title: The health and economic impact and cost-effectiveness of interventions for the prevention of overweight and obesity in Kenya: a stakeholder engaged modelling study
Creators: name: Wanjau, Mary N
Publisher: name: Griffith University
Year: 2023
Subjects: subject: overweight
subject: obesity
subject: health and economic impact
subject: cost-effectiveness
subject: Kenya

description: Globally, overweight and obesity have been identified as leading risk factors for noncommunicable diseases (NCDs). In Kenya, the increasing prevalence of overweight and obesity and related NCDs has created a double burden of disease due to the persisting burden of infectious diseases. There are multiple potentially effective strategies for the prevention and control of overweight and obesity. It is important to ensure that choice of interventions leads to optimal health for the available budget. Health impact assessment and cost effectiveness analysis of interventions provide evidence to guide such policy decisions. This thesis aims to assess the health and economic impact of overweight and obesity in Kenya and assess the impact and cost-effectiveness of interventions for the prevention of overweight and obesity in Kenya. The thesis applies the Assessing Cost-Effectiveness (ACE) approach to priority setting with stakeholder engagement as part of the due process. The Kenya Obesity Model, a proportional multistate life table model was developed and used to conduct three assessments. In the first assessment, the future course of the population disease burden in Kenya that is attributable to high body mass index (BMI) is modelled, against an upward trend in BMI. This is implemented by estimating the impact of the elimination of exposure to high BMI (&gt;22.5kg/m2) on health adjusted life years, health adjusted life expectancy, and the burden of 27 obesity-related diseases. In the second assessment, the potential impact of achieving Kenya’s set obesity target (halting the rise of overweight, including obesity, by 2025) is quantified. Outcomes assessed include the impact on health, healthcare costs and productivity gains. The Human Capital Approach to estimate productivity gains. In the third assessment the potential health impact, economic impact, and cost-effectiveness of interventions for the prevention and control of overweight and obesity in adults in Kenya is estimated. Interventions for inclusion were selected from two broad strategies identified by stakeholders. Considering a health system perspective, two interventions were assessed for cost-effectiveness. Incremental cost-effectiveness ratios (ICERs) were calculated. The Human Capital Approach was used to estimate productivity gains. For all the three assessments, the 2019 Kenya population was modelled over their remaining lifetime with risks for the related NCDs rising only from age 20 and no burden among children. Within the model, the productivity outcomes are estimated for the 2019 working population in Kenya (20 years up to retirement age of 65 years) over their lifetime. Deterministic and probabilistic sensitivity analyses were conducted to quantify uncertainty. Findings showed that elimination of high BMI could see approximately 83·5 million health-adjusted life years (HALYs) saved, and the health-adjusted life expectancy increased by 2·3 (95% uncertainty interval [UI] 2·0-2·8) years for females and 1·0 (95% UI 0·8-1·1) years for males. Halting the rise of overweight in the year 2025 was estimated to save 6.8 million HALYs (95%UI 5.8- 7.9 million) over the lifetime of the 2019 Kenyan population or 135 HALYs per 1,000 persons. About US$ 755 million in body mass-related healthcare costs could be saved by 2044 (US$ 15 per capita) equivalent to 16% of Kenya’s current annual healthcare expenditure. The total productivity gains resulting from a reduction in obesity-related mortality and morbidity (combined) could be as high as ~US$ 5.8 billion by 2044. When interventions were evaluated, the findings show that all modelled interventions would yield substantial health gains, healthcare cost savings and productivity gains. There were wide differences in the sizes of the impacts, with two specific interventions (a 20% tax on sugar-sweetened beverages and mandatory kilojoule menu labelling) resulting in good impact while two more broad scenarios that were assumed to results in large changes in consumption patterns had very large impacts (i.e., a change in national consumption levels scenario and a change in consumption levels related to supermarket food purchase). The two interventions were found to be very cost effective without cost offsets, and dominant (health promoting and cost-saving) with cost offsets included. These interventions could be considered for implementation as part of Kenya’s NCD control plans. The magnitude of the health and economic impact of overweight and obesity in Kenya underscores the need to prioritise prevention and control of overweight and obesity and related NCDs in Kenya. The Kenya Obesity Model infrastructure can be used in future research work to help set priorities for NCD control in Kenya and similar settings.