Association between obstructive sleep apnoea and cancer: a cross-sectional, population-based study of the DISCOVERY cohort.

OBJECTIVES: Nocturnal hypoxia in obstructive sleep apnoea (OSA) is a potential risk factor for cancer. We aimed to investigate the association between OSA measures and cancer prevalence in a large national patient cohort. DESIGN: Cross-sectional study. SETTINGS: 44 sleep centres in Sweden. PARTICIPANTS: 62 811 patients from the Swedish registry for positive airway pressure (PAP) treatment in OSA, linked to the national cancer registry and national socioeconomic data (the course of DIsease in patients reported to Swedish CPAP, Oxygen and VEntilator RegistrY cohort). OUTCOME MEASURES: After propensity score matching for relevant confounders (anthropometric data, comorbidities, socioeconomic status, smoking prevalence), sleep apnoea severity, measured as Apnoea-Hypopnoea Index (AHI) or Oxygen Desaturation Index (ODI), were compared between those with and without cancer diagnosis up to 5 years prior to PAP initiation. Subgroup analysis for cancer subtype was performed. RESULTS: OSA patients with cancer (n=2093) (29.8% females, age 65.3 (SD 10.1) years, body mass index 30 (IQR 27-34) kg/m2) had higher median AHI (n/hour) (32 (IQR 20-50) vs 30 (IQR 19-45), n/hour, p=0.002) and median ODI (n/hour) (28 (IQR 17-46) vs 26 (IQR 16-41), p<0.001) when compared with matched OSA patients without cancer. In subgroup analysis, ODI was significantly higher in OSA patients with lung cancer (N=57; 38 (21-61) vs 27 (16-43), p=0.012)), prostate cancer (N=617; 28 (17-46) vs 24, (16-39)p=0.005) and malignant melanoma (N=170; 32 (17-46) vs 25 (14-41),p=0.015). CONCLUSIONS: OSA mediated intermittent hypoxia was independently associated with cancer prevalence in this large, national cohort. Future longitudinal studies are warranted to study the potential protective influence of OSA treatment on cancer incidence.

Nasal polyposis is a risk factor for nonadherence to CPAP treatment in sleep apnea: the population-based DISCOVERY study.

STUDY OBJECTIVES: The aim was to evaluate nasal polyposis as a risk factor for nonadherence to continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). METHODS: This was a population-based, longitudinal analysis of patients starting CPAP treatment for OSA in the Swedish quality registry Swedevox between 2010 and 2018. Data were cross-linked with national registries. The impact of nasal polyposis on CPAP adherence was analyzed using uni- and multivariable logistic and linear regression models. Relevant confounders (age, sex, usage of nasal and oral steroids) were identified using a direct acyclic graph. RESULTS: Of 20,521 patients with OSA on CPAP treatment (29.5% females), 331 (1.6%) had a diagnosis of nasal polyposis at baseline. At the 1-year follow-up, nasal polyposis was associated with an increased risk of CPAP usage < 4 hours/night (unadjusted odds ratio [OR] 1.21; 95% confidence interval [CI] 0.95-1.55); adjusted OR 1.38; 95% CI 1.08-1.77). In this group, unadjusted nocturnal mean CPAP usage was 15.4 minutes (95% CI -31.62 to 0.83) shorter and was an adjusted 24.1 minutes (95% CI -40.6 to -7.7) shorter compared with patients with OSA without nasal polyposis. CONCLUSIONS: Nasal polyposis is associated with reduced CPAP usage per night. These results highlight the importance of diagnosing nasal polyposis in patients with OSA before the start of CPAP treatment. Treatment of the condition may improve adherence, efficacy, and patient outcomes. CITATION: Bengtsson C, Grote L, Ljunggren M, Ekström M, Palm A. Nasal polyposis is a risk factor for nonadherence to CPAP treatment in sleep apnea: the population-based DISCOVERY study. J Clin Sleep Med. 2023;19(3):573-579.

Adherence to CPAP therapy in Down syndrome: the population-based DISCOVERY study.

STUDY OBJECTIVES: Persons with Down syndrome (DS) have an increased risk of obstructive sleep apnea (OSA) needing continuous positive airway pressure (CPAP), but data on the therapy and outcomes in this population are scarce. We aimed to compare patient characteristics and outcomes of CPAP treatment for patients with OSA with and without DS. METHODS: This was a population-based, longitudinal study on patients initiating CPAP therapy between July 2010 and March 2018 in Sweden and a population-based sex- and age-matched control group (control:case ratio 5:1), with linked data from the Swedish National Patient Registry and the Prescribed Drug Registry (DISCOVERY study cohort). RESULTS: Patients with DS (n = 64) had a higher apnea-hypopnea index (51.7 ± 30.3 vs 36.8 ± 29.1 events/h, P < .001), Epworth Sleepiness Scale score (13.7 ± 5.9 vs 11.0 ± 4.9, P = .001), rate of previous surgery of tonsils and/or adenoids (21.9% vs 8.2%, P = .001), and more thyroid replacement hormone therapy (45.3% vs 7.8%, P < .001), but lower use of cardiovascular drugs (7.8% vs 22.3%, P = .003) compared with controls. At follow-up after 1.3 ± 0.9 years, there were no differences in nocturnal CPAP usage time (5.6 ± 2.4 vs 5.5 ± 2.0 hours, P = .77), CPAP adherence ≥ 4 hours/night (62% vs 65%, P = .93), or improvement in Epworth Sleepiness Scale score (-5.4 ± 6.8 vs -5.0 ± 2.0, P = .84) between DS and non-DS patients. CONCLUSIONS: OSA severity was substantially higher in patients with DS despite an increased rate of tonsil surgery. Treatment outcomes in terms of adherence and improved daytime sleepiness were comparable between groups, underlining the importance of both OSA diagnosis and treatment in patients with DS. CITATION: Svensson M, Ekström M, Sundh J, Ljunggren M, Grote L, Palm A. Adherence to CPAP therapy in Down syndrome: the population-based DISCOVERY study. J Clin Sleep Med. 2023;19(3):453-458.

Hypoxemia severity and survival in ILD and COPD on long-term oxygen therapy - The population-based DISCOVERY study.

BACKGROUND AND AIM: Whether long-term oxygen therapy (LTOT) improves survival in interstitial lung disease (ILD) is unclear. A recent study reported similar survival in ILD patients with severe hypoxemia on LTOT vs. moderate hypoxemia without LTOT, and proposed that LTOT could be indicated in ILD already at moderate hypoxemia. The aim of this study was to compare survival by severity of hypoxemia in patients with ILD and COPD, respectively, treated with LTOT. METHODS: A population-based, longitudinal study of adults starting LTOT for ILD or COPD 1987-2018. Transplant-free survival was compared between moderate (PaO2 7.4-8.7 kPa) and severe (PaO2<7.4 kPa) hypoxemia using Cox regression, adjusted for age, sex, BMI, smoking status, WHO performance status, year of starting LTOT, diagnosis of heart failure, ischemic heart disease and diabetes mellitus. RESULTS: In total, 17,084 patients were included, with ILD and moderate (n = 470) or severe hypoxemia (n = 2,408), and COPD with moderate (n = 2,087) or severe hypoxemia (n = 12,119). Compared with in COPD, ILD patients on LTOT had lower transplant-free survival after one year (41.9 vs. 67.1%) and two years (20.3 vs. 46.5%). In COPD worse hypoxemia was associated with slightly increased risk of death/lung transplantation, aHR 1.07 (1.00-1.14), a difference not shown in ILD, aHR 0.91 (0.80-1.03). CONCLUSION: Transplant-free survival did not differ in ILD patients between moderate and severe hypoxia despite LTOT.

Course of DISease In patients reported to the Swedish CPAP Oxygen and VEntilator RegistrY (DISCOVERY) with population-based controls.

PURPOSE: Chronic hypoxic and hypercapnic respiratory failure and obstructive sleep apnoea (OSA) are chronic diseases associated with decreased quality of life and increased mortality. The rationale behind the set up the retrospective nationwide DISCOVERY cohort was to study several questions including disease course and risk factors for incident disease, impaired quality of life, hospitalisation risk and mortality in patients with chronic respiratory failure with long-term oxygen therapy (LTOT), long-term mechanical ventilation (LTMV) and obstructive sleep apnoea (OSA) on treatment with continuous positive airway pressure (CPAP). PARTICIPANTS AND SETTINGS: Data from the national quality registry for respiratory insufficiency and sleep apnoea (Swedevox) and a population-based control group from Statistics Sweden were merged with governmental registries, the Swedish Cancer Registry, the Swedish Cause of Death Registry, the Swedish Drug registry, the Swedish National Patient Registry and the Swedish Dental Health Registry and with national quality registries for diabetes, rheumatic diseases (Swedish Rheumatology Quality Registry), stroke (RiksStroke), heart failure (RiksSvikt), acute heart infarction care (SwedeHeart) and intensive care (SIR) and with socioeconomic data from Statistics Sweden (SCB). FINDINGS TO DATE: The cohort comprises 25 804 unique patients with LTOT since 1987 (54.1% females, age 73.3±9.8 years, body mass index (BMI) 26.6±6.5 kg/m2), 8111 with LTMV since 1996 (48.6% women, age 60.6±16.9 years, BMI 32.9±10.8 kg/m2), 65 809 with OSA on CPAP since 2010 (29.5% women, age 57.2±12.5 years, BMI 31.9±6.2 kg/m2) and 145 224 persons in a population-based control group from same time span up to March 2018 (51.7% women, age 49.9±20.4 year, BMI 24.9±4.0 years). FUTURE PLANS: In patients with chronic respiratory failure and sleep apnoea important questions regarding comorbidity burden, hospitalisation rate, mortality and treatment outcomes are still unexplored to a large extent. The DISCOVERY cohort will provide unique opportunities by its size and comprehensiveness to fill this clinically relevant gap of knowledge.

[Thoracal actinomycosis - a diagnostic challenge]. / Torakal aktinomykos ­ allvarlig sjukdom och en diagnostisk svår utmaning - Men med rätt behandling är prognosen god.

Actinomycotic infection of the chest structures is rare but can be serious. Diagnosis is difficult, since both culture of the bacterium and pathological investigation require special methods. Investigations therefore usually take many months before the correct treatment can be started. The most common differential diagnosis is a chest malignancy. Treatment is long-term antibiotics. We here present three cases which illustrate the clinical and radiological findings and the diagnostic difficulties.

Can STOP-Bang and Pulse Oximetry Detect and Exclude Obstructive Sleep Apnea?

BACKGROUND: Obstructive sleep apnea (OSA) is related to postoperative complications and is a common disorder. Most patients with sleep apnea are, however, undiagnosed, and there is a need for simple screening tools. We aimed to investigate whether STOP-Bang and oxygen desaturation index can identify subjects with OSA. METHODS: In this prospective, observational multicenter trial, 449 adult patients referred to a sleep clinic for evaluation of OSA were investigated with ambulatory polygraphy, including pulse oximetry and the STOP-Bang questionnaire in 4 Swedish centers. The STOP-Bang score is the sum of 8 positive answers to Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index >35 kg/m, Age >50 years, Neck circumference >40 cm, and male Gender. RESULTS: The optimal STOP-Bang cutoff score was 6 for moderate and severe sleep apnea, defined as apnea-hypopnea index (AHI) ≥15, and the sensitivity and specificity for this score were 63% (95% CI, 0.55-0.70) and 69% (95% CI, 0.64-0.75), respectively. A STOP-Bang score of <2 had a probability of 95% (95% CI, 0.92-0.98) to exclude an AHI >15 and a STOP-Bang score of ≥6 had a specificity of 91% (95% CI, 0.87-0.94) for an AHI >15. The items contributing most to the STOP-Bang were the Bang items. There was a positive correlation between AHI versus STOP-Bang and between AHI versus oxygen desaturation index, Spearman ρ 0.50 (95% CI, 0.43-0.58) and 0.96 (95% CI, 0.94-0.97), respectively. CONCLUSIONS: STOP-Bang and pulse oximetry can be used to screen for sleep apnea. A STOP-Bang score of <2 almost excludes moderate and severe OSA, whereas nearly all the patients with a STOP-Bang score ≥6 have OSA. We suggest the addition of nightly pulse oximetry in patients with a STOP-Bang score of 2-5 when there is a need for screening for sleep apnea (ie, before surgery).

Misclassification of hypertrophic cardiomyopathy: validation of diagnostic codes.

PURPOSE: To validate diagnostic codes for hypertrophic cardiomyopathy (HCM), analyze misclassfications, and estimate the prevalence of HCM in an unselected Swedish regional cohort. PATIENTS AND METHODS: Using the hospitals' electronic medical records (used for the Swedish National Patient Register), we identified 136 patients from 2006 to 2016 with the HCM-related codes 142.1 and 142.2 (International Classification of Diseases). RESULTS: Of a total of 129 residents in the catchment area, 88 patients were correctly classified as HCM (positive predictive value 68.2%) and 41 patients (31.8%) were misclassified as HCM. Among the 88 HCM patients (52.2% males), 74 were alive and 14 were dead (15.9%). This yields an HCM prevalence of 74/183,337, that is, 4.0 diagnosed cases per 10,000 in the adult population aged ≥18 years. The underlying diagnoses of misclassified cases were mainly hypertension (31.7%) and aortic stenosis (22.0%). Other types of cardiomyopathies accounted for several cases of misclassification: dilated (nonischemic or ischemic), left ventricular noncompaction, and Takotsubo. Miscellaneous diagnoses were amyloidosis, pulmonary stenosis combined with ventricular septal defect, aortic insufficiency, athelete's heart, and atrioventricular conduction abnormality. The mean age was not significantly different between HCM and misclassified patients (65.8±15.8 vs 70.1±13.4 years; P=0.177). There were 47.8% females among HCM and 60.8% females among misclassified (P=0.118). CONCLUSION: One-third of patients diagnosed as HCM are misclassified, so registry data should be interpreted with caution. A correct diagnosis is important for decision-making and implementation of optimal HCM care; efforts should be made to increase awareness of HCM and diagnostic competence throughout the health care system.

[Black smoke lung disease ­ a new disease in Sweden]. / Sotrökslunga är en ny sjukdom i Sverige - Exponering för rök från biomassa är orsaken.

Black smoke lung disease - a new disease in Sweden We describe two elderly female patients, immigrants to Sweden from Afghanistan, with intensive longtime exposure to smoke from biomass, and who presented with bronchial stenosis and severe bronchial obstruction. CT and X-ray showed bizarre perihilar infiltrates in the lungs. Bronchoscopy revealed black narrow bronchi with a middle lobe stenosis in one of the patients. These findings indicate the diagnosis bronchial anthracofibrosis (BAF). The here described findings are seen mainly in elderly never-smoking women from developing countries who have spent years cooking food in poorly ventilated kitchens. With increased immigration from these countries such cases will be seen in industrialized countries as well. Active tuberculosis must always be excluded but otherwise no more active investigations such as biopsies are warranted. We suggest that this disease should be termed ¼black smoke disease« to differentiate it from coal workers' pneumoconiosis, silicosis, and other classical occupational diseases which can have similar clinical and radiological pictures. This term is easily understood even by non-medical persons and illustratess both the etiology and the black bronchi.

The impact of obesity and weight gain on development of sleep problems in a population-based sample.

OBJECTIVES: The objective of this study was to investigate the role of obesity and weight gain in the development of sleep problems in a population-based cohort. MATERIAL AND METHODS: A population-based sample of men (n = 1896, aged 40-79 years) and women (n = 5116, age ≥20 years) responded to questionnaires at baseline and follow-up after 10-13 years. Sleep problems were assessed through questions about difficulties initiating sleep (DIS), difficulties maintaining sleep (DMS), excessive daytime sleepiness (EDS), and insomnia. Body mass index (BMI) was calculated from self-reported weight and height at both baseline and follow-up, while confounding factors (physical activity, tobacco and alcohol use, somatic disease, and snoring) were based on responses at baseline. RESULTS: Although overweight and obese subjects reported more sleep problems at baseline, there was no independent association between BMI level at baseline and development of new sleep problems. Subjects in the quartile with the highest rise in BMI with a weight gain exceeding 2.06 kg/m2 had a higher risk of developing DMS [adjusted odds ratio (OR) 1.58; 95% confidence interval (CI) 1.25-2.01), EDS (2.25; 1.65-3.06], and insomnia (2.78; 1.60-4.82). Weight gain was not associated with the development of DIS. CONCLUSIONS: Weight gain is an independent risk factor for developing several sleep problems and daytime sleepiness. The presence of overweight and weight gain should be considered when treating patients with sleep problems.