Deep Report on Hypertension
Note: This post (and the underlying report) was updated in October 2023 after additional research and analysis.
Summary:
We find that advocacy for top sodium control policies to control hypertension to be highly-cost effective (~36,620 DALYs per USD 100,000, which is at least 10x as cost-effective as giving to a GiveWell top charity).
Beyond raw cost-effectiveness estimates (which are highly uncertain), the cause looks highly promising, given the high quality of evidence underlying the theory of change.
Reinforcing this, the expert consensus supports the fact that this is an effective solution for a growing problem.
Further support comes from the fact the harder-to-quantify downsides to the intervention (e.g. lower freedom of choice) are comparatively low.
Our detailed cost-effectiveness analysis can be found here, as can the full report can be read here.
Introduction: This report on hypertension is the culmination of three iterative rounds of research: (i) an initial shallow research round involving 1 week of desktop research; (ii) a subsequent intermediate research round involving 2 weeks of desktop research and expert interviews; and (iii) a final deep research round involving 3 weeks of desktop research, expert interviews, and the commissioning of surveys and quantitative modelling. Note also that an initial version of this report was published in July 2023, before being updated with further research in October 2023.
Importance: Globally, hypertension is certainly a problem, and causes a significant health burden of 248 million disability-adjusted life years (DALYs) in 2024, as well as an accompanying net economic burden equivalent to 748 million foregone doublings of GDP per capita, each of which people typically value at around 1/5th of a year of healthy life. And the problem is only expected to grow between 2024 and 2100, as a result of factors like high sodium consumption, ageing, and population growth.
Neglectedness: Government policy is far from adequate, with only 4% of countries currently implementing the top WHO-recommended ideas on sodium reduction, and this not expected to change much going forward – based on the historical track record, any individual country has only a 1% chance per annum of introducing such policies. At the same time, while there are NGOs working on hypertension and sodium reduction (e.g. in China, India and Latin America) – and while some are impact-oriented in focusing on poorer countries where the disease is growing far more rapidly than in wealthier countries – fundamentally, not enough is being done.
Tractability: There are many potential solutions to the problem of hypertension (e.g. reducing dietary sodium, increasing potassium consumption, and pharmacological agents); however, we find that the most cost-effective solution is likely to be advocacy for top sodium reduction policies – specifically: a sodium tax; mandatory food reformulation; a strategic location intervention to change food availability in public institutions like hospitals, schools, workplaces and nursing homes; a public education campaign; and front-of-pack labelling. The theory of change behind this intervention package is as such:
Step 1: Lobby a government to implement top sodium reduction policies.
Step 2a: Sodium tax reduces sodium consumption.
Step 2b: Mandatory food reformulation reduces sodium consumption.
Step 2c: Strategic location intervention reduces sodium consumption.
Step 2d: Public education reduces sodium consumption.
Step 2e: Mandatory front-of-pack labelling reduces sodium consumption.
Step 3: Lower sodium consumption in a single country reduces blood pressure and hence the global disease burden of hypertension
Using the track record of past sodium control and sugar tax advocacy efforts and of general lobbying attempts (i.e. an “outside view”), and combining this with reasoning through the particulars of the case (i.e. an “inside view”), our best guess is that policy advocacy for top sodium reduction policies has a 6% chance of success. Meanwhile, based on various systematic reviews and meta-analyses, and after robust discounts and checks (e.g. for a conservative theoretical prior of a null hypothesis; for endogeneity; or for publication bias), we expect that top sodium reductions policies to significantly reduce sodium consumption: (a) sodium tax (-77 mg/person/day); (b) mandatory food reformulation (-226 mg/person/day); (c) strategic location intervention (-23 mg/day); (d) public education campaign (-35 mg/day); and (e) mandatory front-of-pack labelling (-53 mg/day). Finally, based on a quantitative model we commissioned an external expert epidemiologist – itself using parameters from meta-analyses and other empirical data – we expect that lower sodium consumption of 1mg/person/day in a single country will lead to a 0.000008% reduction in the global disease burden of hypertension.
There are externalities to the top sodium reduction interventions – both positive, like a reduced disease burden of stomach cancer; or negative, like reduced freedom of choice as a result of a sodium tax. However, the impact of these externalities are marginal relative to the burden of hypertension itself (0.7% for stomach cancer) or low (-10% for freedom of choice). What is significant is the gain in cost-effectiveness (around 300%) from implementing the intervention in the most promising countries rather than the average one – that is, those countries suffering from some combination of a higher national disease burden, greater neglect by their governments and NGOs, and state fragility.
Implementation Issues: From our interviews with NGOs working in the space, we find that there is a lack of funding; and this is backed up by observations from the academic literature. However, on the talent side of things, the NGOs we interviewed were more optimistic; they tended to believe that there is not a talent gap.
Outstanding Uncertainties: There are a number of outstanding uncertainties, of which the three most important involve: (a) our use of point estimations (n.b. relying on them is reasonable given that we are ultimately interested in mean estimates, but caution is also warranted, as significant variance is possible); (b) the very simplified methodology we use to project the future disease burden of hypertension; and (c) the highly uncertain estimates of the probability of advocacy success.
Conclusion: Overall, our view is that advocacy for top sodium reduction policies to control hypertension is an extremely cost-effective cause area, and we recommend that nonprofits, grantmakers, policy advocacy organizations, and indeed government themselves, implement the highly-impactful ideas detailed in this report.
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Regarding increasing potassium intake:
A few weeks ago, I heard about this as a good idea via a podcast which claimed that getting closer to the potassium recommendations would remove a large part of the problems of high sodium consumption. I switched my salt to 2⁄3 sodium and 1⁄3 potassium a few weeks ago, and until now I didn’t notice negative effects on taste[1].
Given that potassium is not that expensive, my impression was that a public policy of “everyone, potassium is x% part of table salt from now on” would lead to a large chunk of the benefits without people having to change their taste preferences a lot (by both decreasing sodium by x% and increasing potassium consumption correspondingly). This would increase the prize of salt significantly, which should have similar effects to a sodium tax (the prices would still amount to low single-digit cent costs per day even for high salt consumption).
I would be curious about your thoughts on this, given that you have researched this topic a lot more deeply :)
Nonetheless I could still imagine that there are a number of foods with completely excessive amounts of salt for which other interventions would still be a good idea.
I trust the nutritionist enough to be confident that this change is a good idea for me personally, but I did not look up the sources and I might well have misunderstood the effect-size of increasing potassium consumption
Hi Mart,
Thanks for your interest! You would have seen the discussion of potassium in the section on potential interventions—and I think the TLDR is that it does look good, but does cost money. Hence, we’re pursuing sodium reduction right now; but as we work with our partners doing the actual advocacy reach-out to governments, we’ll definitely get them to raise potassium as an option. Hopefully, in the long term, economies of scale make these more cost-competitive.
That makes a lot of sense—in practice, there are many relevant considerations and other interventions might well be preferable in many contexts.
The expert opinion
also sounds as if potassium-enriched salt surely helps to some degree, but probably isn’t a solution by itself. And I get the impression that research in the coming years will probably improve the uncertainties here.
Apart from this, I am a bit surprised that the costs (“perhaps double the price”) would be a problem for richer countries. If I am understanding this right, this should still be obviously worth it as a health expenditure? A very simple estimate might be:
lost expected life due to high blood pressure: ~2 years (scaling the DALY burden to a single person)
expected gains from switching to potassium-enriched salt: ~1/2 year (I am guessing)
expected costs: 80 years * 2⁄3 kg/year * $10/kg = ~$550
resulting cost-effectiveness (assuming 1 year = 1 DALY): $1100 / DALY averted
Of course this isn’t comparable to GiveWell effectiveness, but it is really cheap compared to other health expenses.
The thing is that potassium salt (or mixed sodium/potassium salts) are available in rich country; it’s really just a matter of uptake. Consumers might not know or think much about the health aspects of things; they might not be price sensitivity; and even “double” is an off the cuff estimate by the expert, and it probably depends on country and location (e.g. f I check Walmart’s e-commerce website, Morton’s potassium salt is 10x as expensive as normal salt).
So it goes back to policy, and whether governments should just regulate sodium content even in salt—we didn’t really explore this, given the higher evidence base and cheapness of salt policies.
That makes a lot of sense!
This describes me quite well in many of my health choices, and unfortunately this is apparently really common.
In my case, I also did not find salt that is pre-mixed at a price that makes sense to me—I bought a pharma-grade bag of KCl and mixed it with usual table salt myself[1], which resulted in a net-price that is 3x of the usual sodium salt.
That sounds very reasonable—I’ll be looking forward to hearing about updates in the future!
with the hope that diluting by 1⁄3 will not be too much for the anti-hygroscopic components of the store-bought table salt
Wow thanks I didn’t know about the potassium alternative ( and in as doctor), that’s exciting I might look into it for myself!
Would not be a difficult cost effectiveness analysis to see if this made sense, nice idea.
I just realized that I could also just follow the links and found a part of the answer
in section 4.1 1) g)
and also
in section 3.3. Global Salt NGO, point 2.
I am happy to learn that people are working on this :) And it does make sense that the increased price also creates difficulties for adoption. This certainly isn’t a trivial problem. Also, I agree that the public relations perspective is important. Here in Germany, there were large health problems due to missing Iodine, which were reduced by fortifying table salt—but even though the necessity for Iodine hasn’t changed, people/products are starting to use the fortified salt less.
I really like this post.
I was just commenting on a post about the value of maintaining the umbrella organisation and label “Effective Altruism.” This study is a perfect example of why it’s important.
This is an idea that I, and I suspect many others, would never have even thought about, so we come to the EA forum and we learn about new ways to help.
The way you wrote the post (EA-style) enables us to compare this with any other EA work, obviously with increasing degrees of uncertainty as we move further afield, but still in a quantitative way with clear assumptions that can be modified with new data.
Humans often innovate by analogy. Seeing this initiative in the area of health and well-being might trigger ideas in other fields. For example, what is maybe novel (to me) about this approach is that often when we look at poorer countries, we instinctively focus on what we can do to get them to be more like us, to remove the problems they have that we don’t have, because we are not poor. But here you focus on a problem that we in the rich West also have, a problem that is not uniquely due to poverty—but you show that it can still enable a very effective intervention. I ask myself, are there aspects of say AI Safety or Bio-safety where we could make a powerful intervention but we neglect them because they are not immediately obvious? (I don’t know, but it’s good to think like this).
Thanks, Denis!
I think the main takeaway for other cause areas would probably just be how impactful changing government policy is—you trade off (a) needing to persuade governments in the first place, for (b) massive scale of impact and also (c) much, much lower counterfactual cost of government expenditure relative to EA expenditure. There’s a lot of stuff that may not be worth doing if the price was less money to GiveWell; but not if the price was the US government running a slightly higher budget deficit.
Good perspective. Thanks for answering!
Also in support of the sodium tax is that we’ve seen health taxes used as a cost-effective way improve health/save lives in tobacco, alcohol, and sugar sweetened beverages. For tobacco, taxation is the most cost-effective of all the tobacco control measures. I’m not surprised to see the evidence point to a sodium tax.
Definitely—though I think mandatory reformulation is the best amongst the existing top solutions we recommend. It shows the largest effect size under the modelled parameters, but also it’s probably less politically toxic—taxes are comparatively harder. We see this with climate too, where people favour quotas/quantitative limits over taxes even if the effects are literally identical.
Very nice summary, Joel. Please note that in addition to the SSASS cluster-randomized clinical trial https://www.nejm.org/doi/full/10.1056/nejmoa2105675, there has also been this more recent cluster-randomized potassium substitution trial: https://www.nature.com/articles/s41591-023-02286-8 & an older cluster-randomized potassium substitution trial https://www.sciencedirect.com/science/article/pii/S0002916523294599?via%3Dihub.
The final table in the Supplement is essential to understanding the conclusion of the above study published recently in Nature Medicine—in summary sodium reduction per se didn’t have an impact, but as best I can tell that could be because sodium reduction wasn’t achieved at all.
This article by Derek Denton offers a great deal of useful information on this topic: https://www.nature.com/articles/1000489.
Hi Joel,
Has this research led to any concrete grants, or prompted GiveWell to estimate the cost-effectiveness of advocating for taxing sodium?
Hi Vasco,
(1) In hypertension/salt reduction policy, CEARCH (in collaboration with the donors we advise) has made 150k in grants (specifically, projects advocating for—and assisting governments in implementing—reformulation policies to reduce sodium in food).
In diabetes/soda taxes, CEARCH has made 63k in grants (specifically, technical assistance to improve enforcement of and compliance with SSB taxes).
(2) For the the bigger GW grantmakers, I’m unsure how much I can share given confidentiality, and I don’t want to falsely give the impression that these grantmakers have already developed any specific views/positions/recommendations in this area, but I think I can broadly share that:
(a) FP previously asked us to help evaluate two large global NGO that worked on salt policy, with a specific focus on trying estimate the counterfactual advocacy success rate of salt policy advocacy campaigns (it’s about 10%). We ended up making a positive recommendation, particularly for RTSL and its salt reduction work. Note that FP already supports RTSL’s trans fat reduction work.
(b) GiveWell is currently considering making a salt grant to RTSL, but I understand it’s exploratory in nature (see how this goes, then follow-up from there). They have also done some internal CEAs of SSB taxation projects; I think their major concern (a frustration shared by us) relates to high uncertainty over the existing GBD estimates of the SSB burden (n.b. the estimates changed wildly from one iteration of the GBD to the next, and it’s not clear to us how or why the methodology changed). FWIW, I don’t see any evidence that the GBD estimates are systematically biased (particularly upwards, which would be the main concern), so we’re happy to go ahead.
(3) Broadly speaking, I’ll say that while there is very good reason think that health policy to prevent NCDs is extremely cost-effective (NCDs are a big and growing problem + policy offers large scale of impact at low cost), it’s also very risky, and very much hits-based EV-maximizing grantmaking, which is not something many grantmakers or donors are comfortable with. Correspondingly, we’ve only been able to move about 100k per annum so far in this area (compared to something like mental health, where we helped a partner move 10x that).
Thanks for the great context, Joel!
Which organisation would you recommend to someone wanting to maximise human-years in a fully causal and risk neutral way (the organisation does not have to work on non-communicable diseases (NCDs))? What is your best guess for its cost-effectiveness in terms of additional human-years per aditional $ spent as a fraction of that of GiveWell’s top charities, which I estimate to be 0.0128 human-year/$? It would be great if you could briefly explain why, such as by linking to any supporting cost-effectiveness analyses (CEAs). I am asking because I suspect increasing human-years as cost-effectively as possible is the most cost-effective way to decrease negative animal-years of wild animals, via increasing cropland supporting food consumption.
I thought GiveWell was quite risk neutral considering their extensive funding of deworming. I also wonder why Open Philanthropy’s (OP’s) Global Public Health Policy (GPHP) team is not focussing on diabetes and hypertension.
Hi Vasco,
(1) We’ve generally looked at DALYs (and not just deaths/YLL averted), but given the high cost-effectiveness of both hypertension/salt & diabetes/SSB in DALY terms (with the former being somewhat less cost-effective but having deaths make up like 90% of the burden), they’re plausible candidates (CEAs linked in the cause evaluation result spreadsheet). Trans fat/tobacco/alcohol are other plausible candidates—given the clear scientific evidence on mortality + it being difficult to beat policy ideas for cost-effectiveness. You’ll probably also have more speculative stuff like funding development of new vaccines or doing biological control of mosquitoes, but we haven’t done any deep research there.
Nuclear/volcanic winter famine mitigation is another candidate (CEA in the spreadsheet), though obviously there’s a strong self-defeating element from a WAW perspective.
(2) GiveWell’s grantmaking criteria include not just cost-effectiveness but also evidence of effectiveness (which means excluding those high-uncertainty high-EV stuff), though I would say that there is a distinction between their public facing recommendations (which do need to work within the constraint of retail donor risk aversion) and some of what GiveWell funds through other means (e.g. the explicitly more maximization-oriented All Grants Fund or via recommendation to OP). Some riskier stuff GiveWell/OP has funded include alcohol policy and pesticide suicide prevention.
(3) Chris Smith and his team are great, but extremely limited in their time, so I don’t think there’s much ability to expand beyond lead and air pollution right now, even if they wanted to. Also, it’s always important to keep in mind that OP isn’t any different from other research/grantmaking organizations insofar as the researchers/programme officers are constrained by donor preference and risk aversion (specifically GV’s).
Thanks, Joel! I guess you would recommend donating to Resolve to Save Lives (RTSL) in order to increase human-years as cost-effectively as possible.
Expanding cropland is a great way to increase food production in nuclear and volcanic winters.
I do think RTSL’s salt policy work (and other salt policy projects, particularly ImagineLaw in the Philippines) are reasonably good bets for maximizing life years saved. That said, I don’t an individual donation to RTSL would help insofar as smaller donors can’t purpose restrict it (see their donation button at https://resolvetosavelives.org/).
In practice, I would suggest donating to CEARCH’s GHD policy regranting budget (via https://exploratory-altruism.org/work-with-us/, or just email me and I’ll put you in touch with our fiscal sponsor), making a note on purpose-restriction if you wish, and then your donation goes out as part of a broader consolidated package (e.g. that 63k grant we made on SSB tax enforcement was me personally and 5 other EA donors pulling together).
On nuclear/volcanic winter—won’t the direct effect just be straightforwardly mass extinction of wild animals, which eliminates their suffering? And in contrast, a lot of currently valuable farmland may just not be usable when temperatures shift, so there may not be an offset. A lot of uncertainty regardless, and reasonable people can disagree.
“High Impact Philanthropy Fund @ PPF” links to CEARCH’s contact page, so I suppose people always have to email you in order to make a donation, thus discouraging small donations. I wonder whether there is an easy low cost way of enabling these.
Hi Vasco, thanks for flagging out. I’ve updated our Work With Us page to include the direct donation link (additional 1-3% in fees, but more convenient; if donors prefer minimizing fees, they should feel free to reach out and we can guide them through the cheaper wire transfer)
Thanks, Joel!
Thanks for clarifying, Joel! I plan to recommend people donate to CEARCH’s High Impact Philanthropy Fund (HIPF) in a post I am writing which I will share in this thread once it is published. Is HIPF trying to avert as many DALYs as possible in a risk neutral way? If so, I do not have to recommend restricted donations. Do you have a guess for HIPF’s marginal cost-effectiveness as a fraction of that of GiveWell’s top charities? I would guess 55 as implied by CEARCH’s CEA of advocating for taxing sugar-sweetened beverages (SSBs).
Impact, nuclear, and volcanic winters would decrease the number of wild animals a lot, but replacing forested area with cropland to produce more food would decrease them further.
Our grantmaking always aims at maximizing DALYS averted (with income and other stuff translated to DALYs too).
In terms of cost-effectiveness, it’s nominally 30-50x GW, but GiveWell is more rigorous in discounting, so our figures should be inflated relative to GW. Based on some internal analysis we did of GW’s greater strictness in individual line-item estimation and in the greater number of adjustments they employ, we think a more conservative estimate is that our estimates may be up to 3x inflated (i.e. something we think is 10x GW may be closer to 3x GW, which is why we use a 10x GW threshold for recommending GHD causes in the first place—to ensure that what we recommend is genuinely >GW, and moving money to the new cause area is +EV).
So my more conservative guess for our grantmaking is that it’s closer to 9-15x GW, but again I have to emphasize the high uncertainty (and riskiness, which is the inherent price we pay for these ultra high EV policy interventions).
Thanks, Joel! Do you also think your estimate that donating to Giving What We Can (GWWC) this year is 13 times as cost-effective as GiveWell’s top charities is also 3 times as high as it should be, such that your best guess is that it is 4.33 (= 13⁄3) times as cost-effective as GiveWell’s top charities (although there is large uncertainty)? Or is the adjustment only supposed to be applicable to CEARCH’s CEAs listed here?
Hey Vasco, the adjustment is specific to GiveWell vs us (or indeed, non-GW CEAs), since GiveWell probably is the most rigorous in discounting, while other organizations are less so, for various reasons (mainly time—that’s true for us, and why we just use a rough 10x GW threshold; and it’s true of FP too; Matt Lerner goes into detail here on the tradeoff between drilling down vs spending researcher time finding and supporting more high EV opportunities instead).
Relative to every other organization, I don’t find CEARCH to be systematically overoptimistic in the same way (at least for our deep/final round CEAs).
For our GWWC evaluation, I think the ballpark figure (robustly positive multiplier) probably still holds, but I’m uncertain about the precise figure right now, after seeing some of GWWC’s latest data (they’ll release their 2023-24 impact evaluation soon).
I have now published the post where I recommend HIPF. It looks into the cost-effectiveness of interventions accounting for soil nematodes, mites, and springtails.