Association between hemoglobin and all-cause mortality in patients with obstructive sleep apnea and hypertension: insights from an observational study.

Obstructive sleep apnea (OSA) is a widespread disorder impacting more than one billion individuals globally. Hypertension, a frequent cardiovascular comorbidity associated with OSA, can exacerbate and advance the condition. Recent research has identified a synergistic effect between anemia and OSA concerning the development of hypertension. This study explores the relationship between hemoglobin (Hb) and follow-up and 365-day all-cause mortality in individuals suffering from OSA and hypertension. Data were obtained from the MIMIC-IV database. Kaplan-Meier (KM) analyses and Cox proportional hazards models were utilized to assess associations with outcomes. Restricted cubic spline (RCS) models were selected to assess nonlinear relationships. A total of 6155 patients with first-time hospitalization for OSA and hypertension were included in this study. The KM survival curves demonstrated that the survival rate for the lowest Hb quartile (Q1) was significantly lower than that of the other quartiles. Findings from the multivariable Cox regression analysis revealed that elevated Hb correlates with a significant decrease in mortality risk. The RCS analysis demonstrated an L-shaped nonlinear relationship between Hb and outcome events (P-Nonlinear < 0.05). The relationship between Hb and outcome events remained consistent across all subgroups, further supporting the robustness of the conclusions drawn in this study. Hemoglobin is closely associated with all-cause mortality in patients with OSA and hypertension and can serve as an effective biomarker for risk management and prognostic assessment upon admission. Monitoring Hb in patients with OSA and hypertension and actively correcting anemia when present may improve prognostic survival.