TABLE 3.

Subgroup analyses of populations in the included studies investigating the effects of l-arginine supplementation on blood pressure in adults¹

				Heterogeneity
	Number of studies	WMD (95% CI)	P	I 2	Tau-squared	P between subgroups
Subgroup analyses of l-arginine supplementation on SBP
Overall effect	30	−6.40 (−8.74, −4.05)	<0.001	90.4%	34.77
Baseline SBP						0.831
<130 mmHg	14	−5.39 (−8.26, −2.53)	<0.001	88.2%	22.79
≥130 mmHg	16	−7.38 (−11.45, −3.30)	<0.001	92.2%	60.11
Trial duration						0.150
≤24 d	9	−8.96 (−14.57, −3.34)	0.002	95.4%	65.91
>24 d	21	−5.26 (−7.66, −2.87)	<0.001	84.1%	23.21
Intervention dose						<0.001
≤9 g/d	17	−9.36 (−12.24, −6.49)	<0.001	93.0%	32.00
>9 g/d	13	−1.66 (−4.36, 1.03)	0.226	50.8%	11.71
Sex						<0.001
Male	8	−7.52 (−14.79, −0.26)	0.042	93.7%	97.47
Female	9	−4.62 (−7.19, −2.05)	<0.001	79.9%	10.93
Both	13	−6.82 (−10.69, −2.95)	0.001	89.8%	41.81
Health status						0.101
Healthy	9	−4.64 (−8.15, −1.13)	0.010	80.2%	19.09
Unhealthy	21	−7.22 (−10.29, −4.16)	<0.001	92.3%	43.84
Baseline BMI (kg/m2)						0.142
Normal (18.5–24.9)	4	−6.86 (−11.36, −2.36)	0.003	80.3%	15.54
Overweight (25–29.9)	11	−5.91 (−9.47, −2.35)	<0.001	86.2%	28.17
Obese (≥30)	6	−7.93 (−15.87, 0.001)	0.050	91.9%	88.35
Subgroup analyses of l-arginine supplementation on DBP
Overall effect	28	−2.66 (−3.93, −1.39)	<0.001	84.0%	7.14
Baseline DBP						0.785
<80 mmHg	18	−2.17 (−4.35, −0.004)	0.050	87.6%	16.26
≥80 mmHg	10	−3.44 (−5.15, −1.73)	<0.001	71.4%	4.24
Trial duration						<0.001
≤24 d	7	−4.82 (−7.21, −2.43)	<0.001	89.9%	5.97
>24 d	21	−1.99 (−3.27, −0.71)	0.002	60.9%	4.65
Intervention dose						<0.001
≤9 g/d	16	−4.26 (−5.61, −2.91)	<0.001	83.6%	4.28
>9 g/d	14	−0.15 (−1.99, 1.68)	0.869	45.5%	4.94
Sex						<0.001
Male	7	−0.51 (−1.91, 0.88)	0.471	0.0%	0.00
Female	9	−3.60 (−4.86, −2.35)	<0.001	59.6%	1.68
Both	12	−2.95 (−6.01, 0.10)	0.058	89.0%	23.53
Health status						<0.001
Healthy	9	−2.09 (−3.53, −0.65)	0.004	24.0%	1.04
Unhealthy	19	−2.86 (−4.40, −1.31)	<0.001	86.6%	7.64
Baseline BMI (kg/m2)						<0.001
Normal (18.5–24.9)	4	−2.86 (−5.60, −0.12)	0.041	49.7%	3.64
Overweight (25–29.9)	11	−3.17 (−4.14, −2.20)	<0.001	6.3%	0.17
Obese (≥30)	6	−3.32 (−6.87, 0.22)	0.067	68.7%	12.88

¹ P < 0.05 was considered significant. DBP, diastolic blood pressure; SBP, systolic blood pressure; WMD, weighted mean difference.