risk reward

Tuesday, March 20, 2018

Before UMBC beat Virginia, no other 16th ranked team had won a game in the NCAA’s March Madness. Not in 135 previous games. Before that win, #1 never lost and #16 never won. But those words changed from always and never to rarely. The odds of the upset rose to 1 out of 136 or less than 1%. Fans of college basketball fans learned an important lesson; always and never do not exist in the real world and especially in medicine.

Risk-reward is always at play when a patient received advice for medical care. Surgeons who are technically gifted have patients who develop complications during and after surgery, from infection and bleeding to non-healing wounds. A gifted clinical doctor may have a misstep or two in proving a diagnosis caring for a patient who presents with confusing symptoms. Even when the diagnosis is firm, treatment options may have a potential for causing harm. Often there is time for discussion and contemplation before choosing a treatment plan but in emergency situations, decisions need to be made in minutes or less.

Heart Cath

Heart catheterizations have become almost routine. A cardiologist threads a thin catheter through an artery in the groin or arm and directs it into the coronary arteries that supply blood to heart muscle, looking for a narrowing or blockage. If found, blood flow can be improved or restored using a balloon to restore flow and a stent to keep the artery propped open. The benefit is preventing a heart attack and keeping the heart muscle pumping as normally as possible. There are minor complications, like bleeding or infection where the catheter is inserted through the skin. But here are also major complications like heart attack, stroke and death. Depending upon the health of the patient, statistics suggest the risk of complication is between 0.06% and 0.17% (between 1 in 600 and 1in 1600).

In an emergency situation, in the midst of a heart attack, where a coronary artery is completely blocked and heart muscle is dying, most people would accept a 1 in a thousand chance of harm when they are 100% having a heart attack.

Stroke

The numbers aren’t always so easy. Strokes occur when an artery in the brain is blocked preventing blood supply. That part of the brain turns off and the part of the body it controls stops working. The window of time to intervene with clot busting drugs (thrombolytics: thrombo=clot + lytic= dissolve) is very narrow, about 3-4 ½ hours after the onset of symptoms. If the patient is a thrombolytic candidate, the treatment can help return blood supply to the brain in more than one third of patients, but the complication of causing irreparable bleeding into the brain can be as high as 6%. The sooner the patient gets to the ER and the sooner the clot busting drug is given, the less likely the complication of bleeding. Other therapies, including removing the clot using catheters are also a possible, but not necessarily available at most hospitals. Treatment decisions by patient and family about risk-reward have to be made in minutes, and sometimes that decision is not clear cut.

Atrial Fibrillation

Preventing a stroke in the first place would be the way to go. Atrial fibrillation an irregular heart rhythm, is one of the major risk factors for causing stroke. Blood clots can form inside the heart and then potentially break off and travel (embolize) to the brain, blocking an artery and causing a stroke. Anticoagulation with a blood thinner may be an appropriate treatment, but its complication is bleeding. The question becomes how much benefit versus how much risk. Calculators (like CHADS-VASC) can be used to help decide whether anticoagulation is beneficial and other calculators (HasBled) to decide their risk of bleeding. Together, the doctor and patient can sit down and decide. At the end of the day, regardless of the decision that might be addressed and revised over the years, the patient will either 100% have prevented a stroke or not, and 100% would have bled or not.

Always and never do not exist in medicine. Minimizing risk is the goal of any treatment that has potential benefit, but that risk is never zero and treatment does not always work. Virginia learned a valuable lesson; a #1 team had never lost in the NCAA first round, but never no longer exists for them. They 100% lost and UMBC 100% won, no matter what the statistics might have predicted. It’s that lesson that also applies to doctors, patients and families. Medicine isn’t a black and white science, but people aren’t always happy with shades of gray.

 

 

 

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aspirin, statistics and super bowl coaching

Monday, February 2, 2015

In medicine, much is made of statistical analysis and its importance for determining which test might be appropriate to make a diagnosis and what treatment might follow. The rigors of statistics try to persuade even the most skeptical person about the benefit or risk of a situation.

Consider this situation. A decision needs to be made that in one analysis will be successful 20% of the time, will have no change in 40% and will result in harm the other 40%. Another study looking at similar data over a longer period of time and concluded that success would be achieved only 41% of the time. It would be difficult to recommend the routine use of such a treatment unless there was a compelling situation. With just a few seconds left in this year’s Super Bowl, the Seattle Seahawk coaches chose to pass the ball on the one yard line, instead of letting their “beast mode” running back Marchand Lynch carry the ball. Disaster befell the team as the pass was intercepted, New England wins and Pete Carroll is thought to have made the worst coaching blunder in the history of football.

Back to the numbers from statistics pros Nathan Jahnke, and Neil Greenberg. Jahnke writes for profootballfocus.com and reports that in the 2014 season, Lynch had 5 attempts from the one yard line and had scored once, had no gain twice and had lost yardage twice (20%, 40%, 40%). Greenberg, of the Washington Post, reviewed Lynch’s whole career and found that he scored from the one yard line in only 15 of 36 attempts (41%). Though much of statistics are mental gymnastics, this time it seems that the national outcry for the Seahawks to run the ball may not have been 100% warranted.

Monday morning quarterback is a tough position to play, even though most people feel well qualified and sometimes compelled to assume the role. It begins with knowing what happened and then presupposing that a positive outcome would occur had a different, “better” decision been made. The basis for most of these day after analyses often rely upon dogma and how can that ever be wrong. Dogma is a set of principles or facts that laid down by an authority that are incontrovertibly true. In medicine, changing dogma is an arduous process akin to changing the course of a large ship. It takes great time and effort to alter its direction since momentum can be a very powerful force to overcome.

Aspirin is a great drug and is recommended in many situations and its use to decrease the risk of heart attack and stroke is correct…but at what cost. According to researchers, regular aspirin use may decrease the risk of nonfatal heart attacks by 20% and all heart events by 10%. However, those aspirin users were 30% more likely to have a serious gastrointestinal bleed (bleeding from the stomach lining or ulcer). There is a concept of numbers needed to treat. In this case, it takes 162 people taking daily aspirin to prevent a nonfatal heart attack, but in that group, two people would develop serious bleeding episodes. Aspirin helps make platelets less sticky, decreasing the ability for blood to clot, but it also is irritating to the lining of the stomach and intestine. Remember that aspirin is really an acid, salicylic acid.

There are good studies that show that aspirin is very beneficial in patients who have already had a heart attack, decreasing the risk of a second heart attack by 20-30%. For people with atrial fibrillation, aspirin may be the drug of choice to thin the blood and prevent stroke. The key for doctors and patients is to individualize the use of aspirin to the patient’s clinical situation and balance risk and reward. The US Preventive Services Task Force recommends the use of aspirin on a case by case basis. The dogma that everybody should take aspirin is being tempered with the daylight that comes when researchers ask why a treatment is being recommended. “Because it has always been done that way” is no longer an acceptable answer.

It’s always good to hold dogma’s feet to the fire and quarterbacking on a Monday morning offers a prime opportunity to do so. The success of day after opinion is always 100% but that statistic is also open to interpretation.

PLEASE DO NOT STOP TAKING ASPIRIN IF IT HAS BEEN RECOMMENDED BY YOUR DOCTOR.

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