Google Trends for Hypertension

New York—A 10-year analysis of data from Google found that there was a significant variation in people searching for “hypertension” and “high blood pressure (BP)” on the Web site search engine. The researchers indicated that people were more likely to search for those terms in the cold months, with consistency in both the Northern and Southern hemispheres.

In the United States, more people searched for those terms in February than any other month, while the fewest people searched for those terms in July. In Australia, the search volume was highest in August (a cold month) and lowest in December (a warm month).

Researchers presented the results during the ASH meeting at a featured poster session titled Assessing Patterns of Global Interest in Hypertension Using Internet Search Engine Data.

Nilay Kumar, MD, the study’s lead author, said in an interview with First Report Managed Care that a mathematical model found there was less than a 1 in 10,000 chance that the findings were due to chance.

“This is very, very significant,” Dr. Kumar said. “It means that observations from the Internet, search volumes from a certain area, or search volumes in a certain time, can probably be used to generate an
estimate of how a disease is happening in a particular space at a particular time. If you were seeing a spike in search activity in a certain month, you could anticipate that a lot more people will be showing up to the [emergency room] with heart disease. That can increase preparedness for healthcare agencies. This data can really add to our surveillance capabilities.”

Dr. Kumar said Google made their search data public through “Google Trends,” which allows anyone to examine the most popular search terms during a particular time of the year.

Dr. Kumar said studies have shown that high BP and other cardiovascular diseases (CVDs), such as myocardial infarctions and chest pain, have seasonal variations. The incidence peaks in the winter when the temperature decreases and is lowest in the summer when the temperature rises. Dr. Kumar said he and his colleagues were interested to see if that same trend was found on the Internet. “If so, that would be something that could aid in surveillance for [CVD],” Dr. Kumar said. “We could tell when you would have greater incidence of a certain disease. If Alabama was getting the most hits for hypertension, perhaps they have the most people with high [BP].”

The researchers evaluated data from January 2004 to March 2014. In the United States and
Australia, they found that the number of times people searched for “high [BP]” or “hypertension” was lowest in the summer and highest in the winter. They also discovered that the overall interest in hypertension on Google was lower in 2013 and 2014 than it was 10 years ago.

“It is a little concerning because hypertension prevalence and incidence has actually gone up, and mortality from [CVD] has increased,” Dr. Kumar said. “You would think that interest in it would be higher compared to 10 years ago. Maybe better education and better patient resources are needed so that their interest in the disease would [increase].”

Dr. Kumar noted that the Centers for Disease Control and Prevention (CDC) currently analyzes census data from samples to determine the incidence of diseases, which takes several months. He suggested that Google data could also be helpful. Dr. Kumar and his co-authors are evaluating Google data on other CVDs and plan to release the information later this year.

“This is data in real-time,” he said. “It is a very significant advantage. While [the CDC] data is cleaner, this data has a lot of noise. A lot of people [who] are going online probably do not have hypertension, but over billions of observations, you will probably see a certain trend. That is very important.”—Tim Casey