Phenotypes of sickle cell intensive care admissions: an unsupervised machine learning approach in a single-center...

Sickle cell disease (SCD) is associated with multiple known complications and increased mortality. This study aims to further understand the profile of intensive care unit (ICU) admissions of SCD patients. In this single-center retrospective cohort (approval number 0926-11), we evaluated SCD-related ICU admissions at our hospital in São Paulo, Brazil. Admissions were clustered using clinical data and organ dysfunction at ICU admission. A hierarchical clustering method was used to distinguish phenotypes. From 140 admissions obtained, 125 were included. The mean age was 30 years, 48% were male, and SS genotype was predominant (71.2%). Non-surgical causes of admissions accounted for 85.6% (n = 107). The mean Sequential Organ Failure Assessment score (SOFA) was 4 (IQR 2-7). Vasopressors were required by 12% and mechanical ventilation by 17.6%. After analysis of the average silhouette width, the optimal number of clusters was 3: cluster 1 (n = 69), cluster 2 (n = 25), cluster 3 (n = 31). Cluster 1 had a mean age of 29 years, 87% of SS genotype, and mean SOFA of 4. Cluster 2 had a mean age of 37 years, 80% of SS genotype, and mean SOFA of 8. Cluster 3 had a mean age of 26 years, 29% of SS genotype, and mean SOFA of 3. The need for mechanical ventilation was 11.6%, 44%, and 9.7%, respectively. Mortality was significantly higher in cluster 2 (44%, p = 0.012). This cohort of critical SCD admissions suggested the presence of three different profiles. This can be informative in the ICU setting to identify SCD patients at higher risk of worse outcomes.