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Product-Related Emphasis of Skin Disease Information Online
Weimin Hu, PhD;
Elaine C. Siegfried, MD;
Daniel Mark Siegel, MD
Arch Dermatol. 2002;138:775-780.
ABSTRACT
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Background In 2000, 41 million people searched for medical information online.
The quality of that information is unregulated, variable, and not well studied.
Objective To quantify and compare the numbers and types of Internet sites matched
for 10 diverse skin conditions through different search systems.
Design Search strategies were performed at 6-month intervals via Netscape Navigator,
using 3 search engines and 1 directory. Ten skin conditions were chosen to
represent common (psoriasis and eczema), cosmetic (wrinkles and cellulite),
difficult-to-treat (alopecia, mastocytosis, granuloma annulare, and xanthoma),
and uncommon (dermatitis herpetiformis and epidermolysis bullosa) problems.
Search strings were designed to generate lists of Web sites that provide educational
or product-related information. Results were compared.
Setting The Saint Louis University information technology server, July 9, 1999,
December 16, 1999, and February 5, 2000.
Main Outcome Measures Comparisons of the total number, top 10 ranking, and type (educational
vs product-related) of sites that matched through different search systems
at 6-month intervals.
Results The total number of matched sites for different skin conditions varied
up to 100-fold. This number increased by 30% to 316% between July and December
1999. The largest number of Web sites related to wrinkles, followed by Web
sites related to common conditions. Product-related sites outnumbered educational
sites, especially for common and cosmetic conditions. Although there were
differences in the total number of sites found through different search engines,
the ratios of product-related to educational sites were similar. Different
search engines yielded different top 10 match lists for the same condition.
The top 10 lists included higher proportions of educational sites than the
total match lists for all conditions except cellulite. Within the top 10 lists,
the rank order of well respected sites varied by search engine used and changed
over time.
Conclusions Patients are increasingly accessing the growing body of data available
through the Internet. Most Web sites contain information related to products.
Until standards are enacted to govern the distribution of online medical information,
consumers are at risk for obtaining misinformation and buying ineffective
products. To better guide patients, physicians must become familiar with this
ever-changing information.
INTRODUCTION
IN RECENT years, the Internet has become a useful tool for gathering
data. More people are turning to the Internet to find information about their
illnesses and treatment options. In 1999, 25 million people searched for health
and medical information online. This was expected to grow to 33 million in
2000,1 but was reported at a staggering 41
million.2 The number of Internet sites containing
medical information has correspondingly skyrocketed. In 1997, more than 10 000
health-related English-language sites existed on the Web,3
while in 1998, more than 25 000 Web sites were health-related.4 In 2000, 4.9 million people shopped for health products
online.2 Consumers must be cautious about receiving
medical products and advice over the Internet, because many sites are market-driven
and not regulated for scientific accuracy. Although some standards have been
developed in recent years, including those of the American Medical Association,
Chicago, Ill, and the code of e-Health ethics,5
consumers will be at risk for obtaining misinformation and ineffective products
until a "reliability seal" is used. The aims of this study were to quantify
and to compare the numbers and types of Internet sites matched for 10 diverse
skin conditions through different search systems.
MATERIALS AND METHODS
We used a Netscape Navigator (version 4.0; Mountain View, Calif) browser,
selected 3 search engines, and performed similar searches July 9, 1999, and
December 16, 1999. Excite (http://www.excite.com) was used as the
primary search engine. AltaVista (http://www.altavista.com) and
Northern Light (http://www.northernlight.com) were used for comparison.
These search engines are characterized by the size of their library (index),
mode of matching, and system of ranking matched sites. Excite is one of the
most popular search services on the Web. It browses a medium-sized index and
is used by America Online's NetFind (http://www.aol.com) and by
Netscape as their default search engines. AltaVista has one of the largest
indexes of any search engine.6 Its advanced
search syntax is powerful and flexible and allows for detailed queries, making
it popular among experienced Web searchers. Excite and AltaVista were established
in 1995, and Northern Light opened to general use in August 1997. Northern
Light is well organized and powerful, with a large index.7
We also used Yahoo (http://www.yahoo.com) as an example of a search
directory. A directory's index is much smaller than that of a search engine,
composed of a group of personally submitted Web sites.
Using these 3 major search engines and 1 directory, we compared the
results of the following Internet searches. The names of 10 skin conditions
were used as the main search strings: psoriasis, eczema, wrinkles, cellulite, jalopecia, mastocytosis, granuloma annulare, xanthoma, dermatitis herpetiformis, and epidermolysis bullosa. The use of specific syntax in an advanced search
may generate more sites than a simple search. For example, in AltaVista's
simple search, a disease name alone may find different results from those
of a disease name surrounded by quotation marks and preceded by a plus sign,
which forces an exact match to be present in the results. However, in our
search, a change of syntax did not yield different results, ie, the same number
of sites was generated by using dermatitis herpetiformis or +"dermatitis herpetiformis." For the searches conducted through Excite or Northern Light, we used
the following as the search string to find the sites that were related to
products: the name of the disease AND (amazing OR breakthrough
OR sale OR products). For the educational sites, we used the following
as the search string: the name of the disease AND education. For the sites devoted strictly to education, we used the following
as the search string: the name of the disease AND education
NOT (amazing OR breakthrough OR sale OR products OR clients) (Table 1). AltaVista's search syntax necessitated
a slightly different but equivalent string through its advanced search option.8 In addition, for a subset of 6 conditions, we searched
the top 10 matched Web sites and classified them into either an educational
or a product-related category. For 3 major conditions, we specifically looked
for well respected sites, such as the National Alopecia Areata Foundation
(http://www.alopeciaareata.com), among their top 10 lists. This
subset of searches was conducted July 9, 1999, and February 5, 2000.
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Table 1. Search Strategies Using Psoriasis
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RESULTS
THE SIGNIFICANT INCREASE IN WEB SITES
The total numbers of matched sites for different skin conditions found
through Excite in July and December 1999 are shown in Figure 1A. Among the diseases that we investigated, wrinkles was
associated with the largest number of sites: 13 545 in July and 19 159
in December (a 41% increase during this period). Xanthoma was associated with
the fewest number of sites: 103 in July and 274 in December (a 166% increase).
The other diseases in the study were ranked according to their number of sites
as follows: psoriasis, 7071 in July and 12 668 in December (a 79% increase);
eczema, 6004 in July and 8272 in December (a 38% increase); cellulite, 3081
in July and 4004 in December (a 30% increase); alopecia, 2316 in July and
3039 in December (a 31% increase); epidermolysis bullosa, 427 in July and
1776 in December (a 316% increase); dermatitis herpetiformis, 375 in July
and 909 in December (a 142% increase); mastocytosis, 185 in July and 664 in
December (a 259% increase); and granuloma annulare, 135 in July and 297 in
December (a 120% increase). The total numbers of matched sites were different
for searches through AltaVista and Northern Light (see the third subsection
in this section and Figure 2A),
but the ratios of different conditions were comparable (data not shown).
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Figure 1. A, The total number of sites matched
through Excite between July 1999 and December 1999, by skin condition. B,
The percentage of product-related, educational, and strictly educational sites
found through Excite for different conditions in July 1999 (calculated by
dividing the number of product-related, educational, or strictly educational
sites by the total number of sites for each condition). EB indicates epidermolysis
bullosa; DH, dermatitis herpetiformis; and GA, granuloma annulare.
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Figure 2. A, Comparison of the total number
of sites for different conditions matched through Excite, AltaVista, and Northern
Light in July 1999 (calculated by dividing the number of sites found by Excite
or AltaVista by that found by Northern Light). B, The percentage of product-related
sites for different conditions matched through Excite, AltaVista, and Northern
Light in July 1999 (calculated by dividing the number of product-related sites
by the total number of sites matched by the same search engine). C, The percentage
of educational sites for different conditions found by Excite, AltaVista,
and Northern Light in July 1999 (calculated by dividing the number of educational
sites by the total number of sites matched by the same search engine). EB
indicates epidermolysis bullosa; DH, dermatitis herpetiformis; and GA, granuloma
annulare.
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THE PRODUCT-RELATED SITES VS THE EDUCATIONAL SITES
The total number of matched sites varied up to 100-fold for different
skin conditions, and increased for all conditions during the second half of
1999. These diseases with fewer sites initially had larger percentage increases
over time.
The percentages of the product-related sites were higher than those
of the educational or strictly educational sites for most conditions that
we investigated (Figure 1B). For
example, 66% of psoriasis-related sites were devoted to products, and only
7% were designated solely for educational purposes. The difference between
the number of product-related sites and educational sites was dramatic for
the common conditions (psoriasis and eczema) and cosmetic concerns (wrinkles
and cellulite). The difference was less significant for epidermolysis bullosa,
granuloma annulare, and xanthoma. An exception was mastocytosis, for which
there were slightly more educational sites than product-related sites.
The percentage of sites that included products increased with the total
number of sites (Figure 1). For
example, psoriasis, with the second highest total number of sites (n = 7071),
had 4700 sites (66%) containing information about products. Conversely, xanthoma,
with the fewest number of sites (n = 103), had only 10 sites (10%) related
to products. The percentages of educational sites (which may involve some
products) and strictly educational sites were similar among different skin
conditions regardless of their total number of sites (Figure 1B). For example, there were 7071 sites for psoriasis, and
only 7% were devoted purely to educational purposes. Similarly, there were
103 sites for xanthoma, and only 4% were related solely to education.
THE DIFFERENCE BETWEEN SEARCH ENGINES
There is a difference in the total number of sites found through different
search engines.
Excite yielded the fewest number of sites and Northern Light yielded
the most sites for all conditions except cellulite (Figure 2A). In general, fewer than one third of the number of sites
were found through Excite compared with Northern Light. The Yahoo search directory
yielded a small fraction of Web sites found by the search engines. For example,
in July 1999, Yahoo matched 57 sites for wrinkles, compared with 13 545
matches found through Excite. Specialized search strings attempted on Yahoo
were of low and often no yield.
Although the total numbers of sites found by different search engines
were different, the percentages of the product-related sites and strictly
educational sites found by these engines were similar. For example, in July
1999, Northern Light matched 26 790 sites for eczema, AltaVista matched
24 060 sites, and Excite matched only 6004 sites. However, the percentages
of product-related sites found by these engines were comparable: 58% for Excite,
55% for AltaVista, and 50% for Northern Light (Figure 2B). Similarly, the percentages for eczema educational sites
in Excite, AltaVista, and Northern Light were 7%, 9%, and 7%, respectively
(Figure 2C).
THE TOP 10 LISTS
Internet users usually focus on the top 10 matches. Therefore, we investigated
the nature of the top 10 sites for a subset of 6 skin conditions and found
little overlap among the match lists generated by the 3 search engines. The
largest overlap occurred for psoriasis and dermatitis herpetiformis, for which
3 of Excite's top 10 list were also found by Northern Light and AltaVista.
There was no overlap among the 3 top 10 sites for alopecia and xanthoma.
Compared with the total search results, a higher percentage of the top
10 sites was educational (Figure 3).
For example, 50% to 60% of the top 10 psoriasis sites were educational, compared
with fewer than 10% among the total matched psoriasis sites. The exceptions
were the top 10 lists for cellulite, which included 8 to 10 product-related
sites.
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Figure 3. The product-related and educational
sites in the top 10 lists found through Excite, AltaVista, and Northern Light
in July 1999. The top 10 lists for 6 different conditions were generated through
each search engine. Each site was classified manually as a product-related
or educational site.
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The percentages of product-related and educational sites within the
top 10 lists depended more on the nature of the skin condition than the search
engine. For common diseases, such as psoriasis and eczema, at least half of
the top 10 sites generated by the 3 search engines introduced products (Figure 3). For cellulite, a cosmetic concern,
all but 2 sites among the 3 top 10 lists introduced products. In contrast,
for the uncommon and difficult-to-treat diseases, dermatitis herpetiformis
and xanthoma, all but 2 sites among the 6 top 10 lists offered educational
information. We also surveyed the top 10 lists for some well respected sites
(Table 2). The rank order of these
sites varied by search engine and changed over time. For example, the National
Alopecia Areata Foundation was not among the top 10 lists generated by any
search engine in July 1999, but in February 2000, it was the number 1 match
on Excite and AltaVista and was number 2 on Northern Light.
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Table 2. Well-Respected Sites in the Top 10 Lists
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COMMENT
Patients seeking medical information are increasingly using the Internet.
In 1997, 22 million users searched health topics online. In 1999, the number
climbed to 25 million and was expected to reach 33 million in 2000,9 but estimates exceeded these expectations by 24%.4 Worldwide, there are now more than 100 000 biomedical
Internet sites.10 Medical products and medical
care are available online.9 The Internet has
provided consumers with benefits such as quick and easy access, but the line
between objective information and promotional content is often blurred. The
risks are misinformation and money wasted. Although many attempts have been
made to rate Internet medical information sites, these Web-based instruments
have not been validated11 and add little to
the morass of online information. In this study, we surveyed Internet information
for 10 skin conditions covered on English-language Web sites. We were particularly
interested in the potential to access different information through different
search systems and to compare the number of sites devoted to sales and products
with those related to education.
Our data show that the number and the nature of matched sites are first
determined by the prevalence of the condition. Common diseases are the subjects
of many more Web sites than unusual conditions. In addition, for common diseases
and cosmetic concerns, Internet information is biased toward products. These
findings are not surprising, because the number of consumers seeking information
is proportional to the prevalence of the condition. Common diseases are obvious
targets for marketing. Uncommon conditions had the fewest number of Web sites,
but had a disproportionately large increase in the number of new Web sites
during the second half of 1999. Epidermolysis bullosa and mastocytosis were
the subjects of the greatest increase. This may reflect an increased prevalence
of Web site testimonials of personal trauma experienced by individuals with
these disorders.
The unique designs of search systems affect search results. Search systems
are a Web browser's primary guides. As of February 1999, there were 800 million
estimated Web pages stored on the World Wide Web. At most, only 16% of Web
sites are reached by the most comprehensive search systems.6, 12
There are 2 types of search systems: directories and search engines. Yahoo,
a directory, searches a personally screened index composed of submitted Web
site summaries and looks for matches only in those summaries. Search engines,
such as Excite, AltaVista, and Northern Light, are characterized by their
larger, unique computer-generated indexes. A search engine's index is screened
to match and rank a subject by the unique search engine software. Excite's
index library contains 1.5 million fully indexed Web pages, while AltaVista
and Northern Light have indexes of more than 16 million.13
The results of our study were consistent with the general experience of search
engines' yielding more extensive match lists than directories. In addition,
different search engines yielded varying numbers of potentially informative
sites. Excite, with its small index, located only a fraction of the sites
found by the other 2 search engines.
Despite the different total numbers of matched search sites, the proportions
of sites devoted to specific skin conditions, as well as those related to
products and education, were similar among the different search systems. All
the search engines used in our study yielded a larger number of product sites
than educational sites. This result suggests that a browser's choice of search
engine is unlikely to affect exposure to sales gimmicks.
Although the relative yields of educational and product-related sites
were similar for different search engines, they generated different top 10
lists. Each search engine follows a unique set of rules to rank its matches.
For all search engines, the location and frequency of the keyword are the
most important factors in ranking Web sites. Keywords in the title or near
the beginning of the text carry more weight than those appearing later in
the Web page. Web sites with frequently appearing keywords are usually considered
more relevant. In addition to these rules, each search engine has its own
well guarded scheme in ranking sites. This variation yielded different top
10 lists that matched through different search engines. Compared with the
total match lists, the top 10 lists included higher proportions of sites devoted
to education vs those promoting products, except for cellulite. However, 50%
to 100% of the top 10 lists for common and cosmetic conditions were product-related
sites. This finding suggests that consumers should be especially cautious
when seeking information about common and cosmetic skin conditions.
This study was designed to distinguish between educational and product-related
Internet sites, but many Web pages are mixed. Medscape (http://www.medscape.com) and WebMD (http://www.webmd.com), for example, have features
of educational value but are inherently commercial, as they are supported
by industry. To more specifically distinguish between sites aimed at patient
support rather than marketing, we examined the top 10 lists generated by different
search engines for psoriasis, eczema, and alopecia areata, to locate the home
pages for well established and well respected patient support organizations.
The chances of finding those sites among the top 10 were better in February
2000 than in July 1999, although in one third of the cases, the well respected
sites were not number 1. Because many patients misinterpret a search engine's
ranking as an expression of quality,14 they
can be misled by choosing the number 1 Web site. For example, in February
2000, patients who used Excite to search eczema would
consider the number 2 hit, Eczema Mailing List
(http://website.lineone.net/~eczema), more reliable than the number 5 hit, National Eczema
Association for Science and Education (http://www.eczema-assn.org/index.html), while in fact, the opposite is true. Therefore, in Web browsing,
the rank of a site is not necessarily related to its quality.
Health information online is dramatically increasing. During the second
half of 1999, the number of Web sites we found for 10 skin diseases increased
by 30% to 316%. As patients increasingly use the Internet to learn about their
medical conditions and treatment options, physicians can help guide them by
becoming and staying familiar with this ever-changing information. The Hardin
Meta Directory of Internet services (http://www.lib.uiowa.edu/hardin) provides user-friendly lists of links on medical topics. Medical societies
or patient advocacy groups assist dermatologists and their patients in gathering
reliable information from other Web sites, such as those listed in Table 3. Informative Web sites sponsored
by the federal government include healthfinder (http://www.healthfinder.gov), the Food and Drug Administration (http://www.fda.gov),
and PubMed, the world's largest medical database (http://www.ncbi.nlm.nih.gov/PubMed). Additional informative sites that could be valuable to the reader
in evaluating the reliability of a World Wide Web site include the Committee
for the Scientific Investigation of Claims of the Paranormal (http://www.csicop.org), The Scientific Review of Alternative Medicine (http://www.hcrc.org/sram), Quackwatch (http://www.quackwatch.com), and Healthcare
Reality Check on-line (http://www.hcrc.org). Finally, on the site
of the Clinical Digital Libraries Project Web Quality Bibliography (http://www.bama.ua.edu/~smaccall/qualitybib.html), there is an
extensive list of articles discussing the quality of medical information.
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Table 3. Some Useful Web Sites
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AUTHOR INFORMATION
Accepted for publication June 18, 2001.
Corresponding author and reprints: Elaine Siegfried, MD, Central
Dermatology, 1034 S Brendwood Blvd, Suite 600, St Louis, MO 63117 (e-mail: siegfried{at}centralderm.com).
From the Departments of Dermatology (Drs Hu and Siegfried) and Pediatrics
(Dr Siegfried), Saint Louis University School of Medicine, St Louis, Mo; and
the Department of Dermatology, School of Medicine, State University of New
York at Stony Brook (Dr Siegel). Dr Hu is now with the Department of Dermatology,
Case Western Reserve University School of Medicine, Cleveland, Ohio. Dr Siegfried
is now with Central Dermatology, St Louis.
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