Synergistic effects of short sleep duration and metabolic syndrome on major adverse cardiovascular events in older adults with obstructive sleep Apnea: A prospective cohort study.

BACKGROUND

This study aimed to investigate the synergistic effect of short sleep duration (SSD) and metabolic syndrome (MetS) on the incidence of major adverse cardiovascular events (MACE) among patients with obstructive sleep apnea (OSA).

METHODS

A prospective cohort of 1115 OSA patients was categorised into four groups: Reference (neither MetS nor SSD; n = 412), MetS only (n = 592), SSD only (n = 39), and MetS-SSD (both conditions; n = 72) groups. SSD was defined as a total sleep time (TST) < 6 h/night. The primary outcome was MACE incidence. Cox proportional hazards models were used to assess risks after adjusting for confounders, including age, gender, body mass index, apnea duration, carotid atherosclerosis, chronic kidney disease, and drinking history.

RESULTS

During a median 42-month follow-up, MACE incidence demonstrated a significant ascending gradient across the four groups (p = 0.011): Reference (7.5%), MetS only (10.6%), SSD only (15.4%), and MetS-SSD (19.4%). Fully adjusted models revealed that patients with MetS-SSD had a significantly elevated MACE risk (hazard ratio [HR] = 3.014, 95% confidence interval [CI]: 1.491-6.094, p = 0.002), while neither condition alone showed a significant association. MetS and SSD demonstrated a significant interaction effect. Subgroup analysis confirmed a particularly high risk in patients aged 60-75 years (HR = 3.896, p = 0.001) and those with mild-to-moderate OSA (HR = 4.533, p = 0.002).

CONCLUSION

MetS and SSD coexistence synergistically increases the MACE risk in elderly OSA patients, independent of traditional OSA severity metrics. Thus, a combined assessment of metabolic health and sleep patterns is essential in cardiovascular risk stratification for OSA patients.