, 0.66 to 0.72), and those with ACEi/ARB use after recovery (aHR, 0.70; 95% CI, 0.67 to 0.73).

CONCLUSIONS

This study demonstrated lower mortality associated with ACEi/ARB use in Veterans with diabetes, proteinuria, and AKI, regardless of recovery. Results favored earlier ACEi/ARB initiation.

A Centralized EHR-Based Model for the Recruitment of Rural and Lower Socioeconomic Participants in Pragmatic Trials: A Secondary Analysis of the Diuretic Comparison Project

Importance

Participant diversity is important for reducing study bias and increasing generalizability of comparative effectiveness research.

Objective

Demonstrate the operational efficiency of a centralized electronic health record (EHR)-based model for recruiting difficult-to-reach participants in a pragmatic trial.

Design, Setting, and Participants

This comparative effectiveness study was a secondary analysis of Diuretic Comparison Project, a randomized clinical trial conducted between 2016 and 2022 (mean [SD] follow-up, 2.4 [1.4] years) comparing 2 commonly prescribed antihypertensives, which used an EHR-based recruitment model. Electronic study workflows, in tandem with routine clinical practice, were adapted by 72 Veteran Affairs (VA) primary care networks. Data were analyzed from August to December 2022.

Main Outcomes and Measures

Measures reflecting recruitment capacity (monthly rate), operational efficiency (median time for completion of electronic procedures), and geographic reach (percentage of patients recruited from rural areas) were examined.

Results

A total of 13 523 patients with hypertension (mean [SD] age, 72 [5.4] years; 13 092 male [96.8%]) were recruited from 537 outpatient clinics. Approximately 205 patients were randomized per month and a median of 35 days (Q1-Q3, 23-80 days) was needed to complete electronic recruitment. The annual income was below the national median for 69% of the cohort. Patients from all 50 states, Puerto Rico, and the District of Columbia were included and 45% resided in rural areas.

Conclusions and Relevance

In this secondary analysis of a multicenter pragmatic trial, a centralized EHR-based recruitment model was associated with improved participation from underrepresented groups. These participants often are difficult to reach, with their exclusion potentially biasing trial results; eliminating in-person study visits and local site involvement can minimize barriers for the recruitment of patients from rural and lower socioeconomic areas.

Trial Registration

The Diuretic Comparison Project (DCP) was registered on ClinicalTrials.gov Identifier: NCT02185417.

Practical issues in pragmatic trials: the implementation of the Diuretic Comparison Project

BACKGROUND/AIMS

The US Department of Veterans Affairs Point of Care Clinical Trial Program conducts studies that utilize informatics infrastructure to integrate clinical trial protocols into routine care delivery. The Diuretic Comparison Project compared hydrochlorothiazide to chlorthalidone in reduction of major cardiovascular events in subjects with hypertension. Here we describe the cultural, technical, regulatory, and logistical challenges and solutions that enabled successful implementation of this large pragmatic comparative effectiveness Point of Care clinical trial.

METHODS

Patients were recruited from 72 Veterans Affairs Healthcare Systems using centralized processes for subject identification, obtaining informed consent, data collection, safety monitoring, site communication, and endpoint identification with minimal perturbation of the local clinical care ecosystem. Patients continued to be managed exclusively by their clinical care providers without protocol specified study visits, treatment recommendations, or data collection extraneous to routine care. Centralized study processes were operationalized through the application layer of the electronic health record via a data coordinating center staffed by clinical nurses, data scientists, and statisticians without site-based research coordinators. Study data was collected from the Veterans Affairs electronic health record supplemented by Medicare and National Death Index data.

RESULTS

The study exceeded its enrolled goal (13,523 subjects) and followed subjects for the 5-year study duration. The key determinant of program success was collaboration between researchers, regulators, clinicians, and administrative staff at the site level to customize study procedures to align with local clinical practice. This flexibility was enabled by designation of the study as minimal risk and determination that clinical care providers were not engaged in research by the Veterans Affairs Central Institutional Review Board. Cultural, regulatory, technical, and logistical problems were identified and solved through iterative collaboration between clinical and research entities. Paramount among these problems was customization of the Veterans Affairs electronic health record and data systems to accommodate study procedures.

CONCLUSIONS

Leveraging clinical care for large-scale clinical trials is feasible but requires a rethinking of traditional clinical trial design (and regulation) to better meet requirements of clinical care ecosystems. Study designs must accommodate site-specific practice variation to reduce the impact on clinical care. A tradeoff thus exists between designing trial processes tailored to expedite local study implementation versus those to produce a more refined response to the research question. The availability of a uniform and flexible electronic health record in the Department of Veterans Affairs played a major role in the success of the trial. Conducting Point of Care research in other healthcare systems without such research-friendly infrastructure presents a more formidable challenge.

Telephone informed consent in a pragmatic point-of-care clinical trial embedded in primary care

BACKGROUND

One benefit of pragmatic clinical trials is reduction of the burden on patients and clinical staff while facilitating a learning healthcare system. One way to decrease the work of clinical staff is through decentralized telephone consent.

METHODS

The Diuretic Comparison Project (DCP) was a nationwide Point of Care pragmatic clinical trial conducted by the VA Cooperative Studies Program. The purpose of the trial was to compare the clinical effectiveness on major CV outcomes of two commonly used diuretics, hydrochlorothiazide and chlorthalidone, in an elderly patient population. Telephone consent was allowed for this study because of its minimal risk designation. Telephone consent was more difficult than initially anticipated and the study team constantly adjusted methods to find timely solutions.

RESULTS

The major challenges can be categorized as call center-related, telecommunications, operational, and study population based. In particular, the possible technical and operational pitfalls are rarely discussed. By presenting hurdles here, future studies may avoid these challenges and start studies with a more effective system in place.

CONCLUSIONS

DCP is a novel study designed to answer an important clinical question. The lessons learned from implementing a centralized call center for the Diuretic Comparison Project helped the study reach enrollment goals and develop a centralized telephone consent system that can be utilized for future pragmatic and explanatory clinical trials.

CLINICAL TRIAL REGISTRATION

The study is registered on ClinicalTrials.gov; NCT02185417 [https://clinicaltrials.gov/ct2/show/NCT02185417]. The contents do not represent the views of the U.S. Department of Veterans Affairs or the United States Government.

Ascertainment of stroke from administrative data to support a pragmatic embedded clinical trial

The goal of this observational study was to identify stroke hospitalizations using International Classification of Disease (ICD)-10 codes and use these codes to develop an ascertainment algorithm for use in pragmatic clinical trials, reducing or eliminating the need for manual chart adjudication in future. Using VA (Veterans Affairs) electronic medical records, 9959 patient charts with ICD-10 codes indicating stroke were screened and a sample of 304 were adjudicated by three clinical reviewers. Hospitalizations were categorized as stroke or non-stroke and positive predictive value (PPV) was calculated for each ICD-10 code that was sampled. The adjudicated codes were categorized for use in a decision tool for identifying stroke in a clinical trial. Of the 304 hospitalizations adjudicated, 192 met the definition of stroke. Of the ICD-10 codes evaluated, I61 yielded the highest PPV (100%) while I63.x yielded the 2nd highest PPV (90%) with a false discovery rate of 10%. A relatively high PPV of ≥80% was associated with codes I60.1-0.7, I61, I62.9 and I63, which accounted for nearly half of all cases reviewed. Hospitalizations associated with these codes were categorized at positive stroke cases. The incorporation of large administrative datasets, and elimination of trial specific data collection, increases efficiencies, while reducing costs. Accurate algorithms must be developed to allow for identification of clinical endpoints from administrative databases to offer a reliable alternative to study-specific case report form completion. This study demonstrates an example of how to apply medical record data to a decision tool for clinical trial outcomes. CSP597 or clinicaltrials.gov NCT02185417.

Concordance between clinical outcomes in the Systolic Blood Pressure Intervention Trial and in the electronic health record

BACKGROUND

Randomized trials are the gold standard for generating clinical practice evidence, but follow-up and outcome ascertainment are resource-intensive. Electronic health record (EHR) data from routine care can be a cost-effective means of follow-up, but concordance with trial-ascertained outcomes is less well-studied.

METHODS

We linked EHR and trial data for participants of the Systolic Blood Pressure Intervention Trial (SPRINT), a randomized trial comparing intensive and standard blood pressure targets. Among participants with available EHR data concurrent to trial-ascertained outcomes, we calculated sensitivity, specificity, positive predictive value, and negative predictive value for EHR-recorded cardiovascular disease (CVD) events, using the gold standard of SPRINT-adjudicated outcomes (myocardial infarction (MI)/acute coronary syndrome (ACS), heart failure, stroke, and composite CVD events). We additionally compared the incidence of non-CVD adverse events (hyponatremia, hypernatremia, hypokalemia, hyperkalemia, bradycardia, and hypotension) in trial versus EHR data.

RESULTS

2468 SPRINT participants were included (mean age 68 (SD 9) years; 26% female). EHR data demonstrated ≥80% sensitivity and specificity, and ≥ 99% negative predictive value for MI/ACS, heart failure, stroke, and composite CVD events. Positive predictive value ranged from 26% (95% CI; 16%, 38%) for heart failure to 52% (95% CI; 37%, 67%) for MI/ACS. EHR data uniformly identified more non-CVD adverse events and higher incidence rates compared with trial ascertainment.

CONCLUSIONS

These results support a role for EHR data collection in clinical trials, particularly for capturing laboratory-based adverse events. EHR data may be an efficient source for CVD outcome ascertainment, though there is clear benefit from adjudication to avoid false positives.

The impact of COVID-19 on a large pragmatic clinical trial embedded in primary care

INTRODUCTION

The COVID-19 pandemic had significant impact on clinical care and clinical trial operations, but the impact on decentralized pragmatic trials is unclear. The Diuretic Comparison Project (DCP) is a Point-of Care (POC) pragmatic trial testing whether chlorthalidone is superior to hydrochlorothiazide in preventing major cardiovascular (CV) events and non-cancer death. DCP utilized telephone consent, data collection from the electronic health record and Medicare, forwent study visits, and limited provider commitment beyond usual care. We assessed the impact of COVID-19 on recruitment, follow-up, data collection, and outcome ascertainment in DCP.

METHODS

We compared data from two 8-month periods: Pre-Pandemic (July 2019-February 2020) and Mid-Pandemic (July 2020-February 2021). Consent and randomization rates, diuretic adherence, blood pressure (BP) and electrolyte follow-up rates, records of CV events, hospitalization, and death rates were compared.

RESULTS

Providers participated at a lower rate mid-pandemic (65%) than pre-pandemic (71%), but more patients were contacted (7622 vs. 5363) and consented (3718 vs. 3048) mid-pandemic than pre-pandemic. Patients refilled medications and remained on their randomized diuretic equally (90%) in both periods. Overall, rates of BP, electrolyte measurements, and hospitalizations decreased mid-pandemic while deaths increased.

CONCLUSIONS

While recruitment, enrollment, and adherence did not suffer during the pandemic, documented blood pressure checks and laboratory evaluations decreased, likely due to fewer in-person visits. VA hospitalizations decreased, despite a considerable number of COVID-related hospitalizations. This suggests changes in clinical care during the pandemic, but the limited impact on DCP's operations during a global pandemic is an important strength of POC trials.

CLINICAL TRIAL REGISTRATION

NCT02185417.

Chlorthalidone vs. Hydrochlorothiazide for Hypertension-Cardiovascular Events

BACKGROUND

Whether chlorthalidone is superior to hydrochlorothiazide for preventing major adverse cardiovascular events in patients with hypertension is unclear.

METHODS

In a pragmatic trial, we randomly assigned adults 65 years of age or older who were patients in the Department of Veterans Affairs health system and had been receiving hydrochlorothiazide at a daily dose of 25 or 50 mg to continue therapy with hydrochlorothiazide or to switch to chlorthalidone at a daily dose of 12.5 or 25 mg. The primary outcome was a composite of nonfatal myocardial infarction, stroke, heart failure resulting in hospitalization, urgent coronary revascularization for unstable angina, and non-cancer-related death. Safety was also assessed.

RESULTS

A total of 13,523 patients underwent randomization. The mean age was 72 years. At baseline, hydrochlorothiazide at a dose of 25 mg per day had been prescribed in 12,781 patients (94.5%). The mean baseline systolic blood pressure in each group was 139 mm Hg. At a median follow-up of 2.4 years, there was little difference in the occurrence of primary-outcome events between the chlorthalidone group (702 patients [10.4%]) and the hydrochlorothiazide group (675 patients [10.0%]) (hazard ratio, 1.04; 95% confidence interval, 0.94 to 1.16; P = 0.45). There were no between-group differences in the occurrence of any of the components of the primary outcome. The incidence of hypokalemia was higher in the chlorthalidone group than in the hydrochlorothiazide group (6.0% vs. 4.4%, P<0.001).

CONCLUSIONS

In this large pragmatic trial of thiazide diuretics at doses commonly used in clinical practice, patients who received chlorthalidone did not have a lower occurrence of major cardiovascular outcome events or non-cancer-related deaths than patients who received hydrochlorothiazide. (Funded by the Veterans Affairs Cooperative Studies Program; ClinicalTrials.gov number, NCT02185417.).

Effect of Intensive versus Standard BP Control on AKI and Subsequent Cardiovascular Outcomes and Mortality: Findings from the SPRINT EHR Study

Background

Adjudication of inpatient AKI in the Systolic Blood Pressure Intervention Trial (SPRINT) was based on billing codes and admission and discharge notes. The purpose of this study was to evaluate the effect of intensive versus standard BP control on creatinine-based inpatient and outpatient AKI, and whether AKI was associated with cardiovascular disease (CVD) and mortality.

Methods

We linked electronic health record (EHR) data from 47 clinic sites with trial data to enable creatinine-based adjudication of AKI. Cox regression was used to evaluate the effect of intensive BP control on the incidence of AKI, and the relationship between incident AKI and CVD and all-cause mortality.

Results

A total of 3644 participants had linked EHR data. A greater number of inpatient AKI events were identified using EHR data (187 on intensive versus 155 on standard treatment) as compared with serious adverse event (SAE) adjudication in the trial (95 on intensive versus 61 on standard treatment). Intensive treatment increased risk for SPRINT-adjudicated inpatient AKI (HR, 1.51; 95% CI, 1.09 to 2.08) and for creatinine-based outpatient AKI (HR, 1.40; 95% CI, 1.15 to 1.70), but not for creatinine-based inpatient AKI (HR, 1.20; 95% CI, 0.97 to 1.48). Irrespective of the definition (SAE or creatinine based), AKI was associated with increased risk for all-cause mortality, but only creatinine-based inpatient AKI was associated with increased risk for CVD.

Conclusions

Creatinine-based ascertainment of AKI, enabled by EHR data, may be more sensitive and less biased than traditional SAE adjudication. Identifying ways to prevent AKI may reduce mortality further in the setting of intensive BP control.

Design of a pragmatic clinical trial embedded in the Electronic Health Record: The VA's Diuretic Comparison Project

BACKGROUND

Recent US guidelines recommend chlorthalidone over other thiazide-type diuretics for the treatment of hypertension based on its long half-life and proven ability to reduce CVD events. Despite recommendations most clinicians prescribe hydrochlorothiazide (HCTZ) over chlorthalidone (CTD). No randomized controlled data exist comparing these two diuretics on cardiovascular outcomes.

METHODS

The Diuretic Comparison Project (DCP) is a multicenter, two-arm, parallel, Prospective Randomized Open, Blinded End-point (PROBE) trial testing the primary hypothesis that CTD is superior to HCTZ in the prevention of non-fatal CVD events and non-cancer death. Patients with hypertension taking HCTZ 25 or 50 mg were randomly assigned to either continue their current HCTZ or switch to an equipotent dose of CTD. The primary outcome is time to the first occurrence of a composite outcome consisting of a non-fatal CVD event (stroke, myocardial infarction, urgent coronary revascularization because of unstable angina, or hospitalization for acute heart failure) or non-cancer death. The trial randomized 13,523 patients at 72 VA medical centers. The study is conducted by a centralized research team with site procedures embedded in the electronic health record and all data collected through administrative claims data, with no study related visits for participants. The trial will have 90% power to detect an absolute reduction in the composite event rate of 2.4%.

RESULTS

Enrollment ended in November 2021. There are 4128 participting primary care providers and 16,595 patients individually consented to participate, 13,523 of whom were randomized.

CONCLUSIONS

DCP should provide much needed evidence as to whether CTD is superior to HCTZ in preventing cardiovascular events in hypertensive patients.

CLINICAL TRIAL REGISTRATION

NCT02185417 [https://clinicaltrials.gov/ct2/show/NCT02185417].

β-Blocker Use and Cardiovascular Outcomes in Hemodialysis: A Systematic Review

Rationale & Objective

There is conflicting evidence regarding the type of β-blockers to use in dialysis patients. This systematic review seeks to determine whether highly dialyzable β-blockers are associated with higher rates of cardiovascular events and mortality in hemodialysis patients than poorly dialyzable β-blockers.

Study Design

A systematic review of the existing literature was conducted. A meta-analysis was performed using data from the selected studies.

Setting & Study Populations

Participants were from the United States, Canada, and Taiwan. The mean ages of participants ranged from 55.9-75.7 years.

Selection Criteria for Studies

We searched the Ovid MEDLINE database from 1990 to September 2020. Studies without adult hemodialysis participants and without comparisons of at least 2 β-blockers of different dialyzability were excluded.

Data Extraction

Baseline and adjusted outcome data were extracted from each study.

Analytical Approach

Random-effects models were used to calculate pooled risk ratios using fully adjusted models from individual studies.

Results

Four cohort studies were included. Pooling fully adjusted models, highly dialyzable β-blockers did not influence mortality (HR, 0.94; 95% CI, 0.81-1.08; I² = 0.84) compared with poorly dialyzable β-blockers but were associated with a reduction in cardiovascular events (HR, 0.88; 95% CI, 0.83-0.93). There was significant heterogeneity between studies (I² = 0.35). Only 1 study reported on adverse events. Intradialytic hypotension was more common in those on carvedilol (a poorly dialyzable β-blocker) compared with those on metoprolol (a highly dialyzable β-blocker; adjusted incidence rate ratio, 1.10; 95% CI, 1.09-1.11).

Limitations

No randomized controlled trials were identified. Each study used different analytic methods and different definitions for outcomes. Classifications of β-blockers varied. Only 1 study reported on adverse events.

Conclusions

Pooled data suggest highly dialyzable β-blockers are associated with similar mortality events and fewer cardiovascular events compared with poorly dialyzable β-blockers.

Impact of Antihypertensive Drug Class on Outcomes in the SPRINT

BACKGROUND

The primary objective of this analysis is to assess if greater exposure to any major antihypertensive drug class was associated with reduced primary composite outcome events in SPRINT (Systolic Blood Pressure Intervention Trial).

METHODS

This is a secondary analysis of the SPRINT trial evaluating whether longitudinal, time varying exposure to any major antihypertensive drug class had any impact on primary outcome events, after adjusting for effects of randomization arm, time varying achieved systolic blood pressure, other drug class exposure, and baseline characteristics.

RESULTS

Nine thousand two hundred fifty-two participants were included. After adjustments, exposure of one year or greater to thiazide-type diuretics or renin-angiotensin system blockers was associated with significantly fewer primary events than exposure of less than one year (hazard ratio, 0.78 [95% CI, 0.64-0.94]). There was no significant difference with longer versus shorter exposure to calcium channel blockers. Greater exposure to beta-blockers was associated with an increase in primary events compared with exposure of <1 year (hazard ratio, 1.35 [95% CI, 1.13-1.62]). Furthermore, thiazide-type diuretics were associated with a reduction in heart failure events and renin-angiotensin system blockers with reduced myocardial infarction. Both were associated with less cardiovascular deaths.

CONCLUSIONS

The SPRINT trial demonstrated a lower target blood pressure led to reductions in adverse cardiovascular events. This analysis suggests greater exposure to thiazide-type diuretics and renin-angiotensin system blockers also contributed to reduced adverse cardiovascular events. Greater exposure to beta-blockers was associated with increased cardiovascular events.

Does experience matter? The relationship between nephrologist characteristics and end stage kidney disease patient outcomes

BACKGROUND

Nephrology offers the unique opportunity to directly link patients to providers, allowing the study of patient outcomes at the provider level. The purpose of this analysis was to determine whether nephrologist experience, defined as years in nephrology practice, was associated with clinical outcomes.

DESIGN

Physician data contained within the American Medical Association (AMA) Physician Masterfile was combined with patient and Medicare claims data from the United States Renal Data System (USRDS) for the calendar year 2012, with follow up extending through June 30, 2014. Associations with important healthcare outcomes including mortality in patients receiving maintenance renal replacement therapy (RRT), waitlisting for kidney transplantation, and receipt of a kidney transplant were determined with broad adjustment for both patient and provider level variables, with attention on tertile of provider time in practice.

RESULTS

We identified 256,324 patients on maintenance RRT cared for by 6193 nephrologists. Nephrologists with the least experience were more likely to be female, reside in a region with ≥1,000,000 people, have a Doctor of Osteopathic Medicine degree, and have a listed maintenance of certification status as "yes." Overall, 30.2% of the cohort died at a mean follow up of 1.99 years. Compared to those with the 0-10 years of experience, receipt of care from nephrologists with more experience was associated with lower mortality (AHR 0.97 CI 0.94-0.99 for nephrologists with 11-20 years) and increased listing for kidney transplantation (AHR 1.10; CI 1.01-1.21 for nephrologists with >21 years experience). Experience level did not result in a difference in kidney transplantation rates.

CONCLUSIONS

Receipt of maintenance RRT from nephrologists with greater experience was associated with decreased mortality and increased listing for kidney transplantation, an effect that remained significant after multiple adjustments for important patient and nephrologist variables.

Pragmatic clinic randomized trial to improve chronic kidney disease care: Design and adaptation due to COVID disruptions

BACKGROUND

We describe a clinic-randomized trial to improve chronic kidney disease (CKD) care through a CKD-clinical decision support (CKD-CDS) intervention in primary care clinics and the challenges we encountered due to COVID-19 care disruption.

METHODS/DESIGN

Primary care clinics (N = 32) were randomized to usual care (UC) or to CKD-CDS. Between April 17, 2019 and March 14, 2020, more than 7000 patients had accrued for analysis by meeting study-eligibility criteria at an index office visit: age 18-75, laboratory criteria for stage 3 or 4 CKD (eGFR 15-59 mL/min/1.73 m2), and one or more opportunities algorithmically identified to improve CKD care such as blood pressure (BP) or glucose control, angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) use, discontinuance of a nonsteroidal anti-inflammatory drug (NSAID), or nephrology referral. At CKD-CDS clinics, CDS provided individualized treatment suggestions that were printed for patients and clinicians at the start of office encounters and were viewable within the electronic health record. By initial design, the impact of the CKD-CDS intervention on care gaps was to be assessed 12 months after the index date, but COVID-19 caused major disruptions to care delivery during the intervention period. In response to disruptions, the intervention was temporarily suspended while we expanded CDS use for telehealth encounters and programmed new criteria for displaying the CKD-CDS to intervention patients due to clinic closures and scheduling changes.

DISCUSSION

We describe a NIH-funded pragmatic trial of web-based EHR-integrated CKD-CDS and modifications necessary mid-study to complete the study as intended in the face of COVID-19 pandemic challenges.

Abstract P268: The Impact Of Covid-19 On A Large Pragmatic Clinical Trial Embedded In Primary Care

Introduction: The COVID-19 pandemic has had a significant impact on traditional clinical trial operations, but it is unclear whether the impact persists in pragmatic trials with a centralized study design. The Diuretic Comparison Project (DCP) is a Point-of Care pragmatic trial that operates through a usual care system to compare chlorthalidone and hydrochlorothiazide at preventing major cardiovascular (CV) events and non-cancer death. We assessed the impact of the COVID-19 pandemic on the centralized recruitment, patient follow-up, data collection, and outcome ascertainment performed in the DCP.

Methods: We assessed operations in two 8-month periods: Pre-COVID-19 (Jul 2019 - Feb 2020) and Mid-COVID-19 (Jul 2020 - Feb 2021). Enrollment, study medication adherence, blood pressure (BP) and electrolyte follow-up rates, VA records of CV events, all-cause hospitalization, and death rates were compared.

Results: Providers agreed to participate at a lower rate, but more patients were contacted and randomized during mid-COVID-19. While BP evaluations decreased, the rates of electrolyte, major CV, and medication prescription records were comparable to the pre-COVID-19 period ( Table 1 ).

Conclusions: The DCP was able to recruit and maintain critical data collection at the pre-COVID-19 levels. There were some decreases in BP evaluations, likely due to fewer in-person visits. All-cause VA hospitalizations also decreased, despite rises in COVID-related hospitalizations and death. While the impact on outcome and safety rates awaits complete data from Medicare, the DCP has demonstrated a promising centralized design that can support pragmatic trial operations during a pandemic.

Estimated GFR Variability and Risk of Cardiovascular Events and Mortality in SPRINT (Systolic Blood Pressure Intervention Trial)

RATIONALE AND OBJECTIVE

Although low estimated glomerular filtration rate (eGFR) is associated with cardiovascular disease (CVD) events and mortality, the clinical significance of variability in eGFR over time is uncertain. This study aimed to evaluate the associations between variability in eGFR and the risk of CVD events and all-cause mortality.

STUDY DESIGN

Longitudinal analysis of clinical trial participants.

SETTINGS AND PARTICIPANTS

7,520 Systolic Blood Pressure Intervention Trial (SPRINT) participants ≥50 year of age with 1 or more CVD risk factors.

PREDICTORS

eGFR variability, estimated by the coefficient of variation of eGFR assessments at the 6th, 12th, and 18-month study visits.

OUTCOMES

The SPRINT primary CVD composite outcome (myocardial infarction, acute coronary syndrome, stroke, heart failure, or CVD death) and all-cause mortality from month 18 to the end of follow-up.

ANALYTICAL APPROACH

Cox models were used to evaluate associations between eGFR variability and CVD outcomes and all-cause mortality. Models were adjusted for demographics, randomization arm, CVD risk factors, albuminuria, and eGFR at month 18.

RESULTS

Mean age was 68 ± 9 years; 65% were men; and 58% were White. The mean eGFR was 73 ± 21 (SD) mL/min/1.73 m² at 6 months. There were 370 CVD events and 154 deaths during a median follow-up of 2.4 years. Greater eGFR variability was associated with higher risk for all-cause mortality (hazard ratio [HR] per 1 SD greater variability, 1.29; 95% CI, 1.14-1.45) but not CVD events (HR, 1.05; 95% CI, 0.95-1.16) after adjusting for albuminuria, eGFR, and other CVD risk factors. Associations were similar when stratified by treatment arm and by baseline CKD status, when accounting for concurrent systolic blood pressure changes, use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and diuretic medications during follow up.

LIMITATIONS

Persons with diabetes and proteinuria > 1 g/d were excluded.

CONCLUSIONS

In trial participants at high risk for CVD, greater eGFR variability was independently associated with all-cause mortality but not CVD events.

Prevalence and correlates of sleep apnea among US Veterans with chronic kidney disease

The prevalence and correlates of sleep apnea (SA) among Veterans with chronic kidney disease (CKD), a population at high risk of both SA and CKD, are unknown. We performed a cross-sectional analysis of 248 Veterans (18-89 years) selected only for presence of moderate to severe CKD. All participants underwent full, unattended polysomnography, measurement of renal function and a sleepiness questionnaire. Logistic regression with backward selection was used to identify predictors of prevalent SA (apnea-hypopnea index [AHI, ≥15 events/hr] and prevalent nocturnal hypoxia [NH, % of total sleep time spent at <90% oxygen saturation]). The mean age of our cohort was 73.2 ± 9.6 years, 95% were male, 78% were Caucasian and the mean body mass index (BMI) was 30.3 ± 4.8 kg/m² . The prevalence of SA was 39%. There was no difference in daytime sleepiness among those with and without SA. In the final model, older age, higher BMI and diabetes mellitus (DM) were associated with higher odds of SA, after controlling for age, BMI, race and sex. Higher BMI, DM, unemployed/retired status, current smoking and higher serum bicarbonate level were associated with prevalent NH. To sum, SA was common among Veterans with moderate to severe CKD. Although some traditional risk factors for SA were associated with SA in this population, sleepiness did not correlate with SA. Further study is needed to validate our findings and understand how best to address the high burden of SA among Veterans with CKD.

The impact of outpatient acute kidney injury on mortality and chronic kidney disease: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) has been extensively studied in hospital settings. Limited data exist regarding outcomes for patients with outpatient AKI who are not subsequently admitted. We investigated whether outpatient AKI, defined by a 50% increase in creatinine (Cr), is associated with increased mortality and renal events.

METHODS

In this retrospective study, outpatient serum Cr values from adults receiving primary care at a health system during an 18-month exposure period were used to categorize patients into one of five groups (no outpatient AKI, outpatient AKI with recovery, outpatient AKI without recovery, outpatient AKI without repeat Cr and no Cr). Principal outcomes of all-cause mortality and renal events (50% decline in estimated glomerular filtration rate to <30 mL/min/1.73 m2) were examined using Cox proportional hazards models.

RESULTS

Among 384 869 eligible patients, 51% had at least one Cr measured during the exposure period. Outpatient AKI occurred in 1.4% of patients while hospital AKI occurred in only 0.3% of patients. The average follow-up was 5.3 years. Outpatient AKI was associated with an increased risk of all-cause mortality {adjusted hazard ratio [aHR] 1.90 [95% confidence interval (CI) 1.76-2.06]} and results were consistent across all AKI groups. Outpatient AKI was also associated with an increased risk of renal events [aHR 1.33 (95% CI 1.11-1.59)], even among those who recovered.

CONCLUSIONS

Outpatient AKI is more prevalent than inpatient AKI and is a risk factor for all-cause mortality and renal events, even among those who recover kidney function. Further research is necessary to determine risk factors and identify strategies for preventing outpatient AKI.

The SPRINT trial suggests that markers of tubule cell function in the urine associate with risk of subsequent acute kidney injury while injury markers elevate after the injury

Urine markers can quantify tubular function including reabsorption (α-1 microglobulin [α1m]) and β-2-microglobulin [β2m]) and protein synthesis (uromodulin). Individuals with tubular dysfunction may be less able to compensate to insults than those without, despite similar estimated glomerular filtration rate (eGFR) and albuminuria. Among Systolic Blood Pressure Intervention Trial (SPRINT) participants with an eGFR under 60 ml/min/1.73m2, we measured urine markers of tubular function and injury (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule-1 [KIM-1], interleukin-18 [IL-18], monocyte chemoattractant protein-1, and chitinase-3-like protein [YKL-40]) at baseline. Cox models evaluated associations with subsequent acute kidney injury (AKI) risk, adjusting for clinical risk factors, baseline eGFR and albuminuria, and the tubular function and injury markers. In a random subset, we remeasured biomarkers after four years, and compared changes in biomarkers in those with and without intervening AKI. Among 2351 participants, 184 experienced AKI during 3.8 years mean follow-up. Lower uromodulin (hazard ratio per two-fold higher (0.68, 95% confidence interval [0.56, 0.83]) and higher α1m (1.20; [1.01, 1.44]) were associated with subsequent AKI, independent of eGFR and albuminuria. None of the five injury markers were associated with eventual AKI. In the random subset of 947 patients with repeated measurements, the 59 patients with intervening AKI versus without had longitudinal increases in urine NGAL, IL-19, and YKL-40 and only 1 marker of tubule function (α1m). Thus, joint evaluation of tubule function and injury provided novel insights to factors predisposing to AKI, and responses to kidney injury.

Change in albuminuria and subsequent risk of end-stage kidney disease: an individual participant-level consortium meta-analysis of observational studies

BACKGROUND

Change in albuminuria as a surrogate endpoint for progression of chronic kidney disease is strongly supported by biological plausibility, but empirical evidence to support its validity in epidemiological studies is lacking. We aimed to assess the consistency of the association between change in albuminuria and risk of end-stage kidney disease in a large individual participant-level meta-analysis of observational studies.

METHODS

In this meta-analysis, we collected individual-level data from eligible cohorts in the Chronic Kidney Disease Prognosis Consortium (CKD-PC) with data on serum creatinine and change in albuminuria and more than 50 events on outcomes of interest. Cohort data were eligible if participants were aged 18 years or older, they had a repeated measure of albuminuria during an elapsed period of 8 months to 4 years, subsequent end-stage kidney disease or mortality follow-up data, and the cohort was active during this consortium phase. We extracted participant-level data and quantified percentage change in albuminuria, measured as change in urine albumin-to-creatinine ratio (ACR) or urine protein-to-creatinine ratio (PCR), during baseline periods of 1, 2, and 3 years. Our primary outcome of interest was development of end-stage kidney disease after a baseline period of 2 years. We defined an end-stage kidney disease event as initiation of kidney replacement therapy. We quantified associations of percentage change in albuminuria with subsequent end-stage kidney disease using Cox regression in each cohort, followed by random-effects meta-analysis. We further adjusted for regression dilution to account for imprecision in the estimation of albuminuria at the participant level. We did multiple subgroup analyses, and also repeated our analyses using participant-level data from 14 clinical trials, including nine clinical trials not in CKD-PC.

FINDINGS

Between July, 2015, and June, 2018, we transferred and analysed data from 28 cohorts in the CKD-PC, which included 693 816 individuals (557 583 [80%] with diabetes). Data for 675 904 individuals and 7461 end-stage kidney disease events were available for our primary outcome analysis. Change in ACR was consistently associated with subsequent risk of end-stage kidney disease. The adjusted hazard ratio (HR) for end-stage kidney disease after a 30% decrease in ACR during a baseline period of 2 years was 0·83 (95% CI 0·74-0·94), decreasing to 0·78 (0·66-0·92) after further adjustment for regression dilution. Adjusted HRs were fairly consistent across cohorts and subgroups (ie, estimated glomerular filtration rate, diabetes, and sex), but the association was somewhat stronger among participants with higher baseline ACR than among those with lower baseline ACR (p_interaction<0·0001). In individuals with baseline ACR of 300 mg/g or higher, a 30% decrease in ACR over 2 years was estimated to confer a more than 1% absolute reduction in 10-year risk of end-stage kidney disease, even at early stages of chronic kidney disease. Results were generally similar when we used change in PCR and when study populations from clinical trials were assessed.

INTERPRETATION

Change in albuminuria was consistently associated with subsequent risk of end-stage kidney disease across a range of cohorts, lending support to the use of change in albuminuria as a surrogate endpoint for end-stage kidney disease in clinical trials of progression of chronic kidney disease in the setting of increased albuminuria.

FUNDING

US National Kidney Foundation and US National Institute of Diabetes and Digestive and Kidney Diseases.

Clock gene expression is altered in veterans with sleep apnea

Clock gene dysregulation has been shown to underlie various sleep disorders and may lead to negative cardio-metabolic outcomes. However, the association between sleep apnea (SA) and core clock gene expression is unclear. We performed a cross-sectional analysis of 49 Veterans enrolled in a study of SA outcomes in veterans with chronic kidney disease, not selected for SA or sleep complaints. All participants underwent full polysomnography and next morning whole blood collection for clock gene expression. We defined SA as an apnea-hypopnea index ≥15 events/h; nocturnal hypoxemia(NH) was defined as ≥10% of total sleep time spent at <90% oxygen saturation. We used quantitative real-time PCR to compare the relative gene expression of clock genes between those with and without SA or NH. Clock genes studied were Bmal1, Ck1δ, Ck1ε, Clock, Cry1, Cry2, NPAS2, Per1, Per2, Per3, Rev-Erb-α, RORα, and Timeless. Our cohort was 90% male, mean age was 71 yr (SD 11), mean body mass index was 30 kg/m² (SD 5); 41% had SA, and 27% had NH. Compared with those without SA, Per3 expression was reduced by 35% in SA ( P = 0.027). Compared with those without NH, NPAS2, Per1, and Rev-Erb-α expression was reduced in NH (50.4%, P = 0.027; 28.7%, P = 0.014; 31%, P = 0.040, respectively). There was no statistical difference in expression of the remaining clock genes by SA or NH status. Our findings suggest that SA or related NH and clock gene expression may be interrelated. Future study of 24 h clock gene expression in SA is needed to establish the role of clock gene regulation on the pathway between SA and cardio-metabolic outcomes.

Efficacy of Patient Activation Interventions With or Without Financial Incentives to Promote Prescribing of Thiazides and Hypertension Control: A Randomized Clinical Trial

IMPORTANCE

Evidence-based guidelines recommend thiazide diuretics as a first-line therapy for uncomplicated hypertension; however, thiazides are underused, and hypertension remains inadequately managed.

OBJECTIVE

To test the efficacy of a patient activation intervention with financial incentives to promote thiazide prescribing.

DESIGN, SETTING, AND PARTICIPANTS

The Veterans Affairs Project to Implement Diuretics, a randomized clinical trial, was conducted at 13 Veterans Affairs primary care clinics from August 1, 2006, to July 31, 2008, with 12 months of follow-up. A total of 61 019 patients were screened to identify 2853 eligible patients who were not taking a thiazide and not at their blood pressure (BP) goal; 598 consented to participate. Statistical analysis was conducted from December 1, 2017, to September 12, 2018.

INTERVENTIONS

Patients were randomized to a control group (n = 196) or 1 of 3 intervention groups designed to activate patients to talk with their primary care clinicians about thiazides and hypertension: group A (n = 143) received an activation letter, group B (n = 128) received a letter plus a financial incentive, and group C (n = 131) received a letter, financial incentive, and a telephone call encouraging patients to speak with their primary care clinicians.

MAIN OUTCOMES AND MEASURES

Primary outcomes were thiazide prescribing and BP control. A secondary process measure was discussion between patient and primary care clinician about thiazides.

RESULTS

Among 598 participants (588 men and 10 women), the mean (SD) age for the combined intervention groups (n = 402) was 62.9 (8.8) years, and the mean baseline BP was 148.1/83.8 mm Hg; the mean (SD) age for the control group (n = 196) was 64.1 (9.2) years, and the mean baseline BP was 151.0/83.4 mm Hg. At index visits, the unadjusted rate of thiazide prescribing was 9.7% for the control group (19 of 196) and 24.5% (35 of 143) for group A, 25.8% (33 of 128) for group B, and 32.8% (43 of 131) for group C (P < .001). Adjusted analyses demonstrated an intervention effect on thiazide prescribing at the index visit and 6-month visit, which diminished at the 12-month visit. For BP control, there was a significant intervention effect at the 12-month follow-up for group C (adjusted odds ratio, 1.73; 95% CI, 1.06-2.83; P = .04). Intervention groups exhibited improved thiazide discussion rates in a dose-response fashion: group A, 44.1% (63 of 143); group B, 56.3% (72 of 128); and group C, 68.7% (90 of 131) (P = .004).

CONCLUSIONS AND RELEVANCE

This patient activation intervention about thiazides for hypertension resulted in two-thirds of patients having discussions and nearly one-third initiating a prescription of thiazide. Adding a financial incentive and telephone call to the letter resulted in incremental improvements in both outcomes. By 12 months, improved BP control was also evident. This low-cost, low-intensity intervention resulted in high rates of discussions between patients and clinicians and subsequent thiazide treatment and may be used to promote evidence-based guidelines and overcome clinical inertia.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00265538.

Race, Ethnicity, and End-of-Life Care in Dialysis Patients in the United States

BACKGROUND

End-of-life care is a prominent consideration in patients on maintenance dialysis, especially when death appears imminent and quality of life is poor. To date, examination of race- and ethnicity-associated disparities in end-of-life care for patients with ESRD has largely been restricted to comparisons of white and black patients.

METHODS

We performed a retrospective national study using United States Renal Data System files to determine whether end-of-life care in United States patients on dialysis is subject to racial or ethnic disparity. The primary outcome was a composite of discontinuation of dialysis and death in a nonhospital or hospice setting.

RESULTS

Among 1,098,384 patients on dialysis dying between 2000 and 2014, the primary outcome was less likely in patients from any minority group compared with the non-Hispanic white population (10.9% versus 22.6%, P<0.001, respectively). We also observed similar significant disparities between any minority group and non-Hispanic whites for dialysis discontinuation (16.7% versus 31.2%), as well as hospice (10.3% versus 18.1%) and nonhospital death (34.4% versus 46.4%). After extensive covariate adjustment, the primary outcome was less likely in the combined minority group than in the non-Hispanic white population (adjusted odds ratio, 0.55; 95% confidence interval, 0.55 to 0.56; P<0.001). Individual minority groups (non-Hispanic Asian, non-Hispanic black, non-Hispanic Native American, and Hispanic) were significantly less likely than non-Hispanic whites to experience the primary outcome. This disparity was especially pronounced for non-Hispanic Native American and Hispanic subgroups.

CONCLUSIONS

There appear to be substantial race- and ethnicity-based disparities in end-of-life care practices for United States patients receiving dialysis.

Ultrafiltration rate in conventional hemodialysis: Where are the limits and what are the consequences?

BACKGROUND

Ultrafiltration rate (UFR) has attracted attention as a modifiable aspect of volume management.

OBJECTIVE

The objective of this review is to summarize the evidence that links UFR to patient outcomes and discuss UFR cut-offs proposed, and discuss possible consequences of adapting UFR as a quality metric.

RESULTS

Higher UFRs has been associated with younger age, longer dialysis vintage, greater prevalence of comorbidities, higher Kt/V, lower weight, greater interdialytic weight gain, lower residual renal function, and shorter treatment times. Many of the characteristics associated with high UFRs have also been independently associated with poor patient outcomes. Four observational studies have assessed the association between UFR and patient mortality. All of them reported an association between higher UFR and greater patient mortality, though the studies differed in their definition of UFR, follow-up, and adjustment for confounding. Evidence for the association between higher UFR and potential mediations of the mortality association, such as interdialytic hypotension, cardiac remodeling, and cardiovascular events was less consistent. There was a graded association between higher UFRs and all-cause mortality; no definitive cut-off for acceptable UFR can be established based on the current evidence. Targeting UFR in isolation might result in volume expansion and worsening patient outcomes. Residual confounding likely contributed to the findings of the observational studies. No randomized controlled trials addressed the questions.

CONCLUSION

Evidence supporting UFR limits is weak and confounded. Randomized controlled trials are needed before UFR can be used as a quality of care indicator.

Hospital Readmission Rates Following AMI: Potential Interventions to Improve Efficiency

OBJECTIVES

Quality of care utilization measures for patients admitted to the hospital with an acute myocardial infarction (AMI) include length of stay (LOS) and 30-day readmission rates. Our aim was to test whether efforts resulting in reduced LOS in patients diagnosed as having AMI would result in a higher risk of readmission within 30 days of hospital discharge and whether specific interventions could be targeted to reduce readmissions.

METHODS

Using data supplied by the Veterans Affairs Inpatient Evaluation Center, we analyzed both the readmissions within 30 days of an AMI and LOS and determined the timing of readmissions and associated diagnoses.

RESULTS

During 2013-2015, 35 (13.3%) of 263 patients with AMI were readmitted within 30 days of discharge compared with 19 (13.4%) of 142 patients during 2016 (not significant). During the same time, LOS was <3 days in most patients. From 2013 to 2015, the initial hospital time was 6 ± 6 days, whereas time out of the hospital before readmission was 11 ± 8 days; these times did not differ from 2016. Initial therapeutic decisions were based on coronary anatomy in >90% of patients with a decision to proceed with revascularization in most patients. Diagnoses during readmission to the hospital were also similar during early and later time periods and most frequently were a result of either coronary artery bypass grafting-related complications from the initial hospitalization or elective coronary artery bypass grafting. Acute coronary syndrome-related diagnoses and recurrent noncardiac causes of chest pain also were common diagnoses during both time periods and did not involve extensive workup during the readmission.

CONCLUSIONS

Readmissions for patients with AMI were stable during a 4-year period, at a time that efforts to reduce LOS were emphasized. Because a significant proportion of readmissions involved noncardiac sources of chest pain, improved communication between the emergency department and in-patient cardiology services at the time of triage may be a feasible way to improve efficiency of utilization.

Association of Increased Urinary Albumin With Risk of Incident Clinical Fracture and Rate of Hip Bone Loss: the Osteoporotic Fractures in Men Study

Prior studies suggest that increased urine albumin is associated with a heightened fracture risk in women, but results in men are unclear. We used data from Osteoporotic Fractures in Men (MrOS), a prospective cohort study of community-dwelling men aged ≥65 years, to evaluate the association of increased urine albumin with subsequent fractures and annualized rate of hip bone loss. We calculated albumin/creatinine ratio (ACR) from urine collected at the 2003-2005 visit. Subsequent clinical fractures were ascertained from triannual questionnaires and centrally adjudicated by review of radiographic reports. Total hip BMD was measured by DXA at the 2003-2005 visit and again an average of 3.5 years later. We estimated risk of incident clinical fracture using Cox proportional hazards models, and annualized BMD change using ANCOVA. Of 2982 men with calculable ACR, 9.4% had ACR ≥30 mg/g (albuminuria) and 1.0% had ACR ≥300 mg/g (macroalbuminuria). During a mean of 8.7 years of follow-up, 20.0% of men had an incident clinical fracture. In multivariate-adjusted models, neither higher ACR quintile (p for trend 0.75) nor albuminuria (HR versus no albuminuria, 0.89; 95% CI, 0.65 to 1.20) was associated with increased risk of incident clinical fracture. Increased urine albumin had a borderline significant, multivariate-adjusted, positive association with rate of total hip bone loss when modeled in ACR quintiles (p = 0.06), but not when modeled as albuminuria versus no albuminuria. Macroalbuminuria was associated with a higher rate of annualized hip bone loss compared to no albuminuria (-1.8% more annualized loss than in men with ACR <30 mg/g; p < 0.001), but the limited prevalence of macroalbuminuria precluded reliable estimates of its fracture associations. In these community-dwelling older men, we found no association between urine albumin levels and risk of incident clinical fracture, but found a borderline significant, positive association with rate of hip bone loss. © 2016 American Society for Bone and Mineral Research.

Renal Function and Death in Older Women: Which eGFR Formula Should We Use?

Background. The Berlin Initiative Study (BIS) eGFR equations were developed specifically for aged populations, but their predictive validity compared to standard formulae is unknown in older women. Methods. In a prospective study of 1289 community-dwelling older women (mean age 79.5 years), we compared the performance of the BIS1 SCr-based equation to the CKD-EPIcr and the BIS2 SCr- and Scysc-based equation to the CKD-EPIcr,cysc to predict cardiovascular and all-cause mortality. Results. Prevalence of specific eGFR category (i.e., ≥75, 60-74, 45-59, and <45) according to eGFR equation was 12.3%, 38.4%, 37.3%, and 12.0% for BIS1; 48.3%, 27.8%, 16.2%, and 7.8% for CKD-EPIcr; 14.1%, 38.6%, 37.6%, and 9.6% for BIS2; and 33.5%, 33.4%, 22.0%, and 11.1% for CKD-EPIcr,cysc, respectively. Over 9 ± 4 years, 667 (51.8%) women died. For each equation, women with eGFR <45 were at increased risk of mortality compared to eGFR ≥75 [adjusted HR (95% CI): BIS1, 1.5 (1.1-2.0); CKD-EPIcr, 1.7 (1.3-2.2); BIS2, 2.0 (1.4-2.8); CKD-EPIcr,cysc, 1.8 (1.4-2.3); p-trend <0.01]. Net reclassification analyses found no material difference in discriminant ability between the BIS and CKD-EPI equations. Results were similar for cardiovascular death. Conclusions. Compared to CKD-EPI, BIS equations identified a greater proportion of older women as having CKD but performed similarly to predict mortality risk. Thus, the BIS equations should not replace CKD-EPI equations to predict risk of death in older women.

Geographic variation of parathyroidectomy in patients receiving hemodialysis: a retrospective cohort analysis

Background

Secondary hyperparathyroidism (SHPT) is associated with adverse outcomes in patients receiving maintenance dialysis. Parathyroidectomy is a treatment for SHPT; whether parathyroidectomy utilization varies geographically in the US is unknown.

Methods

A retrospective cohort analysis was undertaken to identify all patients aged 18 years or older who were receiving in-center hemodialysis between 2007 and 2009, were covered by Medicare Parts A and B, and had been receiving hemodialysis for at least 1 year. Parathyroidectomy was identified from inpatient claims using relevant International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. Patient characteristics and End-Stage Renal Disease Network (a proxy for geography) were ascertained. Adjusted odds ratios for parathyroidectomy were estimated from a logistic model.

Results

A total of 286,569 patients satisfied inclusion criteria, of whom 4435 (1.5%) underwent PTX. After adjustment for a variety of patient characteristics, there was a 2-fold difference in adjusted odds of parathyroidectomy between the most- and least-frequently performing regions. Adjusted odds ratios were more than 20% higher than average in four networks, and more than 20% lower in four networks.

Conclusions

Parathyroidectomy use varies substantially by geography in the US; the factors responsible should be further investigated.

Past Decline Versus Current eGFR and Subsequent Mortality Risk

A single determination of eGFR associates with subsequent mortality risk. Prior decline in eGFR indicates loss of kidney function, but the relationship to mortality risk is uncertain. We conducted an individual-level meta-analysis of the risk of mortality associated with antecedent eGFR slope, adjusting for established risk factors, including last eGFR, among 1.2 million subjects from 12 CKD and 22 other cohorts within the CKD Prognosis Consortium. Over a 3-year antecedent period, 12% of participants in the CKD cohorts and 11% in the other cohorts had an eGFR slope <-5 ml/min per 1.73 m(2) per year, whereas 7% and 4% had a slope >5 ml/min per 1.73 m(2) per year, respectively. Compared with a slope of 0 ml/min per 1.73 m(2) per year, a slope of -6 ml/min per 1.73 m(2) per year associated with adjusted hazard ratios for all-cause mortality of 1.25 (95% confidence interval [95% CI], 1.09 to 1.44) among CKD cohorts and 1.15 (95% CI, 1.01 to 1.31) among other cohorts during a follow-up of 3.2 years. A slope of +6 ml/min per 1.73 m(2) per year also associated with higher all-cause mortality risk, with adjusted hazard ratios of 1.58 (95% CI, 1.29 to 1.95) among CKD cohorts and 1.43 (95% CI, 1.11 to 1.84) among other cohorts. Results were similar for cardiovascular and noncardiovascular causes of death and stronger for longer antecedent periods (3 versus <3 years). We conclude that prior decline or rise in eGFR associates with an increased risk of mortality, independent of current eGFR.

Estimated GFR and Mortality in Older Men: Are All eGFR Formulae Equal

BACKGROUND

Recently, the first estimated glomerular filtration rate (eGFR) formula specifically developed for community-dwelling older adults, the Berlin Initiative Study Equation 2 (BIS2), was reported. To date, however, no study has examined the performance of the BIS2 to predict death in older adults as compared to equations used clinically and in research.

METHODS

We prospectively followed 2,994 community-dwelling men (age 76.4 ± 5.6) enrolled in the MrOS Sleep Study. We calculated baseline eGFR from serum creatinine and cystatin-C using the BIS2, Chronic Kidney Disease Epidemiology (CKD-EPIcr,cysc), CKD-EPIcysc and CKD-EPIcr equations. Analyses included Cox-proportional hazards regression and net reclassification improvement (NRI) for the outcomes of all-cause and cardiovascular death.

RESULTS

Follow-up time was 7.3 ± 1.9 years. By BIS2, 42 and 11% had eGFR <60 and <45, respectively, compared to CKD-EPIcr (23 and 6%), CKD-EPIcysc (36 and 13%) and CKD-EPIcr,cysc (28 and 8%). BIS2 eGFR <45 was associated with twofold higher rate of all-cause mortality when compared to eGFR ≥75 after multivariate adjustment (HR 2.1, 95% CI 1.5-2.8). Results were similar for CKD-EPIcr,cysc <45 (HR 2.1, 95% CI 1.6-2.7) and CKD-EPIcysc <45 (HR 2.1, 95% CI 1.7-2.7) and weaker for CKD-EPIcr <45 (HR 1.5, 95% CI 1.2-2.0). In NRI analyses, when compared to CKD-EPIcr,cysc, both BIS2 and CKD-EPIcr equations more often misclassified participants with respect to mortality. We found similar results for cardiovascular death.

CONCLUSION

The BIS2 did not outperform and the CKD-EPIcr was inferior to the cystatin C-based CKD-EPI equations to predict death in this cohort of older men. Thus, the cystatin C-based CKD-EPI equations are the formulae of choice to predict death in community-dwelling older men.

Telehealth by an Interprofessional Team in Patients With CKD: A Randomized Controlled Trial

BACKGROUND

Telehealth and interprofessional case management are newer strategies of care within chronic disease management. We investigated whether an interprofessional team using telehealth was a feasible care delivery strategy and whether this strategy could affect health outcomes in patients with chronic kidney disease (CKD).

STUDY DESIGN

Randomized clinical trial.

SETTING & PARTICIPANTS

Minneapolis Veterans Affairs Health Care System (VAHCS), St. Cloud VAHCS, and affiliated clinics March 2012 to November 2013 in patients with CKD (estimated glomerular filtration rate < 60mL/min/1.73m(2)).

INTERVENTIONS

Patients were randomly assigned to receive an intervention (n=451) consisting of care by an interprofessional team (nephrologist, nurse practitioner, nurses, clinical pharmacy specialist, psychologist, social worker, and dietician) using a telehealth device (touch screen computer with peripherals) or to usual care (n=150).

OUTCOMES

The primary end point was a composite of death, hospitalization, emergency department visits, or admission to skilled nursing facilities, compared to usual care.

RESULTS

Baseline characteristics of the overall study group: mean age, 75.1±8.1 (SD) years; men, 98.5%; white, 97.3%; and mean estimated glomerular filtration rate, 37±9mL/min/1.73m(2). Telehealth and interprofessional care were successfully implemented with meaningful engagement with the care system. One year after randomization, 208 (46.2%) patients in the intervention group versus 70 (46.7%) in the usual-care group had the primary composite outcome (HR, 0.98; 95% CI, 0.75-1.29; P=0.9). There was no difference between groups for any component of the primary outcome: all-cause mortality (HR, 1.46; 95% CI, 0.42-5.11), hospitalization (HR, 1.15; 95% CI, 0.80-1.63), emergency department visits (HR, 0.92; 95% CI, 0.68-1.24), or nursing home admission (HR, 3.07; 95% CI, 0.71-13.24).

LIMITATIONS

Older population, mostly men, potentially underpowered/wide CIs.

CONCLUSIONS

Telehealth by an interprofessional team is a feasible care delivery strategy in patients with CKD. There was no statistically significant evidence of superiority of this intervention on health outcomes compared to usual care.

Timing of dialysis initiation, duration and frequency of hemodialysis sessions, and membrane flux: a systematic review for a KDOQI clinical practice guideline

BACKGROUND

In 2006, NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) published clinical practice guidelines for hemodialysis adequacy. Recent studies evaluating hemodialysis adequacy as determined by initiation timing, frequency, duration, and membrane type and prompted an update to the guideline.

STUDY DESIGN

Systematic review and evidence synthesis.

SETTING & POPULATION

Patients with advanced chronic kidney disease receiving hemodialysis.

SELECTION CRITERIA FOR STUDIES

We screened publications from 2000 to March 2014, systematic reviews, and references and consulted the NKF-KDOQI Hemodialysis Adequacy Work Group members. We included randomized or controlled clinical trials in patients undergoing long-term hemodialysis if they reported outcomes of interest.

INTERVENTIONS

Early versus late dialysis therapy initiation; more frequent (>3 times a week) or longer duration (>4.5 hours) compared to conventional hemodialysis; low- versus high-flux dialyzer membranes.

OUTCOMES

All-cause and cardiovascular mortality, myocardial infarction, stroke, hospitalizations, quality of life, depression or cognitive function scores, blood pressure, number of antihypertensive medications, left ventricular mass, interdialytic weight gain, and harms or complications related to vascular access or the process of dialysis.

RESULTS

We included 32 articles reporting on 19 trials. Moderate-quality evidence indicated that earlier dialysis therapy initiation (at estimated creatinine clearance [eClcr] of 10-14mL/min) did not reduce mortality compared to later initiation (eClcr of 5-7mL/min). More than thrice-weekly hemodialysis and extended-length hemodialysis during a short follow-up did not improve clinical outcomes compared to conventional hemodialysis and resulted in a greater number of vascular access procedures (very low-quality evidence). Hemodialysis using high-flux membranes did not reduce all-cause mortality, but reduced cardiovascular mortality compared to hemodialysis using low-flux membranes (moderate-quality evidence).

LIMITATIONS

Few studies were adequately powered to evaluate mortality. Heterogeneity of study designs and interventions precluded pooling data for most outcomes.

CONCLUSIONS

Limited data indicate that earlier dialysis therapy initiation and more frequent and longer hemodialysis did not improve clinical outcomes compared to conventional hemodialysis.

The association of periodontal disease with kidney function decline: a longitudinal retrospective analysis of the MrOS dental study

BACKGROUND

Identifying modifiable risk factors for chronic kidney disease (CKD) is essential for reducing its burden. Periodontal disease is common, modifiable and has been implicated as a novel potential CKD risk factor, but evidence of its association with kidney function decline over time is limited.

METHODS

In a longitudinal retrospective cohort of 761 elderly men with preserved kidney function [estimated glomerular filtration rate > 60 mL/min/1.73 m(2) using a calibrated creatinine and cystatin C (eGFRcr-cys) equation] at baseline, we performed multivariable Poisson's regression to examine the association of severe periodontal disease with incident CKD, defined as incident eGFRcr-cys <60 mL/min/1.73 m(2) and rapid (>5% annualized) eGFRcr-cys decline. Severe periodontal disease was defined in two ways: (i) ≥5 mm proximal attachment loss in 30% of teeth examined (European Workshop in Periodontology Group C, European Workshop); and (ii) 2+ interproximal sites with attachment loss ≥6 mm and 1+ interproximal sites with probing depth ≥5 mm (Centers for Disease Control/American Academy of Periodontology, CDC/AAP).

RESULTS

At baseline, the mean age was 73.4 (SD 4.8) years, the median eGFRcr-cys was 82.4 mL/min/1.73 m(2), and 35.5 and 25.4% of participants had severe periodontal disease by European Workshop and CDC/AAP criteria, respectively. After a mean follow-up of 4.9 years (SD 0.3), 56 (7.4%) participants had incident CKD. Severe periodontal disease was associated with a 2-fold greater rate of incident CKD [incidence rate ratio (IRR) 2.01 (1.21-3.44), P = 0.007] after adjusting for confounders compared with not severe periodontal disease by European Workshop criteria but did not reach statistical significance by CDC/AAP criteria [IRR 1.10 (0.63-1.91), P = 0.9].

CONCLUSIONS

Severe periodontal disease may be associated with incident clinically significant kidney function decline among a cohort of elderly men.

Changes in secondary hyperparathyroidism-related biochemical parameters and medication use following parathyroidectomy

BACKGROUND

Little is known about changes in parathyroid hormone (PTH), calcium and phosphorous levels after parathyroidectomy in hemodialysis patients. We studied the effects of parathyroidectomy on these biochemical values in a large cohort of patients receiving maintenance hemodialysis.

METHODS

This retrospective cohort study included patients identified in both the United States Renal Data System and the database of a large dialysis organization who underwent parathyroidectomy in 2007-09, were aged ≥ 18 years, had Medicare Parts A and B as primary payer and had received hemodialysis for ≥ 1 year pre-parathyroidectomy. Descriptive statistics were calculated for continuous variables; categorical variables were used to characterize the population and evaluate monthly laboratory and medication use; median values were calculated for laboratory measures.

RESULTS

Among 1402 parathyroidectomy patients, mean age was 48.9 years, 52.4% were males, 58.8% were African American and mean dialysis duration was 7.5 years. Median PTH levels increased over the year before parathyroidectomy from 1039 to 1661 pg/mL and decreased afterward to 98 pg/mL at 1 month; levels remained ≥ 897 pg/mL for 10% of patients. Median calcium levels fell from 9.6 mg/dL before to 7.9 mg/dL 1 month after parathyroidectomy; levels were ≤ 7.1 mg/dL for 25% and remained ≤ 7.2 mg/dL for the lowest 25% at 3 months. Median phosphorous level was 6.8 mg/dL immediately before parathyroidectomy, decreased to 3.8 mg/dL immediately after and reached 5.8 mg/dL at 1 year.

CONCLUSIONS

While PTH levels dropped after parathyroidectomy for most patients, surgery was sometimes ineffective in reducing levels and sometimes led to over-suppression. Hypocalcemia could be profound and long lasting, suggesting the need for prolonged vigilance.

Clinical outcomes after parathyroidectomy in a nationwide cohort of patients on hemodialysis

BACKGROUND AND OBJECTIVES

Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods.

RESULTS

Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1).

CONCLUSIONS

Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.

Cystatin C and cognitive impairment 10 years later in older women

BACKGROUND

Results of prospective studies examining the association between cystatin C and incident cognitive impairment have been inconsistent. We tested the hypothesis that there is a U-shaped association in older women between cystatin C and risk of incident cognitive impairment 10 years later.

METHODS

We conducted a longitudinal analysis of a prospective cohort of 1,332 community-dwelling elderly women without dementia at baseline who had baseline cystatin C and serum creatinine measurements and completed an extended cognitive battery of neuropsychological tests with determination of cognitive status 10 years later. Incident cognitive impairment was defined as either new onset of adjudicated diagnosis of mild cognitive impairment or dementia.

RESULTS

Incident mild cognitive impairment or dementia was identified among 140 (26.0%) women in quartile 1 (Q1), 122 (22.6%) in Q2, 121 (22.5%) in Q3, and 156 (28.9%) in Q4 of cystatin C. In the fully adjusted model, compared to women in Q2-Q3 of cystatin C, adjusted odds ratios (95% CI) for incident cognitive impairment were 1.31 (0.98-1.75) for Q1, and 1.25 (0.94-1.66) for Q4 Compared to women in Q2-Q3 of estimated glomerular filtration rate (eGFRCysC), adjusted odds ratios (95% CI) for incident cognitive impairment after 10 years of follow-up were 1.18 (0.88-1.58) for Q4 (eGFRCysC 76.1-109.4mL/min/1.73 m(2)) and 1.26 (0.94-1.67) for Q1 (eGFRCysC 21.8-55.5mL/min/1.73 m(2)).

CONCLUSIONS

These results support a U-shaped association between cystatin C concentration and risk of cognitive impairment or dementia 10 years later, but the association is not independent of potential confounding factors.