organized curiosity

Improving health care through research


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Can Nova Scotia health research help Vietnam’s children?

PatVietnamThe last two weeks, my wife and I escaped the ice, snow and cold of Nova Scotia and went to Vietnam for a holiday and for research (we did manage to still get back in time for two storms in one week) .

Vietnam is a great place to visit. The people are warm and helpful. It has thousands of years of culture. The food is amazing and there are incredible sights to be seen. I loved the excitement of the cities and the calm of the countryside. We ate in excellent restaurants and squatted on small stools to eat street food. The only meal we were disappointed in was at an upscale restaurant.

Vietnam has a population of 93 million and is growing at about 1% per year. Hanoi, the capital is a city of 6 million. There are about 26 million children in Vietnam.

The first thing I noticed after we left the new international airport at Hanoi was the motor bikes. Thousands flow down each street and crossing the road is an art. One just has to walk out and bikes flow around you like a school of fish. The two most amazing things are that at intersections they weave between each other and that motorbikes carry everything including chickens, entire families and trees.

We also noticed that everyone is connected via cell phones. Every street has 2 or 3 phone stores and there are 131 cell phone subscriptions per 100 people in Vietnam compared to 81 per 100 people in Canada.

Vietnam is a low income country but is making progress and joining the official ranks of the lower middle income countries of the world. The economy is growing at 5.4%, about two and a half times the rate of Canada’s growth. Poverty, however, is still a huge problem. The Gross National Income per person in Vietnam is about $1740US compared to the $52,200US in Canada.

We found the Vietnamese warm, entrepreneurial, energetic and very proud of their country. At the end of the first millennia, they freed themselves from the Chinese and established their independence. From the 1860’s till the mid 1950’s, France was a colonial occupier. The Japanese were in charge during the Second World War.  In my youth, I protested the Vietnam war.  The American war (as it is called in Vietnam) lasted for a decade before the collapse of Saigon in 1975.  After that the Vietnamese fought another war, a limited regional war with the Chinese.  Vietnam remains a single party country with the only party being the communist party.

I ended up in Vietnam because of a meeting hosted by the Graham Boeckh Foundation in Montreal last year where I gave a talk about Strongest Families. Strongest Families is the distance child mental health program that was begun at the IWK with funding from the Canadian Institutes of Health Research. Eliot Goldner from Simon Fraser University suggested I join the Grand Challenges project he was doing with Dr. Vu Cong Nguyen from the Institute of Population, Health and Development in Hanoi and add a child mental health component.

So, I was in Vietnam to discuss starting a Strongest Families Vietnam program.

There are very few child psychiatrists or child psychologists in Vietnam. The culture has, until now, had a difficult time dealing with child discipline and a recent UNICEF report found that over 90% of children experienced psychological aggression and 65% experienced physical punishment in the previous month.

The group of scientists, NGO and governmental officials that I met were among the most thoughtful and innovative individuals I have ever encountered. Their focus was on improving child behavior problems using the best science, adapted to the Vietnamese culture. Beginning with a small feasibility study, we hope to have funding from Grand Challenges Canada and the Vietnamese government to do a larger study. Perhaps we will have a nation wide Strongest Families Vietnam program. It is a bit ironic that it may be easier to scale up an innovative program in a low income country with few resources than in a developed country such as Canada.

~Dr. Patrick McGrath

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Screening Everyone For Disease Is Not Always Good

crowdscreeningblog

Shouldn’t we want to know early if we have a disease?  It just seems obvious that we would want to screen for everything and treat it before it got bad. You have probably heard about big companies that each year give all of their executives an amazingly thorough checkup including lots of ultrasounds and even whole body MRI and extensive blood and urine analysis. The latest idea is to get your whole genome analysed.  You can do it for $795 to $3000.  Many more population screening tests are being promoted.

Population Screening is giving a test to everyone, even if they have no symptoms, to see if they have the earliest stages of a disease. But screening makes sense only if:

  1. The test is accurate.
  2. The test does not trigger harm.
  3. There is a treatment that works.
  4. The treatment is better if it is given early
  5. The treatment has a cost that is reasonable

So let’s look at these issues.

It is surprising to many that lots of population screening tests are not really that accurate. Of course it depends on what you mean by accurate.

The traditional way of defining accurate is sensitivity and specificity.  Sensitivity is the proportion of true positives and specificity is the proportion of true negatives that the test correctly identifies.  You might have seen a screening  blood test for Alzheimer’s Disease mentioned on the news as a breakthrough discovery from an international group led out of Kings College in London England.  They correctly identified 85% of people with dementia (sensitivity) and 88% of people who did not have dementia (specificity).  Not only the newspaper but also reputable associations touted this test as a promising way to screen for Alzheimer’s. That is all pretty impressive for a blood test. But is it true? Look at this tree plot diagram from a blog by Professor David Colquhoun.

Screen Blog

He showed that given that about 10% of us will develop Alzheimer’s, out of 1000 people tested, there would be 193 with a positive test result but 108 would be false positives.  That means the 56% of people would be told in error they were developing Alzheimer’s.  This is called the False Discovery Rate. They would be told they had a disease that they did not have.  They would likely worry about normal lapses in memory.  They might make life decisions such as taking early retirement because of the false information. They might get depressed because they thought they were going to get Alzheimer’s.  So thank goodness, the government is not going to fund this test.

One way screening tests do harm is they trigger follow up tests. Follow up tests cost money and have risks of harm. Some harm is relatively minor such as having to come into the hospital for a test. Some may cause some pain. And some follow up tests have small but serious risks. People (not many) have had serious effects or even died from tests. Also, with so many tests being done, diagnostic tests for people with symptoms may be delayed

With Alzheimer’s, there is no test to confirm if you have the early stages of the disease. So more than half the people who tested positive using that test would be stuck with a wrong test with no way of finding out if it were wrong.

But what about the true positives?  Might they not benefit from screening? Some would say, that is not so bad if there were a good treatment for Alzheimer’s.  Everyone could take it.  But there is no good treatment for Alzheimer’s disease. The treatments for Alzheimer’s are expensive and convey very little benefit. On average they may slow symptoms by a few weeks or months.  As well, there is no evidence that these drugs are more effective if taken early. So there is no way of benefiting from a true positive result.

I read a very interesting article that summarized studies of attempts to add years to life by screening in diseases in adults that cause death. This systematic review found scant evidence that any screening program in adults delays death at all. Moreover, there have been recent challenges to screening for breast cancer and for prostate cancer. Needless to say, these ideas are controversial.

That is not to say that all screening programs are bad. Many of the screening programs that we do in babies where we detect serious illnesses that can be treated have value. For example, screening for PKU. Without screening there is almost certain very serious results and early death. With screening and early intervention there is a good quality of life.

As well, these arguments do not apply to diagnostic tests. Diagnostic tests are given to people when there is suspicion of disease. They can be helpful and form the basis of much of our medical care. However, a recent systematic review of 140 studies of new diagnostic tests showed only minimal effects on patient outcomes even if they changed treatment. So we are not getting that much better with new diagnostic tests.

There are two other uses of screening tests that can be valid. First, to screen high risk people for a specific disease when there is a good treatment that can be usefully given earlier. Second, to screen for inclusions into randomized trials. A major problem in research occurs when people with different diseases are included in a trial. The results may be a mess. So refining who goes into a trial can help immensely in figuring out if a treatment works.  This use of screening will eventually help patients if a better treatment is found. It is very different from population screening of people who have no symptoms.

So, as you can see, I am skeptical about population screening. It may do more harm than good. We should look carefully at all population screening programs.

~Dr. Patrick McGrath