Background/Purpose: Intake of sugar is associated with increased incident gout. Sugar taxes have been effective at reducing the intake of sugar in several jurisdictions. We aimed to model the impact of a sugar tax on incident gout (assuming causality through increased serum urate levels and a consequent increase in incident gout), quality adjusted life years (QALY) lost and the excess economic cost of new incident gout.

Methods: We modelled the effect of a sugar tax on incident gout in the US population (n=330M) on the study by Choi and colleagues (Arthritis Care & Research 2008;59:109-116). Our model assumptions were a 20% ad velorum (value of the item) taxation level, a price elasticity of -0.95 (defined as the percentage change in the quantity demanded over the percentage chance in price). A passthrough rate of 100% (the amount of tax passed through from the manufacturer to the consumer), a 2.5% per annum discount rate, healthcare inflation rate of 6.5% per annum, and a marginal disutility rate of 0.05 (this is the impact on QALY of a diagnosis of gout). We modelled incident gout rates using the Atherosclerosis Risk in Communities Study (ARIC), Coronary Artery Risk Development in Young Adults Study (CARDIA), and both the Original and Offspring cohorts of the Framingham Heart Studies (FHS). We modelled 3, 5, 10 and 15 year incident gout from < 3.0mg/dL up to 6mg/dL in 0.1mg/dl increments. Our outcomes were incident gout, increases in QALY and economic savings from the reduced gout. In modelling all time points we simulated death using US life tables. We assumed a societal perspective for costs (i.e. costs of treatment were considered regardless to whom they accrue), and a marginal cost of gout over non-gout of US$6,560 per annum. We undertook sensitivity analyses of key input parameters. We did not model the revenue to the government of the sugar tax.

Results: We fitted linear models to the raw incident gout rates from < 3mg/dL to 6mg/dL from the combined cohorts. This enabled fine scale prediction of the effect of sugar tax on reducing SU and consequent incident gout.

We found a reduction in incident gout was achievable (n=84,830) with a 20% ad velorum sugar tax over 15 years (Table 1). Based on this reduction in incident gout we were also able to model a saving of 26,398 QALY over 15 years. This led to a saving of 3.15B in net present value.

Sensitivity analyses demonstrated the model was robust to changes in key inut variables.

Conclusion: Assuming a causal relationship, based purely on the reduction in incident gout, QALY savings and economic savings, we provide evidence supporting a sugar tax to be an effective public health measure to address the growing incidence of gout. The reduction in gout and the consequent savings of QALY and costs should be included when considering the implementation of a sugar tax.

Table 1: Main model Results

ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-sugar-tax-results-in-reduced-incident-gout-quality-adjusted-life-years-lost-and-economic-cost-from-gout-a-health-economic-analysis/