Intersectionality and COVID-19: Academic Medicine Faculty's Lived Experiences of Well-Being, Workload, and Productivity During the Pandemic.

Purpose: The aim of this study was to utilize an intersectional framework to examine academic faculty's lived experiences during COVID-19. Specifically, we set out to: (1) describe the multiple intersectional identities (e.g., gender, race/ethnicity, rank, caregiver status, disability status) represented by the faculty, (2) examine potential disparities in well-being, workload, and productivity linked to these intersectional factors, and (3) identify qualitative themes endorsed by faculty as they relate to lived experiences during COVID-19. Methods: This was a cross-sectional mixed-methods research study. The Center for Women in Medicine and Science (CWIMS) at the University of Minnesota developed and implemented a survey between February-June of 2021 in response to national reports of disparities in the impacts of COVID-19 on faculty with lived experiences from multiple intersections. Results: There were 291 full-time faculty who participated in the study. Quantitative findings indicated that faculty with multiple intersectional identities (e.g., woman+assistant professor+caregiver+underrepresented in medicine) reported greater depression symptoms, work/family conflict, and stress in contrast to faculty with fewer intersectional identities. Furthermore, faculty with more intersectional identities reported higher clinical workloads and service responsibilities and lower productivity with regard to research article submissions, publications, and grant submissions in contrast to faculty with fewer intersectional identities. Qualitative findings supported quantitative findings and broadened understanding of potential underlying reasons. Conclusions: Findings confirm anecdotal evidence that faculty with lived experiences from multiple intersections may be disproportionately experiencing negative outcomes from the pandemic. These findings can inform decisions about how to address these disparities moving into the next several years with regard to promotion and tenure, burnout and well-being, and faculty retention in academic medical settings. Given these findings, it is also important to intentionally plan responses for future public health crises to prevent continued disparities for faculty with multiple intersectional identities.

Multidisciplinary approach to congenital central hypoventilation syndrome during pregnancy: case report.

Congenital central hypoventilation syndrome is a rare genetic disorder that affects control of breathing caused by variants in the paired-like homeobox 2B (PHOX2B) gene. During pregnancy, women with congenital central hypoventilation syndrome are at risk for hypoventilation and require frequent assessments of oxygenation and ventilation during wakefulness and sleep on their ventilator. This could potentially lead to adjustments in the ventilator settings or a change in the assisted ventilation modality. We report the case of a 31-year-old pregnant woman with congenital central hypoventilation syndrome and an implanted cardiac pacemaker who underwent prenatal genetic testing for congenital central hypoventilation syndrome and who delivered a healthy newborn by cesarean delivery. She received collaborative multidisciplinary care from a team that included specialists in obstetrics, maternal and fetal medicine, medical genetics, sleep and pulmonary medicine, cardiology, and anesthesiology. She used bilevel positive airway pressure therapy throughout pregnancy and after cesarean delivery without requiring adjustments in the bilevel positive airway pressure settings. Our case highlights the importance of multidisciplinary care in women with congenital central hypoventilation syndrome during pregnancy to optimize pregnancy and fetal outcomes.

Associations of Late-Life Sleep Medication Use With Incident Dementia in the Atherosclerosis Risk in Communities Study.

BACKGROUND: Sleep medications may contribute to dementia development or indicate sleep disturbances that are markers of or contributors to neurologic disease. The objective of this study was to examine the use of sleep medications and incident dementia in a community-based cohort of older adults. We hypothesize late-life sleep medication use is associated with a greater risk of dementia. METHODS: The Atherosclerosis Risk in Communities (ARIC) study is an ongoing community-based cohort study. ARIC participants taking barbiturates, benzodiazepines, antidepressants, non-benzodiazepine receptor agonists (Z-drugs), or other hypnotics in 2011-2013 were categorized as sleep medication users. Participants were followed through 2019 for incident dementia. Logistic regression propensity scores were used to match sleep medication users with nonusers (1:2). Cox proportional hazards regression models were used to estimate hazard ratios (HR) for time to dementia diagnosis with adjustment for demographics, lifestyle characteristics, and cardiovascular risk factors. RESULTS: One-quarter of the eligible ARIC participants used sleep medications. In the matched sample (N = 4 197; 69% female; mean age 75.3 + 5.0 years), 632 dementia cases were ascertained over a median follow-up of 6.5 years. In the fully adjusted model, sleep medication use compared to nonuse was associated with a 48% greater risk of dementia (HR: 1.48; 95% confidence interval (CI): 1.26-1.74). CONCLUSION: To expand on these findings, studies with longer follow-up and earlier assessment of sleep medication use are needed. Furthermore investigation of the potential dose-response association of multiple sleep medications and the potential causal role of sleep medications in the development of dementia may be clinically meaningful.

Using a Community-Based Participatory Approach to Address Gender Equity in Academic Medicine: The Center for Women in Medicine and Science at the University of Minnesota.

Many medical schools are instituting gender equity initiatives to address long-standing inequities (e.g., salary, leadership positions, resource distribution) between women and men in academic medicine. However, few theory-driven models exist with built-in metrics to assess the impact of gender equity initiatives. The authors describe the theory- and metric-driven process used to create the Center for Women in Medicine and Science (CWIMS) at the University of Minnesota (UMN) Medical School. An innovative theory-driven approach using community-based participatory research (CBPR) was used to create and organize CWIMS. CBPR acknowledges community members (e.g., faculty members, staff), academic organizational representatives (e.g., department heads, center directors), and administrative leaders (e.g., deans) as equal contributors in carrying out all aspects of gender equity work. CBPR values collaborative approaches that empower faculty, promote co-learning and co-creation of initiatives among all university partners, and build upon already existing community strengths and resources. Four CWIMS action groups were created using CBPR principles. The action groups are retention and recruitment; mentoring; salary, resource, and leadership equity; and strategic communications and collaborations. Faculty members across all medical school departments joined these 4 action groups to co-create and carry out all CWIMS gender equity initiatives. The process of developing the CWIMS center and action groups, the CBPR theoretical model guiding the approach, the initiatives developed by the action groups and metrics created, and the outcomes achieved to date are described. In addition, 4 lessons learned from the development of the CWIMS-use of theoretically driven and evidence-based models is key to building a sustainable organization; bottom-up and top-down engagement of partners is crucial for sustainability; passion and innovation are critical for long-term momentum; and not all faculty members and leaders will be enthusiastic about gender equity issues-are shared for the benefit of other medical schools wanting to develop similar centers.

Restless legs syndrome associated with use of stevia nonnutritive sweetener.

None: Restless legs syndrome is a common sensorimotor movement disorder affecting an estimated 15-20% of the general adult population in the United Sates. Several drugs and drug classes have been shown to either cause and/or exacerbate symptoms of restless legs syndrome. With the epidemic of obesity and the heightened awareness of the harmful effects of added sugars, the consumption of low and no-calorie sweeteners has substantially increased. We report a case where the patient developed restless legs syndrome symptoms with the use of a stevia extract-based no calorie sweetener. To our knowledge, this is the first case report of restless legs syndrome possibly associated with low or no-calorie sweetener use.

Obstructive Sleep Apnea Knowledge: Attitudes and screening practices of Minnesota dental hygienists.

Purpose: Reported cases of obstructive sleep apnea (OSA) range between 4% to 9%, however between 70% to 90% of adults in the United States remain undiagnosed. The purpose of this study was to determine the current knowledge and attitudes of OSA among Minnesota dental hygienists and inventory OSA screening protocols currently used in dental practices.Methods: The cross sectional study used an adapted Obstructive Sleep Apnea Knowledge and Attitude (OSAKA) survey instrument. Survey items included demographic variables, and measured attitudes, knowledge and perceived knowledge about OSA, routine screening procedures, and use of validated OSA screening protocols. Paper surveys were mailed to a random sample of 750 licensed Minnesota dental hygienists. Analyses included descriptive statistics (counts and frequencies), and analytic tests (one-way ANOVA, Pearson's correlation, and t-tests, Cronbach's alpha), as appropriate.Results: Twenty-six percent of the returned surveys met inclusion criteria (n=197) and were used in the final analyses. Respondent age ranged from 19 to 70 years and mean years in practice experience was 19.9. The majority (93.9%) were in general practice and had completed an associate degree (59.6%). The mean (SD) self-rated OSA knowledge was 3.5 (3.3) on a scale of 0-10, attitude score was 3.2 (0.8) on a 5-point Likert scale, and knowledge score was 9.5 (range 0-17). No significant differences were found by age, degree type, or years in practice and OSA knowledge or attitudes. Routine practices included head and neck exams (89.3%), taking blood pressure (41.6%). Using a validated OSA screening protocol was reported by 9.6% of the respondents.Conclusion: Dental hygienists perceive that assessing patients for OSA is important, however they have moderate knowledge of the disease. Results support incorporating OSA into dental hygiene practice through additions to the dental hygiene education curriculum and ongoing professional development courses with the goal of improving the screening and referral of patients presenting with OSA symptoms.

Sleep Apnea and Heart.

Scientific investigations in the past few decades have supported the important role of sleep in various domains of health. Sleep apnea is a highly prevalent yet underdiagnosed sleep disorder representing a valid cardiovascular risk factor, particularly for hypertension. While several studies have demonstrated the benefits of sleep apnea treatment on subclinical cardiovascular measures, there is a paucity of studies proving reduction of cardiovascular events and mortality. Sufficient and high-quality sleep is also important in the maintenance of cardiovascular health. Future investigations should focus on improving identification of patients at greatest risk of adverse cardiovascular s sequalae of sleep apnea and testing the therapeutic benefit of sleep apnea treatment in this vulnerable group.

An Update on Dual Orexin Receptor Antagonists and Their Potential Role in Insomnia Therapeutics.

STUDY OBJECTIVES: Current pharmacological options for the treatment of insomnia insufficiently meet the needs of all insomnia patients. Approved treatments are not consistently effective in improving sleep onset and sleep maintenance, while also having complicated safety profiles. These limitations highlight the unmet need for additional medications and treatment strategies. Initial research suggests that the dual orexin receptor antagonists (DORAs) may offer an additional pharmaceutical option to treat insomnia in some patients. METHODS: We reviewed the existing literature on dual orexin receptor antagonists in PubMed databases using the search terms "orexin receptor antagonist," "almorexant" "filorexant," "lembroexant" and "suvorexant"; searches were limited to English language primary research articles, clinical trials, and reviews. RESULTS: Targeting the orexin receptor system for treatment of insomnia offers an additional and alternative pharmacological approach to more common gamma aminobutyric acid agonist sedative hypnotic treatment. Effectiveness is not well established in the current literature; however, the literature does suggest efficacy. Preclinical reports also suggest the potential for treatment in individuals with comorbid Alzheimer disease and insomnia. CONCLUSIONS: DORAs offer an additional treatment option for insomnia. More clinical trials are needed to robustly evaluate their safety and effectiveness in several subclasses of individuals with insomnia. Given the published literature, head-to-head comparisons to existing treatment for insomnia are warranted.

Sleep quality in temporomandibular disorder cases.

OBJECTIVE: The aim of this study was to characterize self-reported sleep quality (SQ) in cases with temporomandibular disorder (TMD) and to compare their results with those of healthy controls. METHODS: The Pittsburgh Sleep Quality Index (PSQI) was used to measure SQ in a convenience sample of 609 TMD cases and 88 controls. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I diagnostic nomenclature was used, but Axis I diagnoses were based on the consensus of two reliable criterion examiners and not the RDC/TMD algorithms. The PSQI scores for TMD cases were calculated also for the RDC/TMD Axis II measures assessing chronic pain and disability, depression, and nonspecific physical symptoms. PSQI scores of the TMD cases were compared with those from controls. RESULTS: TMD cases with one to five TMD diagnoses (n = 609) had a mean PSQI score of 7.0 [95% confidence interval (CI) = 6.7-7.4]. In comparison, the mean score was 5.2 (95% CI = 4.6-5.9) for control subjects. For the subset of TMD cases with pain-free diagnoses (n = 113), the PSQI score was similar to controls with 5.1 (95% CI = 4.5-5.6), whereas it was significantly different for cases with pain-related diagnoses 7.5 (95% CI = 6.6-8.3; n = 87). Although the number of TMD diagnoses and participant age had some influence on SQ, psychosocial status, and pain-related impairment assessed with RDC/TMD Axis II measures had the strongest association with SQ, in particular, dysfunctional chronic pain. CONCLUSION: SQ is impaired in TMD patients with pain-related diagnoses, and even more in those with dysfunctional pain. This relationship between sleep and pain suggests that SQ should be assessed in TMD pain patients, especially in those with significant Axis II involvement.

Comparison of Endothelial Function in Asian Indians Versus Caucasians.

BACKGROUND: Asian Indians have markedly increased mortality due to coronary artery disease (CAD). Impaired endothelial function has been linked to an increased risk of acute cardiovascular events. We tested the hypothesis that endothelial function was attenuated in Asian Indians and Caucasians. METHODS: We studied 14 Asian Indians [mean age: 30 ± 6 years; mean body mass index (BMI): 25 ± 3 kg/m(2)] and 11 Caucasians (mean age: 30 ± 5 years; mean BMI: 26 ± 2 kg/m(2)). All 25 subjects were healthy men and nonsmokers without any history of CAD or diabetes and were not taking medications. Endothelial function was evaluated by ultrasound measures of flow-mediated dilatation (FMD) and endothelium-independent nonflow mediated vasodilatation (NFMD) of the brachial artery, in the morning immediately after awakening (6 a.m.) in a fasting state. RESULTS: Mean age, BMI, apnea-hypopnea index, heart rate, and blood pressure were similar in both groups (P = >0.05). When correcting for body surface area, brachial artery diameter was not different between the two groups (2.1% ± 0.3% vs. 2.2% ± 0.4%; P = 0.29). FMD and NFMD were similar in Asian Indians and Caucasians (5.9% ± 4.1% vs. 5.7% ± 2.6%, P = 0.70; 16.4% ± 8% vs. 14.8% ± 4.1%, P = 0.58, respectively). CONCLUSION: Endothelial function in Asian Indian men is not attenuated in comparison to Caucasian men.

Effects of weight gain and weight loss on regional fat distribution.

BACKGROUND: Normal-weight adults gain lower-body fat via adipocyte hyperplasia and upper-body subcutaneous (UBSQ) fat via adipocyte hypertrophy. OBJECTIVES: We investigated whether regional fat loss mirrors fat gain and whether the loss of lower-body fat is attributed to decreased adipocyte number or size. DESIGN: We assessed UBSQ, lower-body, and visceral fat gains and losses in response to overfeeding and underfeeding in 23 normal-weight adults (15 men) by using dual-energy X-ray absorptiometry and abdominal computed tomography scans. Participants gained ∼5% of weight in 8 wk and lost ∼80% of gained fat in 8 wk. We measured abdominal subcutaneous and femoral adipocyte sizes and numbers after weight gain and loss. RESULTS: Volunteers gained 3.1 ± 2.1 (mean ± SD) kg body fat with overfeeding and lost 2.4 ± 1.7 kg body fat with underfeeding. Although UBSQ and visceral fat gains were completely reversed after 8 wk of underfeeding, lower-body fat had not yet returned to baseline values. Abdominal and femoral adipocyte sizes, but not numbers, decreased with weight loss. Decreases in abdominal adipocyte size and UBSQ fat mass were correlated (ρ = 0.76, P = 0.001), as were decreases in femoral adipocyte size and lower-body fat (ρ = 0.49, P = 0.05). CONCLUSIONS: UBSQ and visceral fat increase and decrease proportionately with a short-term weight gain and loss, whereas a gain of lower-body fat does not relate to the loss of lower-body fat. The loss of lower-body fat is attributed to a reduced fat cell size, but not number, which may result in long-term increases in fat cell numbers.

Leptin signaling in adipose tissue: role in lipid accumulation and weight gain.

RATIONALE: The link between obesity, hyperleptinemia, and development of cardiovascular disease is not completely understood. Increases in leptin have been shown to impair leptin signaling via caveolin-1-dependent mechanisms. However, the role of hyperleptinemia versus impaired leptin signaling in adipose tissue is not known. OBJECTIVE: To determine the presence and significance of leptin-dependent increases in adipose tissue caveolin-1 expression in humans. METHODS AND RESULTS: We designed a longitudinal study to investigate the effects of increases in leptin on adipose tissue caveolin-1 expression during weight gain in humans. Ten volunteers underwent 8 weeks of overfeeding, during which they gained an average weight of 4.1±1.4 kg, with leptin increases from 7±3.8 to 12±5.7 ng/mL. Weight gain also resulted in changes in adipose tissue caveolin-1 expression, which correlated with increases in leptin (rho=0.79, P=0.01). In cultured human white preadipocytes, leptin increased caveolin-1 expression, which in turn impaired leptin cellular signaling. Functionally, leptin decreased lipid accumulation in differentiating human white preadipocytes, which was prevented by caveolin-1 overexpression. Further, leptin decreased perilipin and fatty acid synthase expression, which play an important role in lipid storage and biogenesis. CONCLUSIONS: In healthy humans, increases in leptin, as seen with modest weight gain, may increase caveolin-1 expression in adipose tissue. Increased caveolin-1 expression in turn impairs leptin signaling and attenuates leptin-dependent lowering of intracellular lipid accumulation. Our study suggests a leptin-dependent feedback mechanism that may be essential to facilitate adipocyte lipid storage during weight gain.

Screening for obstructive sleep apnea in early outpatient cardiac rehabilitation: feasibility and results.

BACKGROUND: Obstructive sleep apnea (OSA) has been recognized as a risk factor for cardiovascular disease and mortality. The aim of this study was to determine the feasibility and efficacy of implementing a screening program for OSA in early outpatient cardiac rehabilitation (CR) and to estimate the risk for OSA in this population. METHODS: From 535 consecutive patients enrolled in early outpatient CR we screened 383 (72%) patients and classified them as low- vs. high-risk for OSA using the Berlin questionnaire. Those considered at high-risk for OSA were referred for further evaluation. We assessed the yield and feasibility of the screening program, patient compliance with referral, and the percentage of patients diagnosed with OSA after polysomnography. RESULTS: Mean age was 63 ± 12 years, 70% were men, 20% had diabetes, 65% had hypertension, and 58% had experienced a recent myocardial infarction. Two hundred and one patients (52%) had a high risk for OSA based on the questionnaire. Of the 169 who completed the CR program, only 111 (78%) were referred for further evaluation (Fig. 1). Of the 74 patients who completed their OSA work-up, 39 were found to have OSA with an apnea-hypopnea index of ≥ 5 events/h. CONCLUSIONS: Implementation of a simple screening program for OSA in early outpatient CR is feasible with minimal incremental resources. A significant percentage of patients at high-risk decline further evaluation, suggesting that their perceived risk for OSA and its consequences may be low.

Effect of weight gain on cardiac autonomic control during wakefulness and sleep.

Obesity has been associated with increased cardiac sympathetic activation during wakefulness, but the effect on sleep-related sympathetic modulation is not known. The aim of this study was to investigate the effect of fat gain on cardiac autonomic control during wakefulness and sleep in humans. We performed a randomized, controlled study to assess the effects of fat gain on heart rate variability. We recruited 36 healthy volunteers, who were randomized to either a standardized diet to gain ≈4 kg over 8 weeks followed by an 8-week weight loss period (n=20) or to serve as a weight-maintainer control (n=16). An overnight polysomnogram with power spectral analysis of heart rate variability was performed at baseline, after weight gain, and after weight loss to determine the ratio of low-frequency to high-frequency power and to examine the relationship between changes in heart rate variability and changes in insulin, leptin, and adiponectin levels. Mean weight gain was 3.9 kg in the fat gain group versus 0.1 kg in the maintainer group. Low frequency/high frequency increased both during wakefulness and sleep after fat gain and returned to baseline after fat loss in the fat gain group and did not change in the control group. Insulin, leptin, and adiponectin also increased after fat gain and fell after fat loss, but no clear pattern of changes was seen that correlated consistently with changes in heart rate variability. Short-term fat gain in healthy subjects is associated with increased cardiac sympathetic activation during wakefulness and sleep, but the mechanisms remain unclear.

Patients with obstructive sleep apnea exhibit impaired endothelial function after myocardial infarction.

BACKGROUND: Impaired brachial flow-mediated dilation (FMD) is associated with risk for subsequent cardiovascular events in patients after myocardial infarction (MI). These patients often have obstructive sleep apnea (OSA). We tested the hypothesis that patients with OSA post MI will exhibit more severe impairment in FMD. METHODS: We studied 64 patients with MI admitted to our hospital. OSA was determined using polysomnography. FMD was measured using high-resolution ultrasonography, with researchers blind to the OSA diagnosis. RESULTS: The mean age was 60 ± 11 years, and the mean BMI was 29 (26, 32 kg/m(2)), 84% of patients were men, 39% had moderate to severe OSA (apnea-hypopnea index [AHI] > 15), and 31% of the patients had mild OSA (5 ≤ AHI < 15). FMD was severely impaired in patients with moderate to severe OSA (0.8% ± 0.7%) as compared with patients without OSA (4.7% ± 0.8%, P = .001) and with mild OSA (3.9% ± 0.8%, P = .015). Linear regression showed that FMD was associated with log nocturnal nadir oxygen saturation (minSaO(2)) (ß = 31.17, P = .0001), age (ß = -0.11, P = .006). MinSaO(2) was an independent predictor of FMD after adjustment for possible confounders (ß = 26.15, P = .001). CONCLUSIONS: FMD is severely impaired in patients with moderate to severe OSA post MI, which may be partially related to nocturnal hypoxemia. Patients with OSA may, therefore, be at higher risk for subsequent cardiovascular events after an MI. Identifying and treating OSA may have important implications in the long-term prognosis of patients post MI. Further studies are necessary to determine if the presence of OSA would affect the long-term occurrence of cardiovascular events after an MI.

Modest visceral fat gain causes endothelial dysfunction in healthy humans.

OBJECTIVES: The aim of this study was to determine the impact of fat gain and its distribution on endothelial function in lean healthy humans. BACKGROUND: Endothelial dysfunction has been identified as an independent predictor of cardiovascular events. Whether fat gain impairs endothelial function is unknown. METHODS: A randomized controlled study was conducted to assess the effects of fat gain on endothelial function. Forty-three normal-weight healthy volunteers were recruited (mean age 29 years; 18 women). Subjects were assigned to gain weight (approximately 4 kg) (n=35) or to maintain weight (n=8). Endothelial function (brachial artery flow-mediated dilation [FMD]) was measured at baseline, after fat gain (8 weeks), and after weight loss (16 weeks) for fat gainers and at baseline and follow-up (8 weeks) for weight maintainers. Body composition was measured by dual-energy X-ray absorptiometry and abdominal computed tomographic scans. RESULTS: After an average weight gain of 4.1 kg, fat gainers significantly increased their total, visceral, and subcutaneous fat. Blood pressure and overnight polysomnography did not change after fat gain or loss. FMD remained unchanged in weight maintainers. FMD decreased in fat gainers (9.1+/-3% vs. 7.8+/-3.2%, p=0.003) but recovered to baseline when subjects shed the gained weight. There was a significant correlation between the decrease in FMD and the increase in visceral fat gain (rho=-0.42, p=0.004), but not with subcutaneous fat gain (rho=-0.22, p=0.15). CONCLUSIONS: In normal-weight healthy young subjects, modest fat gain results in impaired endothelial function, even in the absence of changes in blood pressure. Endothelial function recovers after weight loss. Increased visceral rather than subcutaneous fat predicts endothelial dysfunction. (Fat Gain and Cardiovascular Disease Mechanisms; NCT00589498).

Cardiovascular consequences of obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is a form of sleep disordered breathing with a high prevalence rate and is often underdiagnosed. OSA is associated with hypertension, coronary artery disease, stroke, peripheral vascular disease, heart failure, and arrhythmias. The presence of OSA may be a strong predictor of fatal cardiovascular events in patients with cardiovascular disease (CVD). Increased sympathetic drive, activation of metabolic and inflammatory markers, and impaired vascular function are some of the proposed mechanisms that could explain the association between OSA and cardiovascular diseases. Understanding these mechanisms is important for identifying treatment strategies. The presence of OSA should be considered in clinical practice, especially in patients with CVD. Randomized intervention studies are needed to establish whether early identification and treatment of OSA patients reduces cardiovascular morbidity.

Day-night variation of acute myocardial infarction in obstructive sleep apnea.

OBJECTIVES: This study sought to evaluate the day-night variation of acute myocardial infarction (MI) in patients with obstructive sleep apnea (OSA). BACKGROUND: Obstructive sleep apnea has a high prevalence and is characterized by acute nocturnal hemodynamic and neurohormonal abnormalities that may increase the risk of MI during the night. METHODS: We prospectively studied 92 patients with MI for which the time of onset of chest pain was clearly identified. The presence of OSA was determined by overnight polysomnography. RESULTS: For patients with and without OSA, we compared the frequency of MI during different intervals of the day based on the onset time of chest pain. The groups had similar prevalence of comorbidities. Myocardial infarction occurred between 12 am and 6 am in 32% of OSA patients and 7% of non-OSA patients (p = 0.01). The odds of having OSA in those patients whose MI occurred between 12 am and 6 am was 6-fold higher than in the remaining 18 h of the day (95% confidence interval: 1.3 to 27.3, p = 0.01). Of all patients having an MI between 12 am and 6 am, 91% had OSA. CONCLUSIONS: The diurnal variation in the onset of MI in OSA patients is strikingly different from the diurnal variation in non-OSA patients. Patients with nocturnal onset of MI have a high likelihood of having OSA. These findings suggest that OSA may be a trigger for MI. Patients having nocturnal onset of MI should be evaluated for OSA, and future research should address the effects of OSA therapy for prevention of nocturnal cardiac events.

Natural course of complex sleep apnea--a retrospective study.

Patients with complex sleep apnea syndrome (CompSAS) have obstructive sleep apnea but develop troublesome central sleep apnea activity or Cheyne-Stokes breathing when provided continuous positive airway pressure (CPAP) therapy. We examined whether CompSAS activity persists with long-term CPAP treatment. We retrospectively identified all patients with CompSAS who underwent two therapeutic polysomnograms (PSGs) separated by at least 1 month during 2003-2005. We compared PSG findings between the initial and follow-up study and noted clinical responses to therapy. We identified 13 CompSAS patients meeting criteria. Most follow-up PSGs were ordered after an abnormal overnight oximetry on CPAP or because of CPAP intolerance after 195 (49-562) days. The residual apnea-hypopnea index (AHI) on CPAP decreased from 26 (23-40) on the first PSG to 7 (3-21.5) on the follow-up PSG. Only seven patients reached AHI < 10 and 6 had AHI > or = 10 ("CPAP nonresponders") at follow-up. "CPAP nonresponders" were sleepier (Epworth Sleepiness Score 13 [12.5-14] vs 9 [6-9.5], p = 0.03) and trended toward lower body mass index (29.7 [28.6-31.6] vs 34.3 [32.5-35.1], p = 0.06). Both groups were equally compliant with CPAP therapy. Although the AHI tends to improve over time in CompSAS patients treated with CPAP, in this retrospective study nearly half-maintained a persistently elevated AHI. A prospective trial is merited to determine the optimal treatment for these patients.