Publications

2017

Kramer, Daniel B, Matthew R Reynolds, Sharon-Lise Normand, Craig S Parzynski, John A Spertus, Vincent Mor, and Susan L Mitchell. (2017) 2017. “Nursing Home Use After Implantable Cardioverter-Defibrillator Implantation in Older Adults: Results from the National Cardiovascular Data Registry.”. Journal of the American Geriatrics Society 65 (2): 340-47. https://doi.org/10.1111/jgs.14520.

OBJECTIVES: To evaluate the incidence and characteristics of nursing home (NH) use after implantable cardioverter-defibrillator (ICD) implantation.

DESIGN: Cohort study.

SETTING: Medicare beneficiaries in the National Cardiovascular Data Registry-ICD Registry.

PARTICIPANTS: Individuals aged 65 and older receiving ICDs between January 1, 2006, and March 31, 2010 (N = 192,483).

MEASUREMENTS: Proportion of ICD recipients discharged to NHs directly after device placement, cumulative incidence of long-term NH admission, and factors associated with immediate discharge to a NH and time to long-term NH admission.

RESULTS: Over 4 years, 40.6% of the cohort died, and 35,939 (18.7%) experienced at least one NH admission, including 4.0% directly discharged to a NH after ICD implantation and 2.8% admitted to long-term NH care during follow-up. The cumulative incidence of long-term NH admission, accounting for the competing risk of death, was 1.7% at 1 year, 3.8% at 3 years, and 4.6% at 4 years; 20.1% of individuals admitted to a NH died there. Factors most strongly associated with direct NH discharge and time to long-term NH care were older age (adjusted odds ratio (AOR) = 2.09, 95% confidence interval (CI) = 2.01-2.17 per 10-year increment; adjusted hazard ratio (AHR) = 1.88, 95% CI = 1.80-1.97, respectively), dementia (AOR = 2.60, 95% CI = 2.25-3.01; AHR = 2.50, 95% CI = 2.14-2.93, respectively), and Medicare Part A claim for NH stay in prior 6 months (AOR = 3.96, 95% CI = 3.70-4.25; AHR = 2.88, 95% CI = 2.65-3.14, respectively).

CONCLUSION: Nearly one in five individuals are admitted to NHs over a median of 1.6 years of follow-up after ICD implantation. Understanding these outcomes may help inform the clinical care of these individuals.

Kramer, Daniel B, Timothy Tsai, Poorna Natarajan, Elise Tewksbury, Susan L Mitchell, and Thomas G Travison. (2017) 2017. “Frailty, Physical Activity, and Mobility in Patients With Cardiac Implantable Electrical Devices.”. Journal of the American Heart Association 6 (2). https://doi.org/10.1161/JAHA.116.004659.

BACKGROUND: This study aimed to demonstrate the feasibility of measuring frailty in patients with cardiac implantable electrical devices while validating the physiologic significance of device-detected physical activity by evaluating its association with frailty and mobility.

METHODS AND RESULTS: Outpatients with cardiac implantable electrical devices compatible with physical activity analysis with at least 7 days of data were eligible. Office testing included frailty status (Study of Osteoporotic Fractures instrument), gait speed (m/s), mobility according to the Timed Up and Go (TUG) test (seconds), and daily physical activity (h/d) as measured by cardiac implantable electrical device. Among 219 patients, Study of Osteoporotic Fractures testing found 39.7% to be robust, 47.5% prefrail, and 12.8% frail. The mean gait speed for the cohort was 0.8±0.3 m/s, mean TUG time was 10.9±4.4 seconds, and mean activity was 2.8±1.9 h/d. Frail patients were markedly more likely to have gait speeds <0.8 m/s (OR 6.25, 95% CI 1.79-33.3). In unadjusted analyses each 1-hour increase in mean daily activity was associated with a 46% reduction of frail phenotype (OR 0.54, 95% CI 0.40-0.74) versus robust and with a 27% reduction in the odds of having the prefrail phenotype (OR 0.73, 95% CI 0.62-0.86). After adjustment this association per hour of activity persisted, with an adjusted OR for frailty of 0.71 (95% CI 0.51-0.99) and adjusted OR for prefrailty of 0.81 (95% CI 0.67-0.99).

CONCLUSIONS: Frailty and mobility limitation are common among cardiac implantable electrical device patients and are correlated to device-detected physical activity.

Kramer, Daniel B, Paul W Jones, Tyson Rogers, Susan L Mitchell, and Matthew R Reynolds. (2017) 2017. “Patterns of Physical Activity and Survival Following Cardiac Resynchronization Therapy Implantation: The ALTITUDE Activity Study.”. Europace : European Pacing, Arrhythmias, and Cardiac Electrophysiology : Journal of the Working Groups on Cardiac Pacing, Arrhythmias, and Cardiac Cellular Electrophysiology of the European Society of Cardiology 19 (11): 1841-47. https://doi.org/10.1093/europace/euw267.

AIMS: Cardiac resynchronization therapy with implantable defibrillator backup (CRT-D) improves outcomes, but predictors and markers of response remain limited. Physical activity information collected by CRT devices may provide insights to CRT response and the relationship between activity changes and survival.

METHODS AND RESULTS: Patients entered into the LATITUDE remote monitoring system from 2008 to 2012 after receipt of a new CRT-D were eligible. Mean daily activity was calculated from LATITUDE uploads at baseline (first 3-10 days following implant) and 6 months (180-210 days). Pairwise differences for baseline-6-month activity were calculated, and survival according to quintiles of 6-month activity change was assessed. Cox regression was used to examine the adjusted association between survival and baseline-6-month activity change. A total of 26 509 patients were followed for a median of 2.3 years (mean age 70.2 ± 11.0 years, 70.7% male). Mean baseline activity was 66.2 ± 47.7 min/day, with mean paired increase at 6 months of 37.1 ± 48.2 min/day [95% CI (confidence interval), 36.5-37.6, P < 0.0001], though 15.5% of patients did not improve or worsened at 6 months. Survival at 3 years was significantly higher in the largest baseline-6-month activity change quintile vs. the lowest quintile (88.9% vs. 62.1%, log-rank P-value < 0.001). Adjusted for age and gender, higher 6-month activity change was associated with a lower risk of death (adjusted hazard ratios 0.65 per 30 min increase in activity, 95% CI, 0.63-0.67).

CONCLUSIONS: Change in physical activity between baseline and 6 months following CRT implantation is strongly associated with survival.

Kramer, Daniel B, Daniel Habtemariam, Yaw Adjei-Poku, Michelle Samuel, Diane Engorn, Matthew R Reynolds, and Susan L Mitchell. (2017) 2017. “The Decisions, Interventions, and Goals in ImplaNtable Cardioverter-DefIbrillator TherapY (DIGNITY) Pilot Study.”. Journal of the American Heart Association 6 (9). https://doi.org/10.1161/JAHA.117.006881.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are commonly implanted in older patients, including those with multiple comorbidities. There are few prospective studies assessing the clinical course and end-of-life circumstances for these patients.

METHODS AND RESULTS: We prospectively followed 51 patients with ICDs for up to 18 months to longitudinally assess in terms of (1) advance care planning, (2) health status, (3) healthcare utilization, and (4) end-of-life circumstances through quarterly phone interviews and electronic medical record review. The mean age was 71.1±8.3, 74.5% were men, and 19.6% were non-white. Congestive heart failure was predominant (82.4%), as was chronic kidney disease (92%). At baseline, a total of 12% of subjects met criteria for major depression, and 78.4% met criteria for mild cognitive impairment. From this initial study cohort, 76% survived to 18 months and completed all follow-up interviews, 18% died, and 19% withdrew or were lost to follow-up. Though living will completion and healthcare proxy assignment were common (cumulative outcome at 18 months 88% and 98%, respectively), discussions of prognosis were uncommon (baseline, 9.8%; by 18 months, 22.7%), as were conversations regarding ICD deactivation (baseline, 15.7%; by 18 months, 25.5%). Five decedents with available data received shocks in the days immediately prior to death, including 3 of whom ultimately had their ICDs deactivated prior to death.

CONCLUSIONS: We demonstrated the feasibility of prospective enrollment and follow-up of older, vulnerable ICD patients. Early findings suggest a high burden of cognitive and psychological impairment, poor communication with providers, and frequent shocks at the end of life. These findings will inform the design of a larger cohort study designed to further explore the experiences of living and dying with an ICD in this important patient population.

Ransford, Benjamin, Daniel B Kramer, Denis Foo Kune, Julio Auto de Medeiros, Chen Yan, Wenyuan Xu, Thomas Crawford, and Kevin Fu. (2017) 2017. “Cybersecurity and Medical Devices: A Practical Guide for Cardiac Electrophysiologists.”. Pacing and Clinical Electrophysiology : PACE 40 (8): 913-17. https://doi.org/10.1111/pace.13102.

Medical devices increasingly depend on software. While this expands the ability of devices to perform key therapeutic and diagnostic functions, reliance on software inevitably causes exposure to hazards of security vulnerabilities. This article uses a recent high-profile case example to outline a proactive approach to security awareness that incorporates a scientific, risk-based analysis of security concerns that supports ongoing discussions with patients about their medical devices.

Strom, Jordan B, Daniel B Kramer, Yun Wang, Changyu Shen, Jason H Wasfy, Bruce E Landon, Elissa H Wilker, and Robert W Yeh. (2017) 2017. “Short-Term Rehospitalization across the Spectrum of Age and Insurance Types in the United States.”. PloS One 12 (7): e0180767. https://doi.org/10.1371/journal.pone.0180767.

Few studies have examined rates and causes of short-term readmissions among adults across age and insurance types. We compared rates, characteristics, and costs of 30-day readmission after all-cause hospitalizations across insurance types in the US. We retrospectively evaluated alive patients ≥18 years old, discharged for any cause, 1/1/13-11/31/13, 2006 non-federal hospitals in 21 states in the Nationwide Readmissions Database. The primary stratification variable of interest was primary insurance. Comorbid conditions were assessed based on Elixhauser comorbidities, as defined by administrative billing codes. Additional measures included diagnoses for index hospitalizations leading to rehospitalization. Hierarchical multivariable logistic regression models, with hospital site as a random effect, were used to calculate the adjusted odds of 30-day readmissions by age group and insurance categories. Cost and discharge estimates were weighted per NRD procedures to reflect a nationally representative sample. Diagnoses for index hospitalizations leading to rehospitalization were determined. Among 12,533,551 discharges, 1,818,093 (14.5%) resulted in readmission within 30 days. Medicaid insurance was associated with the highest adjusted odds ratio (AOR) for readmission both in those ≥65 years old (AOR 1.12, 95%CI 1.10-1.14; p <0.001), and 45-64 (AOR 1.67, 95% CI 1.66-1.69; p < 0.001), and Medicare in the 18-44 group (Medicare vs. private insurance: AOR 1.99, 95% CI 1.96-2.01; p <0.001). Discharges for psychiatric or substance abuse disorders, septicemia, and heart failure accounted for the largest numbers of readmissions, with readmission rates of 24.0%, 17.9%, 22.9% respectively. Total costs for readmissions were 50.7 billion USD, highest for Medicare (29.6 billion USD), with non-Medicare costs exceeding 21 billion USD. While Medicare readmissions account for more than half of the total burden of readmissions, costs of non-Medicare readmissions are nonetheless substantial. Medicaid patients have the highest odds of readmission in individuals older than age 44, commonly due to hospitalizations for psychiatric illness and substance abuse disorders. Medicaid patients represent a population at uniquely high risk for readmission.