Risk factors and laboratory test results associated with severe illness and mortality in COVID-19 patients: A systematic review

Siti Setiati, Kuntjoro Harimurti, Eka Dian Safitri, Respati W Ranakusuma, Siti Rizny F Saldi, Muhammad K Azwar, Jessica Marsigit, Yupitri Pitoyo, Widyaningsih Widyaningsih



We aimed to systematically review all relevant studies related to the risk factors and laboratory test results associated with severe illness and mortality in COVID-19 patients.


We utilised PubMed, Scopus, ProQuest, Wiley Online Library, ScienceDirect and MedRxiv to search for studies, with additional hand-searched journals. We included systematic reviews/meta-analyses, cohort and case control studies of suspected and/or confirmed COVID-19 cases with severe illness and/or mortality as outcomes. We included laboratory test results and risk factors. We assessed risk of bias using ROBIS-I and Newcastle-Ottawa Scale assessment tool. Type of study, risk of bias, and precision of results determined evidence sufficiency.


Of 26 records included, sufficient evidence suggested the association between age >60 years, hypertension, coronary heart disease, DM, serum LDH 250-500 U/L, LDH >500 U/L, and lymphopenia (lymphocyte count ≤1.0 x 109 /L) and severe illness of COVID-19. CD3+CD8+ cell count ≤ 75 cell/μl, D-dimer > 1 mg/L, AKI stage 2 and 3, proteinuria ≥1+, hematuria ≥1+, and peak serum creatinine > 13.26 μmol/L are associated with mortality.


Age >60 years, hypertension, DM, and coronary heart disease are the risk factors for severe illness of COVID-19. Laboratory test results associated with severe illness are serum LDH 250-500 U/L, LDH >500 U/L, and lymphopenia, whereas test results associated with mortality are CD3+CD8+ cell count ≤ 75 cell/μl, AKI stage 2 and 3, proteinuria ≥1+, hematuria ≥1+, D-dimer > 1 mg/L, peak serum creatinine > 13.26 μmol/L.


COVID-19; severe illness; mortality; risk factor; laboratory test


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