key: cord-0790666-yqzfpclt
authors: Galvain, Thibaut; Patel, Suzi; Kabiri, Mina; Tien, Stephanie; Casali, Gianluca; Pournaras, Dimitri J.
title: Cost-effectiveness of bariatric and metabolic surgery, and implications of COVID-19 in the UK
date: 2021-07-27
journal: Surg Obes Relat Dis
DOI: 10.1016/j.soard.2021.07.009
sha: b33eb5765307bb8b0f2703c22d20903a2bec8ff3
doc_id: 790666
cord_uid: yqzfpclt

BACKGROUND: People living with obesity have been among those most disproportionately impacted by the COVID-19 pandemic, highlighting the urgent need for increased provision of bariatric and metabolic surgery (BMS). OBJECTIVES: To evaluate the possible clinical and economic benefits of BMS compared with non-surgical treatment options in the UK, considering the broader impact that COVID-19 has on people living with obesity. METHODS: A Markov model compared lifetime costs and outcomes of BMS and conventional treatment, from the UK perspective, amongst patients with BMI ≥40 kg/m(2), or BMI ≥35 kg/m(2) with obesity-related comorbidities (Group A), or BMI ≥35 kg/m(2) with type 2 diabetes mellitus (T2DM; Group B). Inputs were sourced from clinical audit data and literature sources; direct and indirect costs were considered. Model outputs included costs and quality-adjusted life years (QALYs). Scenario analyses whereby patients experienced COVID-19 infection, BMS was delayed by five years, and BMS patients underwent endoscopy were conducted. RESULTS: In both groups, BMS was dominant versus conventional treatment, at a willingness-to-pay threshold of £25,000/QALY. When COVID-19 infections were considered, BMS remained dominant and, over 1,000 patients, prevented 117 deaths, 124 hospitalizations and 161 ICU admissions in Group A, and 64 deaths, 65 hospitalizations and 90 ICU admissions in Group B. Delaying BMS by 5 years resulted in higher costs and lower QALYs in both groups compared to not delaying treatment. CONCLUSIONS: Increased provision of BMS would be expected to reduce COVID-19-related morbidity and mortality, as well as obesity-related comorbidities, ultimately reducing the clinical and economic burden of obesity.

People living with obesity have been among those most disproportionately impacted by the COVID-19 pandemic, highlighting the urgent need for increased provision of bariatric and metabolic surgery (BMS). 5

To evaluate the possible clinical and economic benefits of BMS compared with nonsurgical treatment options in the UK, considering the broader impact that COVID-19 has on people living with obesity.

There is a paucity of effective interventions for obesity, with the exception of bariatric and metabolic surgery (BMS). [1] [2] [3] However, despite positive Diabetes Surgery Summit (DSS) and UK National Institute for Health and Care Excellence (NICE) recommendations, [4, 5] the provision of BMS is particularly limited in the UK 5 relative to other European countries.[6, 7] As a result, many patients living with obesity in the UK do not have access to the most effective treatment. [7] People living with obesity have been among those most disproportionately impacted by the COVID-19 pandemic, due to high rates of hospitalization, intensive care unit admission and mortality,[8-10] with increasing BMI linked to more severe COVID-10 19 .

[10] This highlights an urgent need to improve access to interventions shown to address known risk factors for COVID- 19 . The pandemic has also led to the delay or cancellation of many elective procedures, including BMS.

[11] Delayed surgical treatment for obesity has been shown to impair postoperative outcomes, including the likelihood of achieving diabetes remission. [11] Delays as short as one year have 15 also been shown to increase the cost of care versus prompt surgery. [12] There is therefore a need to better understand the potential impact of the COVID-19 pandemic, including delays to BMS, on patients living with obesity and healthcare systems.

The objective of this study was to evaluate the potential clinical and economic 20 benefits of BMS compared with conventional, non-surgical treatment options from a healthcare payer and a societal perspective in the UK, considering the broader impact that COVID-19 has on patients living with obesity. 

A cost-effectiveness analysis (CEA) was performed using a Markov model with a lifetime horizon, as with previously published analyses, [13, 14] to evaluate the economic impact of BMS from a UK healthcare payer and a societal perspective.

In alignment with the 2 nd Diabetes Surgery Summit (DSS-II) and NICE guidelines, [4, 5 5 ] the following two populations were considered in the CEA: patients with BMI ≥40 kg/m 2 or BMI ≥35 kg/m 2 with obesity-related comorbidities (Group A), and patients with BMI ≥35 kg/m 2 with type 2 diabetes mellitus (T2DM; Group B).

The base case analysis compared the two most common types of BMSlaparoscopic gastric bypass and laparoscopic sleeve gastrectomy -with conventional 10 treatment, defined as supervised diet and exercise programs with or without pharmacotherapy. Distinct, procedure-specific inputs were utilized for the two different types of BMS. Outputs were calculated as an average of the two, weighted according to their relative utilization in UK clinical practice.

A scenario analysis was conducted to quantify the impact of BMS relative to 15 conventional treatment among patients living with obesity and infected with COVID- 19 . In this scenario, all patients experienced infection once during one cycle one year after treatment. Infections could lead to hospitalization, intensive care unit (ICU) admission and/or death. These events were adjusted according to patients' BMI levels. [8, 15, 16] The results were compared with the base case analysis (no 20 consideration of COVID-19 infection). 5 An additional scenario analysis was conducted wherein BMS treatment and effects thereof were delayed for 5 years, in line with waiting times reported in the literature. [17] . Prior to BMS, all patients received conventional treatment and experienced the effects thereof.

The potential impact of endoscopy screening being required for all patients 5 undergoing BMS and post-operative surveillance endoscopy being required for sleeve gastrectomy patients, in line with recent International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) statements, [18, 19] was also investigated.

Extended details of the study methodology can be found in the supplementary material. 

Model baseline characteristics (mean age, mean BMI, proportion of females and proportion with T2DM) were obtained from audit data on patients that underwent 5 BMS in the Bristol, UK area. All other clinical inputs, including the efficacy and safety of BMS and conventional treatment, were sourced from the literature. Table 4 and those specific to the endoscopy scenario analysis in Supplementary Table 5 . Supplementary Table 6 . 20

Costs included the cost of treatment and the costs associated with each comorbidity.

Where possible, unit costs were derived from NHS reference costs (inflated to 2019 J o u r n a l P r e -p r o o f 7 GBP values); all costs were UK-specific. Cost inputs are summarized in Supplementary Table 7 .

Societal impact was measured by incorporating productivity losses/gains, based on employment rate and work impairment, into the model, which were dependent on BMI. 5

An annual discount rate of 3.5% was chosen for both costs and utilities, as per the NICE reference case. [21] 

Model outputs included costs and QALYs. These were used to calculate the costeffectiveness of BMS versus conventional treatment, represented as incremental 10 cost-effectiveness ratios (ICER; the difference in cost between two interventions, divided by the difference in their effect [QALYs] (Table 2) .

Compared to the base case (no consideration of COVID-19 infection), BMS was 10 associated with a per-patient increase in incremental survival years (+2.12 and +1.04 in Group A and Group B, respectively), QALYs (+0.37 and +0.08, respectively) and incremental costs (+£3,889 and +£4,082, respectively; Table 2 ).

Compared to the base case, NMB remained positive, increasing by £5,298 to £115,322 in Group A and decreasing by £2,027 to £62,468 in Group B. 15

The results of the COVID-19 scenario analyses were most sensitive to variation in the risk of COVID-19-related death per BMI unit (Supplementary Figure 3) .

In Group A and Group B, delaying BMS by 5 years was associated with less cost savings (-4.2% and -12.3%, respectively), fewer QALYs gained (-10.2% and -4.5%, 20 respectively) and a reduction in survival years (-8.6% and -5.7%, respectively) compared to not delaying the treatment (Table 3) . 10 Compared to the base case, NMB remained positive, decreasing by £11,381 to £98,643 in Group A, and by £3,284 to £61,211 in Group B. BMS was dominant versus conventional treatment in both groups.

When pre-operative endoscopy for all patients and post-operative endoscopy for 5 sleeve gastrectomy patients every 3 years were considered, BMS was associated with higher costs relative to the base case analysis, but remained cost saving compared with conventional treatment, in both groups (Supplementary Table 10 ).

The results of this study show that BMS is expected to lead to a reduction in costs 10 and an increase in HRQoL, yielding substantial NMB over a lifetime horizon. Further, from a societal perspective, BMS was shown to be cost saving within a maximum of 4 years for the UK NHS.

These results are in agreement with multiple prior studies showing that BMS offers significant health benefits to patients living with obesity and T2DM, including a 15 reduction in mortality and comorbidities, [22, 23] and is a cost-effective treatment option for healthcare providers. [14, 24, 25] Despite this, patient access to BMS is 

This study considered multiple populations in line with those most strongly recommended by DSS-II and NICE and a broad range of comorbidities, [4, 5] and utilized a lifetime horizon, helping to understand the potential long-term impact of 13 BMS. It is important to note that, although the highest level of evidence was prioritized, the sourcing of data occurred via targeted reviews, as opposed to systematic literature searching, which possibly resulted in relevant data being missed. In addition, given the absence of studies able to evaluate causal inference, data informing the COVID-19 scenario analysis was based on observational studies 5 alone. However, the latest evidence on BMS was utilized, with longer follow-up times than evidence used in previously published cost-effectiveness analyses. [13, 14] Due to a lack of complete data across all populations, the clinical data do not 3 † Conventional treatment comprised behavior change strategies to increase patients' physical activity or decrease inactivity, improve eating 4 behavior and the quality of the person's diet, and reduce energy intake. 3 † Conventional treatment comprised behavior change strategies to increase patients' physical activity or decrease inactivity, improve eating 4 behavior and the quality of the person's diet, and reduce energy intake. 

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