Risk of chronic kidney disease in patients with obstructive sleep apnea

Nocturnal hypoxemic burden and micro- and macrovascular disease in patients with type 2 diabetes

BACKGROUND

Micro- and macrovascular diseases are common in patients with type 2 diabetes mellitus (T2D) and may be partly caused by nocturnal hypoxemia. The study aimed to characterize the composition of nocturnal hypoxemic burden and to assess its association with micro- and macrovascular disease in patients with T2D.

METHODS

This cross-sectional analysis includes overnight oximetry from 1247 patients with T2D enrolled in the DIACORE (DIAbetes COhoRtE) study. Night-time spent below a peripheral oxygen saturation of 90% (T90) as well as T90 associated with non-specific drifts in oxygen saturation (T90non - specific), T90 associated with acute oxygen desaturation (T90desaturation) and desaturation depths were assessed. Binary logistic regression analyses adjusted for known risk factors (age, sex, smoking status, waist-hip ratio, duration of T2D, HbA1c, pulse pressure, low-density lipoprotein, use of statins, and use of renin-angiotensin-aldosterone system inhibitors) were used to assess the associations of such parameters of hypoxemic burden with chronic kidney disease (CKD) as a manifestation of microvascular disease and a composite of cardiovascular diseases (CVD) reflecting macrovascular disease.

RESULTS

Patients with long T90 were significantly more often affected by CKD and CVD than patients with a lower hypoxemic burden (CKD 38% vs. 28%, p < 0.001; CVD 30% vs. 21%, p < 0.001). Continuous T90desaturation and desaturation depth were associated with CKD (adjusted OR 1.01 per unit, 95% CI [1.00; 1.01], p = 0.008 and OR 1.30, 95% CI [1.06; 1.61], p = 0.013, respectively) independently of other known risk factors for CKD. For CVD there was a thresholdeffect, and only severly and very severly increased T90non-specific was associated with CVD ([Q3;Q4] versus [Q1;Q2], adjusted OR 1.51, 95% CI [1.12; 2.05], p = 0.008) independently of other known risk factors for CVD.

CONCLUSION

While hypoxemic burden due to oxygen desaturations and the magnitude of desaturation depth were significantly associated with CKD, only severe hypoxemic burden due to non-specific drifts was associated with CVD. Specific types of hypoxemic burden may be related to micro- and macrovascular disease.

Adaptive responses to chronic intermittent hypoxia: contributions from the European Sleep Apnoea Database (ESADA) Cohort

Obstructive sleep apnoea (OSA) is a common disease in the general population, and is associated with increased cardiovascular risk and several comorbidities. Obesity favours upper airway collapsibility, but other pathophysiological traits have been identified, i.e. upper airway muscle activity, modulation of the respiratory drive, and the arousal threshold. OSA causes chronic intermittent hypoxia, inflammatory activation and autonomic imbalance with diurnal and nocturnal sympathetic hyperactivity. Disentangling so many components to investigate the pathogenesis of OSA's consequences is very hard clinically. However, albeit imperfect, clinical medicine constitutes a major source of inspiration for basic research, and a mutual exchange of information is essential between clinicians and physiologists to improve our understanding of disease states. OSA is no exception, and this narrative review will summarize the results of clinical studies performed over the years by the European Sleep Apnoea Database (ESADA) Study Group, to explore the variables linked to markers of intermittent hypoxia as opposed to the traditional assessment of OSA severity based on the frequency of respiratory events during sleep (the Apnoea Hypopnoea Index). The results of the clinical studies indicate that intermittent hypoxia variables are associated with several comorbidities, although evidence of a cause-effect relationship is still missing in many cases. It is also possible that adaptive rather than maladaptive responses could be evoked by intermittent hypoxia. The intensity, duration and frequency of intermittent hypoxia episodes causing adaptive rather than maladaptive responses, and their clinical implications, deserve further investigation.

Meta-analysis of the effects of CPAP therapy on estimated glomerular filtration rate in patients with obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is highly prevalent in patients with chronic kidney disease and may lead to a loss of kidney function. However, it remains unclear whether or not continuous positive airway pressure (CPAP) treatment improves the estimated glomerular filtration rate (eGFR) in patients with OSA. This meta-analysis was designed to investigate the effect of CPAP therapy on eGFR in patients with OSA.

METHODS

We searched the electronic databases Web of Science, Cochrane Library, PubMed, and Embase through June 1, 2022. Information about patients, CPAP duration, gender distribution, pre- and post-CPAP treatment eGFR, and age of patients were collected for further analysis. We applied the standardized mean difference (SMD) with a 95%confidence interval (CI) to analyze the pooled effects. Both Stata 12.0 software and Review Manager 5.2 software were employed for all statistical analyses.

RESULTS

A sample of 13 studies with 519 patients was included in the meta-analysis. There was no significant change of eGFR levels before and after CPAP usage for patients with OSA (SMD =  - 0.05, 95%CI: - 0.30 to 0.19, Z = 0.43, p = 0.67). However, subgroup analysis revealed that the level of eGFR was obviously decreased after CPAP therapy in patients with OSA and CPAP use duration > 6 months (SMD =  - 0.30, 95% CI =  - 0.49 to - 0.12, z = 3.20, p = 0.001), and elderly patients (> 60 years) (SMD =  - 0.32, 95% CI =  - 0.52 to - 0.11, z = 3.02, p = 0.002).

CONCLUSIONS

Meta-analysis confirmed that OSA treatment with CPAP has no clinically significant effect on eGFR.

The relationship between obstructive sleep apnea and risk of renal impairment in patients with hypertension, a longitudinal study

OBJECTIVE

Association of obstructive sleep apnea (OSA) with renal damage is undetermined, especially in the population with hypertension, a high-risk group for chronic kidney disease. Therefore, we aimed to explore whether OSA is an independent risk factor for renal impairment in patients with hypertension, by considering the effects of gender, age, obesity and OSA severity.

METHODS

The longitudinal observational study included patients with hypertension and suspected OSA without renal damage at baseline who visited Hypertension Center between January 2011 and December 2018, and followed up till renal outcomes, death, loss to follow-up, or May 31, 2022, using annual health check-ups, hospital readmission or out-patient visits. Main renal outcome was chronic kidney disease (CKD), defined as estimated glomerular filtration rate <60 ml/min per 1.73 m2 and/or positive proteinuria. Cox proportional hazard models were used to evaluate the association, and repeated after propensity score matching. Sensitivity analysis were performed by excluding those with primary aldosteronism.

RESULTS

7961 patients with hypertension were included with 5022 ones with OSA, and 82% were followed up. During median follow-up of 3.42 years, 1486 patients developed CKD. Per 1000 person-year incidence of CKD was 56.72 in OSA group. In Cox regression analysis, OSA and severe OSA group respectively showed 1.21 (95% CI: 1.08-1.35) and 1.27 (95% CI: 1.09-1.47) fold risk for CKD in total, compared with non-OSA group. Overall results remained consistent in propensity score matching and sensitivity analysis.

CONCLUSION

OSA is independently associated with higher risk of chronic kidney disease in hypertension.

The Burden of Comorbidities in Obstructive Sleep Apnea and the Pathophysiologic Mechanisms and Effects of CPAP

Micro-arousals and the repeated desaturation of oxyhemoglobin, which are typical in obstructive sleep apnea syndrome (OSAS), have adverse effects on the health of patients, leading to a wide range of complications such as cardiovascular (arterial hypertension, pulmonary hypertension, chronic heart failure, arrhythmias, myocardial infarction), cerebrovascular (strokes), metabolic (insulin resistance, obesity, diabetes mellitus, metabolic syndrome), gastrointestinal (non-alcoholic liver disease), urinary (chronic renal failure), and neuropsychiatric complications as well as a wide range of malignancies. These, in turn, have multilateral effects on familial, occupational, and social life, as well as increasing the risks of road traffic accidents and accidents at the workplace. Awareness, timely screening, and the prevention of complications play important roles in diagnosing and treating comorbid conditions. This review focuses on comorbidities in OSAS and the effect of Continuous Positive Airway Pressure (CPAP) therapy on their prognoses.

Contrast Enhanced Ultrasonography of Kidney in Chronic Intermittent Hypoxia Rat Model

OBJECTIVES

The objective of our study was to assess the ability of contrast-enhanced ultrasound (CEUS) in evaluating renal microperfusion in an animal model.

METHODS

Twenty Sprague-Dawley rats were subdivided into two groups: the normal and chronic intermittent hypoxia (CIH) groups. In the CIH model, 10 Sprague-Dawley rats were exposed to CIH for 8 weeks to mimic obstructive sleep apnea (OSA). The CEUS parameters of the renal cortex and medulla were obtained and compared between groups. The pathological changes of the kidney tissues were examined by histological staining such as hematoxylin and eosin (H&E) and Masson's trichrome.

RESULTS

CIH caused morphological damage to kidneys. In the cortex, the peak intensity (PI) (P = .009) was significantly lower and time to peak (Ttop) (P = .019) was significantly prolonged in the CIH group compared with the controls. The area under ascending curve (WiAUC) in the medulla and cortex were both significantly lower in the CIH group than those in the control group (P both <.05). CEUS parameters (including PI and WiAUC of the cortex and WiAUC of the medulla) were negatively correlated with serum creatinine (P all <.05). In the medulla, the area under descending curve (WoAUC) was positively correlated with serum creatinine (P = .027), PI was negatively correlated with uric acid (P = .034).

CONCLUSION

CEUS parameters (including Ttop, PI, WoAUC, and WiAUC) reflect renal microvascular changes in CIH. CEUS could be a safe and accurate imaging method to assess renal microvascular damage in CIH rats.

Association of insomnia and short sleep duration, alone or with comorbid obstructive sleep apnea, and the risk of chronic kidney disease

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), sleep fragmentation, and short sleep duration (SD) have been associated with chronic kidney disease (CKD). However, these potential mechanisms for CKD have not been compared in the same cohort. This study investigated the independent and combined impact of OSA and insomnia with short sleep duration on the risk of CKD progression in a sleep clinic population.

METHODS

In a cross-sectional study design, adults with suspected OSA completed an overnight sleep study and a questionnaire that included the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI). They also provided blood and urine samples for measurement of the glomerular filtration rate and urine albumin:creatinine ratio, from which the risk of CKD progression was determined.

RESULTS

Participants (n = 732, 41% female, 55 ± 13 years) were categorized into four groups: no/mild OSA without insomnia (NM-OSA, n = 203), insomnia with SD without OSA (Insomnia-SD, n = 104), moderate-to-severe OSA without insomnia (MS-OSA, n = 242), and comorbid insomnia and OSA with SD (COMISA-SD, n = 183). After stratification, 12.8% of NM-OSA, 15.4% of Insomnia-SD, 28.9% of MS-OSA, and 31.7% of the COMISA-SD participants had an increased risk of CKD progression. Compared to NM-OSA, the odds ratio (OR) for an increased risk of CKD progression was not increased in Insomnia-SD (OR 0.95, confidence interval [CI]: 0.45-1.99) and was increased to the same degree in MS-OSA (OR 2.79, CI: 1.60-4.85) and COMISA-SD (OR 3.04, CI: 1.69-5.47). However, the ORs were similar between the MS-OSA and COMISA-SD groups across all statistical models (p ≥ .883).

CONCLUSIONS

In a sleep clinic population, insomnia with short sleep duration does not increase the risk of CKD progression; nor does it further increase the risk of CKD progression associated with moderate-to-severe OSA.

Adherence Index: sleep depth and nocturnal hypoventilation predict long-term adherence with positive airway pressure therapy in severe obstructive sleep apnea

STUDY OBJECTIVES

Treatment of obstructive sleep apnea with positive airway pressure (PAP) devices is limited by poor long-term adherence. Early identification of individual patients' probability of long-term PAP adherence would help in their management. We determined whether conventional polysomnogram (PSG) scoring and measures of sleep depth based on the odds ratio product would predict adherence with PAP therapy 12 months after it was started.

METHODS

Patients with obstructive sleep apnea referred to an academic sleep center had split-night PSG, arterial blood gases, and a sleep questionnaire. Multiple linear regression analysis of conventional PSG scoring and the odds ratio product both during diagnostic PSG and PAP titration provided an "Adherence Index," which was correlated with PAP use 12 months later.

RESULTS

Patients with obstructive sleep apnea (n = 236, apnea-hypopnea index 72.2 ± 34.1 events/h) were prescribed PAP therapy (82% received continuous PAP, 18% received bilevel PAP). Each patient's adherence with PAP therapy 12 months later was categorized as "never used," "quit using," "poor adherence," and "good adherence." PSG measures that were most strongly correlated with PAP adherence were apnea-hypopnea index and odds ratio product during nonrapid eye movement sleep; the additional contribution of nocturnal hypoxemia to this correlation was confined to those with chronic hypoventilation treated with bilevel PAP. The Adherence Index derived from these measures, during both diagnostic PSG and PAP titration, was strongly correlated with PAP adherence 12 months later.

CONCLUSIONS

Long-term adherence with PAP therapy can be predicted from diagnostic PSG in patients with severe obstructive sleep apnea, which may facilitate a precision-based approach to PAP management.

CITATION

Younes MK, Beaudin AE, Raneri JK, Gerardy BJ, Hanly PJ. Adherence Index: sleep depth and nocturnal hypoventilation predict long-term adherence with positive airway pressure therapy in severe obstructive sleep apnea. J Clin Sleep Med. 2022:18(8):1933-1944.