Abstract
OBJECTIVES: Indicators that predict the severity and outcomes of COVID-19 are essential to guide medical decision-making. This retrospective study explored whether the combined levels of serum amyloid A (SAA) and heparin-binding protein (HBP) in elderly COVID-19 patients are useful in this context. PATIENTS: This retrospective study included COVID-19 patients aged ≥ 60 years admitted to a designated hospital in Hangzhou, China between December 2022 and March 2023. The clinical, epidemiological, radiological, and laboratory parameters of the patients were analyzed. RESULTS: Compared with COVID-19 survivors, the levels of HBP, procalcitonin, SAA, C-reactive protein, D-dimer, and interleukin-6, as well as the white blood cell and neutrophil counts, were significantly elevated in non-survivors, whereas the total protein and lymphocyte count were lower. The admission SAA and HBP levels were significantly elevated in COVID-19 patients compared with reference values and increased with disease severity. Receiver operating characteristic curves were used to evaluate the diagnostic utility of SAA plus HBP levels for predicting COVID-19-associated mortality. An SAA level cut-off of 348.73 mg/L combined with HBP level cut-off of 42.75 ng/mL showed a sensitivity, specificity, and area under the curve of 96.7%, 85.7%, and 0.96, respectively. An admission SAA level ≥ 348.73 mg/L and HBP level ≥ 42.75 ng/mL increased the risk of unfavorable outcomes in elderly COVID-19 patients. CONCLUSION: Combined admission levels of SAA and HBP reliably predicted COVID-19 severity and prognosis in patients aged ≥ 60 years. Elderly patients with elevated SAA and HBP levels at admission should receive aggressive and timely treatment.