Table 2.

Subgroups Analyses and Meta-Regression.

Subgroups Analysis	Studies No	Prevalence	CI 95%	I 2	p	Meta-Regression	B	z	p
Fever
Continent
Asia	170	71.7	59.1–81.6	98.3	<0.001	Male	0.001	1.77	0.54
North America	17	51.5	40.2–62.7	98.8	<0.001	Mean age	0.042	0.61	0.07
Europe	26	68.2	58.1–76.9	99.8	<0.001
						Hypertension	0.002	0.46	0.64
NOS						Diabetes	0.000	0.03	0.97
Moderate	175	76.7	74.5–78.8	95.6	<0.001	Cardiovascular	−0.011	−1.14	0.25
Low	39	72.5	66.1–78	99.7	<0.001	Respiratory	0.004	0.79	0.43
						Renal	−0.008	−1.57	0.11
Month						Liver	−0.001	−0.36	0.72
January	7	81.6	71.6–88.6	95.4	<0.001	Malignancy	−0.004	−0.75	0.45
February	112	82.5	79.5–85	97.5	<0.001	Cerebrovascular	0.003	0.48	0.63
March	49	71.8	67.4–75.9	98	<0.001
April	28	64.9	55.9–73	99	<0.001
May	15	51.1	41.6–60.6	97.9	<0.001
Cough
Subgroups analysis						Meta-regression
Continent
Asia	171	54.7	54.3–55	95	<0.001	Male	−0.001	−0.77	0.44
North America	26	57.7	57.2–58.2	98	<0.001	Mean age	0.000	−0.01	1.00
Europe	17	49	47.9–50.1	99	<0.001
						Hypertension	0.002	0.79	0.43
NOS						Diabetes	−0.004	−1.14	0.25
Moderate	39	55.8	52.2–59.4	95	<0.001	Cardiovascular	−0.007	−1.12	0.26
Low	176	61.6	59.2–63.9	99	<0.001	Respiratory	0.006	1.91	0.06
Month						Renal	−0.001	−0.35	0.73
January	7	63.7	56.7–70.1	89.5	<0.001	Liver	0.000	0.32	0.75
February	112	61.2	58.4–63.8	95	<0.001	Malignancy	0.001	0.34	0.73
March	50	57.8	54.4–61.2	96.8	<0.001	Cerebrovascular	0.001	0.21	0.83
April	28	63.6	57.9–69	98	<0.001
May	15	55	42.4–66.9	98.8	<0.001
Fatigue
Subgroups analysis						Meta-regression
Continent
Asia	142	31.7	29.1–34.4	96.7	<0.001	Male	−0.002	−1.16	0.25
North America	11	36.7	29–45.1	96	<0.001	Mean age	0.040	1.73	0.08
Europe	21	45.7	39–52.6	98.7	<0.001
						Hypertension	0.003	0.84	0.40
NOS						Diabetes	−0.007	−1.68	0.09
Moderate	145	34.5	31.4–37.7	99	<0.001	Cardiovascular	−0.001	−0.18	0.86
Low	30	29.4	24.7–34.5	96	<0.001	Respiratory	0.005	0.91	0.36
						Renal	−0.002	−0.57	0.57
Month						Liver	−0.002	−0.90	0.37
January	7	30.2	24.2–36.9	89.5	<0.001	Malignancy	−0.002	−0.44	0.66
February	98	34.1	31.1–37.2	95.8	<0.001	Cerebrovascular	0.001	0.24	0.81
March	39	29	23.3–35.5	98.6	<0.001
April	18	30.5	22.3–40	98.5	<0.001
May	11	47.8	34–61.9	98	<0.001
Dyspnea
Subgroups analysis						Meta-regression
Continent
Asia	154	22.5	20.3–25	97.9	<0.001	Male	−0.001	−0.80	0.42
North America	14	41.6	26.8–57.9	99	<0.001	Mean age	0.076	3.49	0.00
Europe	26	42.4	36.6–48.5	99	<0.001
						Hypertension	−0.003	−0.70	0.49
NOS						Diabetes	−0.009	−1.78	0.08
Moderate	157	26.2	23.4–29.2	96.8	<0.001	Cardiovascular	−0.001	−0.09	0.93
Low	38	25.5	21.4–30.1	99.5	<0.001	Respiratory	0.015	3.13	0.00
						Renal	0.001	0.29	0.78
Month						Liver	0.003	1.75	0.08
January	6	19.2	15.8–23.1	74.5	0.001	Malignancy	0.004	0.76	0.45
February	103	23.5	20.2–27.2	97.5	<0.001	Cerebrovascular	−0.002	−0.45	0.65
March	43	26.1	22.2–30.5	98.2	<0.001
April	26	33.2	27–40.1	98.8	<0.001
May	14	34.6	23.4–48.4	98.7	<0.001
Expectorant
Subgroups analysis						Meta-regression
Continent
Asia	90	29.8	29.3–30.4	95.4	<0.001	Male	0.000	−0.12	0.90
North America	2	—	—	—	—	Mean age	−0.004	−0.12	0.91
Europe	10	17.5	17–17.9	96.4	<0.001
						Hypertension	−0.006	−0.53	0.60
NOS						Diabetes	0.013	0.80	0.42
Moderate	78	22.4	19.8–25.6	93	<0.001	Cardiovascular	−0.006	−0.57	0.57
Low	24	21.3	17.6–25.6	99	<0.001	Respiratory	−0.046	−1.57	0.12
						Renal	0.037	1.31	0.19
Month						Liver	−0.017	−0.45	0.65
January	5	28.4	21.2–36.9	92.1	<0.001	Malignancy	−0.013	−1.19	0.24
February	58	24.5	21.9–27.3	92.9	<0.001	Cerebrovascular	0.074	1.67	0.10
March	25	20.6	16.7–25.1	98	<0.001
April	8	20.3	11.2–33.8	98.5	<0.001
May	5	10.3	4.2–23.2	98	<0.001
Anorexia
Subgroups analysis						Meta-regression
Continent
Asia	54	20	16–24.6	96.6	<0.001	Male	0.029	3.17	0.00
Europe	6	39.5	25.7–55.2	98	<0.001	Mean age	0.144	1.56	0.12
NOS						Hypertension	−0.080	−1.94	0.05
Moderate	53	16.3	10.3–25	98.6	<0.001	Diabetes	0.029	0.71	0.48
Low	10	22.6	18.3–27.7	96	<0.001	Cardiovascular	−0.018	−0.57	0.57
						Respiratory	0.032	0.52	0.61
						Renal	0.063	0.85	0.40
Month						Liver	−0.334	−2.23	0.03
February	39	20.6	16.4–25.7	96	<0.001	Malignancy	−0.026	−0.12	0.90
March	17	23.4	14.9–34.8	97.6	<0.001	Cerebrovascular	0.053	0.61	0.55
April	5	31	19.2–46.1	98	<0.001
Myalgias
Subgroups analysis						Meta-regression
Continent
Asia	101	15.4	13.8–17.3	96	<0.001	Male	−0.003	−1.00	0.32
North America	13	26.6	17–39.1	98.8	<0.001	Mean age	−0.048	−1.05	0.30
Europe	16	26.7	14.7–13.6	99.5	<0.001
						Hypertension	0.000	−0.02	0.99
NOS						Diabetes	−0.011	−1.26	0.21
Moderate	103	18.2	15.6–21.2	96.8	<0.001	Cardiovascular	0.012	1.05	0.30
Low	27	14.7	11–19.2	99	<0.001	Respiratory	0.003	0.16	0.87
						Renal	0.006	0.22	0.83
Month						Liver	0.026	1.05	0.29
February	66	14.9	12.8–17.3	94	<0.001	Malignancy	0.019	0.30	0.77
March	31	16.3	12.5–21	97.7	<0.001	Cerebrovascular	−0.011	−0.59	0.55
April	18	30.6	21.9–40.9	99	<0.001
May	10	17.3	7.5–35	99	<0.001
Chills
Subgroups analysis						Meta-regression
Continent
Asia	38	13	10.4–16.3	96.4	<0.001	Male	0.001	0.19	0.85
North America	—	—	—	—	<0.001	Mean age	−0.020	−0.23	0.82
Europe	—	—	—	—	<0.001
						Hypertension	−0.011	−1.13	0.26
NOS						Diabetes	0.005	0.55	0.58
Moderate	37	15.3	11.4–20.1	96.5	<0.001	Cardiovascular	—	—	—
Low	8	13.1	9–18.5	97.7	<0.001	Respiratory	—	—	—
						Renal	—	—	—
Month						Liver	—	—	—
February	18	13.3	10.7–16.3	83.6	<0.001	Malignancy	—	—	—
March	11	15.9	9.8–24.7	96.9	<0.001	Cerebrovascular	—	—	—
April	8	16.2	9–27.4	98.2	<0.001
May	5	24.4	12.8–41.4	95.3	<0.001
Sore throat
Subgroups analysis						Meta-regression
Continent
Asia	60	12.3	10.7–14.4	93	<0.001	Male	−0.001	−0.18	0.85
North America	9	21.6	14–31.8	96.6	<0.001	Mean age	−0.090	−1.09	0.28
Europe	10	24.1	10.2–47	99.5	<0.001
						Hypertension	−0.002	−0.08	0.94
NOS						Diabetes	0.008	0.24	0.81
Moderate	66	15.5	13.3–18.1	94.6	<0.001	Cardiovascular	0.009	0.35	0.73
Low	14	10.3	5.5–18.5	99	<0.001	Respiratory	−0.011	−0.09	0.93
						Renal	−0.012	−0.07	0.94
Month						Liver	−0.001	−0.01	0.99
February	37	11.2	9–13.8	93.9	<0.001	Malignancy	−0.005	−0.18	0.86
March	16	12.4	7–21	98.5	<0.001	Cerebrovascular	0.061	0.51	0.61
April	16	25.4	18.8–33.3	97.7	<0.001
May	5	19.3	12.3–29.1	93.2	<0.001
Headache
Subgroups analysis						Meta-regression
Continent
Asia	115	10.2	9.2–28.3	94	<0.001	Male	0.001	0.28	0.78
North America	10	23.6	14.3–36.4	98	<0.001	Mean age	−0.063	−1.83	0.07
Europe	15	27.1	14.1–45.8	99.6	<0.001
						Hypertension	−0.009	−1.15	0.25
NOS						Diabetes	−0.002	−0.24	0.81
Moderate	112	12.9	10.7–15.5	96.9	<0.001	Cardiovascular	0.012	0.96	0.34
Low	29	9.6	6.7–13.6	99	<0.001	Respiratory	0.004	0.54	0.59
						Renal	0.008	1.11	0.27
Month						Liver	−0.018	−0.57	0.57
January	6	13.3	10.1–17.4	81.3	<0.001	Malignancy	0.005	0.70	0.48
February	73	9.4	8.3–10.7	88.3	<0.001	Cerebrovascular	0.002	0.19	0.85
March	33	11	8.4–14.4	97.7	<0.001
April	18	25.6	17.8–35.4	98.7	<0.001
May	10	20.3	9.1–39.1	98	<0.001
Diarrhea
Subgroups analysis						Meta-regression
Continent
Asia	147	16.7	9.2–28.3	93	<0.001	Male	−0.002	−2.23	0.03
North America	16	18.3	12.2–26.6	98	<0.001	Mean age	−0.014	−0.6	0.55
Europe	22	16.8	13.6–20.6	98	<0.001
						Hypertension	0.003	0.64	0.52
NOS						Diabetes	0.002	0.45	0.66
Moderate	150	11.7	10.3–13.2	94	<0.001	Cardiovascular	−0.003	−0.38	0.71
Low	36	10.9	9.1–13.1	98.5	<0.001	Respiratory	0.002	0.42	0.68
						Renal	−0.002	−0.32	0.75
Month						Liver	−0.003	−0.66	0.51
January	7	5.2	3.7–7.5	67	0.006	Malignancy	−0.003	−0.05	0.96
February	94	10.7	9.3–12.2	93.2	<0.001	Cerebrovascular	0.001	0.19	0.85
March	43	11.2	9.7–12.9	92.9	<0.001
April	26	17.4	14.1–21.2	95.9	<0.001
May	13	15.3	8.7–25.4	98	<0.001
Nausea or vomiting
Subgroups analysis						Meta-regression
Continent
Asia	74	7.1	5.7–8.8	94.8	<0.001	Male	−0.003	−1.82	0.07
North America	8	20.1	14.7–26.8	93.3	<0.001	Mean age	−0.040	−1.59	0.11
Europe	12	13.3	8.1–21.2	98.6	<0.001
						Hypertension	0.000	−0.09	0.93
NOS						Diabetes	−0.010	−1.86	0.06
Moderate	75	7	4.8–10.2	98.5	<0.001	Cardiovascular	0.030	2.56	0.01
Low	20	9	7.1–11.4	95.8	<0.001	Respiratory	−0.003	−0.50	0.61
						Renal	0.014	2.57	0.01
Month						Liver	−0.001	−0.26	0.80
February	50	7.5	5.9–9.6	93.4	<0.001	Malignancy	0.001	0.15	0.88
March	21	9.4	6–14.4	97.8	<0.001	Cerebrovascular	−0.017	−2.49	0.01
April	14	13.4	9.6–18.4	96.4	<0.001
May	5	10.2	3.4–27.1	98	<0.001
Rhinorrhea
Subgroups analysis						Meta-regression
Continent
Asia	61	5.9	4.6–7.5	94.9	<0.001	Male	−0.002	−0.36	0.72
North America	7	28.4	20.5–38	94.6	<0.001	Mean age	−0.133	−1.25	0.21
Europe	8	25.1	12.1–44.8	99	<0.001
						Hypertension	−0.017	−0.77	0.44
NOS						Diabetes	−0.006	−0.40	0.69
Moderate	59	9.2	7.2–11.7	95.5	<0.001	Cardiovascular	0.034	1.75	0.08
Low	17	5.9	2.9–11.7	99	<0.001	Respiratory	−0.045	−0.86	0.39
						Renal	0.046	0.70	0.49
Month						Liver	0.033	0.64	0.53
February	41	5.5	4.2–7.1	91	<0.001	Malignancy	0.167	1.35	0.18
March	17	11.1	7.3–16.6	96	<0.001	Cerebrovascular	0.015	0.31	0.76
April	10	21.6	11.9–35.9	98.9	<0.001
Hemoptysis
Subgroups analysis						Meta-regression
Continent
Asia	3.6	3.2	1.6–3.6	98.7	<0.001	Male	−0.006	−1.58	0.11
						Mean age	−0.110	−0.84	0.40
NOS
Moderate	30	4.1	2.6–6.3	92.5	<0.001	Hypertension	0.001	0.08	0.94
Low	11	2.1	0.5–8	99.6	<0.001	Diabetes	−0.020	−0.99	0.32
						Cardiovascular	0.010	1.17	0.24
Month						Respiratory	0.020	0.69	0.49
February	21	2.8	2–4	78.4	<0.001	Renal	0.016	1.53	0.13
March	8	6.9	2.7–16.7	97.7	<0.001	Liver	−0.041	−1.74	0.08
April	6	4	0.8–17.2	99.2	<0.001	Malignancy	−0.135	−1.24	0.22
						Cerebrovascular	0.067	1.26	0.21