Table 1. General characteristics of subpopulations aged 25–74 from multiple cross-sectional community surveys from 2001 to 2009 around Vietnam.

				Subpopulation aged 25–74, extracted for this study††
No	Original Dataset	Total samplesize	Sampling strategy of each survey	Study period	N (%)†††	Men (%)*	Age (Mean±SD)*	Residence Rural (%)*
01	NESH - The national epidemiological surveyon hypertension and its risk factors	9,823	- Multi-stage: 110 people per commune, 3 communesper district, 4 districts per province. −8 provinces†:HN, TB, NA, TN, KH, DL, DT, HC.	2001–2008	9,403 (95.7%)	39.4	45.0±12.4	59.2
02	HF-S - The survey on heart failure andits risk factors	4,840	- Multi-stage: similar to NESH. −4 provinces†:HN, NA, TB, TN.	2003–2004	4,494 (92.9%)	41.3	45.7±12.8	59.0
03	DM-S - The survey on diabetes andits risk factors	2,306	- Multi-stage: similar to NESH. −2 provinces†:HN, TB.	2008–2009	2,098 (91.0%)	35.9	49.9±12.3	43.1
04	NCDS - The survey on non-communicabledisease risk factors	2,362	- Stratified random sampling: 250 individuals in eachsex and 10-year age group using FilaBavi samplingframe† −1 district: Bavi, HT province†	2005	2,357 (99.8%)	48.2	49.3±14.2	100
05	HMPS - The hypertension managementprogramme in rural communes	5,855	- Simple random selection. −3 communes: (controlor pre-intervention): XC from HN, PC and PP fromBavi District, HT†	2004–2009	5,210 (89.0%)	38.1	47.8±12.7	58.8

^†DL: Dac Lac; DT: Dong Thap; FilaBavi: Demographical Surveillance System in Bavi District, Ha Tay Province; KH: Khanh Hoa; HC: HoChiMinh City; HN: Hanoi; HT: Ha Tay; NA: Nghe An; PC: Phu Cuong; PP: Phu Phuong; TB: Thai Binh; TN: Thai Nguyen; XC: Xuan Canh.

^††Exclude people over 75, pregnant women;

^†††Proportion of original sample.

^*Significantly different among original surveys with Chi-square test (p<0.001).