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brandonb

10,054 karma · joined January 17, 2011

Data for good.

Co-Founder at Empirical Health (https://empirical.health). Don't die of heart disease.

Before: Co-Founder @ Cardiogram (ML for heart health)

  CTO at Sift Science (YC S11, machine learning to fight fraud)

  Data Science @ UCSF Cardiology

  HealthCare.gov rescue team

  Google (Android speech recognition, search ads ML)
twitter.com/bballinger

brandonb.cc

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brandonb··on The beautiful mathematics behind OpenAI's sphere packing result
There's a sketch of part of the proof in "the Mellin ansatz." I'd definitely recommend reading the sections before it, though, since they attempt to establish the more foundational connection between sphere packing and harmonic analysis (which is necessary to understand OpenAI's proof).
brandonb··on Universal health coverage could save $1T and 114k lives a year: study
I'd like to believe this, but the study makes a bunch of really hasty assumptions.

The authors derive the $1T number from $1.3T in total cost savings and $304B in incremental spend (incremental spend is due to insuring more people). The $1.3T in cost savings come from five big buckets: lower pharmaceutical prices, Medicare-level payments to providers, reduced administrative overhead, less fraudulent billing, and fewer avoidable emergency department visits and hospitalizations.

The buckets themselves don't necessarily survive much scrutiny.

Take "Medicare-level payments to providers". Hospitals have an operating margin of 2-5%. Medicare pays 50% less than private insurance. So doing this would require either layoffs, cutting salaries for doctors/nurses/etc, or both. This may well be the right decision for society as a whole--that's a big part of the debate here--but there's no free lunch.

The line item of "fewer avoidable emergency department visits and hospitalizations" assumes greater insurance coverage leads to greater access to primary care. It's true that great primary care prevents hospitalizations, and can be a net cost saving under certain assumptions [1]. But, we're actually in a primary care shortage. Existing insurance payments for primary care are low enough that private practices are going out of business and fewer residents are going into family medicine. Cutting rates (the paragraph above) would make this worse.

For "less fraudulent billing," a lot of people in the industry believe that Medicare has a large amount of undetected fraud. That's unfortunately the flip-side of reduced administrative overhead. The authors assume an 8% savings here, but the 2003 paper they cite uses the word "fraud" only twice and doesn't give a number.

Healthcare reform is hard.

[1] Reasonable breakdown on the economics of advanced primary care models: https://olearykm.medium.com/the-cost-equation-for-new-primar...

brandonb··on The beautiful mathematics behind OpenAI's sphere packing result
(OP) The first of ten problems OpenAI solved was an improvement to the Cohn-Elkies bound. I briefly worked with Henry Cohn on sphere packing in undergrad. This topic is actually surprisingly accessible to the amateur mathematician so I thought I'd write up a primer and accessible description of the actual result.
brandonb··on Online clinics and influencers are promoting Cialis as a longevity drug
Can't rule out exercise.
brandonb··on Midlife Vascular Risk Burden and Dementia-Free Survival Years
Previous studies have shown that heart health at 50 predicts brain health at 75.

This study is interesting in that it quantifies the benefit as 12.5 extra dementia-free years. People with 0 risk factors had 30 years of dementia-free survival, vs 17.5 years for people with all 3 risk factors measured.

The risk factors in this specific study are blood pressure, diabetes (HbA1c), and smoking. You could reasonably also include cholesterol/ApoB, inflammation (hs-CRP), and perhaps Lp(a) as potential risk factors.

brandonb··on Worried about your blood pressure? A $399 Ring measures it without a cuff
Blood pressure is a major input into the risk equations for heart attacks, strokes, kidney disease, and so on. For the most part we've used a one-time measurement, assuming it's an average. But if we had a time-series of blood pressure, I could see blood pressure variability actually becoming an important metric.
brandonb··on Inflammation-targeting drug misses mark in heart disease study
We've known for a while that inflammation is an independent risk factor for heart disease, alongside LDL cholesterol (or ApoB), Lp(a), and so on. Inflammation is most commonly measured by by hs-CRP or IL-6.

The ZEUS trial tested an anti-inflammatory injection (ziltivekimab). These phase III results showed a hazard ratio of 0.99, i.e., no effect.

This is evidence for a lipid-first model -- i.e., lipids drive oxidation, which then triggers inflammation.

brandonb··on Macrocyclic peptides: a new "Goldilocks" drug class?
(OP) The first oral macrocyclic peptide was approved by the FDA two weeks ago. It's a cholesterol-lowering drug, the first oral PCSK9 inhibitor -- current PCSK9 inhibitors are injected.

I found the underlying chemistry and scientific process really interesting.

I tried to answer two main questions in this specific article: 1. What was the actual process from 2013-2026 that led to enlicitide? 2. If we were restarting this work in 2026, would AI have helped? If so, at what specific stages?

Happy to answer questions if people have 'em.

brandonb··on AI's top startups are barely publishing their research
FWIW, several YC startups have also published ML research--there were several of us at the last NeurIPS. So perhaps this is a niche that startups can occupy if the big labs don't.
brandonb··on MVP for new AI interface for writing
This is cool -- I like the metaphor of AI as an sharp editor.
brandonb··on Wearable Ring Tracks Glucose, Ketone and Other Biomarkers in Sweat
This is a cool new study from UCSD research group. 11–19% mARD is interesting, although not quite accurate enough to displace CGMs (the FDA-cleared ones have ~8% mARD).

But the sweat angle is could add signal alongside other techniques like Raman or MIR spectroscopy, and maybe a combination of these and an ML system would be accurate enough to use in practice.

brandonb··on Why non-invasive glucose monitoring is hard
Definitely agreed. I'm rooting for Apple, Samsung, Oura, etc to finally crack this problem and some of the techniques in the article (MIR, Raman spectroscopy, wearable foundation models) seem like they're leading in the right direction.
brandonb··on Caffeine and Cardiovascular Disease: AHA Scientific Statement
(OP) Updated the title. This was unfortunately a mis-fire of some of HN's automatic title formatting.
brandonb··on Caffeine and Cardiovascular Disease: AHA Scientific Statement
The lead author ran a study of personalized trigger mapping for Afib, using an n-of-1 study design: https://jamanetwork.com/journals/jamacardiology/fullarticle/...

Unfortunately this particular intervention wasn't successful (not much difference between treatment and control groups). But conceivably, afib triggers is something that varies from person to person and perhaps a future design would tease this out.

brandonb··on FDA Approves a New Pill to Slash Cholesterol Levels
This is the first oral PCSK9 inhibitor; it cuts LDL cholesterol (or ApoB) levels by 50-60%. It uses a different mechanism than a statin so you can layer them to get an 80% or so reduction overall.

It also reduces Lp(a), the strongest hereditary risk factor for heart disease, by 28%.

Previous PCSK9 inhibitors like Repatha were injectables (similar to GLP-1s). Only about 1% of people eligible for injectable PCSK9 inhibitors use them, so having a convenient daily pill is a potentially huge win for prevention.

brandonb··on Smart Ring Aims to Replace the 150-Year-Old Blood Pressure Cuff
The speed of the pressure wave is one signal that correlates with blood pressure. It's a bit like a string being pulled taut -- waves travel faster with higher pressure. The shape of the wave also gives clues. For example, the rise time of the wave tells you something about the resistance encountered, which is a function of blood pressure.

Rather than hand-engineering these features, most modern systems are built on a wearable foundation model that's been trained reconstruct the signal (similar to how an LLM is trained to predict the next word). Those foundation models are picking up on these signals and likely others.

You're right that calibration with a cuff is required of all systems currently on the market.

The Signal Ring folks' claim they can do a blood pressure number without calibration, which is quite novel and seems to be their "secret sauce". They did run a clinical study as well, so presumably more details will come out whenever that's published.

brandonb··on Smart Ring Aims to Replace the 150-Year-Old Blood Pressure Cuff
Likely uses pulse transit time and the shape of the pulse wave to infer changes in blood pressure. I wrote a bit about how this works (in the context of Apple Watch's hypertension notifications) here: https://www.empirical.health/blog/apple-watch-blood-pressure...
brandonb··on Medicare starts covering GLP-1 drugs for weight loss
GLP-1s will cost $50 / month for those eligible.

To be eligible, you need either a BMI of >=35, or a BMI of >=27 and a set of specific health conditions (uncontrolled hypertension, chronic kidney disease, pre-diabetes, etc). You also can't be qualified for GLP-1s under Medicare's previous Part D coverage.

In practice these criteria are narrower than they look. Of the 13 million Medicare beneficiaries with overweight or obesity, about 4 million actually qualify, because most are excluded for already having a diagnosis, like type 2 diabetes or sleep apnea, that covers a GLP-1 another way.

brandonb··on Wearable foundation models: a brief history
(OP here) Happy to answer questions!
brandonb··on Om Malik has died
Very sad news. :(
brandonb··on U.S. health spending on pace to hit $6T
Right now lots of good health companies hiring, including my own (Empirical). https://www.workatastartup.com/ lets you filter YC companies to see health startups, by stage and location (or remote).
brandonb··on U.S. health spending on pace to hit $6T
IMO, there's an interesting opportunity for AI to make healthcare deflationary.

For example, Medicare is launching a new program in July that pays a fixed rate for achieving defined outcomes, like lowering blood pressure or cholesterol. Medicare's explicit goal here is to create incentives to automate the repetitive parts of care delivery with software. (Much of preventive cardiology is surprisingly algorithmic and guideline-driven, so this is more plausible than it seems.)

This reverses the incentives of the current system, where CPT codes incentivize doing more "stuff" (but not necesarily delivering the most effective care efficiently).

If you're a software engineer who cares about health, and have been sitting on the sidelines till now, I think the next few years are a really interesting time to make a contribution.

brandonb··on The worthlessness of Vitamin D is mildly exaggerated
It's pretty well-established science now that vitamin D is a hormone, not a true vitamin. Vitamin D binds a nuclear receptor that regulates roughly 1,000 to 2,000 genes (5-10% of the human genome).

The "Vitamin D" moniker has just stuck around since it was named in 1922.

brandonb··on The worthlessness of Vitamin D is mildly exaggerated
TARGET-D is an in-progress study that supplements vitamin D based on blood levels (your idea).
brandonb··on The worthlessness of Vitamin D is mildly exaggerated
Another more recent trial (TARGET-D) is showing a 52% reduction in heart attack risk: https://www.empirical.health/blog/vitamin-d-heart/

That trial used a dynamically-adjusted dosage of a vitamin D3 supplement, where dosing was set as to keep blood levels within a target range of 40–80 ng/mL. IMO part of the reason this trial is showing better results than the previous clinical trials of vitamin D supplementation quoted in the above article is that vitamin D has bad effects if too low and too high. Adjusting the dose dynamically to achieve an optimal range gets you the benefits without some of the negative effects.

brandonb··on Cholesterol Guidelines Get a Welcome Overhaul
Biggest changes in the new guidelines from the American Heart Association / American College of Cardiology:

  - Universal Lp(a) testing recommended for everyone - Lp(a) is the strongest hereditary risk factor for heart disease.
 -  Risk Equations switched to PREVENT, which predicts both 10-year and 30-year risk.
  - Treatment is now recommended for younger adults, based on these 30-year risk scores.
  - CAC scans recommended in more cases (for intermediate risk).
  - Specific LDL targets are back, after being removed in the 2013 guideline
The actual guidelines are long and make 52 distinct recommendations, but these are the ones that jumped out as the biggest new changes.
brandonb··on AI Growth – Honest AI Tools Directory and Metrics Dashboard
FYI - when I view the page (from New York), the language shows up in French.
brandonb··on Transformers are inherently succinct
This paper is being published at ICLR 2026 (top AI conference), and was selected as one of three outstanding papers.
brandonb··on Eggs are now officially healthy
(OP) The science behind eggs being healthy, or at least not harmful for heart health, has been pretty settled for decades.

Unfortunately, official medical guidelines take a while to catch up. It's only in 2026 that the American Heart Association put out updated dietary guidance which makes it official that most people shouldn't limit dietary cholesterol. Fiber and saturated fat are more important drivers of blood cholesterol, which is still recommended as a major risk factor (alongside blood pressure, inflammation, HbA1c, and so on).

The post also tries to explain why there was a limitation on eggs and cholesterol in the first place, starting from the 1968 guidelines.

brandonb··on Objective metrics that change the most as we age
The graph y axis is showing fractions (i.e., 0.21 is 21%). Sorry for the slightly confusing label.
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