The future of metabolic health and weight loss drugs

Widespread use of GLP-1 weight loss drugs to treat obesity could reduce cumulative all-cause mortality by up to 6.4% in the US and 5.1% in the UK general populations by 2045, our modelling projects. We anticipate mortality reductions in cardiovascular disease (CVD), and lower morbidity in a range of other conditions, if clinical trial results are replicated in the real world. This has significant implications for Life and Health (L&H) insurers, as GLP-1 drugs may reshape claims experience across mortality, longevity and medical insurance products. However, GLP-1 drugs were first developed for diabetes treatment and have not yet proven they can lead to long-term, sustained improvements in population level metabolic health. 

GLP-1 drugs have the potential to reverse the rising rates of diabetes and insulin resistance that are strongly associated with major causes of death. The US, which has the developed world's highest adult obesity level (BMI≥30) at 40.3%, is forecast to exceed 55% adult obesity by 2050 without intervention.  Life expectancy gains have slowed markedly since about 2010 in many advanced markets alongside the rise in obesity, and GLP-1 drug uptake could set off a new wave of mortality improvement. In a head-to-head clinical trial over 72 weeks, injectable semaglutide and tirzepatide produced weight loss averaging 15 – 23kg (33 – 51lb) respectively.

In the US and UK general populations, our modelled baseline scenario projects 4% and 3.2% reductions in cumulative all-cause mortality respectively by 2045, based on GLP-1 drug use. Here we assume majority use in the target overweight and obese population, with some sustained lifestyle changes but variable weight loss outcomes.

Under our pessimistic scenario, in which drug use is limited and impacts are modest, the cumulative reduction would be 2.3% (US) and 1.8% (UK), we project. Yet semaglutide and tirzepatide are not risk-free drugs, and our assessment incorporates many caveats. In real world use, where people do not benefit from support to alter their lifestyle, the risks of discontinuation of the treatment, weight regain and rebound effects are all common. The loss of lean muscle mass and bone density as well as fat is also a risk.

For life insurance underwriting, these findings suggest a potential reduction in major causes of claims in mortality and critical illness portfolios. This may however create financial pressure for longevity portfolios, as extended lifespans increase the duration of pension payouts. Medical insurance faces a near-term challenge from costs of coverage as the drugs are for now expensive on patent. In underwriting, more holistic assessments of metabolic health may in future supplement BMI as core metrics (as in Swiss Re's Life Guide). Yet if individuals purchase insurance after significant weight loss through GLP-1 drug use, it may risk distorting insurers' assumptions of future weight trajectories. Pricing, reserving, and valuation assumptions may need updating if the positive indications from weight loss drugs to treat insulin resistance materialise.

GLP-1 drugs seem unlikely to be the sole solution to societal metabolic ill-health, but L&H insurers could view them as a valuable tool in a holistic approach to obesity treatment that supports positive lifestyle changes. Swiss Re's approach aims to help the industry move beyond observation to actively engage in shaping healthier, more resilient populations.