Baseline inflammatory markers, CPAP adherence, impacts on cardiovascular events, and mortality in obstructive sleep apnea: retrospective naturalistic study

BACKGROUND: Obstructive sleep apnea (OSA) is a known risk factor for cardiovascular (CV) morbidity and mortality. Chronic low-grade inflammation has been identified as a pathophysiological link. Continuous positive airway pressure (CPAP) therapy successfully treats OSA and has positive effects beyond improving breathing patterns during sleep. However, its potential impact on CV morbidity and mortality remains unclear. OBJECTIVES: To determine the association between CV risk, the risk of incident malignancies, and the probability of patient death based on inflammatory parameters, anthropometry and OSA severity parameters, as well as the effectiveness of CPAP therapy. METHODS: We retrospectively analyzed data from 245 patients diagnosed with moderate-to-severe OSA, identified as having an apnea-hypopnea index ≥ 15/h. Adherence was defined as CPAP use ≥ 4 h/night for ≥ 70% of days. We assessed CV history, mortality, polysomnographic data and inflammatory parameters (C-reactive protein, leukocyte count, neutrophil-to-lymphocyte ratio [NLR], monocyte-to-lymphocyte ratio, and platelet-to-white blood cell ratio). Univariate and multivariate logistic regressions were used to identify independent predictors of CV outcomes, malignancy incidence and death within 10 years. RESULTS: Patients poorly adhering to CPAP therapy (39.2%) had significantly higher rates of CV complications (32.8% vs. 15.1%, P = 0.003), malignancies (19.7% vs. 8.3%, P = 0.018), and mortality (14.6% vs. 4.0%, P = 0.003). Non-adherence was a strong independent predictor of CV complications (odds ratio [OR] = 2.75, P = 0.004) and death (OR = 4.07, P = 0.006). In univariate analysis, age, non-adherence, and NLR were significantly associated with the risk of incident malignancy (P = 0.022-0.008); NLR was also significant in multivariate analysis (P = 0.008). The t90 index (time spent below 90% oxygen saturation) was an independent predictor of mortality (OR = 1.03, P = 0.003). CONCLUSIONS: Non-adherence to CPAP therapy is associated with an increased risk of CV complications, malignancies and death in OSA patients. Inflammatory markers and desaturation parameters (particularly t90) are valuable predictors that should be monitored in routine practice to identify high-risk patients. Implementing strategies to improve CPAP adherence may reduce long-term systemic inflammation and clinical risks.