Periodic limb movements during sleep are associated with dyslipidaemia in patients with OSA. Results from the ESADA cohort

<b>Background:</b> Sympathetic system activation may lead to dyslipidaemia. Periodic limb movements during sleep (PLMS) and obstructive sleep apnoea (OSA) are both associated with increased sympathetic tone, and they have been proposed as risk factors for ischaemic heart disease (IHD). PLMS could therefore be an additional risk factor for IHD in OSA; however, the association between PLMS and dyslipidaemia has not been thoroughly investigated in patients with OSA. <b>Methods:</b> Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride levels were investigated in 4209 patients with OSA who participated in the ESADA cohort and had polysomnography as a diagnostic test. Patients were divided into PLMS (n=641) and control (n=3568) groups based on PLMS index≥15/hour. Lipid levels were compared following adjustment for relevant covariates. Inverse probability weighting was used as a sensitivity analysis. <b>Results:</b> Patients with PLMS had a higher prevalence of IHD (11 vs. 6%) despite they had lower BMI and AHI and similar prevalence of hypertension. However, they had higher triglyceride (1.80±1.03 vs. 1.69±0.90 mmol/l, p&lt;0.05) and lower HDL-C (1.20±0.34 vs. 1.24±0.38 mmol/l, p&lt;0.05) concentrations; whilst there was no difference in either TC (4.97±1.09 vs. 4.94±1.07 mmol/l) or LDL-C (3.03±0.96 vs. 2.98±0.98 mmol/l) levels. The results were unchanged after inverse probability weighting. <b>Conclusion:</b> PLMS in OSA are associated with dyslipidaemia which could result in the higher prevalence of cardiovascular disease. Our results highlight PLMS as a potential treatable cardiovascular risk trait in OSA.