Photoplethysmography-new applications for an old technology: a sleep technology review.

Education is integral to the American Academy of Sleep Medicine (AASM) mission. The AASM Emerging Technology Committee identified an important and evolving piece of technology that is present in many of the consumer and clinical technologies that we review on the AASM #SleepTechnology (https://aasm.org/consumer-clinical-sleep-technology/) resource-photoplethysmography. As more patients with sleep tracking devices ask clinicians to view their data, it is important for sleep providers to have a general understanding of the technology, its sensors, how it works, targeted users, evidence for the claimed uses, and its strengths and weaknesses. The focus in this review is photoplethysmography-a sensor type used in the familiar pulse oximeter that is being developed for additional utilities and data outputs in both consumer and clinical sleep technologies. CITATION: Ryals S, Chang A, Schutte-Rodin S, et al. Photoplethysmography-new applications for an old technology: a sleep technology review. J Clin Sleep Med. 2023;19(1):189-195.

Diagnostic Performance of Machine Learning-Derived OSA Prediction Tools in Large Clinical and Community-Based Samples.

BACKGROUND: Prediction tools without patient-reported symptoms could facilitate widespread identification of OSA. RESEARCH QUESTION: What is the diagnostic performance of OSA prediction tools derived from machine learning using readily available data without patient responses to questionnaires? Also, how do they compare with STOP-BANG, an OSA prediction tool, in clinical and community-based samples? STUDY DESIGN AND METHODS: Logistic regression and machine learning techniques, including artificial neural network (ANN), random forests (RF), and kernel support vector machine, were used to determine the ability of age, sex, BMI, and race to predict OSA status. A retrospective cohort of 17,448 subjects from sleep clinics within the international Sleep Apnea Global Interdisciplinary Consortium (SAGIC) were randomly split into training (n = 10,469) and validation (n = 6,979) sets. Model comparisons were performed by using the area under the receiver-operating curve (AUC). Trained models were compared with the STOP-BANG questionnaire in two prospective testing datasets: an independent clinic-based sample from SAGIC (n = 1,613) and a community-based sample from the Sleep Heart Health Study (n = 5,599). RESULTS: The AUCs (95% CI) of the machine learning models were significantly higher than logistic regression (0.61 [0.60-0.62]) in both the training and validation datasets (ANN, 0.68 [0.66-0.69]; RF, 0.68 [0.67-0.70]; and kernel support vector machine, 0.66 [0.65-0.67]). In the SAGIC testing sample, the ANN (0.70 [0.68-0.72]) and RF (0.70 [0.68-0.73]) models had AUCs similar to those of the STOP-BANG (0.71 [0.68-0.72]). In the Sleep Heart Health Study testing sample, the ANN (0.72 [0.71-0.74]) had AUCs similar to those of STOP-BANG (0.72 [0.70-0.73]). INTERPRETATION: OSA prediction tools using machine learning without patient-reported symptoms provide better diagnostic performance than logistic regression. In clinical and community-based samples, the symptomless ANN tool has diagnostic performance similar to that of a widely used prediction tool that includes patient symptoms. Machine learning-derived algorithms may have utility for widespread identification of OSA.

All You Need Is Sleep: the Effects of Sleep Apnea and Treatment Benefits in the Heart Failure Patient.

PURPOSE OF REVIEW: Recognition and treatment of sleep apnea is an important but easily overlooked aspect of care in the heart failure patient. This review summarizes the data behind the recommendations in current practice guidelines and highlights recent developments in treatment options. RECENT FINDINGS: Neuromodulation using hypoglossal nerve stimulation has been increasingly used for treatment of OSA; however, it has not been studied in the heart failure population. Alternatively, phrenic nerve stimulation for treatment of CSA is effective for heart failure patients, and cardiac resynchronization therapy can be effective in improving CSA in pacing-induced cardiomyopathy. In patients suspected to have sleep apnea, polysomnography is recommended to better understand the prognosis and treatment options. Positive airway pressure is the standard treatment for sleep apnea; however, neurostimulation can be especially effective in those with predominantly central events. Understanding the pathophysiology of sleep apnea can guide further management decisions.

Heart rate variability during wakefulness as a marker of obstructive sleep apnea severity.

STUDY OBJECTIVES: Patients with obstructive sleep apnea (OSA) exhibit heterogeneous heart rate variability (HRV) during wakefulness and sleep. We investigated the influence of OSA severity on HRV parameters during wakefulness in a large international clinical sample. METHODS: 1247 subjects (426 without OSA and 821 patients with OSA) were enrolled from the Sleep Apnea Global Interdisciplinary Consortium. HRV parameters were calculated during a 5-minute wakefulness period with spontaneous breathing prior to the sleep study, using time-domain, frequency-domain and nonlinear methods. Differences in HRV were evaluated among groups using analysis of covariance, controlling for relevant covariates. RESULTS: Patients with OSA showed significantly lower time-domain variations and less complexity of heartbeats compared to individuals without OSA. Those with severe OSA had remarkably reduced HRV compared to all other groups. Compared to non-OSA patients, those with severe OSA had lower HRV based on SDNN (adjusted mean: 37.4 vs. 46.2 ms; p < 0.0001), RMSSD (21.5 vs. 27.9 ms; p < 0.0001), ShanEn (1.83 vs. 2.01; p < 0.0001), and Forbword (36.7 vs. 33.0; p = 0.0001). While no differences were found in frequency-domain measures overall, among obese patients there was a shift to sympathetic dominance in severe OSA, with a higher LF/HF ratio compared to obese non-OSA patients (4.2 vs. 2.7; p = 0.009). CONCLUSIONS: Time-domain and nonlinear HRV measures during wakefulness are associated with OSA severity, with severe patients having remarkably reduced and less complex HRV. Frequency-domain measures show a shift to sympathetic dominance only in obese OSA patients. Thus, HRV during wakefulness could provide additional information about cardiovascular physiology in OSA patients. CLINICAL TRIAL INFORMATION: A Prospective Observational Cohort to Study the Genetics of Obstructive Sleep Apnea and Associated Co-Morbidities (German Clinical Trials Register - DKRS, DRKS00003966) https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00003966.

Stevens-Johnson Syndrome After Armodafinil Use.

ABSTRACT: We present the case of a 21-year-old woman in whom Stevens-Johnson syndrome (SJS) developed after initiation of armodafinil. Although this rare and life-threatening reaction is listed on armodafinil's label, no cases have been reported in the literature. This case, in addition to an update of the drug's label after post-marketing research, both support the link between armodafinil and SJS. Providers should maintain a high clinical suspicion for SJS when starting therapy to minimize associated morbidity and mortality by discontinuing armodafinil at the onset of first symptoms.

Effect of Regulatory Requirement for Patient-Specific Prescriptions for Off-Label Medications on the Use of Intravitreal Bevacizumab.

IMPORTANCE: Requirements regulating pharmaceutical prescriptions can affect physicians' choice of therapy in a clinical setting. OBJECTIVE: To evaluate the change in bevacizumab use after the regulatory requirement for patient-specific prescriptions (PSPs) for off-label medications in Ohio. DESIGN, SETTING, AND PARTICIPANTS: This study retrospectively reviewed the aggregate data from the billing records of patients receiving 1.25-mg injections of bevacizumab, 0.3- or 0.5-mg injections of ranibizumab, or 2.0-mg injections of aflibercept for age-related macular degeneration or diabetic macular edema in a 9-member retinal specialty private practice. The review assessed 4488 intravitreal injections in the 3-month period before (May 1 to July 30, 2012) and 5253 injections in the 3-month period after (May 1 to July 30, 2013) the Ohio Board of Pharmacy's requirement of PSPs for bevacizumab. Relative proportions of the drugs used for intravitreal injections were calculated and frequencies were compared. A Likert scale survey was conducted among the 9 physicians to identify reasons for their change in prescription of bevacizumab. The survey inquired about (1) the burden of PSPs, (2) concern about differences in efficacy, and (3) concern about differences in safety. MAIN OUTCOMES AND MEASURES: Difference in drug use before and after the PSP requirement for bevacizumab and the physicians' reasons for change in their drug use. RESULTS: Bevacizumab use decreased from 2752 of 4488 pre-PSP injections (61.3%) to 1503 of 5253 post-PSP injections (28.6%), a change of -32.7% (95% CI, -34.6% to -30.8%; P < .001). Use of 0.5-mg ranibizumab injections increased from 1122 of 4488 pre-PSP injections (25.0%) to 1838 of 5253 post-PSP injections (35.0%), a change of 10.0% (95% CI, 8.2% to 11.8%; P < .001). Use of 0.3-mg ranibizumab injections increased from 0 of 4488 (before US Food and Drug Administration approval) to 429 of 5253 post-PSP injections (8.2%), a change of 8.2% (95% CI, 7.4% to 8.9%; P < .001). Use of aflibercept injections increased from 614 of 4488 pre-PSP injections (13.7%) to 1483 of 5253 post-PSP injections (28.2%), a change of 14.6% (95% CI, 13.0%-16.1%; P < .001). In the survey of the 9 physicians concerning their reasons for decreased use of bevacizumab, 7 (78%) strongly agreed and 1 (11%) agreed that the burden of PSPs changed their choice of drug used for injection. CONCLUSIONS AND RELEVANCE: Use of bevacizumab was reduced by 32.7% 1 year after the regulatory requirement for PSPs for compounded (repackaged) medications. This change seemed to have more association with the requirement for PSPs than with a known change in efficacy or safety concerns. Although this study was based on a single US practice, regulation of repackaged medication for safety concerns should also consider the evaluation of treatment burden, cost, and adherence.