Estimating Clinical Burden and Valuation of Weight Management Strategies (using Willingness to Pay WTP) for Overweight and Obesity in Primary Care Setting in Borneo Sarawak, Malaysia

Overweight and obesity is one of the most serious public health challenges of the 21st century. Despite the consequences of obesity, participation in weight management programs. Aim of this study is to estimate the clinical burden of obese patients in government primary care clinics in Kuching, Sarawak. We use randomized patients from these clinics to carry out a willingness to pay study for weight management and estimated the economic burden of overweight and obesity management in primary care setting in Sarawak. Identifying their willingness to pay will help in formulation and implementation of policies for effective weight management therefore improve the quality of care in future. Clinic based cross-sectional study involving 252 randomly overweight and obese patients (with BMI ≥ 23), age 18 to 59 years old, who attended outpatient department.


Results
Patients indicated their preference for three hypothetical weight reduction programs: diet, exercise, drug and combination of all. Data from secondary sources was used to estimate the prevalence of overweight and obesity in Sarawak. Out of 1,504,779 patients aged 18 to 59 years attending government health clinics in Sarawak, it was estimated that overweight and obesity would account for approximately 30% of

Background
Obesity is a global problem in both developing and developed countries, and has become a leading health burden in the Non-Communicable Diseases (NCD) such as cardiovascular and diabetes [1,2].
Overweight and obesity is one of the most serious public health challenges of the 21st century, and constitute a threat worldwide fall the way from early age to adolescence and to the adulthood [3,4]. In between the accelerated phase of industrialisation and urbanisation in recent decades, the worldwide prevalence of obesity has more than doubled between 1980 and 2014.
Obesity is de ned as an abnormal or excessive accumulation of body fat and it is currently one of the most concerning public health issues, as it is related to a wide range of serious diseases and disorders [5]. Furthermore, obesity has reached epidemic proportions globally, with more than 1 billion adults overweight -at least 300 million of them clinically obese -and is a major contributor to the global burden of chronic disease and disability [6]. In addition, there is a high prevalence of obesity in the general population, making it the principal nutritional problem in the developed world today [7].
In 2014, more than 1.9 billion adults of age 18 years and older, were overweight and of these over 600 million were obese. Overall, about 13% of the world's adult population, 11% of men and 15% of women were obese whereas 39% of adults aged 18 years and over were overweight, comprising of 38% of men and 40% of women 8 . From GutieÂrrez-Fisac et al. reported, between 1987 and 1995/1997 the prevalence of overweight and obesity in the Spanish adult population aged 25-64 y increased by 2.2% and 3.9%, respectively. This increase was seen in both men and women and affected most age groups [7]. According to Kelly et al., they were predicted that by 2030, about 573 million and 1.35 billion adults would have problems with obesity and overweight, respectively [9].
Obesity and overweight have been steadily increasing in ASEAN countries over the last three decades, not just in higher income countries but also in low-and middle-income nations and obesity has become a leading health issue Malaysia is no exception when increased rapidly [10,11]. Where Malaysia is also facing a big challenge in combating this rising obesity epidemic although there is increasing availability and accessibility to health screenings. By comparison, 20 years ago, only 4% of Malaysians were considered obese [10]. Nowadays, Malaysia is reported to have the highest obesity rate in Southeast Asia [12]. Using World Health Organization recommendations for body mass index (BMI), the prevalence of overweight and obesity in Malaysia was found to be 33.6% and 19.5% respectively [13] [14,15,16]. For 2019, NHMSs reported, 1 in 2 adults in Malaysia were overweight or obese. This was found to be highest among: females 54.7% ; Indian ethnicity 63.9% and 55-59 years old age group 60.9% [17].
Overweight and obesity is a complex disorder involving not only a cosmetic concern but it also increases the risk of other medical condition such as heart disease, diabetes and high blood pressure [18]. Prevalence of obesity in any population have far reaching effect on the health of the population. These include increased premature mortality, morbidities associated with many chronic disorders associated with the obesity, and reduced health related quality of life. All these will lead to the substantial increase in budgets of various segments of health systems [19].
In a systematic review of the economic burden of obesity worldwide, Withrow and colleagues concluded that obesity accounted for 0·7-2·8% of a country's total health-care costs, and that obese individuals had medical costs 30% higher than those with normal weight [20]. Obesity imposes signi cant costs on health-care systems; around the world, 2 to 7 percent of all health-care spending relates to measures to prevent and treat this condition, with up to 20 percent of all health-care spending attributable to obesity, through related diseases such as type 2 diabetes and heart disease [21]. Obesity reduces productivity signi cantly and has a direct impact on the country's GDP performance [22]. This can be prove, in 2008 the economic cost of obesity in Canada was estimated at $4.6 billion, up about 19% from $3.9 billion in 2000 [23]. These health-care costs place a burden on government nances. Furthermore, overall economic productivity and employers are both affected by impaired productivity [21]. Malaysia also suffers the highest overall cost for obesity as a percentage of the country's healthcare spending, reaching an alarming 10-20% of the country's healthcare expenditure [22]. Malaysia's total cost for obesity as a percentage of nominal GDP ranks top at a range between 0.4% and 0.8%, far ahead of all other countries in ASEAN [23]. Total (direct and indirect) costs of obesity are highest in Malaysia, are equivalent to between 10% and 19% of national healthcare spending. Indonesia's costs range from 8-16% of national healthcare spending. Costs are lowest in Vietnam (1-3% of national healthcare spending) and Thailand (3-6%) [10].
Despite the grave consequences of overweight and obesity and its long term treatment, the participation in weight reduction management in primary health care is notoriously poor. Patients are less likely than the providers to look to the primary care clinic as a resource for weight management, as they perceived that overweight people should handle their weight on their own and that consultation with a health care provider would not be helpful. Therefore it is essential for health care providers to be aware that their patients are less likely to seek their providers for assistance and thus delivering of consultation on weight management must be initiated by the provider [24].

Willingness to Pay -WTP
The potential bene ts of interventions for weight reduction are substantial. The health benefit has been widely assessed based on the concept of willingness to pay (WTP) which is based on the principles of welfare economic theory and cost benefit analysis. Conferring to the theory of welfare economics, the maximum amount that the individual is willing to pay for such a service or intervention de ned the benefit to an individual of a service or an intervention and the sum of each individual's WTP can be regarded as the benefit to society of the intervention [24].
Among the several methods used for measuring WTP, the contingent valuation (CV) is a comprehensive approach providing a theoretically precise and complete measure of WTP. The contingent valuation (CV) method is a well-known research approach which uses survey techniques to elicit patient's valuation of non-market goods including health [25]. CVM is a nonmarket-valuation method that is used to value speci c changes from the status quo.
CVM is a stated-preference technique, as in the individual "states" his preference. Speci cally, in the CVM individuals are asked about the status quo versus some alternative state of the world, and information is elicited about how the individual "feels" about the alternative relative to the status quo, and their WTP, if anything, for the alternative. Before the CVM question is asked, individuals are presented with background and explanatory material, and often asked other questions.
A higher WTP may indicate a more number of participation if such a program were offered and the WTP also indicate whether a sponsor organization can recover some or all of the intervention costs from program participants based on the participants willingness to pay. If at-risk individuals are willing to pay a signi cant portion of the costs of an intervention, then it may be practicable for sponsors to implement interventions without suffering large nancial burdens. However it is important to take into account that the benefit of such non-market goods (health) may also be subjected to an individual's health and economic condition [25].
Valuation is implicit in most policy decisions, and it is preferable to make it explicit where possible to improve quality and transparency. For that reason the CV method is adopted in this study and a survey is conducted among the overweight and obese patients on their WTP for health improvement secondary to weight reduction management. In the early days of Sarawak, the rst clinic was initiated by missionaries in the early 1900s. Then in the 1940s, clinics were established in rural areas by the Sarawak Medical Department and were called as Dispensaries back then. These Dispensaries were led by 'dressers' or Hospital Assistants (HA) and provided both basic outpatient care and limited in-patient care. Realising that many patients in remote areas faced obstacles in seeking treatment at these clinics due to transport di culties, the colonial government introduced mobile health services (Travelling Dispensaries) in 1948 which mainly bene tted settlements along major riverbanks. Then Mobile health services signi cantly contribute to the health of the population in Sarawak. Mean distance of public outpatient clinics in Sarawak was 11.48 km and travel time of 30 minutes [34]. However, distance and travel time taken could be longer in more remote areas. Therefore, mobile services were established to provide basic healthcare services to populations living outside the clinics' operational area which require access using boat, 4WD or helicopter. These mobile health services provide MCH services and basic curative services. And each mobile team consist of AMO, with or without nurses or may include MO. In 2016, there were 132 mobile health teams in Sarawak: 66 for land transport, 57 for water transport and 9 for air transport.
In addition to the existing health facilities, the 1Malaysia Clinic (1M Clinic) was introduced in 2010, including the mobile 1Malaysia Bus Clinic and 1Malaysia Boat Clinic [35]. There is no 1M Bus Clinic in Sarawak. Static 1M Clinics are in urban areas and mainly serve the urban poor population, whilst the 1Malaysia mobile teams serve remote rural populations. During the interview, the respondent was rst asked if he/she wanted to reduce weight. Those who responded positively were then asked follow-up questions. The participants were given explanations on the economic term used in the questionnaire to ensure complete understanding of the situation. Three hypothetical situations were clari ed to the respondents and they were expected to vote the amount of money they willing to pay if they are in the situation in three different weight reduction methods. These include; drug and exercise, diet with exercises and combinations of all three (Table:1). There were 7 offer prices use in the questionnaire ranging from MYR 50 (USD 11.83) to MYR 500 (USD 118.33) . If they agreed to pay, then the bidding process commenced. The answers were close ended with two options ('yes' and 'no'). However, if the respondents answered 'no' they were asked about the reason and the interview stop there. The bidding started with the lowest value depend on the pre-test and subsequently higher and stop once the respondents state they were unwilling to pay the given amount. If the respondents said no or yes to the entire bidding, open ended question was asked about what the highest amount that they were willing to pay.

Results
From the total 400 patients interviewed, 63% (n = 252) of the overweight and obese patients were willing to reduce their weight and 37% were unwilling to reduce their weight. Table 2 shows preference for each scenario and the amount these patients are willing to pay for each scenario.  With the value obtained from Table 2 and Table 3, estimation of the total amount of WTP among overweight and obese adult patient population in government health clinics in Kuching District and whole Sarawak were calculated for the three scenarios. The results are shown in the Table 4.  This indicates that overweight and obesity are the major clinical burden of disease, not only affecting people across the globe but also in Malaysia itself. Overweight and obesity are the root cause for various non-communicable diseases and often affect the quality of life, productivity and may lead to disability. As the medical cost of managing weight-related chronic diseases increased, it further raises the nancial burdens of our health care system and also will contribute toward additional nancial burdens being placed on public health insurance [39,40]. Economic evaluation assesses the e ciency and allocation of resources to interventions that may improve health care and health outcomes [41].
Therefore, comprehension of the potential morbidity and cost implications is crucial to formulate an effective and cost-effective strategy for weight management. The economic rationale in the study warrants that there should be cost-effectiveness across a spectrum of different weight management interventions in overweight and obesity patients. For that purpose we employed the Willingness to Pay (WTP) based Contingent Valuation Technique (CVM) in this research.
However, in a publicly funded health care system such as in Malaysia, resources are usually scarce with xed amount of resources per annum. If there is a need to carry out changes in the services based on demand and needs of the population, policy makers may have to decide on which services or programs that need to be expand or withhold, within the context of a xed budget allocated, as according to the concept of economic evaluation [42]. Economic evaluation is the process of measuring cost effectiveness which is the cheapest option is a simplistic and mistaken idea [43].
E ciency and its effectiveness in developing strategies for weight management states that all the costs associated with obesity management should be equal or below the WTP for weight management intervention. Hence to translate this information into formulation of strategies for weight management intervention, the cost for weight management intervention via various strategies i.e.; diet and exercise; drug, diet, exercise; drug and exercise in state of Sarawak, Malaysia should be equal or less than the amount of WTP. Therefore in Sarawak should be equal or less than the amount of WTP, MYR 40.0 million (USD 9,295,624.08), MYR of 27.1 million (USD 6,297,785.31) and MYR 22.5 million (USD 5,228,788.54) for three strategies respectively.
To assist policy makers in decision making, the value of health bene ts from the program should be greater than the "opportunity cost" of other programs that are being considered. For instance, weight management intervention via diet and exercise; via drug, diet, exercise; via drug and exercise in Sarawak which were valued as MYR 40.0 million (USD 9,295,624.08), MYR of 27.1 million (USD 6,297,785.31) and MYR 22.5 million (USD 5,228,788.54) respectively from the WTP measurement, can be adopted if these values are greater than the opportunity costs of other competing programs or services available under Ministry of Health. In addition to that, other than valuation of bene ts and barriers for weight management, policy makers may also need to assess other related aspects such as feasibility, budget, cultural concern, time, equity before any decision is made 5 .

Conclusion
Resource allocation for weight management intervention in primary care in the State of Sarawak, Malaysia may depend on several factors such as the evaluation of weight management intervention (objectively measured by the concept of WTP) and the available xed budget from State Health Department. From the ndings in our study, preferably cost of the weight management program should be equal or less than MYR 40.0 million (USD 9,295,624.08), MYR of 27.