Somers, Virend K.

Introduction: The prevalence of obstructive sleep apnea (OSA) in heart failure (HF) patients varies from 30 to 50%. The differences in clinical characteristics, healthcare resource utilization (HCRU), and positive airway pressure (PAP) usage between HF with preserved ejection fraction (HFpEF) vs. HF with reduced ejection fraction (HFrEF) in OSA patients are not well known. Objective: To compare clinical characteristics, PAP usage, and HCRU in OSA patients with HFpEF vs HFrEF. Methods: Retrospective cohort study using US administrative claims data linked to objective PAP usage data over one year. HFpEF and HFrEF were identified by ICD-9/10 codes associated with healthcare encounters 1 year before starting PAP therapy. Pearson’s Chi-squared and Wilcoxon rank-sum tests were used as applicable to compare baseline characteristics and PAP usage, and the pre to post-PAP initiation difference in the number of health care encounters. Results: In total, 7,419 patients with HF and OSA were identified, of which 57% had HFpEF. HFpEF patients were majority female (54%) and older than those with HFrEF (64.1 ± 11.52 vs 59.7 ± 11.24 years, p<0.001). HFpEF had a higher overall comorbidity burden, although coronary artery disease, atrial fibrillation, and other arrhythmias were more prevalent in HFrEF. Both prior to and after PAP therapy, HCRU was higher in HFpEF patients compared to HFrEF (Table 2a). There were no differences in PAP usage between HFpEF and HFrEF (3.6 ± 2.9 vs 3.7 ± 3.0 hrs/night, p=0.070) over the first year of PAP therapy. There was a significant reduction in ER visits and all cause hospitalizations after 1 year of PAP therapy initiation, which was similar between groups (Table 2b). Conclusions: Although there were differences in clinical characteristics between HFpEF and HFrEF patients with OSA, and HFpEF is associated with greater HCRU, PAP therapy usage was similar, and both groups experienced a similar reduction in HCRU after the first year of PAP initiation.

Introduction: Heart failure patients with preserved ejection fraction (HFpEF) frequently have co-morbid obstructive sleep apnea (OSA), although the impact of OSA treatment remains unclear in this patient population. We assessed the association between adherence to positive airway pressure (PAP) therapy and healthcare resource utilization in patients with OSA and HFpEF. Methods: Administrative insurance claims data linked with objective PAP therapy usage data from patients with OSA and HFpEF were used to measure the association of PAP adherence and healthcare resource utilization, defined by hospitalizations and emergency room (ER) visits. US Medicare defines PAP compliance as use for at least 4 hours/night for 70% of nights in a consecutive 30-day period over 90 days. PAP adherent patients met this criteria for all 4 90-day periods, while PAP non-adherent patients did not meet this criteria for any 90-day period over one year. Propensity score methods were used to create well matched groups with differing PAP adherence levels. Results: The study cohort consisted of 4,237 eligible patients (54.0% female, mean age 64.1 years), of whom 40% were considered adherent to PAP therapy (30% intermediate-adherent, 30% non-adherent). After propensity score matching on prior year covariates, during the year after PAP prescription, PAP adherent patients had fewer hospital visits than non-adherent patients, with a 57% reduction in hospitalizations and a 36% reduction in ER visits for PAP adherent patients (Table 1a). These results remained consistent with inverse probability weighting, and furthermore showed a significant difference in hospitalizations between intermediate-adherent and non-adherent patients, but no significant difference in ER visits (Table 1b). Conclusions: Treating OSA with PAP therapy in patients with HFpEF is associated with a reduction in hospitalizations and ER visits. Adherence to PAP therapy is required to realize these clinical benefits.

Abstract Study Objectives Narcolepsy is associated with cardiovascular risk factors; however, the risk of new-onset cardiovascular events in this population is unknown. This real-world study evaluated the excess risk of new-onset cardiovascular events in U.S. adults with narcolepsy. Methods A retrospective cohort study using IBM MarketScan administrative claims data (2014–2019) was conducted. A narcolepsy cohort, comprising adults (≥18 years) with at least two outpatient claims containing a narcolepsy diagnosis, of which at least one was non-diagnostic, was matched to a non-narcolepsy control cohort (1:3) based on cohort entry date, age, sex, geographic region, and insurance type. The relative risk of new-onset cardiovascular events was estimated using a multivariable Cox proportional hazards model to compute adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Results The narcolepsy and matched non-narcolepsy control cohorts included 12 816 and 38 441 individuals, respectively. At baseline, cohort demographics were generally similar; however, patients with narcolepsy had more comorbidities. In adjusted analyses, the risk of new-onset cardiovascular events was higher in the narcolepsy cohort compared with the control cohort: any stroke (HR [95% CI], 1.71 [1.24, 2.34]); heart failure (1.35 [1.03, 1.76]); ischemic stroke (1.67 [1.19, 2.34]); major adverse cardiac event (1.45 [1.20, 1.74]); grouped instances of stroke, atrial fibrillation, or edema (1.48 [1.25, 1.74]); and cardiovascular disease (1.30 [1.08, 1.56]). Conclusion Individuals with narcolepsy are at increased risk of new-onset cardiovascular events compared with individuals without narcolepsy. Physicians should consider cardiovascular risk in patients with narcolepsy when weighing treatment options.

With rising healthcare costs and the rapid increase in remote physiologic monitoring and care delivery, there is increasing need for economical, accurate and non-invasive continuous measures of blood analytes. Based on radio-frequency identification (RFID), we have developed a novel electromagnetic platform technology (the Bio-RFID platform) to non-invasively penetrate inanimate surfaces, capture data from individual radio frequencies, and convert those data into physiologically meaningful information and insights. Here we describe ground-breaking proof-of-principle studies using Bio-RFID to accurately measure various concentrations of analytes in deionized water. The in vitro Bio-RFID platform consists of an acrylic cuvette in the shape of a 4 inch x 4 inch x 8 inch rectangular prism mounted on the Bio-RFID sensor. This apparatus is in turn mounted on a balance that allows the determination of the mass of the analyte being scanned to within 0.1g. The hardware scans through several thousand radio frequencies and sends the data to proprietary software running on a laptop computer. The software displays a spectral scan known as the Bio-RFID signature of the analyte and computes a similarity metric to compare different signatures.We tested the hypothesis that the Bio-RFID platform is able to precisely and non-invasively measure and identify a variety of analytes in vitro. For this assessment, varying solutions of 1) water in isopropyl alcohol; 2) salt in water; and 3) commercial bleach in water were tested, using a randomized double-blind trial design, as proxies for biochemical solutions in general. The Bio-RFID technology was able to detect concentrations of 2000 parts per million (ppm), with evidence suggesting the ability to detect considerably smaller concentration differences. The novel application of a Bio-RFID electromagnetic platform technology accurately detects, measures, and quantifies specific molecules in liquid. While these findings have in vitro commercial applications, these proof-of-principle studies provide strong support for the application of Bio-RFID technology for non-invasive bio-monitoring of physiologically and medically relevant analytes, such as alcohol and glucose, in the human body. These studies were funded by a grant from Know Labs to Mayo Clinic. PB and JHA are employed by Know Labs. VKS and Mayo Clinic acknowledge a financial interest in Know Labs. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cardiovascular health disparities are present in several minority racial and ethnic groups including African Americans, who exhibit an increased risk of hypertension compared to non-Hispanic Whites. Somali Americans, a subgroup of African Americans of East African origins, exhibit high rates of diabetes and obesity, conditions often comorbid with impaired blood pressure (BP) regulation. Importantly, it remains unknown whether the disparate cardiovascular risk profile, namely poor nocturnal BP regulation, manifested in African Americans can be applied to Somali Americans. We therefore examined 24-hour BP patterns in Somali Americans compared to White control participants. We hypothesized that Somali Americans would present with heightened nocturnal BP and heart rate (HR). We utilized ambulatory blood pressure monitoring (ABPM) to quantify 24-hour BP patterns in 25 Somali (10 female, 15 male; age: 34 ± 3 years; BMI: 27 ± 1 kg/m2) and 25 White (13 female, 12 male; age: 38 ± 3 years; BMI: 27 ± 1 kg/m2) individuals. Each ABPM recorded a BP reading every 20 minutes throughout the 24-hour period. Subjects were instructed to abstain from caffeine, alcohol, and vigorous exercise during the recording period. From the 24-hour recording, an ambulatory arterial stiffness index (AASI) was calculated as 1 minus the regression slope of systolic (SAP) and diastolic (DAP) arterial pressure. SAP, DAP, and HR obtained between 12:00am and 6:00am were averaged to compute nocturnal means. BP and HR dipping was determined as the percent change between daytime and nocturnal BP and HR. Statistical analysis included independent samples t-tests to determine differences in BP and HR between racial groups (i.e., Somali vs. White). Nocturnal SAP (105 ± 2 vs. 106 ± 3 mmHg, p = 0.364) and DAP (60 ± 1 vs. 58 ± 2 mmHg, p = 0.093) were not different between Somali and White participants. In contrast, nocturnal HR was significantly higher in Somalis compared to Whites (72 ± 2 vs. 64 ± 2 beats/minute, p = 0.009). Similarly, SAP (12 ± 2% vs. 12 ± 1%, p = 0.437) and DAP (18 ± 2% vs. 21 ± 2%, p = 0.127) dipping were comparable between groups, while Somali individuals exhibited blunted HR dipping (11 ± 2% vs. 19 ± 2%, p = 0.008) compared to Whites. AASI (0.32 ± 0.03 vs. 0.24 ± 0.03 a.u., p = 0.031) was higher in Somali compared to White individuals. These findings suggest Somali Americans present with impaired nocturnal cardiovascular regulation and increased arterial stiffness, which may place this racial minority at increased cardiovascular risk. Future work to investigate the mechanistic relationships of cardiovascular dysfunction in Somali Americans is warranted. Research grant from Sleep Number to Mayo Clinic for studies of sleep and cardiovascular risk in Somali Americans, and by NIH R01-HL160619, T32-DK007013, T32-HL007111, and T32-HL105355. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Hypertension is commonly observed with obstructive sleep apnea (OSA), partly due to dysregulation of sympathetic activity. As OSA is considered male-dominant, potential sex differences in the sympathetic regulation of BP have yet to be explored. Hemodynamic responses to an orthostatic challenge have implications for cardiovascular risk and are sympathetically-modulated. Therefore, we tested the hypothesis that females with OSA have differential BP and HR responses to orthostasis relative to males with OSA. 160 individuals not taking antihypertensive medications completed an overnight polysomnography to identify OSA (apnea-hypopnea index ≥5 events/hr). Orthostatic responses were quantified as the changes (Δ) in BP and HR (assessed via brachial cuff) from rest (10min supine) to 60sec post-standing. Females with (n=17, 42±14yrs, 30.7±6.0kg/m2) and without (n=43, 39±12yrs, 27.6±5.7kg/m2) OSA were compared to males with (n=60, 45±11yrs, 31.4±3.8kg/m2) and without (n=40, 39±13yrs, 27.4±3.1kg/m2) OSA using a one-way ANOVA. There were no between-group differences in age (p>0.05 for post-hoc comparisons) and BMI was lower in both females, and males, without OSA relative to males with OSA (p<0.05 for both). ΔSBP did not differ between females with (1±8mmHg) and without (2±8mmHg) OSA nor between males with (4±8mmHg) and without OSA (5±12mmHg, ANOVA p=0.37). Females with OSA had a blunted ΔDBP relative to females without OSA (5±7 vs. 10±6mmHg, p<0.05), whereas males with and without OSA demonstrated similar responses (9±8 vs. 10±6mmHg, p=0.95). ΔHR did not differ between females with (8±8beats/min) and without OSA (9±11beats/min) nor between males with (13±10beats/min) and without OSA (12±10beats/min, ANOVA p=0.06). ΔDBP was not associated with the apnea-hypopnea index (Spearman's r=-0.19, p=0.47; Spearman’s r=0.23, p=0.08) nor nadir SpO2 (Spearman's r=0.27, p=0.29; Spearman’s r=0.06, p=0.64) in females or males with OSA. These data suggest that OSA influences the DBP response to orthostasis in females to a greater extent than males. As DBP is associated with sympathetic activation, this finding could indicate greater sympathetic dysregulation in females, relative to males, with OSA. This work was supported by the National Institutes of Health T32-HL007111 (JMB), HL134808 (NC), HL065176 (PS and VKS), and HL134885 (VKS). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract Introduction The prevalence of obstructive sleep apnea (OSA) is high in patients with systolic heart failure (HFrEF) and has been associated with poor prognosis in this patient population. The impact of positive airway pressure (PAP) therapy in patients with OSA and HFrEF remains unclear. This retrospective study sought to investigate the association between 1-year adherence to PAP therapy and healthcare resource utilization (HCRU) in patients with newly diagnosed OSA and comorbid HFrEF. Methods A national sample of administrative claims data linked to objective PAP therapy usage was used for this analysis. Included patients either had two healthcare encounters or one hospitalization with a systolic heart failure ICD-10 diagnosis code the year prior to being diagnosed with OSA and initiated on PAP therapy. HCRU was measured as a composite outcome of hospitalizations, and emergency room (ER) visits. Propensity score matching was used to create well-balanced groups with differing PAP adherence levels to assess the association with 1-year HCRU outcomes. Risk-adjusted models were used to generate the number needed to treat (NNT) that referred to the number of patients that need to become adherent to PAP from non-adherent to avoid 1 visit. Results We identified 3,182 patients with OSA and comorbid HFrEF, and after propensity score matching, 738 patients remained in each group (adherent vs. non-adherent). After 1 year of PAP therapy, adherent patients had fewer visits than non-adherent patients (0.92 vs. 1.15 visits per subject, p = 0.006), which was driven by a 24% reduction in ER visits for adherent patients. Composite hospitalization and ER visit costs were lower in adherent versus non-adherent patients ($3,500 vs. $5,879, p=0.03). The NNT for the entire cohort to avoid one visit was 1.5 patients. Conclusion HFrEF patients with comorbid OSA who were adherent to PAP therapy for 1 year have fewer composite hospitalizations and ER visits than patients that were not adherent. These results highlight the clinical and economic benefits of treating OSA in HFrEF patients. Support (if any) Funding Source: ResMed

Abstract Introduction Although diastolic heart failure (HFpEF) patients frequently have comorbid obstructive sleep apnea (OSA), which has been associated with poor prognosis, the impact of positive airway pressure (PAP) therapy remains unclear. This retrospective study sought to investigate the association between 1 year adherence to PAP therapy and healthcare resource utilization (HCRU) in patients with newly diagnosed OSA and comorbid HFpEF. Methods A national sample of administrative claims data linked to objective PAP therapy usage was used for this analysis. Eligible patients either had two healthcare encounters or one hospitalization with a diastolic heart failure ICD-10 diagnosis code the year prior to being diagnosed with OSA and initiated on PAP therapy. HCRU was measured as a composite outcome of hospitalizations and emergency room (ER) visits. Propensity score matching was used to create well-balanced groups with differing PAP adherence levels to assess the association with 1 year HCRU outcomes. Risk-adjusted models were used to generate the number needed to treat (NNT) that referred to the number of patients that need to become adherent to PAP from non-adherent to avoid 1 visit. Results 4,237 patients with OSA and comorbid HFpEF were included. With propensity score matching, 963 PAP adherent and 963 non-adherent patients remained. After 1 year of PAP therapy, adherent patients had fewer visits than non-adherent patients (1.16 visits per subject vs. 1.75, p &lt; 0.001), driven by a 57% reduction in hospitalizations and a 36% reduction in ER visits for adherent patients. Total HCRU costs were lower in adherent patients than in non-adherent patients ($12,732 vs. $15,610, p&lt; 0.01). Converting 1 patient from non-adherent to adherent would avoid 1.25 visits (either ER visit or hospitalization), with an NNT of 0.8. Conclusion HFpEF patients with OSA that are adherent to PAP therapy for 1 year have fewer hospitalizations and ER visits than patients that are not adherent. More importantly, HCRU costs were lower in adherent patients, highlighting the clinical and economic benefits of treating OSA with PAP therapy in HFpEF patients. Support (if any) Funding Source: ResMed

Abstract Introduction Nightshifts represent a substantial proportion of time dedicated to working in the inpatient setting, particularly among ICU staff. Our institution implemented a 24/7 in-person ICU attending model more than a decade ago. With practice growth and more than 200 ICU beds across disciplines, there are now at least 8 ICU attendings in-hospital all night. Yet, little is known about attending staff perceptions and desires about night work, so we began an exploratory analysis. Methods An online survey of 13 multiple-choice, slider scale, and open-ended questions were sent via email to critical care staff physicians of different disciplines within our institution. Results 69 out of 150 physicians completed the survey (46% response rate). Half were between 35 and 45 years old; 29% were age 45 to 55 years old. About half self-identified as a morningness chronotype. Most (84%) work 3- or 4-night shifts consecutively. Most viewed night shift work as having a negative influence on their quality of life (48% “somewhat negative” and 22% “very negative”) and on their health (51% “somewhat negative” and 24% “very negative”). Most would choose to work less nightshifts (37%) or none (29%). During nightshift assignments, about half (53%) self-report an average of 5 hours of sleep per 24-hour period; 18% self-report ≤ 4hours. Only 6% reported 7 or 8 hours of sleep. Mitigating strategies utilized during series of night shifts include use of caffeine (78%), naps (66%) and use of sleeping aids (21%). Outside of the nightshift series, more than half (56%) reported no sleep difficulties while 21% reported onset or maintenance insomnia. Conclusion At our large tertiary hospital employing an in-house nightshift model across multiple ICUs, most staff ICU physicians have a negative perception of night shift work on their quality of life and health. The majority of respondents would choose to work less or no night shifts. How self-reports of limited sleep (average 5 hours) per 24-hour period compare to objectively measured sleep duration in this population remains to be determined in the next phase of this study. Support (if any)

Abstract Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): Mayo Clinic Department of Laboratory Medicine and Pathology. Background Elevated lipoprotein(a) [Lp(a)] is associated with increased risk for atherosclerotic cardiovascular disease (ASCVD). Treatment of patients with elevated Lp(a) usually includes marked reduction in low density lipoprotein cholesterol (LDL-C). However, there are uncertainties about whether all increases in Lp(a) are equivalent in there risk relationship. Purpose The aim of this investigation was to risk stratify patients with elevated Lp(a) mass [Lp(a)-M] based on Lp(a) cholesterol (Lp(a)-C) measurements. We assessed coronary artery disease (CAD) by coronary angiogram and major adverse cardiac events (MACE) in a cohort of patients with elevated Lp(a) mass (≥30mg/dL) over a 15 year followup. Methods Electrophoretic and immunologic assays were used to measure Lp(a)-C and Lp(a)-M, respectively. Univariate and multivariate logistic regression analysis was employed to test for association between Lp(a) and CAD in a cohort patients with elevated Lp(a)-M (≥30mg/dL). The relationship between Lp(a) and time to major cardiac events was evaluated using cox regression analysis. Receiver operator curve (ROC) analyses were used to identify optimal cutoff values for Lp(a)-M and C for predicting CAD in our model. Results We analyzed 179 patients with elevated Lp(a)-M. Cutoff values of 3.3mg/dL for Lp(a)-C and 42.1mg/dL for Lp(a)-M optimally predicted CAD in an ROC analysis. Of these patients, 84 were found to have Lp(a)-C &lt; 3.3mg/dL (low Lp(a)-C), while 95 patients had Lp(a)-C levels ≥ 3.3mg/dL (high Lp(a)-C). High Lp(a)-C was associated with CAD identified on coronary angiography in univariate (OR = 2.17, 95% CI = 1.18 – 4.00, p = 0.013) and multivariate (OR = 3.36, 95% CI = 1.64 – 6.89, p &lt; 0.001) models controlling for traditional risk factors. In univariate analyses high Lp(a)-C was also associated with MACE (HR = 2.38, 95% CI = 1.19 – 4.75, p = 0.01) while Lp(a)-M ≥ 42.1mg/dL (high Lp(a)-M) was not (HR = 1.68, 95% CI = 0.82 – 3.44, p = 0.15) (Table 1, Figure 1). Lp(a)-C remained significantly correlated with MACE after adjusting for traditional risk factors. When included in a model together, Lp(a)-C maintained its significance while Lp(a)-M failed to predict MACE, indicating that Lp(a)-C is a stronger predictor of MACE than Lp(a)-M. Conclusion This study demonstrates that patients with elevated Lp(a)-M and high Lp(a)-C are approximately 2.5 times more likely to encounter MACE over time when compared to patients with elevated Lp(a)-M and low Lp(a)-C. Our investigation suggests that Lp(a)-C can be used to risk stratify patients with elevated Lp(a)-M and identify those at higher risk.