Quality assessment of the included studies examining the relationship between altitude and the prevalence of hypertension
| Study ID | Study design | Definition of hypertension | Definition of awareness | Definition of treatment | Definition of control | Sampling strategy | Response rate | Adequate sample size | Validated measure | Appropriate statistical analysis |
|---|---|---|---|---|---|---|---|---|---|---|
| Sherpa33 | Cross-sectional | ≥130/85 mm Hg or antihypertensive therapy | Self-report of prior diagnosis by a healthcare professional | Self-reported use of a prescribed medication | Medication treatment with BP <140/90 mm Hg | Stratified | 82% | Yes | Yes | Yes |
| Zhao34 | Cross-sectional | ≥140/90 mm Hg or antihypertensive therapy | Self-report of prior diagnosis by a healthcare professional | Self-reported use of a prescribed medication | Medication treatment with BP <140/90 mm Hg | Stratified | 100% | Yes | Yes | Yes |
| Zheng35 | Cross-sectional | ≥140/90 mm Hg or antihypertensive therapy | Self-report of prior diagnosis by a healthcare professional | Self-reported use of a prescribed medication during last 2 weeks | Medication treatment with BP <140/90 mm Hg | Stratified | 96.8% | Yes | Yes | Yes |
| Deji36 | Cross-sectional | ≥140/90 mm Hg or antihypertensive therapy | Self-report prior to the survey | Self-reported use of a prescribed medication during last 2 weeks | Medication treatment with BP <140/90 mm Hg | Randomised | 65% | Yes | Yes | Yes |
| Lei37 | Cross-sectional | ≥140/90 mm Hg | Self-report prior to the survey | Self-reported use of a prescribed medication during last 2 weeks | Medication treatment with BP <140/90 mm Hg | Not reported | 100% | Yes | Yes | Yes |
| Zhang38 | Cross-sectional | ≥140/90 mm Hg or proof of hospital diagnosis | Not reported | Not reported | Not reported | Randomised | 89% | Yes | Yes | Yes |
| Liu11 | Cross-sectional | ≥140/90 mm Hg or antihypertensive therapy | Not reported | Not reported | Not reported | Randomised | 100% | Yes | Yes | Yes |
| Li39 | Cross-sectional | ≥140/90 mm Hg | Not reported | Not reported | Not reported | Random, cluster and multistage | 87% | Yes | Yes | Yes |