LATENT CLASS ANALYSIS: AN INNOVATIVE APPROACH FOR IDENTIFICATION OF CLINICAL AND LABORATORY MARKERS OF DISEASE SEVERITY AMONG COVID-19 PATIENTS ADMITTED TO THE INTENSIVE CARE UNIT

INTRO: Evidence about the phenotypic profile of COVID-19 ICU patients in sub- Saharan Africa remains insufficient. Our study aimed to identify clinical and laboratory phenotype distribution patterns and their usefulness as prognostic markers in COVID-19 patients admitted to the intensive care unit (ICU) in South Africa. METHODS: We used a latent class analysis (LCA) model in a prospective cohort study of clinical and laboratory data collected from 343 COVID-19 patients between 27 March 2020 and 10 February 2021. A sub-analysis was performed to determine sub-phenotypes associated with clinical outcomes among COVID-19 patients and their impact on survival. FINDINGS: Data from 343 COVID-19 patients were analysed. Two distinct phenotypes 1 and 2, comprising 68.46 % and 31.54% patients respectively, were identified. The phenotype 2 patients were characterized by increased coagulopathy markers (D-dimer, median value 1.73 ng/L vs 0.94 ng/L, p <0.001), end-organ dysfunction (creatinine, median 79 umol/L vs 69.5 umol/L, p <0.003), under-perfusion marker (lactate, median value 1.60 mmol/L, vs 1.20 mmol/L, p <0.001), abnormal cardiac function markers (median N‐terminal pro‐brain natriuretic peptide (NT-proBNP) 314 pg/ml vs 63.5 pg/ml, p <0.001 and median high‐sensitivity cardiac troponin (Hs-TropT) 39 ng/l vs 12 ng/ l, p<0.001) and acute inflammatory syndrome (median neutrophil-to-lymphocyte ratio 15.08 vs value 8.68, p <0.001 and monocyte, median value 0.68 × 109/L vs 0.45 × 109/L, p <0.001). Females in class 2 had lower mean haemoglobin levels than females in class 1 (11.88g/dL vs 12.67g/dL, p = 0.014). In a sub-analysis, mortality and survival were characterized in two sub-phenotypes with increased acute inflammatory syndrome, under-perfusion, end-organ dysfunction, and cardiac function markers in sub-phenotype 2. CONCLUSION: The identification of COVID-19 phenotypes and sub-phenotypes among ICU patients could be used as prognostic markers in day-to-day management of patients. Future studies are required in sub-Sahara Africa to elucidate pathophysiological mechanisms underlying these phenotypes.