Is C-reactive protein elevated in obstructive sleep apnea? a systematic review and meta-analysis

Impact of Intermittent Hypoxia Related to Obstructive Sleep Apnoea Syndrome on Low-Grade Inflammation in Hypertensive Patients: Potential Implications for Cardiovascular Risk

There is evidence for a particular relationship between low-grade inflammation (LGI) and intermittent hypoxia (IH) related to obstructive sleep apnoea syndrome (OSAS). However, despite the potential deleterious cardiovascular consequences associated with this LGI in hypertensive patients, few studies have investigated the impact of IH related to OSAS on CRP levels in this subpopulation. In total, 1404 hypertensive patients were selected retrospectively from the Sleep Laboratory database. CRP levels ≥3 mg/L but <10 mg/L were used as cut-offs to identify hypertensive patients with LGI. Logistic regressions were conducted to examine the risk of LGI associated with IH related to OSAS in hypertensive patients. LGI was frequent (33.8%) in hypertensive patients. After adjustment for confounders, multivariate logistic regressions revealed that only moderate to severe OSAS (apnoea-hypopnoea index ≥ 15/h) with high IH (oxygen desaturation index ≥ 15/h) [OR 1.51 (95% CI 1.06-2.14)] was significantly associated with LGI in hypertensive patients (p-value = 0.045). Consistent with our hypothesis, our results demonstrated the existence of a particular subtype of hypertensive patients at high cardiovascular risk characterised by the presence of LGI induced by IH hypoxia related to moderate to severe OSAS, which justifies the establishment of adequate management of this pathology to allow better cardiovascular prevention in this subpopulation.

Causal relationship between levels of myeloperoxidase and obstructive sleep apnea: a bidirectional two-sample Mendelian randomization study

Background

Several observational studies have investigated the association between myeloperoxidase (MPO) and obstructive sleep apnea (OSA). However, the nature of this relationship remains uncertain due to potential selection and confounding biases. To resolve this, we conducted a bidirectional two-sample Mendelian randomization (MR) study to scrutinize the causal relationship between MPO and OSA.

Methods

Instrumental variables (IVs) for OSA were sourced from the publicly available FinnGen dataset, encompassing 38,998 OSA cases and 336,659 controls. Data on MPO were sourced from a study of 21,758 individuals conducted by the European Bioinformatics Institute (EBI). The primary MR analysis utilized the inverse-variance weighted (IVW) method, with MR-Egger intercept and leave-one-out methods assessing pleiotropy and Cochran's Q test determining heterogeneity.

Results

The IVW analysis indicated a causal relationship between heightened MPO levels and an increased incidence of OSA. Individuals with elevated MPO levels manifested a higher propensity to develop OSA, exhibiting an odds ratio (OR) of 1.075 and a 95% confidence interval (CI) of 1.011-1.143 (p = 0.021). Conversely, the reciprocal analysis unveiled no significant association between OSA and heightened MPO levels (p = 0.643). No directional pleiotropy was identified through the MR-Egger intercept test (p > 0.05).

Conclusion

Our study provides evidence of an association between elevated MPO levels and an increased incidence of OSA. However, OSA does not necessarily lead to elevated MPO levels. When patients present with high MPO levels, screening for OSA may be advisable, considering their clinical characteristics.

OSA and Subsequent Risk of Hospitalization With Pneumonia, Respiratory Infection, and Total Infection: The Atherosclerosis Risk in Communities Study

BACKGROUND

OSA has been linked to microaspiration, systemic inflammation, and suboptimal immune function.

RESEARCH QUESTION

Is OSA prospectively associated with risk of hospitalization for pneumonia, respiratory, and total infections?

STUDY DESIGN AND METHODS

Prospective cohort. Participants in the Atherosclerosis Risk in Communities (ARIC) study (N = 1,586) underwent polysomnography in 1996-1998 and were followed up through 2018 for infection-related hospitalizations. The apnea-hypopnea index (AHI; events/h) was used to categorize participants as having severe OSA (≥ 30), moderate OSA (15-29), mild OSA (5-14), or a normal breathing pattern (< 5). Cox regression was used to calculate hazard ratios (HRs) and 95% CIs.

RESULTS

ARIC participants were on average 62.7 (SD = 5.5) years of age, and 52.8% were female. Severe OSA was present in 6.0%, moderate OSA in 12.7%, mild OSA in 30.0%, and normal breathing in 51.3%. A total of 253 hospitalizations with pneumonia occurred over a median 20.4 (max, 22.9) years' follow-up. Participants with severe OSA were at 1.87 times (95% CI, 1.19-2.95) higher risk of hospitalization with pneumonia compared with those with a normal breathing pattern after adjustment for demographics and lifestyle behaviors. Results were attenuated modestly after adjustment for BMI (1.62 [0.99-2.63]), and prevalent asthma and COPD (1.62 [0.99-2.63]). A similar pattern existed for hospitalization with respiratory infection and composite infection (demographic and behavior-adjusted HRs: 1.47 [0.96-2.25] and 1.48 [1.07-2.04], respectively).

INTERPRETATION

Severe OSA was associated with increased risk of hospitalizations with pneumonia in this community-based cohort. OSA patients may benefit from more aggressive efforts to prevent pneumonia and other infectious conditions.

Potential Diagnostic and Monitoring Biomarkers of Obstructive Sleep Apnea-Umbrella Review of Meta-Analyses

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease that imposes a significant impact on the health and wellbeing of patients and a financial burden on individuals, their families, and society. Development of new methods of testing other than an overnight sleep study, such as measurement of serum or plasma biomarkers, may provide an easier diagnostic process to identify patients with OSA and allow earlier initiation of treatment, which might prevent serious comorbidities. We conducted a systematic review and quality assessment of available meta-analyses regarding potential diagnostic and monitoring biomarkers of obstructive sleep apnea. A total of 14 sets of candidate biomarkers displayed differences in levels or concentrations in OSA patients compared to non-OSA controls, and decreased after OSA treatment: CRP, IL-6, TNF-α, Il-8, HCY, ICAM-1, VCAM-1, VEGF, TC, LDLc, HDLc, TG, leptin, MDA, ALT, AST, IGF-1, adiponectin, and cortisol. This review summarizes the evidence for OSA-associated potential biomarkers and demonstrates that the quality of available studies, as measured by AMSTAR2, is often low and associated with a high risk of bias.

A Case-Control Study on the Changes in High-Sensitivity C-Reactive Protein and Tumor Necrosis Factor-Alpha Levels with Surgical Treatment of OSAS

Obstructive sleep apnea syndrome (OSAS) is a common but underdiagnosed condition with significant health and economic implications for society. Inflammatory mediators are proposed to be associated with the presence and severity of OSAS and contribute to morbidity and mortality. This paper details a prospective non-randomized case control study of a cohort of subjects, who underwent surgical treatment of OSAS and were enrolled to assess the sleep parameters and blood levels of selected inflammatory markers at pre-operative and post-operative time points, also comparing them to the levels in a control group. A total of 25 study subjects and 18 control subjects were enrolled. Median values and interquartile range (IQR) of the apnea-hypopnea index (AHI) in the study group pre-operatively and post-operatively were 34 (18.5-45.5) and 13.3 (7.5-27.3), while in the control group 1.4 (1.0-2.1) per hour. The mean (IQR) hs-CRP levels (mg/L) were 1.782 (0.941-5.594) and 1.980 (0.990-5.445) in the study group, pre-operatively and post-operatively, respectively, while 0.891 (0.767-1.436) in the control group. The mean (IQR) TNF-α levels (pg/mL) were 7.999 (6.137-9.216) and 6.614 (5.534-7.460) pre-and post-operatively, respectively, and were 6.000 (5.026-6.823) in the control group. Results demonstrated that both inflammatory markers, hs-CRP and TNF-α, are higher in subjects with OSAS compared to the controls, and their levels decrease, but are still higher than the controls, after successful surgical treatment. Further analysis including the body mass index and age demonstrated that these changes were significant for TNF-α, but not hs-CRP.

Improved Inflammatory and Cardiometabolic Profile After Soft-Tissue Sleep Surgery for Obstructive Sleep Apnea: A Systematic Review and Meta-analysis

Importance

Obstructive sleep apnea (OSA) is associated with a rise in serum inflammatory markers, which may be attenuated by sleep surgery.

Objective

To evaluate whether sleep surgery was associated with improved levels of proinflammatory markers in adults with OSA.

Data Sources

Two authors independently searched Cochrane, Embase, and PubMed databases from inception through June 14, 2022.

Study Selection

Two authors searched the Cochrane, Embase, and PubMed databases for studies comparing preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery.

Data Extraction and Synthesis

Data were extracted from included articles into a structured proforma. Meta-analyses of the standardized mean difference (SMD) were conducted in random-effects models. To ensure relevance to clinicians and patients, the probability of benefit and number needed to treat were calculated for outcomes that demonstrated a statistically significant effect after sleep surgery.

Main Outcomes and Measures

The primary outcome was the preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery, including C-reactive protein (CRP), glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and interleukin-6 (IL-6). Data analysis was performed from April to May 2022.

Results

Of the 3218 studies screened, 26 studies with 1187 patients (mean [SD] age, 42.8 [11.1] years; 932 [78.5%] men and 255 [21.5%] women) were included. Soft-tissue sleep surgery was associated with a large decrease in CRP (SMD, -0.377; 95% CI, -0.617 to -0.137), total cholesterol (SMD, -0.267; 95% CI, -0.417 to -0.116), LDL (SMD, -0.201; 95% CI, -0.344 to -0.058), IL-6 (SMD, -1.086; 95% CI, -1.952 to -0.221), tumor necrosis factor-α (SMD, -0.822; 95% CI, -1.617 to -0.027), triglyceride (SMD, -0.186; 95% CI, -0.301 to -0.071), and leptin (SMD, -0.519; 95% CI, -0.954 to -0.083) in patients with OSA. Meta-regression highlighted that increased age, higher preoperative score for cumulative sleep time percentage with oxyhemoglobin saturation less than 90% (CT90), and greater change in CT90 postoperatively were associated with a greater decrease in serum CRP levels after soft-tissue sleep surgery. A greater reduction in apnea hypopnea index (AHI) was strongly associated with a greater reduction in total cholesterol and LDL. A greater reduction in body mass index and AHI were also associated with a greater increase in HDL.

Conclusions and Relevance

The findings of this systematic review and meta-analysis of 26 studies suggest that sleep surgery is associated with decreased levels of CRP, total cholesterol, LDL, triglyceride, IL-6, leptin, and TNF-α, which may improve the inflammatory and cardiometabolic profile of patients who undergo sleep surgery.

Association between obstructive sleep apnea (OSA) and atrial fibrillation (AF): A dose-response meta-analysis

BACKGROUND

Refractory hypoxemia episodes are characteristic of obstructive sleep apnea (OSA). Patients with OSA suffer from oxidative stress in all systems. Atrial fibrillation (AF) is a type of arrhythmia that may be induced by OSA. In this study, we explored the dose-response relationship between OSA and AF. Our research provides the basis for a novel approach to AF prevention.

METHODS

We screened four databases (PubMed, Embase, the Cochrane Library, and Web of Science) for observational studies on OSA and AF. Studies were collected from database establishment to November 2020. We performed a traditional subgroup meta-analysis. Linear and spline dose-response models were applied to assess the association between the apnea-hypopnea index, an indicator of OSA severity, and the risk of AF. Review Manager version 5.3 software and Stata 16.0 were used for the analysis.

RESULTS

Sixteen observational studies were included in the study. We excluded a study from the conventional meta-analysis. In the subgroup analysis, the odds ratios for new onset AF for no obvious reason, new onset AF after surgical operations, such as coronary artery bypass grafting, and AF after ablation treatment were 1.71 (95% CI 1.37-2.13, P < .05), 2.65 (95% CI 2.32-3.01, P < .05), and 2.93 (95% CI 2.47-3.49, P < .05), respectively. Linear dose-response meta-analysis results revealed that the risk of AF increased with increasing apnea-hypopnea index value.

CONCLUSION

Through dose-response meta-analysis, we found a potential dose-response relationship between OSA severity and the risk of AF. This relationship should be considered in interventions aimed at AF prevention in the future.

Autonomic nervous function and low-grade inflammation in children with sleep-disordered breathing

BACKGROUND

The objective of the study was to assess the relationship between autonomic nervous function and low-grade inflammation in children with sleep-disordered breathing.

METHODS

We enrolled habitually snoring children aged 3-14 years for overnight polysomnography (PSG) and high-sensitivity C-reactive protein (hsCRP) measurement. Low-grade inflammation was defined as hsCRP >1.0 mg/L to <10.0 mg/L. An electrocardiogram recording was extracted from PSG. Heart rate variability was analyzed using time and frequency domain methods.

RESULTS

In total, 190 children were included, with 61 having primary snoring (PS), 39 mild obstructive sleep apnea (OSA), and 90 moderate-to-severe OSA. The average RR interval displayed a significant decline, whereas the low frequency/high frequency (LF/HF) ratio showed an increasing tendency in children with PS, mild OSA, and moderate-to-severe OSA. Mean RR was mainly influenced by age and the apnea hypopnea index (AHI) (all P < 0.01). AHI was an independent risk factor for the altered LF/HF ratio at all sleep stages except N3 stage (all P < 0.05). In the wake stage, low-grade inflammation was an independent risk factor of altered LF/HF ratio (P = 0.014).

CONCLUSIONS

Autonomic nervous function was impaired in children with OSA. The sympathetic-vagal balance was influenced by low-grade inflammation in the wake stage, whereas it was only affected by AHI when falling asleep.

IMPACT

We found that autonomic nervous function was impaired in children with OSA. We found that there was a negative correlation between systemic inflammation and autonomic nervous function in children with SDB only at wake stage. A negative association between systemic inflammation and autonomic nervous function was demonstrated in children in this study. Furthermore, altered LF/HF ratio maybe a good indicator of autonomic nervous dysfunction in children as it only correlated with the SDB severity, not with age.

A portrait of obstructive sleep apnea risk factors in 27,210 middle-aged and older adults in the Canadian Longitudinal Study on Aging

Determining the prevalence and characteristics of individuals susceptible to present with obstructive sleep apnea (OSA) is essential for developing targeted and efficient prevention and screening strategies. We included 27,210 participants aged ≥45 years old (50.3% women) from the Canadian Longitudinal Study on Aging. Using the STOP questionnaire combined to the percentage of body fat (%BF), we estimated the prevalence of individuals at high-risk for OSA in a sex and age-specific manner, and tested the relation with comorbidities, menopause and systemic inflammation. The prevalence was 17.5%, and was lower in women (13.1%) than in men (21.9%). A high level of high-sensitivity C-reactive protein was the strongest factor associated with OSA risk and this association was 1.3-2.3 times higher in women than in men. OSA risk increased with age, cardiovascular diseases, diabetes mellitus, anxio-depressive symptoms, asthma and arthritis. In women, post-menopausal status was associated with a high OSA risk. Nearly 1 adult out of 5 older than 45 is at risk for OSA in Canada. Comorbidities, menopause and systemic inflammation, more than age, explain increased OSA prevalence. Considering this high prevalence and associations with medical and mental comorbidities, health care practitioners should incorporate systematic OSA screening in their clinical procedures.

Systemic inflammatory biomarkers in DSM-5 defined disorders and COVID-19: Evidence from published meta-analyses

On March 11, 2020, the World Health Organization declared the outbreak of the novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) as a global pandemic. At the center of SARS-CoV-2 is the activation of inflammatory markers; remarkably, interleukin 6 and C-reactive protein seem to be consistently elevated in patients with SARS-CoV-2. Here, we showed that increased systemic C-reactive protein and interleukin 6 are common biomarkers of both severe COVID-19 and DSM-5-defined disorders. However, it is not known whether patients with psychiatric disorders with preexisting increased interleukin 6 and C-reactive protein are more vulnerable to severe complications of COVID-19 because of the additive inflammatory processes.

Oxygen saturation as a predictor of inflammation in obstructive sleep apnea

PURPOSE

Obstructive sleep apnea (OSA) is a chronic sleep disorder, and its prevalence is increasing worldwide. This disorder has been consistently associated with several comorbidities. Although it is clear that obstructive sleep apnea severity is associated with inflammation, the trigger for this phenomenon continues to puzzle scientists. Here, we investigated the relationship between obstructive sleep apnea severity and immune parameters.

METHODS

In this cross-sectional epidemiological research, we analyzed the immune profile of 461 adults according to OSA severity (mild, moderate, and severe) and oxygen saturation.

RESULTS

The hallmark of OSA severity - the apnea-hypopnea index (AHI) - weakly correlated with an inflammatory profile. However, individuals who experienced lower oxygen saturation were more likely to exhibit higher total leukocyte and neutrophil counts, a higher neutrophil-lymphocyte ratio (NLR), and an increased concentration of C-reactive protein.

CONCLUSION

Our findings indicated that oxygen saturation is a predictor of inflammation during OSA and should be considered crucial in disease diagnostic and treatment strategies.

The effects of high-sensitivity C-reactive protein on the clinical outcomes in obstructive sleep apnea patients undergoing off-pump coronary artery bypass grafting

PURPOSE

To investigate the relationship between obstructive sleep apnea (OSA) severity and high-sensitivity C-reactive protein (Hs-CRP), and their respective impact on the clinical outcomes in patients undergoing off-pump cardiac artery bypass grafting (OPCABG).

METHODS

We enrolled consecutive eligible patients listed for elective OPCABG who underwent cardiorespiratory polygraphy before surgery between January 2019 and December 2019 in this prospective observational single-center study. Baseline, intraoperative, and postoperative clinical data were compared between absent-mild and moderate-severe OSA groups. Regression analysis investigated the relationship between Hs-CRP level and severity of OSA, and further assessed the factors influencing postoperative atrial fibrillation, duration of hospitalization, and hospital cost.

RESULTS

Patients with moderate-severe OSA accounted for 42.3% (52/123) of the cohort. Partial pressure of carbon dioxide (PCO2), Hs-CRP, apnea hypopnea index (AHI), mean apnea time, maximum apnea time, and oxygen desaturation index ODI ≥ 3% were significantly higher in the moderate-severe OSA group than in the absent-mild OSA group. Left ventricle ejection fraction (LVEF), lowest arterial oxygen saturation (SaO2), and mean SaO2 were significantly lower in the moderate-severe OSA group. Moderate-severe OSA was associated with elevated Hs-CRP level (OR = 2.356, 95% CI 1.101-5.041, P = 0.027). Hs-CRP was an independent risk factor for post-CABG atrial fibrillation (POAF) (OR = 1.212, P = 0.01). Hs-CRP level independently correlated with duration of hospitalization (B = 0.456, P = 0.001) and hospital cost (B = 1.111, P = 0.044).

CONCLUSION

Hs-CRP level was closely related to OSA severity and have potential utility in predicting POAF, duration of hospitalization, and hospital costs in patients undergoing OPCABG.

C-reactive protein in children with obstructive sleep apnea and effects of adenotonsillectomy

OBJECTIVE

C-reactive protein (CRP) is an important serum marker of inflammation associated with cardiovascular outcomes. This study aims to evaluate the association between CRP and childhood obstructive sleep apnea (OSA) and clarify the effects of adenotonsillectomy on serum CRP levels in children with OSA.

METHODS

Children with symptoms suggestive of OSA who underwent an overnight polysomnography were recruited from a tertiary medical center. Their serum CRP levels were measured. For children who underwent adenotonsillectomy for OSA treatment, polysomnography and serum high-sensitivity CRP (hs-CRP) level measurement were conducted after surgery.

RESULTS

This study included 326 children (mean age: 7.2 ± 3.0 years; boys: 67%). Children with apnea-hypopnea index (AHI) > 5 events/h had significantly higher hs-CRP levels than children with AHI of 1-5 events/h and AHI < 1 event/h [median (interquartile range): 0.08 (0.03-0.25) vs 0.03 (0.02-0.14) vs 0.04 (0.01-0.10), P < 0.001]. Log-transformed hs-CRP levels were positively associated with log AHI values (r = 0.2, P < 0.001). In multiple linear regression analysis, hs-CRP levels were independently associated with AHI; 101 children with OSA (ie, AHI > 1) underwent adenotonsillectomy. In children with OSA in the study cohort, a significant reduction of hs-CRP levels did not occur after surgery [from 0.07 (0.02-0.22) to 0.08 (0.03-0.17), P = 0.716]. In children with OSA having abnormal hs-CRP levels (ie, CRP > 1 mg/dL), hs-CRP levels significantly decreased after surgery [from 1.87 (1.11-2.78) to 0.20 (0.07-1.04), P = 0.043].

CONCLUSION

Children with OSA had increased hs-CRP levels. Children with OSA and abnormal hs-CRP levels exhibited significantly reduced hs-CRP levels following adenotonsillectomy.

A review of the "OMICS" for management of patients with obstructive sleep apnoea

Obstructive sleep apnaea (OSA) syndrome is a condition characterised by the presence of complete or partial collapse of the upper airways during sleep, resulting in fragmentation of sleep associated with rapid episodes of intermittent hypoxia (IH), activation of the sympathetic nervous system and oxidative stress. OSA is associated with a broad spectrum of cardiovascular, metabolic and neurocognitive comorbidities that appear to be particularly evident in obese patients, while affecting both sexes in a different manner and varying in severity according to gender and age. In recent years, studies on OSA have increased considerably, but in clinical practice, it is still a highly underdiagnosed disease. To date, the gold standard for the diagnosis of OSA is nocturnal polysomnography (PSG). However, since it is not well suited for a large number of patients, the Home Sleep Test (HST) is also an accepted diagnostic method. Currently, the major aim of research is to identify non-invasive methods to achieve a highly predictive, non-invasive screening system for these subjects. The most recent reports indicate that research in this field has made significant progress in identifying possible biomarkers in OSA, using -OMIC approaches, particularly in the fields of proteomics and metabolomics. In this review, we analyse these OMIC biomarkers found in the literature.

[The role of biomarkers in the detection of the OSA syndrome. A narrative review of the literature]

INTRODUCTION

Obstructive sleep apnoea (OSA) is a common sleep-related breath disorder associated with cardiovascular and cerebrovascular complications, such as hypertension, arrhythmia, coronary artery disease and stroke. Unfortunately, OSA is underdiagnosed.

BACKGROUND

Because of its clinical and therapeutic variability, OSA could benefit a personalized medicine approach. Diagnosis with polysomnography is expensive and access is limited. Clinical scoring systems allow screening of OSA, but many limitations exist. Because of this, biomarkers could be useful for the detection of OSA.

OUTLOOK

Biomarkers specific to OSA would allow for better mass screening and more personalized treatment of the disease. This narrative review of the literature aims to summarize the biomarkers already described for the diagnosis of OSA and clarify both their advantages and limitations in daily practice.

CONCLUSIONS

Our review of the literature did not actually identify an ideal biomarker even if promising research is ongoing.

Evaluation of Blood Levels of C-Reactive Protein Marker in Obstructive Sleep Apnea: A Systematic Review, Meta-Analysis and Meta-Regression

(1) Introduction: High sensitivity C-reactive protein (hs-CRP) and CRP are inflammatory biomarkers associated with several inflammatory diseases. In both pediatric and adult individuals with Obstructive Sleep Apnea (OSA) higher hs-CRP and CRP were observed, compared to controls. With the present systematic review, meta-analysis and meta-regression we expand upon previous meta-analyses in four ways: (1) We included 109 studies (96 in adults and 13 in children); (2) we reported subgroup and meta-regression analyses in adults with OSA compared to controls on the serum and plasma levels of hs-CRP; (3) we reported subgroup and meta-regression analyses in adults with OSA compared to controls on the serum and plasma levels of CRP; (4) we reported serum and plasma levels of both hs-CRP and CRP in children with OSA, always compared to controls. (2) Materials and Methods: The PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases were searched to retrieve articles published until 31 May 2020, with no restrictions. The data included basic information involving the first author, publication year, country of study, ethnicity of participants in each study, age, BMI, and AHI of both groups, and mean and standard deviation (SD) of plasma and serum levels of CRP and hs-CRP. (3) Results: A total of 1046 records were retrieved from the databases, and 109 studies were selected for the analysis (96 studies reporting the blood levels of hs-CRP/CRP in adults and 13 studies in children). For adults, 11 studies reported plasma hs-CRP, 44 serum hs-CRP, 9 plasma CRP, and 32 serum CRP levels. For children, 6 studies reported plasma hs-CRP, 4 serum hs-CRP, 1 plasma CRP, and 2 serum CRP levels. Compared to controls, the pooled MD of plasma hs-CRP levels in adults with OSA was 0.11 mg/dL (p < 0.00001). Compared to controls, the pooled MD of serum hs-CRP levels in adults with OSA was 0.09 mg/dL (p < 0.00001). Compared to controls, the pooled MD of plasma CRP levels in adults with OSA was 0.06 mg/dL (p = 0.72). Compared to controls, the pooled MD of serum CRP levels in adults with OSA was 0.36 mg/dL (p < 0.00001). Compared to controls, the pooled MD of plasma hs-CRP, serum hs-CRP, plasma hs-CRP, and serum hs-CRP in children with OSA was 1.17 mg/dL (p = 0.005), 0.18 mg/dL (p = 0.05), 0.08 mg/dL (p = 0.10), and 0.04 mg/dL (p = 0.33), respectively. The meta-regression showed that with a greater apnea-hypapnea index (AHI), serum hs-CRP levels were significantly higher. (4) Conclusions: The results of the present systematic review, meta-analysis and meta-regression showed that compared to healthy controls plasma and serum levels of hs-CRP and serum CRP level were higher in adults with OSA; for children, and compared to controls, just plasma hs-CRP levels in children with OSA were higher.

Effect of Sleep Surgery on C-Reactive Protein Levels in Adults With Obstructive Sleep Apnea: A Meta-Analysis

OBJECTIVES/HYPOTHESIS

To evaluate associations between sleep surgery and CRP (C-reactive protein) levels in adults with obstructive sleep apnea (OSA).

STUDY DESIGN

Meta-analysis.

METHODS

Two authors independently searched PubMed, Medline, EMBASE, and Cochrane review databases until July 2019. The keywords used were sleep apnea, OSA, sleep apnea syndromes, surgery, C-reactive protein (CRP), and inflammatory markers. The effects of sleep surgery on CRP levels were examined using a random-effects model.

RESULTS

Nine studies with 277 patients were analyzed (mean age: 46.5 years; 92% men; mean sample size: 30.8 patients). The mean change in the apnea-hypopnea index (AHI) after surgery was significantly reduced by -21.1 (95% confidence interval [CI], -28.4 to -13.7) events/hr. Overall, sleep surgery resulted in a significant reduction of CRP levels in patients with OSA (standardized mean difference [SMD] = -0.39, 95% CI, -0.67 to -0.11). Patients with postoperative AHI reduction >20 events/hr achieved a greater reduction in CRP than those with AHI reduction <20 events/hr (SMD: -0.72 vs. -0.14, P for heterogeneity = .007). According to subgroup analysis, differences in the CRP levels after surgery were nonsignificant in the different countries (i.e., United States vs. other countries), CRP types (i.e., CRP vs. high-sensitivity CRP), surgical procedures (i.e., pharyngeal surgery vs. other surgical procedures), and follow-up period (i.e., <6 vs. >6 months).

CONCLUSIONS

Sleep surgery for OSA resulted in a significant reduction of CRP levels in adults. The beneficial effect of surgery on CRP levels is greater in patients with large improvement in OSA (i.e., AHI reduction >20 events/hr) after sleep surgery. Laryngoscope, 131:1180-1187, 2021.

Sleep disturbance in adults with chronic pruritic dermatoses is associated with increased C-reactive protein levels

BACKGROUND

Pruritus is a common symptom that can significantly reduce quality of life through sleep disruption.

OBJECTIVE

To examine features of disturbed sleep in patients with chronic pruritic dermatoses and test the hypothesis that systemic inflammation may serve as a biomarker for impaired sleep in these patients.

METHODS

Cross-sectional analysis of the National Health and Nutrition Examination Survey investigating systemic inflammation using C-reactive protein (CRP) levels. Logistic regression was used to compare patients with and without sleep disturbances, adjusting for demographics (model 1) and medical comorbidities (model 2).

RESULTS

Chronic pruritic dermatoses were associated with multiple sleep disturbances, including nighttime awakenings (model 1: odds ratio [OR], 1.646; 95% confidence interval [CI], 1.031-2.627; model 2: OR, 1.329; 95% CI, 0.888-1.989) and early morning awakening (model 1: OR, 1.669, 95% CI, 1.118-2.493; model 2: OR, 1.582; 95% CI, 1.008-2.481). Mean CRP levels were 52.8% higher among patients with pruritic dermatoses reporting trouble sleeping compared with those who did not (0.663 vs 0.434 mg/dL; P = .034). Trouble sleeping was also positively correlated with CRP levels (β = 0.142, P = .025).

LIMITATIONS

Potential recall bias among participants.

CONCLUSIONS

In addition to confirming sleep disturbances with pruritic dermatoses, we found these disturbances are more likely to present with elevated CRP levels. Clinicians should consider the potential risk for sleep-related and cardiac comorbidities in patients diagnosed with itchy skin conditions.