High levels of lipoprotein(a) could worsen the outcome of COVID-19 due to prothrombotic and proinflammatory properties of lipoprotein(a). We tested the hypotheses that during COVID-19 hospitalization i) increased thrombotic activity and inflammation are associated with lipoprotein(a) levels, and ii) lipoprotein(a) levels are associated with rate of hospital death and discharge. We studied 211 patients admitted to Copenhagen University Hospital in 2020 with COVID-19, that is, prior to any vaccination. Thrombotic activity was marked by elevated D-dimer while inflammation was marked by elevated interleukin-6, C-reactive protein, and procalcitonin. Patients were followed until death (N = 36) or discharge (N = 175). A 2-fold higher D-dimer was associated with 14% (95%CI: 8.1–20%) higher lipoprotein(a). Conversely, 2-fold higher interleukin-6, C-reactive protein, and procalcitonin were associated with respectively 4.3% (0.62–7.8%), 5.7% (0.15–5.2%), and 8.7% (5.2–12%) lower lipoprotein(a). For hospital death, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 1.26 (95%CI:0.91–1.73). Corresponding hazard ratios per 2-fold higher biomarker were 0.93 (0.75–1.16) for D-dimer, 1.42 (1.17–1.73) for interleukin-6, 1.44 (0.95–2.17) for C-reactive protein, and 1.44 (1.20–1.73) for procalcitonin. For hospital discharge, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 0.91 (95%CI:0.79–1.06). Corresponding hazard ratios per 2-fold higher biomarker were 0.86 (0.75–0.98) for D-dimer, 0.84 (0.76–0.92) for interleukin-6, 0.80 (0.71–0.90) for C-reactive protein, and 0.76 (0.67–0.88) for procalcitonin. In COVID-19 patients, thrombotic activity marked by elevated D-dimer was associated with higher lipoprotein(a) while elevated inflammatory biomarkers of interleukin-6, C-reactive protein, and procalcitonin were associated with lower lipoprotein(a); however, elevated lipoprotein(a) was not associated with rate of hospital death or discharge. [Display omitted] • 211 patients hospitalized for COVID-19 were followed until death or discharge. • Thrombotic activity marked by D-dimer was associated with higher lipoprotein(a). • Higher interleukin-6, CRP and procalcitonin were associated with lower lipoprotein(a). • Lipoprotein(a) was not associated with death during hospitalization. [ABSTRACT FROM AUTHOR]