Age and Aspirin Dosing in Secondary Prevention of Atherosclerotic Cardiovascular Disease.

BACKGROUND: In patients with atherosclerotic cardiovascular disease, increasing age is concurrently associated with higher risks of ischemic and bleeding events. The objectives are to determine the impact of aspirin dose on clinical outcomes according to age in atherosclerotic cardiovascular disease. METHODS AND RESULTS: In the ADAPTABLE (Aspirin Dosing: A Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness) trial, patients with atherosclerotic cardiovascular disease were randomized to daily aspirin doses of 81 mg or 325 mg. The primary effectiveness end point was death from any cause, hospitalization for myocardial infarction, or hospitalization for stroke. The primary safety end point was hospitalization for bleeding requiring transfusion. A total of 15 076 participants were randomized to aspirin 81 mg (n=7540) or 325 mg (n=7536) daily (median follow-up: 26.2 months; interquartile range: 19.0-34.9 months). Median age was 67.6 years (interquartile range: 60.7-73.6 years). Among participants aged <65 years (n=5841 [38.7%]), a primary end point occurred in 226 (7.54%) in the 81 mg group, and in 191 (6.80%) in the 325 mg group (adjusted hazard ratio [HR], 1.23 [95% CI, 1.01-1.49]). Among participants aged ≥65 years (n=9235 [61.3%]), a primary end point occurred in 364 (7.12%) in the 81 mg group, and in 378 (7.96%) in the 325 mg group (adjusted HR, 0.95 [95% CI, 0.82-1.10]). The age-dose interaction was not significant (P=0.559). There was no significant interaction between age and the randomized aspirin dose for the secondary effectiveness and the primary safety bleeding end points (P>0.05 for all). CONCLUSIONS: Age does not modify the impact of aspirin dosing (81 mg or 325 mg daily) on clinical end points in secondary prevention of atherosclerotic cardiovascular disease.

Internet Versus Noninternet Participation in a Decentralized Clinical Trial: Lessons From the ADAPTABLE Study.

Background Internet-based participation has the potential to enhance pragmatic and decentralized trials, where representative study populations and generalizability to clinical practice are key. We aimed to study the differences between internet and noninternet/telephone participants in a large remote, pragmatic trial. Methods and Results In a subanalysis of the ADAPTABLE (Aspirin Dosing: A Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness) study, we compared internet participants with those who opted for noninternet participation. Study process measures examined included participant characteristics at consent, study medication adherence, and study retention. The clinical outcome examined was a composite of all-cause mortality, hospitalization for myocardial infarction, or hospitalization for stroke. Noninternet participants were older (mean 69.4 versus 67.4 years), more likely to be female (38.9% versus 30.2%), more likely to be Black (27.3% versus 6.0%) or Hispanic (11.1% versus 2.0%), and had a higher number of comorbid conditions. The composite clinical outcome was more than twice as high in noninternet participants. The hazard of nonadherence to the assigned aspirin dosage was 46% higher in noninternet participants than internet participants. Conclusions Noninternet participants differed from internet participants in notable demographic characteristics while having poorer baseline health. Over the course of ADAPTABLE, they also had worse clinical outcomes and greater likelihood of study drug nonadherence. These results suggest that trials focused on internet participation select for younger, healthier participants with a higher proportion of traditionally overrepresented patients. Allowing noninternet participation enhances diversity; however, additional steps may be needed to promote study retention and study medication adherence. Registration Information clinicaltrials.gov. Identifier: NCT02697916.

Importance of patient engagement in the conduct of pragmatic multicenter randomized controlled trials: The ADAPTABLE experience.

BACKGROUND/AIMS: Actively engaging patient partners in the conduct of trials is crucial to ensure the studies answer genuine, patient-centered, unmet clinical needs, and to facilitate participant recruitment and retention. The aim of this article is to demonstrate the feasibility of patient engagement within a large pragmatic multicenter randomized controlled trial, specifically for the purposes of dissemination of study information/updates and to favorize recruitment and retention. METHODS: In the patient-centric, pragmatic ADAPTABLE randomized trial, transparent and timely dissemination of information on the study updates to the trial participants was undertaken to create meaningful engagement and to facilitate retention. A national panel of patient partners, the Adaptors, were directly involved in this information dissemination strategy, and study participants were engaged both nationally and locally to design recruitment methods iteratively during the conduct of the trial. All Adaptors had a lived experience with cardiovascular disease. RESULTS: Adaptors attended bi-weekly meetings facilitated by the director of the study's patient-powered research network. They drafted and/or edited newsletters and ad hoc educational information written in a lay-friendly manner for study participants, which were regularly distributed to the ADAPTABLE community, in addition to online forums where participants could share their experience of their involvement in ADAPTABLE. To spur recruitment, a patient-driven initiative was to draft letters sharing their story, which were distributed by the local study teams. Patient partners thought that using patients' voice to provide their perspectives on why they believed this project was important would be more engaging for prospective participants than traditional approaches. CONCLUSIONS: ADAPTABLE's experience has demonstrated the feasibility of engaging patients as partners in the conduct of a large-scale, multi-center, pragmatic randomized controlled trial. Future trials should embrace and iteratively improve this model by engaging patient partners as early as study protocol development and funding applications, and quantify its impact on the effectiveness and value of the trial.

Validation of Cardiovascular End Points Ascertainment Leveraging Multisource Electronic Health Records Harmonized Into a Common Data Model in the ADAPTABLE Randomized Clinical Trial.

BACKGROUND: The ADAPTABLE trial (Aspirin Dosing: A Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness) is the first randomized trial conducted within the National Patient-Centered Clinical Research Network to use the electronic health record data formatted into a common data model as the primary source of end point ascertainment, without confirmation by standard adjudication. The objective of this prespecified study is to assess the validity of nonfatal end points captured from the National Patient-Centered Clinical Research Network, using traditional blinded adjudication as the gold standard. METHODS: A total of 15 076 participants with established atherosclerotic cardiovascular disease were randomized to two doses of aspirin (81 mg and 325 mg once daily). Nonfatal end points (hospitalization for nonfatal myocardial infarction, nonfatal stroke, and major bleeding requiring transfusion of blood products) were captured with the use of programming algorithms applied to National Patient-Centered Clinical Research Network data. A random subset of end points was independently reviewed by a disease-specific expert adjudicator. The positive predictive value of the programming algorithms were calculated separately for end points listed as primary and as nonprimary diagnoses. RESULTS: A total of 225 end points were identified (91 myocardial infarction events, 89 stroke events, and 45 bleeding events), including 142 (63%) that were listed as primary diagnoses. Complete source documents were missing for 14% of events. The positive predictive value were 90%, 72%, and 93% for hospitalizations for myocardial infarction, stroke, and major bleeding, respectively, as compared to adjudication. When only primary diagnoses were considered, positive predictive value were 93%, 91%, and 97%, respectively. When only nonprimary diagnoses were considered, positive predictive value were 82%, 36%, and 71%. CONCLUSIONS: As compared with blinded adjudication, clinical end point ascertainment from queries of the National Patient-Centered Clinical Research Network distributed harmonized data was valid to identify hospitalizations for myocardial infarction in ADAPTABLE. The proportion of contradicted events was high for hospitalizations for bleeding and strokes when nonprimary diagnoses were analyzed, but not when only primary diagnoses were considered.

Comparative Effectiveness of Aspirin Dosing in Cardiovascular Disease.

BACKGROUND: The appropriate dose of aspirin to lower the risk of death, myocardial infarction, and stroke and to minimize major bleeding in patients with established atherosclerotic cardiovascular disease is a subject of controversy. METHODS: Using an open-label, pragmatic design, we randomly assigned patients with established atherosclerotic cardiovascular disease to a strategy of 81 mg or 325 mg of aspirin per day. The primary effectiveness outcome was a composite of death from any cause, hospitalization for myocardial infarction, or hospitalization for stroke, assessed in a time-to-event analysis. The primary safety outcome was hospitalization for major bleeding, also assessed in a time-to-event analysis. RESULTS: A total of 15,076 patients were followed for a median of 26.2 months (interquartile range [IQR], 19.0 to 34.9). Before randomization, 13,537 (96.0% of those with available information on previous aspirin use) were already taking aspirin, and 85.3% of these patients were previously taking 81 mg of daily aspirin. Death, hospitalization for myocardial infarction, or hospitalization for stroke occurred in 590 patients (estimated percentage, 7.28%) in the 81-mg group and 569 patients (estimated percentage, 7.51%) in the 325-mg group (hazard ratio, 1.02; 95% confidence interval [CI], 0.91 to 1.14). Hospitalization for major bleeding occurred in 53 patients (estimated percentage, 0.63%) in the 81-mg group and 44 patients (estimated percentage, 0.60%) in the 325-mg group (hazard ratio, 1.18; 95% CI, 0.79 to 1.77). Patients assigned to 325 mg had a higher incidence of dose switching than those assigned to 81 mg (41.6% vs. 7.1%) and fewer median days of exposure to the assigned dose (434 days [IQR, 139 to 737] vs. 650 days [IQR, 415 to 922]). CONCLUSIONS: In this pragmatic trial involving patients with established cardiovascular disease, there was substantial dose switching to 81 mg of daily aspirin and no significant differences in cardiovascular events or major bleeding between patients assigned to 81 mg and those assigned to 325 mg of aspirin daily. (Funded by the Patient-Centered Outcomes Research Institute; ADAPTABLE ClinicalTrials.gov number, NCT02697916.).

Computable Phenotype Implementation for a National, Multicenter Pragmatic Clinical Trial: Lessons Learned From ADAPTABLE.

BACKGROUND: Many large-scale cardiovascular clinical trials are plagued with escalating costs and low enrollment. Implementing a computable phenotype, which is a set of executable algorithms, to identify a group of clinical characteristics derivable from electronic health records or administrative claims records, is essential to successful recruitment in large-scale pragmatic clinical trials. This methods paper provides an overview of the development and implementation of a computable phenotype in ADAPTABLE (Aspirin Dosing: a Patient-Centric Trial Assessing Benefits and Long-Term Effectiveness)-a pragmatic, randomized, open-label clinical trial testing the optimal dose of aspirin for secondary prevention of atherosclerotic cardiovascular disease events. METHODS AND RESULTS: A multidisciplinary team developed and tested the computable phenotype to identify adults ≥18 years of age with a history of atherosclerotic cardiovascular disease without safety concerns around using aspirin and meeting trial eligibility criteria. Using the computable phenotype, investigators identified over 650 000 potentially eligible patients from the 40 participating sites from Patient-Centered Outcomes Research Network-a network of Clinical Data Research Networks, Patient-Powered Research Networks, and Health Plan Research Networks. Leveraging diverse recruitment methods, sites enrolled 15 076 participants from April 2016 to June 2019. During the process of developing and implementing the ADAPTABLE computable phenotype, several key lessons were learned. The accuracy and utility of a computable phenotype are dependent on the quality of the source data, which can be variable even with a common data model. Local validation and modification were required based on site factors, such as recruitment strategies, data quality, and local coding patterns. Sustained collaboration among a diverse team of researchers is needed during computable phenotype development and implementation. CONCLUSIONS: The ADAPTABLE computable phenotype served as an efficient method to recruit patients in a multisite pragmatic clinical trial. This process of development and implementation will be informative for future large-scale, pragmatic clinical trials. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02697916.

Rationale and Design of the Aspirin Dosing-A Patient-Centric Trial Assessing Benefits and Long-term Effectiveness (ADAPTABLE) Trial.

Importance: Determining the right dosage of aspirin for the secondary prevention treatment of atherosclerotic cardiovascular disease (ASCVD) remains an unanswered and critical question. Objective: To report the rationale and design for a randomized clinical trial to determine the optimal dosage of aspirin to be used for secondary prevention of ASCVD, using an innovative research method. Design, Setting, and Participants: This pragmatic, open-label, patient-centered, randomized clinical trial is being conducted in 15 000 patients within the National Patient-Centered Clinical Research Network (PCORnet), a distributed research network of partners including clinical research networks, health plan research networks, and patient-powered research networks across the United States. Patients with established ASCVD treated in routine clinical practice within the network are eligible. Patient recruitment began in April 2016. Enrollment was completed in June 2019. Final follow-up is expected to be completed by June 2020. Interventions: Participants are randomized on a web platform in a 1:1 fashion to either 81 mg or 325 mg of aspirin daily. Main Outcomes and Measures: The primary efficacy end point is the composite of all-cause mortality, hospitalization for nonfatal myocardial infarction, or hospitalization for a nonfatal stroke. The primary safety end point is hospitalization for major bleeding associated with a blood-product transfusion. End points are captured through regular queries of the health systems' common data model within the structure of PCORnet's distributed data environment. Conclusions and Relevance: As a pragmatic study and the first interventional trial conducted within the PCORnet electronic data infrastructure, this trial is testing several unique and innovative operational approaches that have the potential to disrupt and transform the conduct of future patient-centered randomized clinical trials by evaluating treatments integrated in clinical practice while at the same time determining the optimal dosage of aspirin for secondary prevention of ASCVD. Trial Registration: ClinicalTrials.gov Identifier: NCT02697916.

CaMKII regulates the depalmitoylation and synaptic removal of the scaffold protein AKAP79/150 to mediate structural long-term depression.

Both long-term potentiation (LTP) and depression (LTD) of excitatory synapse strength require the Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII) and its autonomous activity generated by Thr-286 autophosphorylation. Additionally, LTP and LTD are correlated with dendritic spine enlargement and shrinkage that are accompanied by the synaptic accumulation or removal, respectively, of the AMPA-receptor regulatory scaffold protein A-kinase anchoring protein (AKAP) 79/150. We show here that the spine shrinkage associated with LTD indeed requires synaptic AKAP79/150 removal, which in turn requires CaMKII activity. In contrast to normal CaMKII substrates, the substrate sites within the AKAP79/150 N-terminal polybasic membrane-cytoskeletal targeting domain were phosphorylated more efficiently by autonomous compared with Ca2+/CaM-stimulated CaMKII activity. This unusual regulation was mediated by Ca2+/CaM binding to the substrate sites resulting in protection from phosphorylation in the presence of Ca2+/CaM, a mechanism that favors phosphorylation by prolonged, weak LTD stimuli versus brief, strong LTP stimuli. Phosphorylation by CaMKII inhibited AKAP79/150 association with F-actin; it also facilitated AKAP79/150 removal from spines but was not required for it. By contrast, LTD-induced spine removal of AKAP79/150 required its depalmitoylation on two Cys residues within the N-terminal targeting domain. Notably, such LTD-induced depalmitoylation was also blocked by CaMKII inhibition. These results provide a mechanism how CaMKII can indeed mediate not only LTP but also LTD through regulated substrate selection; however, in the case of AKAP79/150, indirect CaMKII effects on palmitoylation are more important than the effects of direct phosphorylation. Additionally, our results provide the first direct evidence for a function of the well-described AKAP79/150 trafficking in regulating LTD-induced spine shrinkage.

Striatal magnetic resonance spectroscopy abnormalities in young adult SAPAP3 knockout mice.

BACKGROUND: Obsessive compulsive disorder (OCD) is a debilitating condition with lifetime prevalence of 1-3%. OCD typically arises in youth but delays in diagnosis impede optimal treatment and developmental studies of the disorder. Research using genetically modified rodents may provide models of etiology that enable earlier detection and intervention. The SAPAP3 knockout (KO) transgenic mouse was developed as an animal model of OCD and related disorders (OCRD). KO mice exhibit compulsive self-grooming behavior analogous to behaviors found in people with OCRD. Striatal hyperactivity has been reported in these mice and in humans with OCD. METHODS: Striatal and medial frontal cortex 9.4 Tesla proton spectra were acquired from young adult SAPAP3 KO and wild-type control mice to determine whether KO mice have metabolic and neurochemical abnormalities. RESULTS: Young adult KO mice had lower striatal lactate (P=0.006) and glutathione (P=0.039) levels. Among all mice, striatal lactate and glutathione levels were associated (R=0.73, P=0.007). We found no group differences in medial frontal cortex metabolites. At the age range studied, only 1 of 8 KO mice had skin lesions indicative of severe compulsive grooming. CONCLUSION: Young adult SAPAP3 KO mice have striatal but not medial frontal cortex MRS abnormalities that may reflect striatal hypermetabolism accompanied by oxidative stress. These abnormalities typically preceded the onset of severe compulsive grooming. Our findings are consistent with striatal hypermetabolism in OCD. Together, these results suggest that striatal MRS measures of lactate or glutathione might be useful biomarkers for early detection of risk for developing compulsive behavior disorders.

Palmitoylation of A-kinase anchoring protein 79/150 regulates dendritic endosomal targeting and synaptic plasticity mechanisms.

NMDA receptor-dependent long-term potentiation (LTP) and depression (LTD) are forms of synaptic plasticity underlying learning and memory that are expressed through increases and decreases, respectively, in dendritic spine size and AMPA receptor (AMPAR) phosphorylation and postsynaptic localization. The A-kinase anchoring protein 79/150 (AKAP79/150) signaling scaffold regulates AMPAR phosphorylation, channel activity, and endosomal trafficking associated with LTP and LTD. AKAP79/150 is targeted to dendritic spine plasma membranes by an N-terminal polybasic domain that binds phosphoinositide lipids, F-actin, and cadherin cell adhesion molecules. However, we do not understand how regulation of AKAP targeting controls AMPAR endosomal trafficking. Here, we report that palmitoylation of the AKAP N-terminal polybasic domain targets it to postsynaptic lipid rafts and dendritic recycling endosomes. AKAP palmitoylation was regulated by seizure activity in vivo and LTP/LTD plasticity-inducing stimuli in cultured rat hippocampal neurons. With chemical LTP induction, we observed AKAP79 dendritic spine recruitment that required palmityolation and Rab11-regulated endosome recycling coincident with spine enlargement and AMPAR surface delivery. Importantly, a palmitoylation-deficient AKAP79 mutant impaired regulation of spine size, endosome recycling, AMPAR trafficking, and synaptic potentiation. These findings emphasize the emerging importance of palmitoylation in controlling synaptic function and reveal novel roles for the AKAP79/150 signaling complex in dendritic endosomes.

Annual Research Review: Transgenic mouse models of childhood-onset psychiatric disorders.

Childhood-onset psychiatric disorders, such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), mood disorders, obsessive compulsive spectrum disorders (OCSD), and schizophrenia (SZ), affect many school-age children, leading to a lower quality of life, including difficulties in school and personal relationships that persist into adulthood. Currently, the causes of these psychiatric disorders are poorly understood, resulting in difficulty diagnosing affected children, and insufficient treatment options. Family and twin studies implicate a genetic contribution for ADHD, ASD, mood disorders, OCSD, and SZ. Identification of candidate genes and chromosomal regions associated with a particular disorder provide targets for directed research, and understanding how these genes influence the disease state will provide valuable insights for improving the diagnosis and treatment of children with psychiatric disorders. Transgenic mouse models are one important approach in the study of human diseases, allowing for the use of a variety of experimental approaches to dissect the contribution of a specific chromosomal or genetic abnormality in human disorders. While it is impossible to model an entire psychiatric disorder in a single mouse model, these models can be extremely valuable in dissecting out the specific role of a gene, pathway, neuron subtype, or brain region in a particular abnormal behavior. In this review we discuss existing transgenic mouse models for childhood-onset psychiatric disorders. We compare the strength and weakness of various transgenic mouse models proposed for each of the common childhood-onset psychiatric disorders, and discuss future directions for the study of these disorders using cutting-edge genetic tools.

Regulation of postsynaptic structure and function by an A-kinase anchoring protein-membrane-associated guanylate kinase scaffolding complex.

A-kinase anchoring protein (AKAP) 79/150 is a scaffold protein found in dendritic spines that recruits the cAMP-dependent protein kinase (PKA) and protein phosphatase 2B-calcineurin (CaN) to membrane-associated guanylate kinase (MAGUK)-linked AMPA receptors (AMPARs) to control receptor phosphorylation and synaptic plasticity. However, AKAP79/150 may also coordinate regulation of AMPAR activity with spine structure directly through MAGUK binding and membrane-cytoskeletal interactions of its N-terminal targeting domain. In cultured hippocampal neurons, we observed that rat AKAP150 expression was low early in development but then increased coincident with spine formation and maturation. Overexpression of human AKAP79 in immature or mature neurons increased the number of dendritic filopodia and spines and enlarged spine area. However, RNA interference knockdown of AKAP150 decreased dendritic spine area only in mature neurons. Importantly, AKAP79 overexpression in immature neurons increased AMPAR postsynaptic localization and activity. Neither the AKAP79 PKA nor CaN anchoring domain was required for increasing dendritic protrusion numbers, spine area, or AMPAR synaptic localization; however, an internal region identified as the MAGUK binding domain was found to be essential as shown by expression of a MAGUK binding mutant that formed mainly filopodia and decreased AMPAR synaptic localization and activity. Expression of the AKAP79 N-terminal targeting domain alone also increased filopodia numbers but not spine area. Overall, these results demonstrate a novel structural role for AKAP79/150 in which the N-terminal targeting domain induces dendritic filopodia and binding to MAGUKs promotes spine enlargement and AMPAR recruitment.