Rationale: Hospitalized patients with acute-on-chronic hypercapnic respiratory failure due to obesity hypoventilation syndrome (OHS) have increased short-term mortality. It is unknown whether prescribing empiric positive airway pressure (PAP) at the time of hospital discharge reduces mortality compared with waiting for an outpatient evaluation (i.e., outpatient sleep study and outpatient PAP titration). Objectives: An international, multidisciplinary panel of experts developed clinical practice guidelines on OHS for the American Thoracic Society. The guideline panel asked whether hospitalized adult patients with acute-on-chronic hypercapnic respiratory failure suspected of having OHS, in whom the diagnosis has not yet been made, should be discharged from the hospital with or without empiric PAP treatment until the diagnosis of OHS is either confirmed or ruled out. Methods: A systematic review with individual patient data meta-analyses was performed to inform the guideline panel’s recommendation. Grading of Recommendations, Assessment, Development, and Evaluation was used to summarize evidence and appraise quality. Results: The literature search identified 2,994 articles. There were no randomized trials. Ten studies met a priori study selection criteria, including two nonrandomized comparative studies and eight nonrandomized noncomparative studies. Individual patient data on hospitalized patients who survived to hospital discharge were obtained from nine of the studies and included a total of 1,162 patients (1,043 discharged with PAP and 119 discharged without PAP). Empiric noninvasive ventilation was prescribed in 91.5% of patients discharged on PAP, and the remainder received empiric continuous PAP. Discharge with PAP reduced mortality at 3 months (relative risk 0.12, 95% confidence interval 0.05–0.30, risk difference −14.5%). Certainty in the estimated effects was very low. Conclusions: Hospital discharge with PAP reduces mortality following acute-on-chronic hypercapnic respiratory failure in patients with OHS or suspected of having OHS. Well-designed clinical trials are needed to confirm this finding.

Background/Objective: Systemic inflammation is common in chronic obstructive pulmonary disease (COPD), and evidence suggests that inflammatory biomarkers can predict acute exacerbations (AECOPDs). The aim of this study was to analyse whether C-reactive protein (CRP), fibrinogen, white blood cell count (WBC), or the blood cell indices PLR (platelet-to-lymphocyte ratio), SII (systemic immune inflammation index), SIRI (systemic inflammation response index), and AISI (aggregate index of systemic inflammation) can predict future AECOPDs. Methods: In the Tools Identifying Exacerbations (TIE) cohort study, participants with spirometry-confirmed COPD were recruited from primary and secondary care in three Swedish regions and assessed during a stable phase of COPD. AECOPD frequency during the three-year follow-up was reviewed in medical records. Associations were analysed via ordinal logistic regressions. Results: Of the 571 participants, 46% had ≥1 AECOPD during follow-up, and the mean ± SD AECOPD frequency was 0.63 ± 1.2/year. In unadjusted analyses, high levels of CRP (odds ratio 1.86, 95% CI 1.29–2.67), fibrinogen (2.09, 1.38–3.16), WBCs (2.18, 1.52–3.13), SII (1.52, 1.05–2.19), SIRI (1.76, 1.23–2.52), and AISI (1.99, 1.38–2.87) were associated with a higher AECOPD frequency. After adjustment for AECOPD history, age, sex, smoking, body mass index, COPD Assessment Test score, lung function, and inhaled corticosteroid use, associations remained for high levels of CRP (adjusted odds ratio of 1.64; 95% CI of 1.08–2.49), fibrinogen (1.55; 1.07–2.24), and WBC (1.65; 1.10–2.47). Conclusions: CRP, fibrinogen, and WBC, assessed during stable-phase COPD, enhanced AECOPD prediction, whereas PLR, SII, SIRI, and AISI did not.

Early identification of poor adherence to CPAP treatment is of major clinical importance to optimize treatment outcomes in patients with OSA. How do socioeconomic factors influence CPAP adherence? Nationwide, population-based cohort study of patients with OSA receiving CPAP treatment reported to the Swedish quality registry Swedevox between 2010 and 2018 was cross-linked with individual socioeconomic data from Statistics Sweden. Socioeconomic factors associated with CPAP adherence were identified using a multivariate linear regression model, adjusted for age and sex. In total, 20,521 patients were included: 70.7% men; mean age ± SD, 57.8 ± 12.2 years; BMI, 32.0 ± 6.1 kg/m²; apnea-hypopnea index, 36.9 ± 22.1; Epworth Sleepiness Scale, 10.4 ± 5.0; and median nocturnal CPAP use, 355 min (interquartile range, 240-420 min). Adherence after 1.3 ± 0.8 years of CPAP use was significantly (all P < .001) associated with civil status (married vs unmarried: +20.5 min/night), education level (high, ≥ 13 years vs low, ≤ 9 years: +13.2 min/night), total household income (highest/third/second vs lowest quartile: +15.9 min/night, +10.4 min/night, and +6.1 min/night, respectively), and country of birth (born in Sweden with one native parent/born in Sweden with two native parents vs being born abroad: +29.0 min/night and +29.3 min/night, respectively). Civil status, educational level, household income, and foreign background predict CPAP adherence in a clinically significant manner and should be considered when treating OSA with CPAP.

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/m ² ), 8111 with LTMV since 1996 (48.6% women, age 60.6±16.9 years, BMI 32.9±10.8 kg/m ² ), 65 809 with OSA on CPAP since 2010 (29.5% women, age 57.2±12.5 years, BMI 31.9±6.2 kg/m ² ) 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.