Table 1.
Characteristics of the included studies.
| Study | Country | Cases | Controls | Total sample size | Evaluation of microbiota |
|---|---|---|---|---|---|
| Hypertension | |||||
| Silveira-Nunes et al. (33) | Brazil | Reported and treated hypertension (SBP >140 mmHg and DBP >90 mmHg) for more than 10 years (n = 48, mean age: 65.3 ± 15.5 y, male/female: 14:34) | Those with no report of hypertension (n = 32, mean age: 63.3 ± 15.0 y, male/female: 7:25) | 80 | 16S rRNA gene sequencing |
| Palmu et al. (32) | Finland | SBP ≥140 mm Hg, DBP ≥90 mm Hg, or use of antihypertensive medication (n = 3,291, mean age for all subjects: 49.2 ± 12.88 y, male/female for all subjects: 3,819:3,134) | Normotensive individuals from the same cohort (n = 3,662, mean age for all subjects: 49.2 ± 12.88 y, male/female for all subjects: 3,819:3,134) | 6,953 | Metagenomic sequencing |
| Calderon-Perez et al. (29) | Spain | SBP between 140 and 159 mmHg and were not using antihypertensive treatment (n = 29, mean age: 53.7 ± 9.6 y, male/female: 19:10) | SBP <120 mmHg (n = 32, mean age: 41.1 ± 9.1 y, male/female: 16:16) | 61 | 16S rRNA gene sequencing |
| Takagi et al. (34) | Japan | SBP ≥140 mm Hg, DBP ≥90 mm Hg, or current use of antihypertensive drugs (n = 97, median age: 69 (37–87) y, male/female: 49:48) | Healthy controls without gastrointestinal inflammatory diseases or functional gastrointestinal disorders, without use of antibiotics, corticosteroids, immunosuppressants, or acid-suppressing agents within the past 3 months, and without as a history of underlying malignant disease (n = 54, median age: 65.5 (16–88) y, male/female: 21:33) | 151 | 16S rRNA gene sequencing |
| Sun et al. (27) | US | Current use of antihypertensive medication, an SBP ≥140 mm Hg, or a diastolic BP ≥90 mm Hg (n = 186, mean age for all subjects: 55.3 ± 3.4 y, male/female for all subjects: 244:285) | Healthy controls (n = 343, mean age for all subjects: 55.3 ± 3.4 y, male/female for all subjects: 244:285) | 529 | 16S rRNA gene sequencing |
| Mushtaq et al. (26) | China | Grade 3 hypertension (according to the World Health Organization BP classification) (n = 50, mean age: 62.5 ± 10.4 y, male/female: 28/22) | Healthy controls with no history of hypertension, or any other cardiovascular or chronic metabolic disease (n = 30, mean age: 60.5 ± 11 y, male/female: 16/14) | 80 | 16S rRNA gene sequencing and quantitative PCR |
| Dan et al. (23) | China | SBP ≥140 mmHg or DBP ≥90 mmHg (n = 62, mean age: 69.322 ± 10.613 y, male/female: 0:62) | 90 mmHg ≤ SBP ≤ 140 mmHg and 60 mmHg ≤ DBP ≤ 90 mmHg (n = 67, mean age: 69.492 ± 9.630 y, male/female: 0:67) | 129 | 16S rRNA gene sequencing |
| Li et al. (25) | China | SBP ≥140 mmHg, DBP ≥90 mmHg, or by self-reported use of antihypertensive medications in the last 2 weeks irrespective of BP valuesNaive hypertension (n = 63, mean age: 58.4 ± 10.2 y, male/female: 35/28)Anti-hypertensive (n = 104, mean age: 59.8 ± 9.3 y, male/female: 50:54) | Healthy controls (n = 42, mean age: 59.3 ± 9.2 y, male/female: 17:25) | 209 | 16S rRNA gene sequencing |
| Zuo et al. (28) | China | SBP >140 mm Hg and DBP >90 mm Hg (n = 34, median age: 54.5 (49.3–57.8) y, male/female: 31/3) | Healthy controls (n = 15, median age: 58.0 (52.0–60.0) y, male/female: 11:4) | 49 | Metagenomic sequencing |
| Kim et al. (22) | US | SBP ≥140 mmHg (n = 22, not report characteristics of final included subjects) | SBP ≤ 130 mmHg irrespective of subject's antihypertensive drug regimen (n = 18, not report characteristics of final included subjects) | 40 | Metagenomic sequencing |
| Jin et al. (21) | China | SBP ≥140 mmHg or DBP ≥90 mmHg (n = 73, mean age: 53.7 ± 5.7 y, male/female: 66:7) | SBP <120 mmHg and DBP <80 mmHg (n = 68, mean age: 52.5 ± 5.7 y, male/female: 59:9) | 141 | Metagenomic sequencing |
| Yan et al. (19) | China | Primary hypertension: current blood pressure ≥140/90 mm Hg (n = 60, mean age: 57.0 ± 9.6 y, male/female: 35/25) | Gender-, age-, and body weight-matched healthy controls (current blood pressure ≤ 120/80 mm Hg) (n = 60, mean age: 56.0 ± 8.6 y, male/female: 32:28) | 120 | Shotgun metagenomics |
| Hypertension and borderline hypertension/Pre-hypertension | |||||
| Huart et al. (24) | Belgium |
Hypertension: mean 24-h SBP levels ≥130 mm Hg or DBP ≥80 mm Hg or in case of use of antihypertensive medications whatever the BP levels (n = 38, mean age: 52.5 ± 8.2 y, male/female: 38:0) Borderline hypertension: mean 24-h BP levels <130/80 mm Hg with either isolated daytime hypertension (SBP ≥135 mm Hg and DBP ≥85 mm Hg) or nocturnal hypertension (SBP ≥120 mm Hg or DBP ≥70 mm Hg) (n = 7, mean age: 50.3 ± 13.3 y, male/female: 7:0) |
Untreated individuals with mean 24-h BP levels <130/80 mm Hg (n = 9, mean age: 46.2 ± 11.4 y, male/female: 9:0) | 54 | 16S rRNA gene sequencing |
| Han et al. (20) | China |
Hypertension patients: SBP ≥140 mmHg, or DBP ≥90 mmHg without antihypertensive treatments (n = 99, not report characteristics of final included subjects) Pre-hypertension persons: 125 mmHg < SBP ≤ 139 mmHg or 80 mmHg < DBP ≤ 89 mmHg without antihypertensive treatments (n = 56, not report characteristics of final included subjects) |
SBP ≤ 125 mmHg and DBP ≤ 80 mmHg without antihypertensive treatments (n = 44, not report characteristics of final included subjects) | 199 | Viral sequencing |
| Li et al. (18) | China |
Hypertension patients: 140 mmHg ≤ SBP, or 90 mmHg ≤ DBP (n = 99, mean age: 53.6 ± 5.5 y, male/female: 93:6) Pre-hypertension persons: 125 mmHg < SBP ≤ 139 mmHg, or 80 mmHg < DBP ≤ 89 mmHg (n = 56, mean age: 51.8 ± 6.6 y, male/female: 52:4) |
SBP ≤ 125 mmHg, or DBP ≤ 80 mmHg (n = 41, mean age: 53.7 ± 5.9 y, male/female: 32:9) | 196 | Metagenomic sequencing |
| Preeclampsia | |||||
| Chang et al. (30) | China | An elevated systolic BP of ≥160 mm Hg or a diastolic BP of ≥110 mm Hg, proteinuria of ≥3 g/24 h (n = 27, mean age: 31.7 ± 4.9 y, male/female: 0:27) | Healthy pregnant control (n = 36, mean age: 30.4 ± 4.1 y, male/female: 0:36) | 63 | 16S rRNA gene sequencing |
| Pulmonary arterial hypertension | |||||
| Kim et al. (31) | US | Type 1 PAH patients (mean pulmonary arterial pressure 57.4 ± 16.7 mmHg) (n = 19, mean age: 39.5 ±12.7 y, male/female: 3/16; final include: n = 18) | Age- and sex-matched healthy controls (n = 16, mean age: 37 ± 11 y, male/female: 3/13; final included: n = 13) | 31 | Metagenomic sequencing |
DBP, diastolic blood pressure; NOS, Newcastle–Ottawa quality assessment scale; PAH, pulmonary arterial hypertension; SBP, systolic blood pressure.