The Cost-Effectiveness of an Advanced Hybrid Closed-Loop System Compared to Standard Management of Type 1 Diabetes in a Singapore Setting

Background: Despite advances in technology, glycemic outcomes in people with type 1 diabetes (T1D) remain suboptimal. The MiniMed 780G (MM780G) advanced hybrid closed-loop (AHCL) system is the latest technology for T1D management with established safety and efficacy. This study explores the cost-effectiveness of MM780G AHCL compared against multiple daily injections (MDI) plus intermittently scanned continuous glucose monitor (isCGM). Methods: A cost-utility analysis was conducted, simulating lifetime outcomes for 1000 T1D individuals, with baseline hemoglobin A1c of 8.4%, using the IQVIA Core Diabetes Model (CDM) v9.5. A Singapore health care payer perspective was taken with 2023 costs applied. Treatment effects were taken from the ADAPT study and treatment-related events from a combination of sources. T1D complication costs were derived from local literature, and health state utilities and disutilities from published literature. Scenario analyses and probabilistic sensitivity analyses (PSAs) explored uncertainty. Cost-effectiveness was assessed based on willingness-to-pay (WTP) thresholds set to Singapore Dollars (SGD) 45,000 (United States Dollars [USD] 33,087) per quality-adjusted life year (QALY) and Singapore's gross domestic product (GDP) per capita of SGD 114,165 (USD 83,941) per QALY. Results: A switch from MDI plus isCGM to MM780G resulted in expected gains in life-years (+0.78) and QALYs (+1.45). Cost savings through reduction in T1D complications (SGD 25,465; USD 18,723) partially offset the higher treatment costs in the AHCL arm (+SGD 74,538; +USD 54,805), resulting in an estimated incremental cost-effectiveness ratio of SGD 33,797 (USD 24,850) per QALY gained. Findings were robust, with PSA outputs indicating 81% and 99% probabilities of cost-effectiveness at the stated WTP thresholds. Conclusion: MM780G is a cost-effective option for people with T1D managed in a Singapore setting.

Racial/Ethnic Inequities in Use of Diabetes Technologies Among Medicare Advantage Beneficiaries With Type 1 Diabetes

CONTEXT

Racial/ethnic inequities have been observed in diabetes care.

OBJECTIVE

To measure changes in prevalence of continuous glucose monitoring (CGM) and insulin pump therapy among Medicare Advantage beneficiaries with type 1 diabetes by race/ethnicity and to determine the impact of socioeconomic factors on racial/ethnic inequities.

DESIGN

The prevalence of CGM and pump use was assessed by race/ethnicity for Medicare Advantage beneficiaries annually from 2017 through 2020. Models predicting technology use by year, race/ethnicity, age, sex, endocrinology visits, and measures of socioeconomic status were fit.

SETTING

Community.

PATIENTS OR OTHER PARTICIPANTS

Beneficiaries with type 1 diabetes and 2 or more claims with a diabetes diagnosis in the coverage year.

INTERVENTION(S)

Insulin pump or CGM therapy.

MAIN OUTCOME MEASURE(S)

Use of diabetes technology by racial/ethnic group.

RESULTS

Technology use increased from 2017 through 2020 in all racial/ethnic groups. The absolute difference in use between White and Black beneficiaries from 2017 to 2020 remained stable for insulin pumps (10.7% to 10.8%) and increased for CGM (2.6% to 11.1%). The differences in pump use from 2017 to 2020 narrowed between White and Hispanic beneficiaries (12.3% to 11.4%) and White and Asian beneficiaries (9.7% to 6.6%), whereas the opposite occurred for CGM use (3.0% to 15.5% for White vs Hispanic beneficiaries; 1.5% to 8.0% for White vs Asian beneficiaries). Racial/ethnic inequities persisted (P < .0001) after adjusting for other characteristics.

CONCLUSIONS

Differences in diabetes technology use between racial/ethnic groups often persisted from 2017 through 2020 and could not be explained by demographics, socioeconomic status, or endocrinology visits.

Potential cost savings in the United States from a reduction in sensor-detected severe hypoglycemia among users of the InPen smart insulin pen system

BACKGROUND: Severe hypoglycemia is a significant barrier to optimizing insulin therapy in both type 1 and type 2 diabetes and places a burden on the US health care system because of the high costs of hypoglycemia-related health care utilization. OBJECTIVE: To compare the frequency of sensor-detected severe hypoglycemic events (SHEs) among a population of continuous glucose monitoring (CGM) users on insulin therapy after initiation of the InPen smart insulin pen (SIP) system and to estimate the potential hypoglycemia-related medical cost savings across a population of SIP users. METHODS: SIP users of all ages with type 1 or type 2 diabetes were required to have at least 90 days of SIP use with a connected CGM device. The last 14 days of sensor glucose (SG) data within the 30-day period prior to the start of SIP use ("pre-SIP") and the last 14 days of SG data, along with the requirement of at least 1 bolus entry per day within the 61- to 90-day period after SIP start ("post-SIP"), were analyzed. Sensor-detected SHEs (defined as ≥10 minutes of consecutive SG readings at <54 mg/dL) were determined. Once factored, the expected medical intervention rates and associated costs were calculated. Intervention rates and costs were obtained from the literature. RESULTS: There were 1,681 SIP + CGM users from March 1, 2018, to April 30, 2021. The mean number of sensor-detected SHEs per week declined from 0.67 in the pre-SIP period to 0.58 in the post-SIP period (P = 0.008), which represented a 13% reduction. Assuming a range of 5%-25% of all sensor-detected SHEs resulted in a clinical event, the estimated cost reduction associated with reduced SHEs was $12-$59 and $110-$551 per SIP user per month and per year, respectively. For those aged at least 65 years, there were 166 SIP+CGM users and the reduction in the mean number of sensor-detected SHEs per week between the pre-SIP and post-SIP periods was 31%. CONCLUSIONS: Use of the SIP system with a connected CGM is associated with reduced sensor-detected severe hypoglycemia, which may result in significant cost savings. DISCLOSURES: Albert Chien, Glen Im, Kael Wherry, Janice MacLeod, and Robert A Vigersky are employees of Medtronic; Sneha Thanasekaran and Angela Gaetano were affiliated with Medtronic while doing this research. The submitted work did not involve study subject recruitment, enrollment, or participation in a trial and did not fall under human subject protection requirements (per the Department of Health and Human Services CFR Part 46) necessitating Internal Review Board approval or exemption.

Two-year outcomes of leadless vs. transvenous single-chamber ventricular pacemaker in high-risk subgroups

AIMS

This study compares clinical outcomes between leadless pacemakers (leadless-VVI) and transvenous ventricular pacemakers (transvenous ventricular permanent-VVI) in subgroups of patients at higher risk of pacemaker complications.

METHODS AND RESULTS

This study is based on the Micra Coverage with Evidence Development (CED) study. Patients from the Micra CED study were considered in a high-risk subgroup if they had a diagnosis of chronic kidney disease Stages 4-5 (CKD45), end-stage renal disease, malignancy, diabetes, tricuspid valve disease (TVD), or chronic obstructive pulmonary disease (COPD) 12 months prior to pacemaker implant. A pre-specified set of complications and reinterventions were identified using diagnosis and procedure codes. Competing risks models were used to compare reinterventions and complications between leadless-VVI and transvenous-VVI patients within each subgroup; results were adjusted for multiple comparisons. A post hoc comparison of a composite outcome of reinterventions and device complications was conducted. Out of 27 991 patients, 9858 leadless-VVI and 12 157 transvenous-VVI patients have at least one high-risk comorbidity. Compared to transvenous-VVI patients, leadless-VVI patients in four subgroups [malignancy, HR 0.68 (0.48-0.95); diabetes, HR 0.69 (0.53-0.89); TVD, HR 0.60 (0.44-0.82); COPD, HR 0.73 (0.55-0.98)] had fewer complications, in three subgroups [diabetes, HR 0.58 (0.37-0.89); TVD, HR 0.46 (0.28-0.76); COPD, HR 0.51 (0.29-0.90)) had fewer reinterventions, and in four subgroups (malignancy, HR 0.52 (0.32-0.83); diabetes, HR 0.52 (0.35-0.77); TVD, HR 0.44 (0.28-0.70); COPD, HR 0.55 (0.34-0.89)] had lower rates of the combined outcome.

CONCLUSION

In a real-world study, leadless pacemaker patients had lower 2-year complications and reinterventions rates compared with transvenous-VVI pacing in several high-risk subgroups.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT03039712.

Chronic outcomes of leadless vs transvenous single chamber ventricular pacemakers in high-risk subgroups

Background

The Micra leadless pacemaker (LP-VVI) has been shown to have lower chronic complications and device-related reinterventions compared to transvenous ventricular pacemakers (TV-VVI) in a large, real-world population. This study compares the complication and reintervention rate in subgroups with comorbidities associated with higher risk of pacemaker complications and hypothesized to benefit from leadless pacing.

Methods

The longitudinal Micra Coverage with Evidence Development (CED) Study compared the outcomes of Medicare patients receiving LP-VVI to those receiving a TV-VVI in the US. Patients in the Micra CED study were included in this study if they had a diagnosis of chronic kidney disease Stages 4–5 (CKD45), end-stage renal disease (ESRD), malignancy, diabetes, tricuspid valve disease (TVD), or chronic obstructive pulmonary disease (COPD) on any administrative claim in the 12 months prior to pacemaker implant. A pre-specified set of complications and system reinterventions were identified using the relevant diagnosis and procedure codes. Adjusted and unadjusted Fine-Gray competing risks models were used to compare reinterventions and complications between LP-VVI and TV-VVI patients within each subgroup. All results were adjusted for multiple comparisons using a Bonferroni correction. An ad-hoc comparison of a composite endpoint of select reinterventions (system replacement, removal, revision, and lead reinterventions) and device complications was also conducted.

Results

The sample size of patients in each subgroup ranged from 2,032 patients with ESRD to 11,936 patients with diabetes. The percent of LP-VVI patients in each subgroup ranged from 44.0 in the TVD subgroup to 74.9 in the ESRD subgroup. Compared to patients implanted with a TV-VVI, patients with a LP-VVI with malignancy, diabetes, TVD, and COPD had significantly fewer complications (Table 1; Malignancy, HR 0.68, [0.48–0.95]; Diabetes, HR 0.69, [0.53–0.89]; TVD, HR 0.60 [0.44–0.82]; COPD, HR 0.73, [0.55–0.98]). LP-VVI patients with diabetes, TVD, and COPD also had lower rates of reintervention (Table; Diabetes, HR 0.58, [0.37–0.89]; TVD, HR 0.46 [0.28–0.76]; COPD, HR 0.51, [0.29–0.90]). LP-VVI patients with malignancy, diabetes, TVD, and COPD had lower rates of the combined endpoint of device complications and select reinterventions (Table; Malignancy, HR 0.52, [0.32–0.83]; Diabetes, HR 0.52, [0.35–0.77]; TVD, HR 0.44 [0.28–0.70]; COPD, HR 0.55, [0.34–0.89]).

Conclusions

In a real-world study of US Medicare patients, the leadless pacemaker was associated with lower rates of chronic complications and reinterventions at 2 years compared with TV-VVI pacing in several high-risk subgroups.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Medtronic

Inequity in Adoption of Advanced Diabetes Technologies Among Medicare Fee-for-service Beneficiaries

CONTEXT

Health inequity is often associated with race-ethnicity.

OBJECTIVE

To determine the prevalence of insulin pump therapy and continuous glucose monitoring (CGM) among Medicare beneficiaries with type 1 diabetes (T1D) by race-ethnicity, and to compare diabetes-related technology users with nonusers.

DESIGN

The prevalence of technology use (pump, CGM) was determined by race-ethnicity for enrollees in coverage years (CY) 2017-2019 in the Medicare fee-for-service database. Using CY2019 data, technology users were compared with nonusers by race-ethnicity, sex, average age, Medicare eligibility criteria, and visit to an endocrinologist.

SETTING

Community.

PATIENTS OR OTHER PARTICIPANTS

Beneficiaries with T1D and at least 1 inpatient or 2 outpatient claims in a CY.

INTERVENTION(S)

Pump or CGM therapy, visit to an endocrinologist.

MAIN OUTCOME MEASURE(S)

Diabetes-related technology use by race-ethnicity groups.

RESULTS

Between 2017 and 2019, CGM and insulin pump use increased among all groups. Prevalence of insulin pump use was < 5% for Black and Other beneficiaries yet increased from 14% to 18% among White beneficiaries. In CY2019, 57% of White patients used a pump compared with 33.1% of Black and 30.3% of Other patients (P < 0.001). Black patients were more likely than White patients to be eligible because of disability/end-stage renal disease or to be Medicare/Medicaid eligible (both P < 0.001), whether using technology or not. Significant race-ethnicity differences (P < 0.001) existed between technology users and nonusers for all evaluated factors except visiting an endocrinologist.

CONCLUSIONS

Significant race-ethnicity associated differences existed in T1D management. The gap in diabetic technology adoption between Black and White beneficiaries grew between 2017 and 2019.

Contemporaneous Comparison of Outcomes Among Patients Implanted With a Leadless vs Transvenous Single-Chamber Ventricular Pacemaker

Question

How do the performance of leadless VVI pacemakers and transvenous VVI pacemakers compare in a contemporaneous Medicare population?

Findings

In this cohort study including 15 408 patients, despite significant differences in patient characteristics, patients in whom a leadless pacemaker was implanted were observed to have higher rates of pericardial effusion and/or perforation but lower rates of other device-related complications and requirements for device revision at 6 months.

Meaning

The results from this study further develop the evidence on leadless pacemakers in practice and can inform shared decision-making about device choice for patients and physicians.

Importance

The safety and efficacy of leadless VVI pacemakers have been demonstrated in multiple clinical trials, but the comparative performance of the device in a large, real-world population has not been examined.

Objective

To compare patient characteristics and complications among patients implanted with leadless VVI and transvenous VVI pacemakers.

Design, Setting, Participants

The Longitudinal Coverage With Evidence Development Study on Micra Leadless Pacemakers (Micra CED) is a continuously enrolling observational cohort study evaluating complications, utilization, and outcomes of leadless VVI pacemakers in the US Medicare fee-for-service population. Patients implanted between March 9, 2017, and December 1, 2018, were identified and included. All Medicare patients implanted with leadless VVI and transvenous VVI pacemakers during the study period were enrolled. Patients with less than 12 months of continuous enrollment in Medicare prior to leadless VVI or transvenous VVI implant and with evidence of a prior cardiovascular implantable electronic device were excluded, leaving 5746 patients with leadless VVI pacemakers and 9662 patients with transvenous VVI pacemakers. Data were analyzed from May 2018 to April 2021.

Exposures

Medicare patients implanted with leadless VVI pacemakers or transvenous VVI pacemakers.

Main Outcomes and Measures

The main outcomes were acute (30-day) complications and 6-month complications.

Results

Of 15 408 patients, 6701 (43.5%) were female, and the mean (SD) age was 81.0 (8.7) years. Compared with patients with transvenous VVI pacemakers, patients with leadless VVI pacemakers were more likely to have end-stage kidney disease (690 [12.0%] vs 226 [2.3%]; P < .001) and a higher mean (SD) Charlson Comorbidity Index score (5.1 [3.4] vs 4.6 [3.0]; P < .001). The unadjusted acute complication rate was higher in patients with leadless VVI pacemakers relative to transvenous VVI pacemakers (484 of 5746 [8.4%] vs 707 of 9662 [7.3%]; P = .02). However, there was no significant difference in overall acute complication rates following adjustment for patient characteristics (7.7% vs 7.4%; risk difference, 0.3; 95% CI, −0.6 to 1.3; P = .49). Pericardial effusion and/or perforation within 30 days was significantly higher among patients with leadless VVI pacemakers compared with patients with transvenous VVI pacemakers in both unadjusted and adjusted models (unadjusted, 47 of 5746 [0.8%] vs 38 of 9662 [0.4%]; P < .001; adjusted, 0.8% vs 0.4%; risk difference, 0.4; 95% CI, 0.1 to 0.7; P = .004). Patients implanted with leadless VVI pacemakers had a lower rate of 6-month complications compared with patients implanted with transvenous VVI pacemakers (unadjusted hazard ratio, 0.84; 95% CI, 0.68-1.03; P = .10; adjusted hazard ratio, 0.77; 95% CI, 0.62-0.96; P = .02).

Conclusions and Relevance

In this study, despite significant differences in patient characteristics, patients in whom a leadless pacemaker was implanted were observed to have higher rates of pericardial effusion and/or perforation but lower rates of other device-related complications and requirements for device revision at 6 months. Understanding the benefits and risks associated with leadless VVI pacemakers compared with transvenous VVI pacemakers can help clinicians and patients make informed treatment decisions.

The effectiveness and value of novel treatments for cystic fibrosis

DISCLOSURES: Funding for this summary was contributed by Arnold Ventures, California Health Care Foundation, Harvard Pilgrim Health Care, and Kaiser Foundation Health Plan to the Institute for Clinical and Economic Review (ICER), an independent organization that evaluates the evidence on the value of health care interventions. ICER's annual policy summit is supported by dues from Aetna, America's Health Insurance Plans, Anthem, Allergan, Alnylam, AstraZeneca, Biogen, Blue Shield of CA, Boehringer-Ingelheim, Cambia Health Services, CVS, Editas, Express Scripts, Genentech/Roche, GlaxoSmithKline, Harvard Pilgrim, Health Care Service Corporation, HealthFirst, Health Partners, Johnson & Johnson (Janssen), Kaiser Permanente, LEO Pharma, Mallinckrodt, Merck, Novartis, National Pharmaceutical Council, Pfizer, Premera, Prime Therapeutics, Regeneron, Sanofi, Spark Therapeutics, and United Healthcare. Seidner, Rind, and Pearson are employed by ICER. Tice reports contracts to his institution, University of California, San Francisco, from ICER during the conduct of this study. Wherry has nothing to disclose.

The improved survival rate and cost-effectiveness of a 7-day continuous subcutaneous insulin infusion set

AIMS

The purpose of this article is to compare the insulin cost-savings of the Medtronic Extended Infusion Set (or EIS, a.k.a. Extended Wear Infusion Set) designed and labeled for up to 7-day use with rapid-acting insulins to the current standard of care, 2- to 3-day infusion sets.

METHODS

There are three major improvements (reducing insulin waste, plastic waste, and adverse events) with the extended duration of infusion set wear. This analysis focuses on cost savings from reduced insulin wastage during set changes. Studies published on insulin infusion set survival and EIS clinical trial data (NCT04113694) were used to estimate device lifetime performance using a Markov chain Monte Carlo model, including the assessment of adverse effects and device failure. Total costs associated with infusion set change or failure were systematically found in published literature or estimated based on physical usage, and the direct impact on insulin costs was calculated.

RESULTS

Based on the model and clinical data, EIS users can expect to change their infusion sets about 75 fewer times than standard set users each year. The costs related to unrecoverable insulin during an infusion set and reservoir change in the US were estimated to range from $19.79 to $22.48, resulting in approximately $1324 to $1677 in annual cost-savings for the typical user from minimizing insulin wastage.

LIMITATIONS

The study only assessed devices used within a monitored setting, that is, clinical trials. In addition, the variability associated with healthcare standards and costs and individual treatment variability including insulin dosages, contribute to the uncertainties with the calculations.

CONCLUSIONS

Our analysis demonstrates that by extending the duration of infusion set wear, there may be substantial cost savings by reducing insulin wastage.

Comparison of cost-effectiveness of implantable cardioverter defibrillator therapy in patients for primary prevention in Latin America: an analysis using the Improve SCA study

OBJECTIVE

The mortality benefit of implantable cardioverter defibrillators (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) has been well-established, but ICD therapy remains globally underutilized. The results of the Improve SCA study showed a 49% relative risk reduction in all-cause mortality among ICD patients with 1.5 primary prevention (1.5PP) characteristics (patients with one or more risk factors, p < 0.0001). We evaluated the cost-effectiveness of ICD compared to no ICD therapy among patients with 1.5PP characteristics in three Latin American countries and analyzed the factors involved in cost-effectiveness.

METHODS

We used a published Markov model that compares costs and outcomes of ICD to no ICD therapy from local payers' perspective and included country-specific and disease-specific inputs from the Improve SCA study and current literature. We used WHO-recommended willingness-to-pay (WTP) thresholds to assess cost-effectiveness and compared model outcomes between countries.

RESULTS

Incremental costs per QALY (quality-adjusted life year) saved by ICD compared to no ICD therapy are Colombian Pesos COP$46,729,026 in Colombia, Mexican Pesos MXN$246,016 in Mexico, and Uruguayan Pesos UYU$1,213,614 in Uruguay in the base case scenario; all three figures are between 1-3-times GDP per capita for each country. One-way and probabilistic sensitivity analyses confirm the base case scenario results. Non-cardiac accumulated deaths are lower in Mexico, resulting in a comparatively increased cost-effective ICD therapy.

LIMITATIONS

The Improve SCA study was not randomized, so clinical results could be biased; however, measures were taken to reduce this bias. Costs and benefits were modelled beyond the timeline of direct observation in the Improve SCA study.

CONCLUSIONS

ICD therapy is cost-effective in Mexico and Uruguay and potentially cost-effective in Colombia for a 1.5PP population. Variability in ICER estimates by country can be explained by differences in non-cardiac deaths and cost inputs.

Implantable cardioverter defibrillator therapy is cost effective for primary prevention patients in Taiwan: An analysis from the Improve SCA trial

Objective

Implantable cardiac defibrillators (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) are well-established but underutilized globally. The Improve SCA study has identified a cohort of patients called 1.5 primary prevention (1.5PP) based on PP patients with the presence of certain risk factors. We evaluated the cost-effectiveness of ICD therapy compared to no ICD among the PP population and the subset of 1.5PP patients in Taiwan.

Methods

A Markov model was run over a lifetime time horizon from the Taiwan payer perspective. Mortality and utility estimates were obtained from the literature (PP) and the IMPROVE SCA trial (1.5PP). Cost inputs were obtained from the Taiwan National Health Insurance Administration (NHIA), Ministry of Health and Welfare. We used a willingness-to-pay (WTP) threshold of NT$2,100,000, as established through standard WTP research methods and in alignment with World Health Organization recommendations.

Results

The total discounted costs for ICD therapy and no ICD therapy were NT$1,664,259 and NT$646,396 respectively for PP, while they were NT$2,410,603 and NT$905,881 respectively for 1.5PP. Total discounted QALYs for ICD therapy and no ICD therapy were 6.48 and 4.98 respectively for PP, while they were 10.78 and 7.71 respectively for 1.5PP. The incremental cost effectiveness ratio was NT$708,711 for PP and NT$441,153 for 1.5PP, therefore ICD therapy should be considered cost effective for PP and highly cost effective for 1.5PP.

Conclusions

ICD therapy compared to no ICD therapy is cost-effective in the whole PP population and highly cost-effective in the subset 1.5PP population in Taiwan.

Cost-Effectiveness of Ivacaftor Therapy for Treatment of Cystic Fibrosis Patients With the G551D Gating Mutation

OBJECTIVES

Cystic fibrosis (CF) is a rare genetic disease with no cure. Until recently, treatment has targeted symptoms of the disease and not the disease-causing genetic defect. Ivacaftor is included in a new class of breakthrough drugs targeting the genetic defects of CF. We sought to estimate the long-term cost-effectiveness of ivacaftor from a US payer perspective.

METHODS

We developed an individual-level microsimulation model that followed a cohort of heterogeneous US CF patients over a lifetime. The primary outcome of interest was quality-adjusted life years (QALYs). We also compared unadjusted life years, count of acute pulmonary exacerbations, and count of lung transplants over a lifetime between patients treated with ivacaftor plus best supportive care and patients treated with best supportive care alone. We conducted one-way and probabilistic sensitivity analyses to test the impact of various model inputs and uncertainties.

RESULTS

We found a substantial increase in QALYs, life years, and treatment costs over a lifetime for patients treated with ivacaftor plus best supportive care versus best supportive care alone. Discounted results for ivacaftor were 22.92 QALYs and $8 797 840 in total lifetime costs compared to 16.12 QALYs and $2 336 366 lifetime costs for best supportive care alone. The incremental cost-effectiveness ratios (ICERs) were $950 217 per QALY. Results from the probabilistic sensitivity analysis indicated a 0% chance that ivacaftor was cost-effective at a willingness-to-pay (WTP) threshold of $500 000 per QALY.

CONCLUSIONS

Treatment with ivacaftor plus best supportive care versus best supportive care alone is not cost-effective at or near commonly accepted WTP thresholds.

Using Medicare Claims to Identify Acute Clinical Events Following Implantation of Leadless Pacemakers

Background

There is heightened interest in how real-world data (RWD) can be used to supplement or replace traditional mechanisms for collecting clinical information. A critical component in evaluating utility of RWD is assessing the validity and reliability of event measurement. Only two studies have validated Medicare claims with physician-adjudicated data collected in a clinical study and none in the pacemaker patient population. This study compares events identified in physician-adjudicated clinical registry data collected in the Micra Post-Approval Registry (PAR) with events identified via Medicare administrative claims in the Micra Coverage with Evidence (CED) Study.

Methods

Patients who were dually enrolled in the Micra CED and the Micra PAR between March 9, 2017 and December 1, 2017 were included in the validation analysis. All patients intended to be implanted with a Micra device were eligible for participation in the Micra PAR. All Medicare fee-for-service beneficiaries implanted with a Micra device who met the 12-month continuous enrollment criteria were included in the Micra CED. We compared the count of acute (30-day) complications identified in the Medicare claims and the physician-adjudicated PAR data to assess agreement between data sources.

Results

There were 230 patients dually enrolled in the Micra CED and Micra PAR studies during the study period. Overall, there were 17 acute events reported in either the Micra CED or the Micra PAR, with 95% agreement in the identification of events and absence of events between studies. Study disagreement between events reported in either study varied: arteriovenous fistula (50%), pulmonary embolism (67%), hemorrhage/hematoma (75%), and deep vein thrombosis (100%). Among physician-adjudicated events, there was no disagreement between the Micra CED and Micra PAR studies in any event type.

Conclusion

Findings from this study demonstrate high agreement in event identification between Medicare claims data and registries for patients implanted with Micra leadless pacemakers.

Inhibition of methionine adenosyltransferase by the polyamines

The effect of the polyamines, putrescine, spermine, and spermidine, on the activity of extrahepatic methionine adenosyltransferase (MAT II) was studied. The polyamines inhibited MAT II activity at concentrations equal to or greater than 5 mm. Combinations of polyamines were more effective than individual polyamines in inhibiting MAT activity; maximum inhibition approached 80% with combinations of all three polyamines. S-Adenosylmethionine (AdoMet), Pi, and PPi, the products of the MAT reaction, are known to be synergistic inhibitors of the nonhepatic form of the enzyme. Combinations of polyamines plus Pi and/or PPi induced an additive inhibition of the enzyme. AdoMet plus polyamines also resulted in significant inhibition, but inhibition plateaued at about 80%, indicating the presence of a protective mechanism to maintain AdoMet synthesis. Extrahepatic MAT from human and rat tissues was inhibited by the polyamines, indicating that this phenomenon is not species specific. In addition, we examined the effect of polyamines on MAT activity in resting and activated human lymphocytes that were shown to differ in the relative expression of MAT II subunits. Although MAT from mitogen (phytohemagglutinin, PHA)- and superantigen (Staphylococcal enterotoxin B, SEB)-stimulated lymphocytes were similarly inhibited by 10 mM polyamines, at lower concentrations of polyamines (1-5 mM), MAT from SEB-stimulated cells appeared to be more susceptible to inhibition by the polyamines. Inasmuch as SEB is a more physiological stimulator of T cells than PHA, the data suggest a possible role of polyamines in regulating MAT activity.

Improving detection of pediatric elbow fractures by understanding their mechanics

Fractures around the elbow are among the most common fractures in children, but they can also be some of the most elusive to detect. Although elbow fractures result from a variety of stresses applied to the three bones constituting the elbow joint, hyperextension-rotation injuries with valgus or varus stress are the most common cause of elbow fractures. Less common are direct impact injuries to the posterior aspect of the elbow. Because all three bones and their articulations are morphologically different, the various traumatic forces applied result in distinctly different types of fractures in each of the bones. For example, hyperextension with vertical stress produces supracondylar fractures of the distal humerus, longitudinal linear ulnar fractures, and buckle fractures; hyperextension with valgus stress causes impaction fractions of the radial head and neck, transverse olecranon fractures, and medial epicondylar fractures, whereas varus stress produces Monteggia fractures, lateral condylar avulsion fractures, transverse olecranon fractures, and longitudinal linear ulnar fractures. Understanding these forces and their effects is important because it facilitates detection of the wide variety of fractures in their more subtle forms.