Logo: to the web site of Uppsala University

BACKGROUND: Studies on the survival of patients with home mechanical ventilation (HMV) are sparse. We aimed to analyse the impact of controlled hypercapnia on survival over 27 years among patients with HMV in Sweden.

STUDY DESIGN AND METHODS: Population-based cohort study of adult patients starting HMV in the Swedish Registry for Respiratory Failure (Swedevox) during 1996-2022 cross-linked with the National Cause of Death registry. Mortality risk factors were analysed using crude and multivariable Cox regression models, including adjustments for anthropometrics, comorbidities, the underlying diagnosis causing chronic hypercapnic respiratory failure (CRF) and the control of hypercapnia (P _aCO2 ≤6.0 kPa) at follow-up.

RESULTS: We included 10 190 patients (50.1% women, age 62.9±14.5 years). Control of hypercapnia at follow-up after 1.3±0.9 years was associated with lower mortality, hazard ratio (HR) 0.74 (95% CI 0.68-0.80) and the association was strongest in those with pulmonary disease, restrictive thoracal disease (RTD), obesity hypoventilation syndrome (OHS) and amyotrophic lateral sclerosis (ALS). Predictors for increased mortality included age, Charlson Comorbidity Index, supplemental oxygen therapy and acute start of HMV therapy. Median survival varied between 0.8 years (95% CI 0.8-0.9 (n=1401)) for ALS and 7.6 years (95% CI 6.9-8.6 (n=1061)) for neuromuscular disease. Three-year survival decreased from 76% (95% CI 71-80) between 1996 and 1998 to 52% (95% CI 50-55) between 2017 and 2019. When adjusting for underlying diagnosis and age, the association between start year and decreased survival disappeared, HR 1.00 (95% CI 0.99-1.01).

CONCLUSION: Controlling P _aCO2 is a key treatment goal for survival in HMV therapy. Survival differed markedly between diagnosis and age groups, and survival rates have declined as the patient group has aged.

Obstructive sleep apnea (OSA) has been linked to cancer in several clinical and community-based cohorts. The effect in community-based studies free of clinical referral bias needs to be replicated. In this observational prospective cohort study, we pooled data from three community-based prospective cohorts (Uppsala Sleep and Health in Men cohort [UMEN]; Sleep and health in women [SHE]; Men Androgen Inflammation Lifestyle Environment and Stress Cohort [MAILES]; n_Total = 1467). All cohorts had objective data on obstructive sleep apnea and registry linkage data on cancer and cancer mortality. Analyses for different obstructive sleep apnea measures (apnea–hypopnea index [AHI], oxygen desaturation index [ODI], and minimal saturation) as risk factors for cancer incidence (all cancers) were performed using Cox proportional hazards models (follow-up 5–16 years). We did not find an overall increased risk of cancer after adjustment for age, sex, and BMI (HR_AHI [95% CI] = 1.00 [0.98; 1.01] and HR_ODI [95% CI] = 0.99 [0.97; 1.01]). Stratifying by daytime sleepiness did not influence the association. Cancer mortality was not significantly associated with obstructive sleep apnea. Taken together, we did not observe an overall increased risk of cancer or cancer mortality in relation to obstructive sleep apnea, however, our confidence limits remain wide for important diagnostic categories of sleep apnea severity. The relationship between obstructive sleep apnea and cancer needs further investigation in a comprehensive multi-cohort approach with greater statistical precision. For future studies we may need to find and then combine every community-based cohort study that can provide a definitive answer to the question on the risk of cancer from obstructive sleep apnea in the general population.

Telemonitoring of obstructive sleep apnea patients is increasingly being adopted though its cost-effectiveness evidence base is scanty. This study investigated whether telemonitoring is a cost-effective strategy compared with the standard follow-up in patients with obstructive sleep apnea who are starting continuous positive airway pressure treatment. In total, 167 obstructive sleep apnea patients were randomised into telemonitoring (n = 79) or standard follow-up (n = 88), initiated continuous positive airway pressure treatment, and were followed up for 6 months. The frequencies of healthcare contacts, related costs (in USD 2021 prices), treatment effect and compliance were compared between the follow-up approaches using generalised linear models. The cost effectiveness analysis was conducted from a healthcare perspective and the results presented as cost per avoided extra clinic visit. Additionally, patient satisfaction between the two approaches was explored. The analysis showed no baseline differences. At follow-up, there was no significant difference in treatment compliance, and the mean residual apnea–hypoapnea index. There was no difference in total visits, adjusted incidence rate ratio 0.87 (0.72–1.06). Participants in the telemonitoring arm made eight times more telephone visits, 8.10 (5.04–13.84), and about 73% fewer physical healthcare visits 0.27 (0.20–0.36). This translated into significantly lower total costs for the telemonitoring approach compared with standard follow-up, −192 USD (−346 to −41). The form of follow-up seemed to have no impact on the extent of patient satisfaction. These results demonstrate the telemonitoring of patients with obstructive sleep apnea initiating continuous positive airway pressure treatment as a cost saving strategy and can be argued as a potential worthy investment.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) during rapid eye movement (REM) sleep is often characterized with more frequent and lengthy breathing events and greater oxygen desaturation than during other sleep stages. Current evidence suggests an association between OSA and cognitive decline, however whether OSA during REM sleep plays a vital role in this link is understudied.

METHODS: A cross-sectional sample of 728 men and women (aged 59.1 ± 11.3 years) underwent a full night polysomnography for determining apnea-hypopnea index (AHI) and sleep stages. Trail Making Test (TMT) part A and B were conducted during the following day for assessing participants' cognitive function. Linear regression analyses were performed to test the possible association between AHI and AHI during REM sleep with TMT-A and B results. Similar analyses were carried out in a subsample involving participants aged ≥60 years with ≥30 min of REM sleep (n = 356).

RESULTS: Despite a slight difference in TMT-B between participants with and without OSA (AHI ≥5 vs AHI <5, β-coefficient: 4.83, 95 % CI: [-9.44, -0.22], P = 0.040), no other association between AHI or REM-AHI and TMT results were found in the full sample. In older participants (aged ≥60 years), a REM-AHI ≥5 events/hour was associated with longer time taken to finish TMT-A (vs REM-AHI <5 events/hour, 3.93, [0.96, 6.90], P = 0.010). There was no association between REM-AHI and time taken to finish TMT-B in older participants.

CONCLUSIONS: The results indicate that OSA during REM sleep may be of particular concern for attention-related cognitive function in older adults.

UNLABELLED: Obstructive sleep apnoea (OSA) and its associations with lung function.

BACKGROUND: OSA is highly prevalent and characterised by abnormal respiration during sleep. This large, population-based study aimed to investigate the associations between OSA and lung function in subjects aged 50-64 years.

METHOD: The population-based Swedish CArdioPulmonary bioimage Study includes information on anthropometry, comorbidities and spirometry. The current analysis included data from three centres (Gothenburg, Umeå and Uppsala) on whole-night respiratory polygraphy as a meta-analysis examining the overall effect size of lung function on sleep apnoea severity, expressed as ß-coefficient after stratifying for sex and adjusting for age, waist circumference and smoking status.

RESULTS: Data from 9016 participants (54% women, age 58±4 years, body mass index 27±4 kg/m² ) with sleep recordings of good quality were included in the final analysis. Forced expiratory volume during 1 s (FEV ₁ ) (ß=-0.10 (95% CI -0.16 to -0.03)), forced vital capacity (FVC) (-0.15 (-0.21 to -0.10)) and diffusion capacity for carbon monoxide (DL_CO ) (-0.08 (-0.10 to -0.05)) were all negatively associated with the oxygen desaturation index (ODI) and also with per cent of registration with nocturnal oxygen saturation <90% FVC (-0.44 (-0.87 to -0.01)), FEV ₁ (-0.86 (-1.36 to -0.36)) and DL _CO (-0.47 (-0.60 to -0.35)). Additionally, a positive association was observed between FEV ₁ (0.13 (0.05 to 0.22)) and DL _CO (0.07 (0.04 to 0.09)) with the mean nocturnal saturation. There was a negative association between DL _CO and apnoea-hypopnoea index, AHI, (ß=-0.04 (95% CI-0.06 to -0.03)), while no associations were found between FEV ₁ or FVC and AHI.

CONCLUSION: In OSA, lower lung function is more distinctly associated with the nocturnal hypoxic burden than AHI. Potential lung function impairment should be investigated in OSA patients with a high ODI relative to AHI.

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.Participants62 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/m(2)) 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.

Background: Patients with chronic respiratory failure treated with long-term oxygen therapy (LTOT) often have severe breathlessness, impaired exercise performance, and high but variable mortality that is difficult to predict. We aimed to evaluate breathlessness and exercise performance upon starting LTOT as predictors of overall and short-term mortality.

Methods: This was a longitudinal, population-based study of patients who initiated LTOT between 2015 and 2018 in Sweden. Breathlessness was measured using the Dyspnea Exertion Scale, and exercise performance using the 30s-Sit-To-Stand test. Associations with overall and three-month mortality were analyzed using Cox-regression. Subgroup analyses were performed for patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) respectively. The predictive capacity of models was assessed using a C-statistic.

Results: A total of 441 patients (57.6% female, aged 75.4 +/- 8.3 years) were analyzed, of whom 141 (32%) died during a median follow-up of 260 (IQR 75-460) days. Both breathlessness and exercise performance were independently associated with overall mortality in the crude models, but only exercise performance remained independently associated with overall mortality when models were adjusted for other predictors, when short-term mortality was analyzed, or when breathlessness and exercise capacity were analyzed concurrently. The multivariable model including exercise performance but not breathlessness provided a relatively high predictive capacity for overall mortality, C-statistic 0.756 (95% CI 0.702-0.810). Similar results were seen in the COPD and ILD subgroups.

Conclusion: Exercise performance as measured by the 30s-STS may be useful to identify patients with higher mortality on LTOT for optimized management and follow-up.

Accelerometers placed on the thigh provide accurate measures of daily physical activity types, postures and sedentary behaviours, over 24 h and across consecutive days. However, the ability to estimate sleep duration or quality from thigh-worn accelerometers is uncertain and has not been evaluated in comparison with the ‘gold-standard’ measurement of sleep polysomnography. This study aimed to develop an algorithm for sleep estimation using the raw data from a thigh-worn accelerometer and to evaluate it in comparison with polysomnography. The algorithm was developed and optimised on a dataset consisting of 23 single-night polysomnography recordings, collected in a laboratory, from 15 asymptomatic adults. This optimised algorithm was then applied to a separate evaluation dataset, in which, 71 adult males (mean [SD] age 57 [11] years, height 181 [6] cm, weight 82 [13] kg) wore ambulatory polysomnography equipment and a thigh-worn accelerometer, simultaneously, whilst sleeping at home. Compared with polysomnography, the algorithm had a sensitivity of 0.84 and a specificity of 0.55 when estimating sleep periods. Sleep intervals were underestimated by 21 min (130 min, Limits of Agreement Range [LoAR]). Total sleep time was underestimated by 32 min (233 min LoAR). Our results evaluate the performance of a new algorithm for estimating sleep and outline the limitations. Based on these results, we conclude that a single device can provide estimates of the sleep interval and total sleep time with sufficient accuracy for the measurement of daily physical activity, sedentary behaviour, and sleep, on a group level in free-living settings.

Background

Sleep-related breathing disorders (SRBD) are related to cardiovascular outcomes in patients with chronic coronary syndrome (CCS). Whether SRBD-related symptoms are associated with prognostic biomarkers in patients with CCS is not established.

Methods

Associations between frequency (never/rarely, sometimes, often, always) of self-reported SRBD-related symptoms (excessive daytime sleepiness [EDS]; morning tiredness [MT]; loud snoring; multiple awakenings/night; gasping, choking, or apnea when asleep) and levels of biomarkers related to cardiovascular prognosis (high-sensitivity C-reactive protein [hs-CRP], interleukin 6 [IL-6], high-sensitivity cardiac troponin T [hs-cTnT], N-terminal pro B-type natriuretic peptide [NT-proBNP], cystatin C, growth differentiation factor 15 [GDF-15] and lipoprotein-associated phospholipase A₂ activity) were assessed at baseline in 15,640 patients with CCS on optimal secondary preventive therapy in the STABILITY trial. Cross-sectional associations were assessed by adjusted linear regression models testing for trends with the never/rarely category serving as reference.

Results

EDS was associated (geometric mean ratio, 95% confidence interval) with increased levels of IL-6 (often 1.07 [1.03–1.10], always 1.15 [1.10–1.21]), GDF-15 (often 1.03 [1.01–1.06], always 1.07 [1.03–1.11]), NT-proBNP (always 1.22 [1.12–1.33]), and hs-cTnT (always 1.07 [1.01–1.12]). MT was associated with increased levels of IL-6 (often 1.05 [1.01–1.09], always 1.09 [1.04–1.15]), and GDF-15 (always 1.06 [1.03–1.10]). All symptoms were to some degree associated with higher levels of hs-CRP and loud snoring was also associated with decreased levels of NT-proBNP and hs-cTnT.

Conclusions

In patients with CCS, stepwise increased frequency of SRBD-related symptoms, such as EDS and MT, were associated with gradually higher levels of IL-6 and GDF-15, each reflecting distinct pathophysiological pathways.