Validating the use of registries and claims data to support randomized trials: Rationale and design of the Extending Trial-Based Evaluations of Medical Therapies Using Novel Sources of Data (EXTEND) Study

Days at Home After Transcatheter Versus Surgical Aortic Valve Replacement in Low-Risk Patients

BACKGROUND

Days at home (DAH) represents an important patient-oriented outcome that quantifies time spent at home after a medical event; however, this outcome has not been fully evaluated for low-surgical-risk patients undergoing transcatheter aortic valve replacement (TAVR). We sought to compare 1- and 2-year DAH (DAH365 and DAH730) among low-risk patients participating in a randomized trial of TAVR with a self-expanding bioprosthesis versus surgical aortic valve replacement (SAVR).

METHODS

Using Medicare-linked data from the Evolut Low Risk trial, we identified 619 patients: 606 (322 TAVR/284 SAVR) and 593 (312 TAVR/281 SAVR) were analyzed at 1 and 2 years, respectively. DAH was calculated as days alive and spent outside a hospital, inpatient rehabilitation, skilled nursing facility, long-term acute care hospital, emergency department, or observation stay. Mean DAH was compared using the t test.

RESULTS

The mean (SD) age and female sex were 74.7 (5.1) and 74.3 (4.9) years and 34.6% (115/332) and 30.3% (87/287) in TAVR and SAVR, respectively. Postprocedural discharge to rehabilitation occurred in ≤3.0% (≤10/332) in TAVR and 4.5% (13/287) in SAVR. The mean DAH365 was comparable in TAVR versus SAVR (352.2±45.4 versus 347.8±39.0; difference in days, 4.5 [95% CI, 2.3-11.2]; P=0.20). DAH730 was also comparable in TAVR versus SAVR (701.6±106.0 versus 699.6±94.5; difference in days, 2.0 [-14.1 to 18.2]; P=0.81). Secondary outcomes DAH30 and DAH90 were higher in TAVR (DAH30, 26.0±3.6 versus 20.7±6.4; difference in days, 5.3 [4.5-6.2]; P<0.001; DAH90, 85.1±8.3 versus 78.7±13.6; difference in days, 6.4 [4.6-8.2]; P<0.001).

CONCLUSIONS

In the Evolut Low Risk trial linked to Medicare, low-risk patients undergoing TAVR spend a similar number of days at home at 1 and 2 years compared with SAVR. Days spent at home at 30 and 90 days were higher in TAVR. In contrast to higher-risk patients studied in prior work, there is no clear advantage of TAVR versus SAVR for DAH in the first 2 years after AVR in low-surgical-risk patients.

Association Between Claims-Defined Frailty and Outcomes Following 30 Versus 12 Months of Dual Antiplatelet Therapy After Percutaneous Coronary Intervention: Findings From the EXTEND-DAPT Study

Background Frailty is rarely assessed in clinical trials of patients who receive dual antiplatelet therapy (DAPT) after percutaneous coronary intervention. This study investigated whether frailty defined using claims data is associated with outcomes following percutaneous coronary intervention, and if there is a differential association in patients receiving standard versus extended duration DAPT. Methods and Results Patients ≥65 years of age in the DAPT (Dual Antiplatelet Therapy) Study, a randomized trial comparing 30 versus 12 months of DAPT following percutaneous coronary intervention, had data linked to Medicare claims (n=1326), and a previously validated claims-based index was used to define frailty. Net adverse clinical events, a composite of all-cause mortality, myocardial infarction, stroke, and major bleeding, were compared between frail and nonfrail patients. Patients defined as frail using claims data (12.0% of the cohort) had higher incidence of net adverse clinical events (23.1%) compared with nonfrail patients (10.7%; P<0.001) at 18-month follow-up and increased risk after multivariable adjustment (adjusted hazard ratio [HR], 2.24 [95% CI, 1.38-3.63]). There were no differences in effects of extended duration DAPT on net adverse clinical events for frail (HR, 1.42 [95% CI, 0.73-2.75]) and nonfrail patients (HR, 1.18 [95% CI, 0.83-1.68]; interaction P=0.61), although analyses were underpowered. Bleeding was highest among frail patients who received extended duration DAPT. Conclusions Among older patients in the DAPT Study, claims-defined frailty was associated with higher net adverse clinical events. Effects of extended duration DAPT were not different for frail patients, although comparisons were underpowered. Further investigation of how frailty influences ischemic and bleeding risks with DAPT are warranted. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00977938.

Days at home after transcatheter or surgical aortic valve replacement in high-risk patients

BACKGROUND

Days at home (DAH) quantifies time spent at home after a medical event but has not been fully evaluated for TAVR. We sought to compare 1- and 5-year DAH (DAH₃₆₅, DAH₁₈₂₅) among high-risk patients participating in a randomized trial of transcatheter aortic valve replacement (TAVR) with a self-expanding bioprosthesis versus surgical aortic valve replacement (SAVR).

METHODS

We linked data from the U.S. CoreValve High Risk Trial to Medicare Fee-for-Service claims in 456 patients with 450 (234 TAVR/216 SAVR) and 427 (222 TAVR/205 SAVR) analyzed at 1 and 5 years. DAH was calculated as the number of days alive and spent outside of a hospital, skilled nursing facility, rehabilitation, long-term acute care hospital, emergency department, or observation stay.

RESULTS

Mean DAH₃₆₅ was higher in patients who underwent TAVR compared with SAVR (295.1 ± 106.9 vs 267.8 ± 122.3, difference in days 27.2 [95% CI 6.0, 48.5], P = .01). Compared with SAVR, TAVR patients had a shorter index length of stay (LOS) (7.4 ± 4.5 vs 12.5 ± 9.0, difference in days -5.1 [-6.5, -3.8], P < .001). The largest contributions to decreased DAH₃₆₅ were mortality days and total facility days after discharge from the index hospitalization (mortality days-TAVR: 34.7 ± 93.1 vs SAVR: 48.0 ± 108.8, difference in days -13.3 [95% CI -32.1, 5.5], P = .17; total facility days-TAVR: 27.9 ± 47.4 vs SAVR: 36.7 ± 48.9, difference in days -8.8 [95% CI -17.8, 0.1], P = .05). Mean DAH₁₈₂₅ was numerically but not statistically significantly higher in TAVR (TAVR: 1154.2 ± 659.0 vs SAVR: 1067.6 ± 697.3, difference in days 86.6 [95% CI -42.3, 215.6], P = .19). Landmark analysis showed no difference in DAH from years 1 to 5 (TAVR: 1040.4 ± 477.5 vs SAVR: 1022.9 ± 489.3, P = .74).

CONCLUSIONS

In the U.S. CoreValve High Risk Trial linked to Medicare, high-risk patients undergoing TAVR spend an average of 27 additional DAH compared with SAVR in the first year after the procedure due to a shorter index LOS and the additive effect of fewer but nonsignificantly different mortality and total facility days after discharge from the index hospitalization compared with SAVR. After the first year, both groups spend a similar number of DAH. These results describe the postprocedural course of high-risk patients from a patient-centered perspective, which may guide expectations regarding longitudinal health care needs and inform shared decision-making.

Enriching the American Heart Association COVID-19 Cardiovascular Disease Registry Through Linkage With External Data Sources: Rationale and Design

Background The AHA Registry (American Heart Association COVID-19 Cardiovascular Disease Registry) captures detailed information on hospitalized patients with COVID-19. The registry, however, does not capture information on social determinants of health or long-term outcomes. Here we describe the linkage of the AHA Registry with external data sources, including fee-for-service (FFS) Medicare claims, to fill these gaps and assess the representativeness of linked registry patients to the broader Medicare FFS population hospitalized with COVID-19. Methods and Results We linked AHA Registry records of adults ≥65 years from March 2020 to September 2021 with Medicare FFS claims using a deterministic linkage algorithm and with the American Hospital Association Annual Survey, Rural Urban Commuting Area codes, and the Social Vulnerability Index using hospital and geographic identifiers. We compared linked individuals with unlinked FFS beneficiaries hospitalized with COVID-19 to assess the representativeness of the AHA Registry. A total of 10 010 (47.0%) records in the AHA Registry were successfully linked to FFS Medicare claims. Linked and unlinked FFS beneficiaries were similar with respect to mean age (78.1 versus 77.9, absolute standardized difference [ASD] 0.03); female sex (48.3% versus 50.2%, ASD 0.04); Black race (15.1% versus 12.0%, ASD 0.09); dual-eligibility status (26.1% versus 23.2%, ASD 0.07); and comorbidity burden. Linked patients were more likely to live in the northeastern United States (35.7% versus 18.2%, ASD 0.40) and urban/metropolitan areas (83.9% versus 76.8%, ASD 0.18). There were also differences in hospital-level characteristics between cohorts. However, in-hospital outcomes were similar (mortality, 23.3% versus 20.1%, ASD 0.08; home discharge, 45.5% versus 50.7%, ASD 0.10; skilled nursing facility discharge, 24.4% versus 22.2%, ASD 0.05). Conclusions Linkage of the AHA Registry with external data sources such as Medicare FFS claims creates a unique and generalizable resource to evaluate long-term health outcomes after COVID-19 hospitalization.

Outcomes of stroke events during transcatheter aortic valve implantation

BACKGROUND

Despite improvements in the safety of transcatheter aortic valve implantation (TAVI), ~4% of patients experience a procedure-related stroke. Understanding long-term health and healthcare implications of these events may motivate the development and adoption of preventative strategies.  Aims: We aimed to assess the association of TAVI-related ischaemic stroke with subsequent clinical outcomes and healthcare utilisation.

METHODS

We used Medicare fee-for-service claims to identify patients who underwent their first TAVI between January 2012 and December 2017. Previously used ICD-9-CM and ICD-10-CM codes were used to identify TAVI-related ischaemic stroke. Among those with and without TAVI-related ischaemic stroke, we compared the risk of a composite endpoint that included all-cause mortality, acute myocardial infarction, and subsequent stroke using inverse probability treatment weighted Cox regression. We also performed a difference-in-difference analysis to compare 1-year Medicare expenditures and days spent at home during the first year after TAVI.

RESULTS

 Among 129,628 primary TAVI patients, 5,549 (4.3%) had a procedure-related stroke. These patients were more likely to be female and have had prior stroke, peripheral vascular disease, ischaemic heart disease, or renal failure. After adjustment, TAVI-related ischaemic stroke was associated with a higher risk of the 1-year composite outcome (HR 1.67, 95% CI: 1.56-1.78), higher 1-year Medicare expenditures (difference $9,245 [standard error 790], p<0.001), and fewer days at home during the first year (difference 16 days [standard error 1], p<0.001).

CONCLUSIONS

Among Medicare beneficiaries undergoing TAVI, procedure-related ischaemic stroke was associated with worse outcomes, increased Medicare expenditures, and less time spent at home. Procedure-related ischaemic stroke during TAVI remains a critically important and potentially preventable source of patient mortality, morbidity and healthcare utilisation.

Estimation of DAPT Study Treatment Effects in Contemporary Clinical Practice: Findings From the EXTEND-DAPT Study

BACKGROUND

Differences in patient characteristics, changes in treatment algorithms, and advances in medical technology could each influence the applicability of older randomized trial results to contemporary clinical practice. The DAPT Study (Dual Antiplatelet Therapy) found that longer-duration DAPT decreased ischemic events at the expense of greater bleeding, but subsequent evolution in stent technology and clinical practice may attenuate the benefit of prolonged DAPT in a contemporary population. We evaluated whether the DAPT Study population is different from a contemporary population of US patients receiving percutaneous coronary intervention and estimated the treatment effect of extended-duration antiplatelet therapy after percutaneous coronary intervention in this more contemporary cohort.

METHODS

We compared the characteristics of drug-eluting stent-treated patients randomly assigned in the DAPT Study to a sample of more contemporary drug-eluting stent-treated patients in the National Cardiovascular Data Registry CathPCI Registry from July 2016 to June 2017. After linking trial and registry data, we used inverse-odds of trial participation weighting to account for patient and procedural characteristics and estimated a contemporary real-world treatment effect of 30 versus 12 months of DAPT after coronary stent procedures.

RESULTS

The US drug-eluting stent-treated trial cohort included 8864 DAPT Study patients, and the registry cohort included 568 540 patients. Compared with the trial population, registry patients had more comorbidities and were more likely to present with myocardial infarction and receive 2nd-generation drug-eluting stents. After reweighting trial results to represent the registry population, there was no longer a significant effect of prolonged DAPT on reducing stent thrombosis (reweighted treatment effect: -0.40 [95% CI, -0.99% to 0.15%]), major adverse cardiac and cerebrovascular events (reweighted treatment effect, -0.52 [95% CI, -2.62% to 1.03%]), or myocardial infarction (reweighted treatment effect, -0.97% [95% CI, -2.75% to 0.18%]), but the increase in bleeding with prolonged DAPT persisted (reweighted treatment effect, 2.42% [95% CI, 0.79% to 3.91%]).

CONCLUSIONS

The differences between the patients and devices used in contemporary clinical practice compared with the DAPT Study were associated with the attenuation of benefits and greater harms attributable to prolonged DAPT duration. These findings limit the applicability of the average treatment effects from the DAPT Study in modern clinical practice.

Effect of intensive versus limited monitoring on clinical trial conduct and outcomes: A randomized trial

BACKGROUND

Regulatory agencies have endorsed more limited approaches to clinical trial site monitoring. However, the impact of different monitoring strategies on trial conduct and outcomes is unclear.

METHODS

We conducted a patient-level block-randomized controlled trial evaluating the effect of intensive versus limited monitoring on cardiovascular clinical trial conduct and outcomes nested within the CoreValve Continued Access and Expanded Use Studies. Intensive monitoring included complete source data verification of all critical datapoints whereas limited monitoring included automated data checks only. This study's endpoints included clinical trial outcome ascertainment as well as monitoring action items, protocol deviations, and adverse event ascertainment.

RESULTS

A total of 2,708 patients underwent transcatheter aortic valve replacement (TAVR) and were randomized to either intensive monitoring (n = 1,354) or limited monitoring (n = 1,354). Monitoring action items were more common with intensive monitoring (52% vs 15%; P < .001), but there was no difference in the percentage of patients with any protocol deviation (91.6% vs 90.4%; P = .314). The reported incidence of trial outcomes between intensive and limited monitoring was similar for mortality (30 days: 4.8% vs 5.5%, P = .442; 1 year: 20.3% vs 21.3%, P = .473) and stroke (30 days: 2.8% vs 2.4%, P = .458), as well as most secondary trial outcomes with the exception of bleeding (intensive: 36.3% vs limited: 32.0% at 30 days, P = .019). There was a higher reported incidence of cardiac adverse events reported in the intensive monitoring group at 1 year (76.7% vs 72.4%; P = .019).

CONCLUSIONS

Tailored limited monitoring strategies can be implemented without influencing the integrity of TAVR trial outcomes.

The Role of Frailty in Identifying Benefit from Transcatheter Versus Surgical Aortic Valve Replacement

Background: Frailty is associated with a higher risk for adverse outcomes after aortic valve replacement (AVR) for severe aortic valve stenosis, but whether or not frail patients derive differential benefit from transcatheter (TAVR) vs. surgical (SAVR) AVR is uncertain. Methods: We linked adults ≥ 65 years old in the US CoreValve High Risk (HiR) or Surgical or Transcatheter Aortic-Valve Replacement in Intermediate Risk Patients (SURTAVI) trial to Medicare claims, 2/2/2011-9/30/2015. Two frailty measures, a deficit-based (DFI) and phenotype-based (PFI) frailty index, were generated. The treatment effect of TAVR vs. SAVR was evaluated within frailty index (FI) tertiles for the primary endpoint of death and non-death secondary outcomes, using multivariable Cox regression. Results: Of 1,442 (linkage rate = 60.0%) individuals included, 741 (51.4%) individuals received TAVR and 701 (48.6%) received SAVR (mean age 81.8 ± 6.1 years, 44.0% female). Though 1-year death rates in the highest FI tertiles (DFI 36.7%, PFI 33.8%) were 2-3-fold higher than the lowest tertiles (DFI 13.4%, HR 3.02, 95% CI 2.26-4.02, p < 0.001; PFI 17.9%; HR 2.05, 95% CI 1.58-2.67, p < 0.001), there were no significant differences in the relative or absolute treatment effect of SAVR vs. TAVR across FI tertiles for all death, non-death, and functional outcomes (all interaction p-values > 0.05). Results remained consistent across individual trials, frailty definitions, and when considering the non-linked trial data. Conclusions: Two different frailty indices based on Fried and Rockwood definitions identified individuals at higher risk of death and functional impairment but no differential benefit from TAVR vs. SAVR.

Evaluation of Medicare Claims for the Development of Heart Failure Diagnostics

BACKGROUND

Although claims data provide a large and efficient source of clinical events, validation is needed prior to use in heart failure (HF) diagnostic development.

METHODS AND RESULTS

Data from the Multisensor Chronic Evaluations in Ambulatory Heart Failure Patients (MultiSENSE) study, used to create the HeartLogic HF diagnostic, were linked with fee-for-service (FFS) Medicare claims. Events were matched by patient ID and date, and agreement was calculated between claims primary HF diagnosis codes and study event adjudication. HF events (HFEs) were defined as inpatient visits, or outpatient visits with intravenous decongestive therapy. Diagnostic performance was measured as HFE-detection sensitivity and false-positive rate (FPR). Linkage of 791 MultiSENSE subjects returned 320 FFS patients with an average follow-up duration of 0.94 years. Although study and claims deaths matched exactly (n = 14), matching was imperfect between study hospitalizations and acute inpatient claims events. Of 239 total events, 165 study hospitalizations (69%) matched inpatient claims events, 28 hospitalizations matched outpatient claims events (12%), 14 hospitalizations were study-unique (6%), and 32 inpatient events were claims-unique (13%). Inpatient HF classification had substantial agreement with study adjudication (κ = 0.823). Diagnostic performance was not different between claims and study events (sensitivity = 75.6% vs 77.6% and FPR = 1.539 vs 1.528 alerts/patient-year). HeartLogic-detected events contributed to > 90% of the HFE costs used for evaluation.

CONCLUSIONS

Acceptable event matching, good agreement of claims diagnostic codes with adjudication, and equivalent diagnostic performance support the validity of using claims for HF diagnostic development.

Applicability of Transcatheter Aortic Valve Replacement Trials to Real-World Clinical Practice: Findings From EXTEND-CoreValve

OBJECTIVES

The aim of this study was to examine the applicability of pivotal transcatheter aortic valve replacement (TAVR) trials to the real-world population of Medicare patients undergoing TAVR.

BACKGROUND

It is unclear whether randomized controlled trial results of novel cardiovascular devices apply to patients encountered in clinical practice.

METHODS

Characteristics of patients enrolled in the U.S. CoreValve pivotal trials were compared with those of the population of Medicare beneficiaries who underwent TAVR in U.S. clinical practice between November 2, 2011, and December 31, 2017. Inverse probability weighting was used to reweight the trial cohort on the basis of Medicare patient characteristics, and a "real-world" treatment effect was estimated.

RESULTS

A total of 2,026 patients underwent TAVR in the U.S. CoreValve pivotal trials, and 135,112 patients underwent TAVR in the Medicare cohort. Trial patients were mostly similar to real-world patients at baseline, though trial patients were more likely to have hypertension (50% vs 39%) and coagulopathy (25% vs 17%), whereas real-world patients were more likely to have congestive heart failure (75% vs 68%) and frailty. The estimated real-world treatment effect of TAVR was an 11.4% absolute reduction in death or stroke (95% CI: 7.50%-14.92%) and an 8.7% absolute reduction in death (95% CI: 5.20%-12.32%) at 1 year with TAVR compared with conventional therapy (surgical aortic valve replacement for intermediate- and high-risk patients and medical therapy for extreme-risk patients).

CONCLUSIONS

The trial and real-world populations were mostly similar, with some notable differences. Nevertheless, the extrapolated real-world treatment effect was at least as high as the observed trial treatment effect, suggesting that the absolute benefit of TAVR in clinical trials is similar to the benefit of TAVR in the U.S. real-world setting.

Identification of Frailty Using a Claims-Based Frailty Index in the CoreValve Studies: Findings from the EXTEND-FRAILTY Study

Background

In aortic valve disease, the relationship between claims‐based frailty indices (CFIs) and validated measures of frailty constructed from in‐person assessments is unclear but may be relevant for retrospective ascertainment of frailty status when otherwise unmeasured.

Methods and Results

We linked adults aged ≥65 years in the US CoreValve Studies (linkage rate, 67%; mean age, 82.7±6.2 years, 43.1% women), to Medicare inpatient claims, 2011 to 2015. The Johns Hopkins CFI, validated on the basis of the Fried index, was generated for each study participant, and the association between CFI tertile and trial outcomes was evaluated as part of the EXTEND‐FRAILTY substudy. Among 2357 participants (64.9% frail), higher CFI tertile was associated with greater impairments in nutrition, disability, cognition, and self‐rated health. The primary outcome of all‐cause mortality at 1 year occurred in 19.3%, 23.1%, and 31.3% of those in tertiles 1 to 3, respectively (tertile 2 versus 1: hazard ratio, 1.22; 95% CI, 0.98–1.51; P=0.07; tertile 3 versus 1: hazard ratio, 1.73; 95% CI, 1.41–2.12; P<0.001). Secondary outcomes (bleeding, major adverse cardiovascular and cerebrovascular events, and hospitalization) were more frequent with increasing CFI tertile and persisted despite adjustment for age, sex, New York Heart Association class, and Society of Thoracic Surgeons risk score.

Conclusions

In linked Medicare and CoreValve study data, a CFI based on the Fried index consistently identified individuals with worse impairments in frailty, disability, cognitive dysfunction, and nutrition and a higher risk of death, hospitalization, bleeding, and major adverse cardiovascular and cerebrovascular events, independent of age and risk category. While not a surrogate for validated metrics of frailty using in‐person assessments, use of this CFI to ascertain frailty status among patients with aortic valve disease may be valid and prognostically relevant information when otherwise not measured.

Contemporary use of real-world data for clinical trial conduct in the United States: a scoping review

OBJECTIVE

Real-world data (RWD), defined as routinely collected healthcare data, can be a potential catalyst for addressing challenges faced in clinical trials. We performed a scoping review of database-specific RWD applications within clinical trial contexts, synthesizing prominent uses and themes.

MATERIALS AND METHODS

Querying 3 biomedical literature databases, research articles using electronic health records, administrative claims databases, or clinical registries either within a clinical trial or in tandem with methodology related to clinical trials were included. Articles were required to use at least 1 US RWD source. All abstract screening, full-text screening, and data extraction was performed by 1 reviewer. Two reviewers independently verified all decisions.

RESULTS

Of 2020 screened articles, 89 qualified: 59 articles used electronic health records, 29 used administrative claims, and 26 used registries. Our synthesis was driven by the general life cycle of a clinical trial, culminating into 3 major themes: trial process tasks (51 articles); dissemination strategies (6); and generalizability assessments (34). Despite a diverse set of diseases studied, <10% of trials using RWD for trial process tasks evaluated medications or procedures (5/51). All articles highlighted data-related challenges, such as missing values.

DISCUSSION

Database-specific RWD have been occasionally leveraged for various clinical trial tasks. We observed underuse of RWD within conducted medication or procedure trials, though it is subject to the confounder of implicit report of RWD use.

CONCLUSION

Enhanced incorporation of RWD should be further explored for medication or procedure trials, including better understanding of how to handle related data quality issues to facilitate RWD use.

Accuracy of Cardiovascular Trial Outcome Ascertainment and Treatment Effect Estimates from Routine Health Data: A Systematic Review and Meta-Analysis

BACKGROUND

Registry-based randomized controlled trials allow for outcome ascertainment using routine health data (RHD). While this method provides a potential solution to the rising cost and complexity of clinical trials, comparative analyses of outcome ascertainment by clinical end point committee (CEC) adjudication compared with RHD sources are sparse. Among cardiovascular trials, we set out to systematically compare the incidence of cardiovascular events and estimated randomized treatment effects ascertained from RHD versus traditional clinical evaluation and adjudication.

METHODS

We searched MEDLINE (1976 to August 2020) for studies where outcome ascertainment was performed by both RHD and CEC adjudication to compare the incidence of cardiovascular events and treatment effects. We derived ratios of hazard ratios to compare treatment effects from RHD and CEC adjudication. We pooled ratios of hazard ratios using an inverse variance random-effects meta-analysis.

RESULTS

Nine studies (1988-2020; 32 156 patients) involving 10 randomized control trials compared outcome ascertainment with RHD and CEC in patients with or at risk of cardiovascular disease. There was a high degree of agreement and interrater reliability between CEC and RHD outcome determination for all-cause mortality (agreement percentage: 98.4%-100% and κ: 0.95-1.0) and cardiovascular mortality (agreement percentage: 97.8%-99.9% and κ: 0.66-0.99). For myocardial infarction, the κ values ranged from 0.67-0.98, and for stroke the values ranged from 0.52-0.89. In contrast, the κ value for peripheral artery disease was low (κ: 0.27). There was little difference in the randomized treatment effect derived from CEC and RHD ascertainment of events based on the ratios of hazard ratio, with pooled ratios of hazard ratios ranging from 0.93 (95% CI, 0.63-1.39) for cardiovascular mortality to 1.27 (95% CI, 0.67-2.41) for stroke.

CONCLUSIONS

Clinical outcome ascertainment using retrospectively acquired RHD displayed high levels of agreement with CEC adjudication for identifying all-cause mortality and cardiovascular outcomes. Importantly, cardiovascular treatment effects in randomized control trials determined from RHD and CEC resulted in similar point estimates. Overall, our review supports the use of RHD as a potential alternative source for clinical outcome ascertainment in cardiovascular trials. Validation studies with prospectively planned linkage are warranted.

Prognosis of Claims- Versus Trial-Based Ischemic and Bleeding Events Beyond 1 Year After Coronary Stenting

Background It is unknown whether clinical events identified with administrative claims have similar prognosis compared with trial-adjudicated events in cardiovascular clinical trials. We compared the prognostic significance of claims-based end points in context of trial-adjudicated end points in the DAPT (Dual Antiplatelet Therapy) study. Methods and Results We matched 1336 patients aged ≥65 years who received percutaneous coronary intervention in the DAPT study with the CathPCI registry linked to Medicare claims. We compared death at 21 months post-randomization using Cox proportional hazards models among patients with ischemic events (myocardial infarction or stroke) and bleeding events identified by: (1) both trial adjudication and claims; (2) trial adjudication only; and (3) claims only. A total of 47 patients (3.5%) had ischemic events identified by both trial adjudication and claims, 24 (1.8%) in trial adjudication only, 15 (1.1%) in claims only, and 1250 (93.6%) had no ischemic events, with annualized unadjusted mortality rates of 12.8, 5.5, 14.9, and 1.26 per 100 person-years, respectively. A total of 44 patients (3.3%) had bleeding events identified with both trial adjudication and claims, 13 (1.0%) in trial adjudication only, 65 (4.9%) in claims only, and 1214 (90.9%) had no bleeding events, with annualized unadjusted mortality rates of 11.0, 16.8, 10.7, and 0.95 per 100 person-years, respectively. Among patients with no trial-adjudicated events, patients with events in claims only had a high subsequent adjusted mortality risk (hazard ratio (HR) ischemic events: 31.5; 95% CI, 8.9‒111.9; HR bleeding events 23.9; 95% CI, 10.7‒53.2). Conclusions In addition to trial-adjudicated events, claims identified additional clinically meaningful ischemic and bleeding events that were prognostically significant for death.

Comparability of Event Adjudication Versus Administrative Billing Claims for Outcome Ascertainment in the DAPT Study: Findings From the EXTEND-DAPT Study

BACKGROUND

Data from administrative claims may provide an efficient alternative for end point ascertainment in clinical trials. However, it is uncertain how well claims data compare to adjudication by a clinical events committee in trials of patients with cardiovascular disease.

METHODS

We matched 1336 patients ≥65 years old who received percutaneous coronary intervention in the DAPT (Dual Antiplatelet Therapy) Study with the National Cardiovascular Data Registry CathPCI Registry linked to Medicare claims as part of the EXTEND (Extending Trial-Based Evaluations of Medical Therapies Using Novel Sources of Data) Study. Adjudicated trial end points were compared with Medicare claims data with International Classification of Diseases, Ninth Revision codes from inpatient hospitalizations using time-to-event analyses, sensitivity, specificity, positive predictive value, negative predictive value, and kappa statistics.

RESULTS

At 21-month follow-up, the cumulative incidence of major adverse cardiovascular and cerebrovascular events (combined mortality, myocardial infarction, and stroke) was similar between trial-adjudicated events and claims data (7.9% versus 7.2%, respectively; P=0.50). Bleeding rates were lower using adjudicated events compared with claims (5.0% versus 8.6%, respectively; P<0.001). The sensitivity and positive predictive value of comprehensive billing codes for identifying adjudicated events were 65.6% and 85.7% for myocardial infarction, 61.5% and 47.1% for stroke, and 76.8% and 39.3% for bleeding, respectively. Specificity and negative predictive value for all outcomes ranged from 93.7% to 99.5%. All 39 adjudicated deaths were identified using Medicare data. Kappa statistics assessing agreement between events for myocardial infarction, stroke, and bleeding were 0.73, 0.52, and 0.49, respectively.

CONCLUSIONS

Claims data had moderate agreement with adjudication for myocardial infarction and poor agreement but high specificity for bleeding and stroke in the DAPT Study. Deaths were identified equivalently. Using claims data in clinical trials could be an efficient way to assess mortality among Medicare patients and may help detect other outcomes, although additional monitoring is likely needed to ensure accurate assessment of events.

Validation of Administrative Claims to Ascertain Outcomes in Pivotal Trials of Transcatheter Aortic Valve Replacement

OBJECTIVES

The aim of this study was to evaluate the performance of administrative claims in ascertaining trial clinical events committee-adjudicated outcomes in the U.S. CoreValve studies.

BACKGROUND

Real-world data offer tremendous opportunity to improve outcome ascertainment in clinical trials. However, little is known about the validity of outcomes ascertained using real-world data to capture trial endpoints.

METHODS

Patients enrolled in 3 pivotal trials and 2 pre-market continued-access studies evaluating transcatheter aortic valve replacement were linked to Medicare fee-for-service inpatient claims. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and kappa agreement statistic of claims to detect clinical endpoints and procedural complications in trial patients were calculated.

RESULTS

Claims accurately identified trial-adjudicated deaths (sensitivity, specificity, PPV, and NPV all >99.6%; kappa 1.00). Claims had good performance in identifying trial-adjudicated permanent pacemaker implantation (sensitivity 92.2%, specificity 99.1%, PPV 96.1%, NPV 98.2%, kappa 0.93) and aortic valve reintervention (sensitivity 84.4%, specificity 99.6%, PPV 69.1%, NPV 99.8%, kappa 0.76). Claims had more modest performance in ascertaining trial-adjudicated myocardial infarction (sensitivity 63.6%, specificity 97.2%, PPV 29.9%, NPV 99.3%, kappa 0.39) and acute kidney injury (sensitivity 70.2%, specificity 85.4%, PPV 38.2%, NPV 95.7%, kappa 0.41) and the poorest performance for identifying trial-adjudicated bleeding events (sensitivity 86.4%, specificity 36.8%, PPV 35.0%, NPV 86.3%, kappa 0.16).

CONCLUSIONS

Compared with trial-adjudicated outcomes, claims data performed well in ascertaining death and outcomes with procedural billing codes and more modestly in identifying other outcomes. Claims may be cautiously and selectively used to augment data collection in future cardiovascular device trials.

Use of Administrative Claims to Assess Outcomes and Treatment Effect in Randomized Clinical Trials for Transcatheter Aortic Valve Replacement: Findings From the EXTEND Study

BACKGROUND

Whether passively collected data can substitute for adjudicated outcomes to reproduce the magnitude and direction of treatment effect observed in cardiovascular clinical trials is not well known.

METHODS

We linked adults ≥65 years of age in the HiR (US CoreValve Pivotal High Risk) and SURTAVI trials (Surgical or Transcatheter Aortic Valve Replacement in Intermediate-Risk Patients) to 100% Medicare inpatient claims, January 1, 2011, to December 31, 2016. Primary (eg, death and stroke) and secondary trial end points were compared across treatment arms (eg, transcatheter aortic valve replacement [TAVR] versus surgical aortic valve replacement [SAVR]) using trial-adjudicated outcomes versus outcomes derived from claims at 1 year (HiR) or 2 years (SURTAVI).

RESULTS

Among 600 linked HiR participants (linkage rate, 80.0%), the rate of the trial's primary end point of all-cause mortality occurred in 13.7% of patients receiving TAVR and 16.4% of patients receiving SAVR at 1 year by using both trial data (hazard ratio, 0.84 [95% CI, 0.65-1.09]; P=0.33) and claims data (hazard ratio, 0.86 [95% CI, 0.66-1.11]; P=0.34; interaction P value=0.80). Noninferiority of TAVR relative to SAVR was seen by using both trial- and claims-based outcomes (P_{noninferiority}<0.001 for both). Among 1005 linked SURTAVI trial participants (linkage rate, 60.5%), the trial's primary end point was 12.9% for TAVR and 13.1% for SAVR using trial data (hazard ratio, 1.08 [95% CI, 0.79-1.48]; P=0.90), and 11.3% for TAVR and 12.5% for SAVR patients using claims data (hazard ratio, 1.02 [95% CI, 0.73-1.41]; P=0.58; interaction P value=0.89). TAVR was noninferior to SAVR when compared using both trial and claims (P_{noninferiority}<0.001 for both). Rates of procedural secondary outcomes (eg, aortic valve reintervention, pacemaker rates) were more closely concordant between trial and claims data than nonprocedural outcomes (eg, stroke, bleeding, cardiogenic shock).

CONCLUSIONS

In the HiR and SURTAVI trials, ascertainment of trial primary end points using claims reproduced both the magnitude and direction of treatment effect in comparison with adjudicated event data, but nonfatal and nonprocedural secondary outcomes were not as well reproduced. Use of claims to substitute for adjudicated outcomes in traditional trial treatment comparisons may be valid and feasible for all-cause mortality and certain procedural outcomes but may be less suitable for other end points.