Association between D-dimers and in-hospital all-cause mortality in COVID-19 patients at a tertiary hospital in South Africa: A retrospective study.

Background: The COVID‑19 pandemic was caused by the SARS‑CoV‑2 virus. Many studies have shown that D‑dimer levels were elevated in patients hospitalised for severe COVID‑19, and that they served as a marker of poor prognosis with increased mortality in this subpopulation. There is a paucity of data on the prognostic value of D‑dimer levels during the COVID‑19 pandemic in the African population. Objectives: To investigate the relationship between elevated D‑dimer levels on admission and in‑hospital mortality associated with COVID‑19. The study also examined the sociodemographics of the study population, clinical characteristics, length of hospital stay and outcomes, stratified by D‑dimer levels. Methods: A retrospective observational review of COVID‑19 patients admitted via acute medical admissions at Livingstone Tertiary Hospital, Gqeberha, South Africa, was conducted between 1 October 2020 and 30 September 2021, using the national COVID‑19 hospital surveillance (DATCOV) database. D‑dimer levels that were measured within 48 hours of admission and patient outcomes (discharge and in‑hospital all‑cause mortality) were analysed. Statistical significance was set at p<0.05. Results: Of 423 patients with COVID‑19, 267 (63.1%) had elevated D‑dimer levels (>0.5 µg/mL) and 156 (36.9%) had normal D‑dimer levels (≤0.5 µg/mL). Of the 267 with elevated D‑dimer levels, 113 (42.3%) died during their hospital stay, whereas of the 156 with normal D‑dimer levels, 38 (24.4%) died in hospital. D‑dimer levels ≥1.1 µg/mL were associated with increased in‑hospital all‑cause mortality (odds ratio (OR) 2.717; p<0.001). Patients with D‑dimer levels between 1.1 and 2 µg/mL were 2.3 times more likely to die in hospital compared with patients who had a normal D‑dimer level (OR 2.311; p=0.005), and patients with D‑dimer levels >2.0 µg/mL were three times more likely to die in hospital compared with patients with levels ≤0.5 µg/mL (OR 3.047; p<0.001). Apart from elevated D‑dimer levels, age ≥70 years (OR 4.112; p<0.001), the presence of at least one comorbidity (OR 3.638; p<0.001), and specifically hypertension as a comorbidity (OR 3.224; p<0.001), were also found to be significantly associated with increased in‑hospital COVID‑19 mortality. Conclusion: Elevated D‑dimer levels on admission were associated with increased COVID‑19 in‑hospital all‑cause mortality (OR 2.279; p<0.001). Study synopsis: