Can too much disease prevention be hazardous to your health?

December 4th, 2008 by Al Lewis (alewis)

Politicians and pundits everywhere call for more disease prevention as a way to reduce healthcare costs.   Certainly you cannot argue with the logic that “an ounce of prevention is worth a pound of cure.”    Or can you?  It turns out that you can not only argue against that so-called logic, but you can prove that the opposite is true for some conditions.  As Senator Moynihan once said, “everyone is entitled to their own opinions, but not to their own facts.”


True, there are many ways in which public health can be improved through obvious prevention steps.   For instance, why isn’t the federal cigarette tax $1/pack at least?  Why is nicotine, the most addictive common drug on earth, even available at all without a prescription?    Why isn’t every meal ordered in a restaurant accompanied by a calorie count, just like the ones on grocery labels?  Why is commuting to work on a bicycle not tax-deductible, but driving to work is?   Unfortunately, the “prevention” argument isn’t about those common-sense, easily implemented policies which would certainly make this country healthier without additional spending.  


When people talk about “prevention,” it is about spending money to put patients on specific drugs which reduce the risk of heart attacks, asthma attacks and so on.  And that is where Moynihan’s observation comes in — the facts simply don’t support the consensus, at least for some conditions.


Let’s use the example of asthma.   The database of the Disease Management Purchasing Consortium Inc.  ( tracks both asthma drugs and visits to the emergency room (ER) and hospital stays associated with asthma.    The average cost of an attack requiring an ER visit or inpatient stay is about $1000.   The average cost to fill a prescription to prevent or recover from an asthma attack is about $100.   It turns out that asthma attacks which send someone to the ER are rare indeed.  In the commercially insured population, attacks of enough severity to require a trip to the ER happen about 3-4 times a year for every thousand people.  (The rate is much greater for children insured by Medicaid; additional resources spent on prevention could very well be cost-effective for them.)   For a million-member health plan, that might be 3000 or 4000 attacks    Yet that same million-member health plan is paying for hundreds of thousands of prescriptions designed to prevent or recover from asthma attacks. 


Depending on the health plan, the ratio of drugs prescribed to asthma events serious enough to generate an ER or hospital claim ranges from 60-to-1 to 133-to-1.  Suppose an event costs the system $1000, a figure which takes into account that about 20% of people who come to the ER get admitted, and a prescription costs $100.  That means we are paying, on average, anywhere from $6000 to $13,300 to prevent a $1000 event.   


Averages lump together people at all risk levels.  Surely some of those people really are at high enough risk of an attack that they should be inhaling their drugs regularly to prevent one, and have a “rescue inhaler” nearby.    So assume that half the asthma population is high-risk, meaning that their risk of a serious attack is (for example) twice that of the average asthmatics.  This is an extremely safe assumption – most people in disease management would put the high-risk asthma population at 20% or less, and the difference in risk between high-risk and low-risk at far greater than 2:1.  However, because with some people doctors really can’t tell whether their risk is high or low, we will define “high risk” very broadly.


We will also use that safe and conservative assumption that low-risk people have half the risk of the average asthmatic, meaning the high-risk population has more risk than average. The high-risk population no doubt does benefit from prevention, but most of those people are already on drugs.  How do we know this?  The large increase in asthma prescriptions in the last six years is not accompanied by a large decrease in the already-low ER/inpatient attack rate.  One would have to do the math pretty carefully and get more health plan datapoints and perhaps even interview patients and doctors to get an exact figure, but clearly as long as there are patients at different risk levels, the low-risk patients have a risk of attack which is half that of the average patient.  This means that putting low-risk patients on drugs costs $12,000 to $26,600 for every $1000 attack prevented.  


A staggering number to begin with, but one which is probably still understated for two reasons:


  • Because the low-risk patients are far more likely to be treated in the ER and sent home, that $1000 weight-average of inpatient and ER costs is also overstated, making the ratio of prevention cost to attack cost even greater. 


  • The true difference in risk between high-risk and low-risk populations far exceeds a factor of two, making the cost per prevented attack far greater in the low-risk population.  We are just using this arithmetic for illustration.


It’s not just that this is a wasteful negative return on investment.  This is where the catchy title comes in:  It’s also that there are known short-term side effects to these drugs.  Additionally, no one knows what the long-term effect is of inhaling these substances regularly.  Yet low-risk asthma patients are given them as though there are no long-term effects.    So it may very well be the case that ongoing use of these drugs create more long-term health risks than it prevents.


Sometimes an anecdote is worth a thousand statistics.  My very own son has asthma, and was on medication when he was at high risk.  Since he stopped getting frequent attacks (none of which was severe enough for an ER visit) he eventually, against his doctor’s advice, simply stopped using his inhaler.  For a couple of years the health plan sent him reminders and once called to get him to take his drugs, but he didn’t.  That last call from them was about six years ago.  Clearly, though he has asthma, the right solution for him is to do nothing except have an inhaler nearby, and hope that he doesn’t end up in the ER.


Why are we over-prescribing so many asthma drugs and why is the imbalance between drug use and attacks likely to get worse?  It appears that, without regard to costs and benefits, so-called prophylactic asthma drugs designed to be used every day, inhaled corticosteroids, are considered “good” and attacks are considered “bad” while the “rescue” inhalers – the ones people use when they feel an attack coming on, are more considered closer to bad than good due to their potential for overuse.    Doctors and health plans, like everyone else, manages what is measured and incentivized, which in this case is “good” asthma medication.


Like many situations where the “market” seems to be producing the wrong answer, there are many sources of the breakdown causing the “good” drugs to be favored without regard to either cost-effectiveness or marginal therapeutic benefit.    First, doctors expect, with justification, that patients want them to “do something,” when they go for an office visit.  (That is also why you see patients getting antibiotics prescribed for viral infections.)


Second, health plans are graded on the “use of appropriate asthma medication” by the National Committee for Quality Assurance (NCQA), which basically means health plans encourage doctors to prescribe more “good” drugs for asthma in order to score well on their NCQA exam.


Third, health plans are increasingly paying doctors based on their prescribing of these “good” asthma medications.


Fourth, there is a large constituency – pharmaceutical companies – which benefits from high drug use.  The constituency which naturally benefits from low drug use, health plans, has been conflicted by the NCQA rules to encourage more too.


Finally, insured members don’t pay much of the bill for prevention, so they tend to go along with the convenient and reassuring inhaler program.  Like anything else where the full cost isn’t reflected in the price, people will use more of it than if they were paying the full cost.


Bottom line:   it would appear that Mae West’s observation that “too much of a good thing can be wonderful” does not apply to health care.   It is time for policymakers to start thinking in terms of optimums rather than maximums when designing a prevention strategy, starting with asthma.

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One Response to “Can too much disease prevention be hazardous to your health?”

  1. alewis Says:

    Wanna make sure that readers (and judging by the number of comments apparently not many people are reading this; I will agree that it is not as exciting as some other stuff) realize I am focused only on the economics. I gotta think the people who seet these guidelines know something about the science. And it is possible that there are a whole bunch of attacks prevented which would not lead to an ER visit, but which are worth preventing nonetheless.

    Stiil, the economics are quite clear: it costs a lot of money to prevent an ER visit

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