Table 4. The outcomes of meta-regression analysis: multivariate analysis.

Clinical indexes	Multivariate analysis (P value)
	Severe cases	Gender	Age	Interaction
Symptoms
Fever	0.606	0.943	0.725	0.699
Cough	1.169	0.280	0.051	0.137
Headache	0.702	0.528	0.305	0.545
Dyspnea	0.483	0.754	0.703	0.669
Diarrhea	0.964	0.874	0.868	0.907
Sputum production	0.942	0.963	0.844	0.954
Anorexia	0.328	0.349	0.318	0.329
Pharyngalgia	0.860	0.814	0.884	0.847
Muscle ache	0.407	0.480	0.356	0.404
Complications
AKI*	0.148	0.698	0.953	–
Acute cardiac injury*	0.485	0.901	0.486	–
Comorbidities
Any	0.533	0.519	0.241	0.495
Hypertension	0.186	0.074	0.131	0.178
Laboratory indicators
White blood cell (×109/L)
>10	0.345	0.588	0.898	0.512
<4	0.492	0.766	0.109	0.521
4–10	0.518	0.755	0.688	0.563
Decreased lymphocyte count	0.907	0.778	0.248	0.566
Increased D-dimer	0.972	0.529	0.550	–
Increased creatinine	0.659	0.832	0.703	0.754
Increased lactate dehydrogenase	0.313	0.367	0.374	0.271
Increased C-reactive protein level	0.787	0.748	0.727	0.613
Treatment
Use of corticosteroid	0.847	0.984	0.766	0.898
Antibiotic therapy*	0.431	0.089	0.680	–
Antifungal drugs*	0.331	0.418	0.332	–
Intravenous immune globulin*	0.097	0.096	0.526	–
Invasive mechanical ventilation	0.537	0.501	0.794	0.620
Non-invasive mechanical ventilation	0.752	0.450	0.222	0.481
Prognosis
Discharge	0.948	0.989	0.916	0.985
Hospitalization	0.503	0.705	0.558	0.556

*, due to the limited number of included studies, the multivariate analysis can’t be performed in these indexes, so we just performed the univariate analysis. P values in these indexes represents the outcomes of univariate analysis.