Cluster analysis and significance of clinical subtypes in patients with obstructive sleep apnea hypopnea syndrome

Objective: To study the clinical subtypes of obstructive sleep apnea hypopnea syndrome (OSAHS) by cluster analysis, and to discuss the characteristics and clinical significance of these subtypes. Methods: A retrospective analysis was done among patients who were diagnosed with OSAHS in the Sleeping Center of the Second Affiliated Hospital of Soochow University from January 2010 to June 2018. In this cluster analysis, 16 main symptoms, 7 comorbidities and 3 assessment scales were included. After selecting the best model, the parameters and characteristics of different subtypes were compared and analyzed. Results: A total of 2 592 patients with complete data were included in this study. After cluster analysis, they were divided into 4 groups: sleep apnea group (1 173 cases, 45.3%), daytime sleepiness group (518 cases, 20.0%), insomnia and memory loss group (212 cases, 8.2%), mild symptom group (689 cases, 26.6%). In the sleep apnea group, the patients were found to be younger [(40.2±10.4) years old], with higher body mass index (BMI) [(27.7±3.7) kg/m(2)] when compared to the other groups. In addition, the prevalence of comorbidities of this group was found to be lower, whereas the probability of sleep apnea symptom was the highest (94.7%). In daytime sleepiness group, the Epworth Sleepiness Scale (ESS) score was the highest [(12.4±5.5) points], and the probability of daytime sleepiness symptom was also found to be the highest (88.0%). The age of patients in the insomnia and memory loss group was the highest [(51.1±13.0) points], with the highest percentage of women (19.3%). The probability of insomnia was found to be 70.3%, and memory loss symptoms was 88.2% which were the highest when compared to the other groups. The prevalence of comorbidities was the highest, and the scores of short mental state scale (MMSE) and Montreal cognitive assessment (MoCA) were the lowest with a mean of [(28.5±2.4) points] and [(25.4±3.2) points], respectively, among the 4 groups. The probability of most symptoms and comorbidities were found be the lowest in the mild symptom group. There were significant differences in the main symptoms among the 4 groups (P<0.05). Symptoms like sleep apnea, daytime sleepiness, insomnia, memory loss, headache and dry mouth upon awakening were found significantly different in pairwise comparisons among the groups (P<0.002). Conclusion: The patients with OSAHS can be divided into four clinical subtypes by cluster analysis, each of which is significantly heterogeneous, and this is helpful to evaluate the condition and guide individualized treatment.