Table 3 List of inputs and sources used in cost-effectiveness model, Vietnam
Variable name | Input | Source/Description |
|---|---|---|
Clinical events and epidemiology | ||
Blood pressure | See Supplementary Table 1 Supplementary Material | Calculated based on Ha 2011 baseline blood pressure. Reduction in SBP for each intervention was calculated from the reduction of sodium intake with a linear regression using the Law 1991 SBP with no sodium in the diet as reference [13] |
Stroke incidence | See Supplementary Table 2 Supplementary Material | Ha 2011 [13] |
Relative risk of stroke with change in SBP | See Supplementary Table 3 Supplementary Material | Cobiac 2012 and intervention specific change in blood pressure from baseline. Each 1% decrease in SBP equals a 6.3% risk reduction for stroke [17] |
IHD incidence | See Supplementary Table 2 Supplementary Material | Ha 2011 [13] |
Relative risk of IHD with change in SBP | See Supplementary Table 4 Supplementary Material | Cobiac 2012 and intervention specific change in blood pressure from baseline. Each 1% decrease in SBP equals a 3.4% risk reduction for IHD [17] |
Mortality | Vietnam life tables | World Health Organisation and Global Health Observatory; age and gender specific [35] |
Mortality following stroke event | 37% | Tirschwell 2012 [36] |
Long term stroke mortality risk | Year 1: 3.33Year 2: 2.85Year 3: 3.44Year 4: 2.84Year 5+: 1.56 | Kiyohara 2003 [37]. Relative risk of patients with history of stroke compared to healthy controls. Model assumes patients have elevated risk of mortality (1.56x higher) compared to “healthy” population |
Mortality of IHD event | Age specific mortality risk | Southeast Asian NCD impact module dataset through the WHO-CHOICE OneHealth tool |
Long term IHD mortality | Year 1: 18.7%Year 2: 25.0%Year 3: 39.2%Year 4+: Revert back to regular population mortality | Tang 2007 [38]. Model assumes that after Year 3 patients have same mortality risk as rest of “healthy” population |
Resource use and programme costs reported in ₫ (USD) | ||
Cost of lowering sodium content by potassium-enriched salt substitutes per capita | 1791 ₫ (US$ 0.08) | Calculated as the cost of a sodium reduction Government subsidy included in the subsidised scenario. Based on:- 534,798 t of salt produced each year [39]- 70% of salt is in cooking salt, fish sauce and bot canh of which 50% of sodium varieties [24]- US$0.04 to develop 1 kg of low sodium salt [40] |
Personnel Costs for policy implementation and management | Project coordinator, manager, chief accountant, technical specialist etc.: 511,526,874 ₫ (US$ 22,039) per yearProject administrative assistant/secretary, accountant, interpreter, translator: 295,489,873 ₫ (US$ 12,730.88) per yearClerk, Driver, Auxiliary Staff, Messenger, Cleaner: 155,828,979 ₫ (US$ 6714) per yearPer diem daily subsistence allowance: 4,015,413 ₫ (US$ 173.00) | UN-EU 2015 human resource costs inflated to 2019 US$ and converted to ₫ [41].Per diem costs from the International Civil Service Commission [42] |
Human resource requirements for policy implementation and management | Webb 2017 eTable2 | Webb 2017 [26] |
Healthcare costs | ||
Percent of healthcare costs paid by the Government | 54% | Local expert opinion; WHO 2018 [43] |
Cost of stroke event to Government | 13,325,677 ₫ (US$ 574.12) | Khiaocharoen 2012 (one off event cost) [44] |
Long term cost of stroke to Government | 0 | Nguyen 2016 identifies stroke patients are cared for at home by family members [45] |
Cost of IHD event to Government | 17,297,679 ₫ (US$ 745.25) | Nguyen 2016 (one off event cost) [45] |
Long term cost of IHD to Government | 368,835 ₫ (US$ 15.89) | Nguyen 2016 recurring yearly cost for the lifetime of the patient [45] |
Quality of life | ||
Healthy utility (SBP < 130) | Male: 0.734Female: 0.712 | Nguyen 2015 [46] |
Stage 1 hypertension utility (SBP > 130 and < 140) | Male 0.726Female: 0.705 | Nguyen 2015 [46] |
Stroke event disutility | − 0.312 | GBD 2010 [47] |
Long term post-stroke utility | Year 1: 0.66Year 2+: 0.68 | Luengo-Fernandez 2013 [48] |
IHD event disutility | − 0.186 | GBD 2010 [47] |
Long term post-IHD utility | OR = − 0.004 | Nguyen 2015 odds ratio of patients who had a history of experiencing a cerebrovascular event compared to those without event. Applied to life of patient [46] |