Evaluation of adropin indices and PCSK9 in non-diabetic men with severe obstructive sleep apnea

We aimed to investigate the relationship among proprotein convertase subtilisin/kexin type 9 (PCSK9), adropin levels, inflammation, and sleep variables in non-diabetic males with severe obstructive sleep apnea (OSA). This cross-sectional study included adults aged 18 to 65 who underwent polysomnography due to sleep problems between July 2019 and August 2020. Participants were grouped based on their apnea-hypopnea index (AHI). We included 32 males with simple snoring (AHI<5 events/h) as the controls and 48 males with severe OSA (AHI≥30 events/h). Furthermore, patients with severe OSA were divided into two groups based on body mass index (BMI), resulting in three groups in total. Adropin and PCSK9 were analyzed using the enzyme-linked immunosorbent assay method. In severe OSA with BMI≥30 kg/m2, compared to the controls, blood pressure values, interleukin-6 (IL-6), white blood cell (WBC) count, systemic inflammation response index, neutrophil, monocyte counts were found to be higher, but adropin/BMI, adropin/waist circumference, adropin/neck circumference were significantly lower. Adropin/BMI had the highest correlation coefficient with IL-6. Although there was no significant difference in PCSK9 levels among the groups, PCSK9 was independently correlated with the WBC and its subsets. Our study is of clinical importance as it is the first to show a relationship between PCSK9 and inflammation markers in severe OSA. Also, this study demonstrated the potential value of adropin, in combination with BMI, as a valuable indicator for assessing inflammation and OSA severity.