Treatment for sleep apnea by continuous positive airway pressure improves levels of inflammatory markers - a meta-analysis

Abstract

BackgroundObstructive sleep apnea (OSA) is associated with coronary artery disease (CAD). Intermittent hypoxia associated with OSA increases sympathetic activity and may cause systemic inflammation, which may contribute to CAD in patients with OSA. Treatment with continuous positive airway pressure (CPAP) has been shown to change levels of inflammatory markers. We analyzed data from published studies by a systematic meta-analysis.ObjectiveTo asses if treatment for sleep apnea by CPAP will affect levels of inflammatory markers.Data resourcesPubMed, Embase and Cochrane library.MethodsStudy eligibility criteria full text English studies of adult, human subjects, addressing values of at least one of the inflammatory markers before and after CPAP treatment. We used the definition of OSA as an apnea-hypopnea index (AHI) of ≥ 5/h, reported values in mean and standard deviation or median with range.ParticipantsAdult, human.InterventionsCPAP treatment for OSA.Study appraisal and synthesis methodA total of 3835 studies were reviewed for inclusion, while 23 studies pooled for analysis. A total of 14 studies with 771 patients were pooled for C-reactive protein (CRP); 9 studies with 209 patients were pooled for tumor necrosis factor-alpha (TNF-α); and 8 studies with 165 patients were pooled for interleukin-6 (IL-6).Endpoint definitionsThe following inflammatory markers were chosen: CRP, TNF-α, and IL-6.ResultsC-reactive protein: Study level means ranged from 0.18 to 0.85 mg/dl before CPAP treatment and 0.10 to 0.72 mg/dl after CPAP treatment. Mean differences, at a study level, ranged from −0.05 to 0.50. The pooled mean difference was 0.14 [95% confidence interval 0.08 to 0.20, p < 0.00001]. There was heterogeneity in this endpoint (df = 13, p < 0.00001, I2 = 95%).Tumor necrosis factor-α: Study level means ranged from 1.40 to 50.24 pg/ml before CPAP treatment and 1.80 to 28.63 pg/ml after CPAP treatment. Mean differences, at a study level, ranged from −1.23 to 21.61. The pooled mean difference was 1.14 [95% confidence interval 0.12 to 2.15, p = 0.03]. There was heterogeneity in this endpoint (df = 8, p < 0.00001, I2 = 89%).Interleukin-6: Study level means ranged from 1.2 to 131.66 pg/ml before CPAP treatment and 0.45 to 66.04 pg/ml after CPAP treatment. Mean differences, at a study level, ranged from −0.40 to 65.62. The pooled mean difference was 1.01 [95% confidence interval −0.00 to 2.03, p = 0.05]. There was heterogeneity in this endpoint (df = 7, p < 0.00001, I2 = 95%).LimitationsOnly published data. Studies pooled were mainly small, non-randomized trials.ConclusionSleep apnea treatment with CPAP improves levels of inflammatory markers.

The role inflammatory response genes in obstructive sleep apnea syndrome: a review

“…Unlike cytokines, CRP levels are stable in the same individual over 24 h and may reflect the degree of inflammatory response [45]. Their pro-inflammatory and proatherogenic properties were found in endothelial cells, vascular smooth muscle cells, and monocytes-macrophages, where CRP levels are also associated with oxidative stress [46].…”

The Bidirectional Relationship Between Asthma and Obstructive Sleep Apnea: Which Came First?

“…23 High levels of tumor necrosis factor-a have been seen in patients with severe asthma, and treatment of OSA was found to reduce these levels. 24 The systemic inflammatory insults in OSA and asthma also may OSA was present in 6.6% of children with asthma vs 3.8% of those without asthma (P = .16). OSA and/or snoring was present in 27% of children with asthma vs 15% of those without asthma (P = .001).…”

Obstructive sleep apnea and asthma

“…In patients with OSAS, CPAP therapy results in an improvement in the levels of CRP, TNF-α, and IL-6. ( 45 ) TNF-α is a potent proinflammatory cytokine that plays an important role in the pathogenesis of asthma; that is, it interferes with airway smooth muscle contractility. ( 45 ) …”

“…Pacientes com SAOS, ao realizarem terapia com CPAP, apresentam melhoras quanto aos níveis de PCR, TNF-α e IL-6. ( 45 ) O TNF-α é uma potente citocina pró-inflamatória que desempenha um importante papel na patogênese da asma, ou seja, interfere na capacidade contrátil do músculo liso das vias aéreas. ( 45 ) …”