Cost-effectiveness of tobacco control policies in Vietnam: the case of personal smoking cessation support

Cost-effectiveness of tobacco control policiesin Vietnam: the case of personal smokingcessation supportadd_3632 658..670

Hideki Higashi & Jan J. BarendregtThe University of Queensland, School of Population Health, Herston, QLD 4006, Australia

ABSTRACT

Aims To examine the cost-effectiveness of personal smoking cessation support in Vietnam. Design, setting andparticipants We followed-up the population aged 15 years and over in 2006 to model the costs and health gainsassociated with five interventions: physician brief advice; nicotine replacement therapy (patch and gum); bupropion;and varenicline. Threshold analysis was undertaken to determine the price levels of pharmaceuticals for the interven-tions to be cost-effective. A multi-state life table model was constructed such that the interventions affect the smokingcessation behaviour of the age cohorts, and the resulting smoking prevalence defines their health outcomes. Ahealth-care perspective was employed. Measurements Cost-effectiveness is measured in 2006 Vietnamese Dong(VND) per disability-adjusted life year (DALY) averted. We adopted the World Health Organization thresholds of being‘cost-effective’ if less than three times gross domestic product (GDP) per capita (VND 34 600 000) and ‘very cost-effective’ if less than GDP per capita (VND 11 500 000). Findings The cost-effectiveness result of physician briefadvice was VND 1 742 000 per DALY averted (international dollars 543), which was ‘very cost-effective’. Vareniclinedominated bupropion and nicotine-replacement therapies, although it did not fall within the range of being ‘cost-effective’ under different scenarios. The threshold analysis revealed that prices of pharmaceuticals must be substan-tially lower than the levels from other countries if pharmacological therapies are to be cost-effective in Vietnam.Conclusions Physician brief advice is a cost-effective intervention and should be included in the priority list of tobaccocontrol policy in Vietnam. Pharmacological therapies are not cost-effective, and so they are not recommended inVietnam at this time unless pharmaceuticals could be produced locally at substantially lower costs in the future.

Keywords Brief advice, cost-effectiveness, economic evaluation, pharmacological therapy, smoking cessation,tobacco.

Correspondence to: Hideki Higashi, The University of Queensland, School of Population Health, Herston, QLD 4006, Australia.E-mail: [email protected] 6 October 2010; initial review completed 22 December 2010; final version accepted 17 August 2011

INTRODUCTION

Tobacco smoking is a major cause of morbidity and pre-mature deaths world-wide. Tobacco has claimed 100million lives during the 20th century, which is projectedto increase to a billion during this century if no furtheractions are taken [1]. While smoking prevalence isdecreasing in high-income countries, smoking ratesremain high in developing countries. More than 80%of smoking-related deaths in 2030 will take place inlow- and middle-income countries [1].

Vietnam is an emerging middle-income countryin Southeast Asia with a population of 86 million [2].

Economic growth is one of the fastest in the world, withgross domestic product (GDP) per capita increased from$US720 in 2006 to $US1160 in 2010 [3]. Vietnam isalso a country with one of the highest smoking preva-lence in the world. A survey in 2006 revealed the malesmoking rate to be 47% [4]. Given the impact of tobaccosmoking on health, the government launched theNational Tobacco Control Policy (NTCP) in 2000. Sinceits inception, various tobacco control strategies havebeen implemented in the forms of decrees and decisions,including advertisement ban of tobacco products,smoking ban in selected public places and mass mediacampaigns [5]. Excise tax on tobacco products was

RESEARCH REPORT doi:10.1111/j.1360-0443.2011.03632.x

© 2011 The Authors, Addiction © 2011 Society for the Study of Addiction Addiction, 107, 658–670

increased and health warning text messages on cigarettepacks have been enlarged [5]. However, the degree ofimplementation varies, and the strategies have notbeen implemented to its full potential due to resourcelimitations, competing health priorities and otheragendas (e.g. government revenue and socioeconomicimplications).

Higashi et al. [6] examined the cost-effectiveness oftobacco control interventions targeted at the populationlevel as part of the Vietnam Evidence for Health Policy(VINE) Project [7]. This study aims to provide furtherevidence on the cost-effectiveness of personal smokingcessation supports.

METHODS

Interventions

Five interventions were examined in this analysis: physi-cian brief advice; nicotine replacement therapy (NRT)patch; NRT gum; bupropion; and varenicline.

Physician brief advice

Brief advice for smoking cessation support can be admin-istered by physicians or other health professionals,depending on their availability, whenever a smoker con-sults an out-patient health facility for whatever reason(not including emergency services). Given the difficultiesin accessing health-care services, particularly in ruralareas, it is assumed that follow-up visits are not requiredfor the intervention. The scope of intervention includedscreening for smoking status upon arrival to a health-care facility and brief advice after finishing the consulta-tion for which reason the smokers visited. A 1-minutescreening and an 8-minute advice session were assumedto be required for the analysis [8].

Nicotine replacement therapy

While NRT is not available in Vietnam, it was assumedthat the purchase of products would require prescrip-tions. However, given that NRT products can be pur-chased over the counter in many high-income countries,it was assumed that only one visit would be required toreceive the prescriptions for the whole smoking cessationcourse. NRT was assumed to be prescribed for smokerswho have previously visited a health facility and wereadvised to receive medications to quit smoking, with orwithout brief advice from a health professional. Patchand gum were analysed separately, as these two mainforms of NRT have different costs and effectiveness.Three minutes of consultation for a 21-mg patch or2 mg ¥ 10 gum for 8 weeks was assumed for the analysis[8,9].

Bupropion (antidepressant)

Bupropion normally requires two visits to a physician.The starter pack would be provided at the first visit, andthe continuation pack at the second. As with NRT, bupro-pion was assumed to be prescribed only for those whohave previously visited a health facility and were advisedto receive medications to quit smoking, with or withoutbrief advice from a health professional. Three minutesof consultation for the first prescription (150 mg, 30tablets), followed by a second visit and prescription(150 mg, 90 tablets) was assumed for the analysis[8,10,11].

Varenicline (nicotine receptor partial agonist)

Varenicline normally requires two visits to a physician.The starter pack would be provided at the first visit andthe continuation pack at the second. As with NRT,varenicline was assumed to be prescribed only for thosewho have previously visited a health facility and wereadvised to receive medications to quit smoking, with orwithout brief advice from a health professional. Threeminutes of consultation for the first prescription (0.5 mg,11 tablets; 1.0 mg, 14 tablets), followed by a second visitand prescription (1.0 mg, 140 tablets) was assumed forthe analysis [8,10].

Modelling

Model concept

The model comprises a smoking prevalence model and anepidemiological model. The former model was used toestimate the smoking uptake and cessation parametersby fitting the estimated smoking prevalence with theobserved data from past years. The obtained age- andsex-specific smoking uptake and cessation rates werethen input parameters for the latter to model the smokingrate of the base population who will be followed-upthroughout its life-course. The modelled smoking ratewill determine the risk of smoking-related diseases whichthen define the overall health states of the populationcohorts. The interventions were designed to affect thesmoking cessation and uptake rates to reduce smokingprevalence, and thereby improve the health profile of thepopulation. Both models were constructed in MicrosoftExcel, with details provided below.

Smoking prevalence model

The smoking prevalence model is the same as that usedby Higashi et al. [6]. It is a dynamic population model,based on age-specific fertility rates, sex ratio at birth andage-specific mortality rates derived from different surveys.The reference year for the overall analysis was 2006. The

Cost-effectiveness smoking cessation support 659


model was aimed to estimate the smoking uptake andcessation rates using observed data on smoking ratesbetween 1993 and 2006. The population between 1999and 2006 was estimated from the census 1999 data fol-lowing population dynamics, while the population priorto that year was back-calculated from 1999. Data onsmoking rates were obtained from different surveysconducted over three time-points: Vietnam Living Stan-dard Survey (VLSS) 1993; VLSS 1998; and VietnamHousehold Living Standard Survey (VHLSS) 2006. Aweighted least-squares method was employed to modelthe smoking uptake and cessation rates by fitting the esti-mated smoking prevalence with those observed in theabove three surveys (see Appendix S1 for details; support-ing information details are given at the end). The detailsof data sources are summarized in Table 1.

Epidemiological model

The multiple-cohort, multi-state life table model devel-oped by Higashi et al. [6] underwent a slight modification

to accommodate the extra properties required for model-ling an individual approach, but is largely the same. Tensmoking-related diseases were included in modelling thehealth effects of smoking cessation including: ischaemicheart disease (IHD); cerebrovascular accident (CVA);cancer (lung, mouth and oropharynx, oesophagus, pan-creas, bladder, stomach); chronic obstructive pulmonarydisease (COPD); and lower respiratory tract infections.

We followed-up the population of Vietnam aged 15years and over in the base year (i.e. 2006) until extinct.These people were divided further into three exposurecategories of smoking: never smokers, current smokersand ex-smokers. People can move from one category toanother based on smoking uptake and cessation rates, ofwhich the latter is subject to change due to interventioneffects. The schematic depiction of the epidemiologicalmodel is provided in Fig. 1.

The interventions were modelled to determinechanges in epidemiological parameters includingincidence, prevalence and mortality of tobacco-related

Table 1 Data sources.

Parameters Sources of information Remarks

Smoking prevalence modelPopulation Census 1999 [25] 1-year age groupAge-specific fertility rate Population change survey 2006 [26] 5-year age group, 15–49Sex-ratio at birth Population change survey 2006Mortality rate (overall) WHO life table for member states [27],

VINE project [7]5-year age group

Mortality RR (smoking status) CPS-II (M. Thun, personal communication) 5-year age group, 30+Smoking prevalence VLSS 1993and 1998, VHLSS 2006 [28–30] 5-year age group

Epidemiological modelPopulation VINE project 5-year age groupMortality rate (overall) VINE project 5-year age groupMortality RR (smoking status) CPS-II 5-year age group, 30+PYLD Thailand national burden of disease

study 1999 [31]10–15-year age group

(assumed to be similarto Thailand)

Disease parameters (incidence,prevalence, case fatality, remission,disability weight, etc.)

VINE project 5-year age group

RR (smoking and disease) CRA and literature [12,32–34]Intervention costs

Unit cost of out-patient visits WHO [35]Australian pharmaceutical price Australian pharmaceutical benefit scheme [36,37]Regional pharmaceutical price MIMS [38]; MOPH Thailand [39]; Thuoc &

Biet Duoc [40]Smokers’ time cost General Statistics Office [41]Smokers’ travelling time Literature [42]Smokers’ waiting time Literature [43]Exchange rate United Nations Treasury [44]GDP deflator International Monetary Fund [3]

RR: relative risk; PYLD: prevalent years lived with disability; CPS-II: American Cancer Society’s Cancer Prevention Study Phase II; CRA: comparative riskassessment; WHO: World Health Organization; VINE: Vietnam Evidence for Health Policy; VLSS: Vietnam Living Standard Survey; VHLSS: VietnamHousehold Living Standard Survey; GDP: gross domestic product; MIMS: Monthly Index of Medical Specialities; MOPH: Thai Ministry of Public Health.

660 Hideki Higashi & Jan J. Barendregt


diseases, which are the drivers of transition of cohortsfrom one state to another. Potential impact fractions(PIFs) [12] were used to translate the change in smokingprevalence to health outcomes which were expressed indisability adjusted life years (DALYs). The data sourcesof parameters used for this modelling are provided inTable 1. Further details of the epidemiological model areprovided in Appendix S1.

Intervention cost

We assumed a static situation without including theinitial set-up costs for interventions (i.e. policy and guide-line development, training, etc.). Although the inter-ventions may be provided repeatedly to an individualover years, we modelled the cost-effectiveness of a once-off intervention in the base year. This assumption is suf-ficient to establish the ‘in principle’ cost-effectiveness ofthe interventions without relying on further assump-tions, such as changes in effects from multiple inter-ventions or switching from one type of intervention toanother for the same individual. The conceptual frame-work of interventions and the scope of costs included inthe analysis are provided as per Figs 2 and 3. The math-ematical details of costing are given in Appendix S1.

Information on costing was obtained from literature,government database and websites (see Table 1). Weemployed a health-care perspective for the analysiswhich included costs falling on both the governmentand smokers, including time costs. The perspective was

selected to account for the fact that 60–70% of health-care costs are covered by patients in Vietnam [13], and soa governmental perspective would provide misleadinginformation. Cost information in foreign currency wasconverted by the relevant exchange rates, and infor-mation from different years was converted by relevantdeflators to the base year value. Because most phar-maceuticals, except for bupropion, are not available inVietnam, the study employed a scenario-based analysis inwhich different prices of pharmaceuticals were simulated(see Table 1 for data sources for costing). The followingscenarios were included in the analysis:• Australian recommended retail price in 2006 for all

medications (cost-effectiveness analysis: scenario 1);• the lowest price identified from online data base in the

region including Vietnam (cost-effectiveness analysis:scenario 2); and

• price as a percentage of the Australian recommendedretail price in 2006 for all pharmaceuticals at whichlevel the intervention becomes cost-effective (thresholdanalysis: scenario 3).

In all scenarios, the costs for previous visit to a healthfacility were included as prerequisite to receive pharma-cological therapies.

Intervention effect

There is no evidence available on the effects of personalsmoking cessation supports in Vietnam. Therefore, theeffect parameters were obtained from international

Physician brief advice; nicotine replacement therapy (patch/gum); anti-depressant (Bupropion); nicotine receptor partial agonist (Varenicline))

Never smoker Initiation

Current smoker

Former smoker Cessation

Smoking prevalence

Lung cancer, IHD, CVA, COPD, LRTI, other cancers

Death

Mortality (smoking-related

diseases)

Incidence Incidence Incidence

Remission Remission Remission

Mortality (other causes)

Mortality (other causes)

Effect

Figure 1 Epidemiological model. CVA:cerebrovascular accident; COPD: chronicobstructive pulmonary disease; IHD:ischaemic heart disease; LRTI: lowerrespiratory tract infections



Recommend to quit smoking (1 min.)

Visit to a physician (or other health professionals) for any reason

Non-smoker (no intervention) Consultation for the reason of visit

Smoker

Brief advice only (finish)

Smoking cessation brief advice/counselling (7 min.)

Pharmacotherapy only (continue to Figure 3)

Brief advice & pharmacotherapy (continue to Figure 3)

Screening (1 min.)

Figure 2 Event pathway of smoking ces-sation support. Events in the boxes withthick lines are included in the interventioncost

Prescription (Varenicline)

Waiting time (71 min.) Consultation (3 min.)

Prescription (NRT)Prescription (Bupropion)

Repeat above Repeat above

2 weeks

Leave (20 min. travel time)



Visit to a physician for pharmacological therapies (20 min. travel)

3 weeks 8–12 weeks

4 weeks 8 weeks

Figure 3 Event pathway of pharmacologi-cal therapy. Events in the boxes with thicklines are included in the intervention cost(costs in Fig. 2 are also included as pre-requisite). Waiting time includes the timeto purchase medications



literature. Meta-analyses with pooled relative risks (RRs)were available for all interventions from the Cochranedatabase. The RRs employed for the analysis are providedin Table 2.

Intervention effects were modelled to affect thesmoking cessation behaviour of individuals. The conceptof the intervention effect is described as:

C C RRapost

apre= × (1)

where Capre post/ is the proportion of current smokers who

cease smoking at age a pre/post-intervention, and RR isthe relative risk of intervention effect on smoking cessa-tion rate. However, given that not all smokers wouldreceive the interventions, the RRs were adjusted for theproportion of people who actually receive support.

Physician’s brief advice was assumed to be providedopportunistically to all smokers who visited a health facil-ity for any reason. The proportion of people who madea clinical visit in a year was estimated from the VHLSS2006 data [4], as provided in Table 3.

Given that not all smokers visit a health facility in ayear, the RR of brief advice was adjusted as follows:

RR

RR Visit

brief advice

brief adviceliterature

aproportion

=× +1 0. 00 1× −( )Visita

proportion ,(2)

where Visitaproportion is the proportion of people at age a who

visit a health facility in a year.Conversely, pharmacological therapies were assumed

to be provided to smokers who have previously visited ahealth facility and were advised to receive medications toquit smoking, with or without brief advice from a healthprofessional. In the case of medications being prescribedin the absence of previous physician brief advice, theeffects of pharmacological therapies were adjusted in thesame manner as expression 2:

RR RR Visit Visitpharmpharmliterature

aproportion

apr= × + × −1 00 1. ooportion( ),

(2′)

Alternatively, if the smoker received physician briefadvice during the previous visit, the two effects werecombined assuming a multiplicative effect:

RR RR RRcombined brief advice pharm= × . (3)

We assumed a 1-year effect for all interventions,which we applied for the estimation of intervention costs.The smoking cessation rates were modelled to returnto the same level as the status quo for the subsequentyears. Health gains arising from the interventions wereexpressed as DALYs averted.

Accounting for time preference

While there is no agreed-upon discount rate which is tobe used for economic evaluations, 3% was selected forcosts as it is the most widely recommended discountrate in the literature, including WHO-CHOICE [WorldHealth Organization (WHO) Choosing Interventionsthat are Cost-Effective] [14]. Health gains in the futurewere also discounted at the same rate following the WHOrecommendation [14].

Uncertainty analysis

Key input parameters were provided appropriate distribu-tions, including beta, lognormal, triangular and dirichlet(details are provided in Appendix S1). Monte Carlo simu-lation was conducted to provide the uncertainty interval(UI) of cost-effectiveness ratios. Ersatz software [15] wasemployed to perform the simulation by re-sampling thevalues of parameters many times from those distribu-tions. The cost-effectiveness ratios reached convergence

Table 2 Intervention effects of personal cessation supports.

Intervention

RR

MeanLCI95%

HCI95%

Physician brief advice [45] 1.55 1.35 1.79Nicotine replacement therapy (patch) [46] 1.66 1.53 1.81Nicotine replacement therapy (gum) [46] 1.43 1.33 1.53Antidepressant (bupropion) [47] 1.69 1.53 1.85Nicotine receptor partial agonists

(varenicline) [48]2.33 1.95 2.80

LCI: lower confidence interval limit; HCI: higher confidence interval limit;RR: relative risk.

Table 3 Proportion of people visiting a health facility in a year.

Age (years)

Proportion (%)

Male Female

15–19 22.5% 25.5%20–24 20.3% 29.1%25–29 23.2% 40.1%30–34 27.8% 39.4%35–39 29.6% 41.9%40–44 34.6% 44.9%45–49 35.4% 47.0%50–54 39.0% 53.5%55–59 50.7% 61.4%60–64 53.2% 61.9%65–69 58.3% 63.0%70–74 65.0% 64.9%75–79 67.9% 68.7%80+ 65.0% 66.4%

Researcher’s tabulation from Vietnam Household Living Standard Survey(VHLSS) [4].



at roughly 800–1000 iterations, but to be certain wedoubled the number to 2000 times. Additionally, we con-ducted a sensitivity analysis by changing the interventioneffects (RRs) in a range of �50% in order to investigatethe robustness of findings.

Cost-effectiveness threshold

We followed the recommendation of the WHO Commis-sion on Macroeconomics and Health, which suggestsan intervention to be ‘very cost-effective’ if it costs lessthan average per capita income to avert one DALY (VND34 600 000) and ‘cost-effective’ if less than three timesaverage per capita income (VND 11 500 000) [16].

RESULTS

Intervention cost

Table 4 provides the estimated costs of all personalsmoking cessation supports. Among them, physicianbrief advice was the least costly intervention. Pharmaco-logical therapies were by far the most costly. In scenario 1,using Australian price levels, bupropion was the leastcostly intervention, followed by varenicline. NRTs(gum and patch) cost a great deal more than the othertwo medications. For most of the pharmacologicalapproaches, scenario 2 is substantially less costly thanscenario 1, reflecting the regional cost level. Averagecost per intervention for a smoker in scenario 2 rangedbetween VND 24 700 for brief advice to VND 4 690 000for brief advice + NRT patch (international dollars119 and 1462, respectively), indicating substantial

differences between interventions with and withoutpharmacological approaches.

Health gains

Table 5 provides the health gains associated witheach intervention. Varenicline would provide the largesthealth gains among the compared interventions, due toits high effectiveness compared to others. Bupropion andthe NRT patch yield similar health gains, while NRT gumyield the least among the pharmacological therapies.The combination of physician brief advice and eachpharmacological therapy results in higher health gainsthan the sum of each intervention provided individually,due to the assumption of multiplicative effects. From theresults, males have a roughly five-fold health gain overfemales, which is not surprising given the high smokingrate of males compared to females. DALYs averted perperson ranged between 0.011 and 0.056 on average,indicating that 18–91 smokers must receive interven-tions in order to avert one DALY depending on the typeof support.

Cost-effectiveness ratio

Table 6 provides the average and incremental cost-effectiveness ratios (ACERs; ICERs) of interventionsfor scenarios 1 and 2. There is a clear division of costeffectiveness between physician brief advice and pharma-cological therapies. Overall, physician advice is the onlyintervention that is ‘very cost-effective’ (VND 1 742 000,or international dollars 543, per DALY averted).

Conversely, pharmacological therapies are not cost-effective. In scenario 1, varenicline ranks first among the

Table 4 Intervention costs.

Intervention

Total intervention costs (VND billions)

VND per interventione

(scenario 2)

Scenario 1 Scenario 2

Median LUI 95% HUI 95% Median LUI 95% HUI 95%

1. Brief advicea 129 110 149 129 110 149 24 7002. NRT (patch)b 25 142 21 284 29 055 24 474 20 517 28 225 4 680 0003. NRT (gum)c 21 609 18 071 25 043 6168 5213 7100 1 180 0004. Bupropiond 15 744 13 255 18 207 5150 4349 5917 986 0005. Vareniclinec 19 215 16 244 22 323 12 278 10 372 14 247 2 350 0006. 1 + 2 25 181 21 202 29 149 24 506 20 705 28 253 4 690 0007. 1 + 3 21 697 18 193 25 051 6185 5292 7182 1 180 0008. 1 + 4 15 797 13 347 18 216 5193 4406 5935 994 0009. 1 + 5 19 294 16 270 22 361 12 333 10 384 14 238 2 360 000

LUI: lower uncertainty interval limit; HUI: higher uncertainty interval limit. aThis does not distinguish scenarios 1 and 2. bScenario 2: price in Hong Kong[Monthly Index of Medical Specialities (MIMS) [38]]. cScenario 2: price in Thailand [Thai Ministry of Public Health (MOPH) database [39]]). dScenario2: retail price in Vietnam (Deppreo: Unimed Pharmaceuticals Inc. [40]). eDenominator (number of smokers who received smoking cessation support) iscommon to all interventions on average: 5 225 000 (5 065 000 males and 160 000 females). NRT: nicotine replacement therapy; VND: VietnameseDong.



four pharmacological options, while NRT gum the least.The less favourable nature of cost-effectiveness doesnot change with scenario 2, although some of theACERs are substantially lower than those in scenario 1.The incremental analysis shows that brief advice +varenicline dominates all other interventions exceptfor brief advice alone in scenario 1. In scenario 2, briefadvice + bupropion is more cost-effective than briefadvice + varenicline, although it is still beyond the cost-effectiveness threshold level. The results of the sensitivityanalysis on the intervention effects are provided in

Appendix S1. While the numbers change, the conclu-sions on cost-effectiveness do not, except for brief advice +bupropion in scenario 2, which becomes cost-effectiveif the effect was increased by 25% or more.

Figures 4 and 5 provide the scatter-plots on the cost-effectiveness plane from 2000 simulations for scenarios1 and 2. Each dot of the ‘clouds’ represents a cost-effectiveness result, which is considered cost-effective if itfalls below the threshold line. In Fig. 5, most clouds crossthe threshold line, meaning that the cost-effectiveness isuncertain. Figure 6 provides the expansion pathway on

Table 5 Health gains.

Intervention

Health gains (DALYs averted)

DALYs avertedper interventiona

Total Male Female

Median LUI 95% HUI 95% Median Median

1. Brief advice 73 600 47 700 104 000 62 300 11 200 0.0142. NRT (patch) 87 400 67 500 111 000 73 800 13 500 0.0173. NRT (gum) 57 300 44 400 72 600 48 300 8710 0.0114. Bupropion 91 400 70 400 117 000 77 200 14 200 0.0175. Varenicline 177 000 127 000 236 000 149 000 27 100 0.0346. 1 + 2 182 000 140 000 233 000 153 000 28 700 0.0357. 1 + 3 144 000 107 000 185 000 121 000 22 700 0.0288. 1 + 4 188 000 143 000 240 000 158 000 29 500 0.0369. 1 + 5 292 000 216 000 382 000 244 000 46 800 0.056

The health gains of males and females do not add up to total as the median values are determined separately. aDenominator (number of smokers whoreceived smoking cessation support) is common to all interventions on average: 5 225 000 (5 065 000 males and 160 000 females). DALY: disability-adjusted life year; LUI: lower uncertainty interval limit; HUI: higher uncertainty interval limit; NRT: nicotine replacement therapy.

Table 6 ACER and ICER.

Intervention

VND thousands per DALY averted

Scenario 1 Scenario 2

ACER (95% UI) ICER ACER (95% UI) ICER

1. Brief advicea 1742 (1203–2788) 1742 1742 (1203–2788) 17422. NRT (patch)b 287 684 (214 030–388 122) Dominatede 277 069 (209 168–372 469) Dominated3. NRT (gum)c 376 261 (281 029–507 791) Dominated 107 826 (79 492–147 803) Dominated4. Bupropiond 172 582 (127 309–234 954) Dominated 55 854 (41 978–76 234) Dominated5. Vareniclinec 108 412 (78 825–155 497) Dominated 70 018 (49 237–102 529) Dominated6. 1 + 2 137 926 (102 657–185 876) Dominated 134 202 (100 823–181 495) Dominated7. 1 + 3 150 185 (111 459–210 102) Dominated 42 803 (31 511–59 225) Dominated8. 1 + 4 83 507 (61 969–115 779) Dominated 27 760 (20 554–37 872) 44 6659. 1 + 5 65 753 (48 186–92 174) 87 712 41 561 (30 128–59 021) 65 628WHO threshold: cost-effective (<GDP per capita ¥ 3) VND 34 600 thousand per DALY avertedWHO threshold: very cost-effective (<GDP per capita) VND 11 500 thousand per DALY avertedPurchasing power parity (ppp) 2006 1 international dollar = VND 3208.37 [49]

aThis does not distinguish scenarios 1 and 2. bScenario 2: price in Hong Kong [Monthly Index of Medical Specialities (MIMS) [38]]. cScenario 2: price inThailand [Thai Ministry of Public Health (MOPH) database [39]]). dScenario 2: retail price in Vietnam (Deppreo: Unimed Pharmaceuticals Inc. [40]).e‘Dominated’ refers to an intervention that is more costly and/or less effective than other more efficient interventions. DALY: disability-adjusted life year;GDP: gross domestic product; NRT: nicotine replacement therapy; VND: Vietnamese Dong; WHO: World Health Organization; ACER: average cost-effectiveness ratios; ICER: incremental cost-effectiveness ratios.



Figure 4 Scatter plots on the cost-effectiveness plane: scenario 1. DALY: disability-adjusted life year ; NRT: nicotine replacement therapy;VND: Vietnamese Dong

Figure 5 Scatter plots on the cost-effectiveness plane: scenario 2. DALY: disability-adjusted life year ; NRT: nicotine replacement therapy;VND: Vietnamese Dong



the cost-effectiveness plane. The points connected bythe lines represent the expansion pathway of interven-tion options, i.e. the most cost-effective options at variousexpenditure levels, while the points above these lines areinterventions that are ‘dominated’; i.e. interventions forwhich more cost-effective alternatives are available andhence will not be considered for selection.

The price levels of pharmaceuticals at which eachpharmacological therapy alone would be cost-effective (interms of ACER) are provided in Table 7 (scenario 3). Theprice levels are expressed as proportions to the base prices(i.e. from the pharmaceutical benefit scheme, Australia).The threshold was determined at the point where theprobability of the intervention being cost-effective fellwithin the range of 0.50 � 0.03.

The base prices are relatively low for varenicline andbupropion, while NRT products are substantially more

expensive. None the less, the price of pharmaceuticalsmust be 70–90% less than the base prices if these inter-ventions were to be cost-effective.

DISCUSSION

This study examined, for the first time, the cost-effectiveness of personal smoking cessation supportsin Vietnam. Apart from physician brief advice, the cost-effectiveness of smoking cessation support is less favour-able compared to those for population-level interventions[6]. This is in contrast to the findings from high-incomecountries, where cessation supports are generally foundto be cost-effective [17–21]. Gilbert et al. [22] modelledthe cost-effectiveness of NRT and bupropion in theSeychelles, which is one of only a few studies conductedin a developing country setting. Although pharmacologi-cal therapies are not available as yet in the Seychelles[1], their analysis provided favourable cost-effectivenessresults if US price levels were assumed for pharmaceu-ticals, which ranged from $US1324 (bupropion) to$US4597 (NRT spray) per year of life saved in 2002.However, there is a substantial difference in the assump-tions used and is not directly comparable with ourstudy. The effect size of pharmacological therapies wasexpressed as odds ratios incremental to physician coun-selling, which would provide larger health gains thanours. Further, GDP per capita in the Seychelles is more

NRT Patch (S1)

NRT Gum (S1)

Bupropion (S1)

Varenicline (S1)

Brief advice + NRT Patch (S1)

Brief advice + NRT Gum (S1)

Brief advice + Bupropion (S1)

Physician brief advice

Brief advice + Varenicline (S1)

Brief advice + Bupropion (S2)

Brief advice + Varenicline (S2)

Brief advice + NRT Patch (S2)

Brief advice + NRT Gum (S2)

NRT Patch (S2)

NRT Gum (S2)Bupropion (S2)

Varenicline (S2)

0

5,000,000

10,000,000

15,000,000

20,000,000

25,000,000

30,000,000

0 50 100 150 200 250 300 350

Cost (VND Millions)

DALY averted (Thousands)

Scenario 1

Scenario 2

Figure 6 Expansion pathways on the cost-effectiveness plane. DALY: disability-adjusted life year ; NRT: nicotine replacement therapy;VND: Vietnamese Dong

Table 7 Thresholds of pharmaceutical prices (Scenario 3).

Intervention Price level in $AU

NRT (patch) 11.5% ($AU48)NRT (gum) 8.6% ($AU31)Bupropion 19.3% ($AU50)Varenicline 30.6% ($AU96)

% represents the percentage of the Australian price levels; number inparentheses represents the cost of the recommended course in AUD 2006value. $AU: Australian dollars; NRT: nicotine replacement therapy.



than 10 times as high as in Vietnam, and so the thresholdlevel is also significantly different.

The interpretation of results for pharmacologicaltherapies requires due attention. Scenario 1, which usesthe Australian price for all pharmaceutical items, enablescomparison of the relative position of cost-effectivenessbetween different pharmacological approaches. However,the findings do not provide the absolute cost-effectivenessstandings of those therapies compared to other healthinterventions in Vietnam. Conversely, scenario 2 doesnot provide the relative positions of cost-effectivenessbetween different pharmacological therapies, as the costsare obtained from different countries. None the less, theyprovide some indications on what the absolute cost-effectiveness would be like in Vietnam if the pharmaceu-ticals were priced at the regional level. In either case,none of the pharmacological therapies are ‘cost-effective’, which implies that the regional price levels ofpharmaceuticals are too high for Vietnam if the inter-ventions were to be cost-effective.

The main limitation associated with this study is thatthe evidence used in the model is derived mainly from theliterature primarily of high-income country origins.Health risks associated with tobacco smoking wereobtained from the American Cancer Society’s Cancer Pre-vention Study Phase II (CPS-II) in the United States,which provides one of few large-scale cohort studies onthe risk of smoking [23]. Given the inherently differentsmoking patterns between Vietnam and the UnitedStates, we followed Higashi et al. [6] in testing the robust-ness of our findings by using the smoking RRs from aChinese study [24], which provided less favourable cost-effectiveness ratios yet did not materially change thefindings with respect to the cost-effectiveness thresholds.

Evidence of intervention effects was derived similarlyfrom the international literature. However, the sourceswere all meta-analyses from the Cochrane database, withpooled RRs from different countries. Although pharma-cogenetic differences may have some bearing on the effi-cacy of pharmaceuticals, the Cochrane reviews did notidentify significant heterogeneity between ethnic groups,and the sensitivity analysis indicated that the findings aregenerally robust.

The intervention was modelled as a once-off event inthe base year. While it is likely that a certain proportion offailed attempts may try another type of cessation supportin the subsequent years, this is not included in the model.The effects of repeated attempts with different combina-tion of approaches over years are not well known, andtherefore difficult to model. This may have over- or under-estimated the cost-effectiveness, depending on the effectsizes of repeated attempts.

Overall, physician brief advice is a very cost-effectiveoption and should be included in the priority list for

consideration of tobacco control policies in Vietnam. Nopharmacological therapies are cost-effective nor recom-mended for Vietnam at this stage. None the less, as avaluable tool to address the addictive nature of tobacco,pharmacological approach may be added to the prioritylisting in the future should pharmaceuticals be producedlocally at substantially lower costs.

Declarations of interest

J.J.B. owns Epigear International, which sells the Ersatzsoftware.

Acknowledgements

This research was supported by the Atlantic Philanthro-pies under the project of ‘Developing the Evidence Basefor Health Policy in Vietnam’. Higashi received supportfrom the University of Queensland Research Scholarship.The funders had no role in study design, data collectionand analysis, decision to publish, or preparation of themanuscript. The authors would like to acknowledge Pro-fessor Christopher M. Doran (Hunter Medical ResearchInstitute) and the cost-effectiveness team of the afore-mentioned project (Health Strategy and Policy Institute).

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Supporting information

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Appendix S1 Details of methods.

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Cost-effectiveness of tobacco control policies in Vietnam: the case of personal smoking cessation support