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The market of mobile health (mHealth) apps has rapidly evolved in the past decade. With more than 100,000 mHealth apps currently available, there is no centralized resource that collects information on these health-related apps for researchers in this field to effectively evaluate the strength and weakness of these apps.
The objective of this study was to create a centralized mHealth app repository. We expect the analysis of information in this repository to provide insights for future mHealth research developments.
We focused on apps from the two most established app stores, the Apple App Store and the Google Play Store. We extracted detailed information of each health-related app from these two app stores via our python crawling program, and then stored the information in both a user-friendly array format and a standard JavaScript Object Notation (JSON) format.
We have developed a centralized resource that provides detailed information of more than 60,000 health-related apps from the Apple App Store and the Google Play Store. Using this information resource, we analyzed thousands of apps systematically and provide an overview of the trends for mHealth apps.
This unique database allows the meta-analysis of health-related apps and provides guidance for research designs of future apps in the mHealth field.
With the constant expansion of mobile health (mHealth) in the past few years, the market of mobile apps related to health is rapidly evolving, making countless new mobile technologies potentially available to the health care system. According to a new report (May 2014) generated by the Research2Guidance firm [
Currently, most research in this field often investigates the apps individually, either by searching the apps from app stores, or by manually installing each individual app on smartphones or tablets one by one [
Since the Apple App Store (AppStore) is the major representative in the market, we first created an app repository based on all the health related apps from the AppStore. The list of apps was crawled from the Apple iTunes Web pages [
Since the Google Play Store (GooglePlay) is now the biggest app store in the market, we also created an app repository based on the information of all popular health-related apps from the GooglePlay. The list of apps was crawled from the GooglePlay Web pages [
The list of 39 features for each app in the AppStore.
Feature | Annotation |
trackId | Unique app ID |
artistId | Developer ID |
artistName | Name of the developer |
artistViewUrl | The URL for the developer |
artworkUrl100 | The URL for the artwork in 100*100 pixels |
artworkUrl512 | The URL for the artwork in 512*512 pixels |
artworkUrl60 | The URL for the artwork in 60*60 pixels |
averageUserRating | Average of user ratings |
averageUserRatingForCurrentVersion | Average of user ratings for current version |
bundleId | Bundle ID |
contentAdvisoryRating | Content ratings by content advisor |
currency | Currency |
description | Description of the app |
features | Features |
fileSizeBytes | File size in bytes |
formattedPrice | Price in currency format |
genreIds | Categories IDs |
genres | Categories |
ipadScreenshotUrls | The URLs for the iPad screenshot |
isGameCenterEnabled | Whether it is game center enabled |
kind | The kind of content |
languageCodesISO2A | Language codes ISO2A |
price | Price |
primaryGenreId | Primary category ID |
primaryGenreName | Primary category name |
releaseDate | Release date |
releaseNotes | Release notes |
screenshotUrls | The URLs for screenshot |
sellerName | Seller name |
sellerUrl | The URL for the seller |
supportedDevices | Supported devices |
trackCensoredName | Name (censored) |
trackContentRating | Content rating |
trackName | App name |
trackViewUrl | The URL for the app |
userRatingCount | The number of user ratings |
userRatingCountForCurrentVersion | The number of user ratings for current version |
version | Version number |
wrapperType | The name of object |
The list of 27 features for each app in the GooglePlay.
Features | Annotation |
trackId | Unique app ID |
artworkUrl | The URL for the artwork |
averageUserRating | Average of user ratings |
badge | Developer badge |
category | Category |
contentRating | Content rating |
description | Description of the app |
developerEmail | Developer email address |
developerId | Developer ID |
developerName | Name of the developer |
developerPrivacy | The link to the developer privacy notation |
developerWebsite | Developer website |
fileSize | File size |
formattedPrice | Price in currency format |
inAppPurchase | Whether it is in app purchase or not |
installs | Number of installations |
price | Price |
releaseNotes | Release notes |
requiresAndroid | Android OS requirement |
screenshotUrls | The URLs for screenshot |
screenshotVideoUrls | The URLs for video screenshot |
trackName | App name |
trackViewUrl | The URL for the app |
updated | Update date |
userRatingCount | The number of user ratings |
userRatingCountDistribution | The numbers of ratings with 5, 4, 3, 2, or 1 stars |
version | Version number |
In the US market, there are 74,211 apps listed in the Apple iTunes Health & Fitness and Medical subcategories as of December 4, 2014. By removing duplicated entries, we obtained 62,621 totally unique apps in these two subcategories. We note the category of each app is defined by the app’s owner (developer or seller) and approved by Apple’s customer service, so the app categorization was done in the server side (API) and was used directly as our app selection criteria. The primary categories of some apps are neither Health & Fitness nor Medical, but others, such as Lifestyle, Education, Sports, Food & Drink, or Games. To reduce the ambiguity, we only included the 47,883 apps with either Health & Fitness or Medical as their primary category in our app repository. In addition to the US market, this repository contains the information of mHealth apps from the AppStore distributed in four other countries with the most established Internet markets [
The number of apps in different stores and regions.
Store_region_category | Appsa | Free apps | % of free apps | Sum of user ratingsb | Sum of user ratings (free)c | % of user ratings (free apps) |
AppStore_BR_Health&Fitness | 25,931 | 16,761 | 65 | 79,738 | 60,924 | 76 |
AppStore_BR_Medical | 20,047 | 13,313 | 66 | 24,169 | 18,074 | 75 |
AppStore_CN_Health&Fitness | 25,845 | 16,732 | 65 | 164,314 | 137,011 | 83 |
AppStore_CN_Medical | 19,857 | 13,173 | 66 | 14,765 | 12,128 | 82 |
AppStore_JP_Health&Fitness | 25,962 | 16,809 | 65 | 204,012 | 141,292 | 69 |
AppStore_JP_Medical | 19,961 | 13,250 | 66 | 21,008 | 16,426 | 78 |
AppStore_RU_Health&Fitness | 25,926 | 16,774 | 65 | 139,488 | 96,348 | 69 |
AppStore_RU_Medical | 19,912 | 13,198 | 66 | 19,736 | 15,679 | 79 |
AppStore_US_Health&Fitness | 26,762 | 17,521 | 65 | 3,596,338 | 2,877,808 | 80 |
AppStore_US_Medical | 21,121 | 14,357 | 68 | 866,582 | 671,408 | 77 |
AppStore_Top5Regions_Health&Fitness | 27,157 | 17,813 | 66 | 4,183,890 | 3,313,383 | 79 |
AppStore_Top5Regions_Medical | 21,607 | 14,729 | 68 | 946,260 | 733,715 | 78 |
GooglePlay_US_Health&Fitness | 6894 | 5155 | 75 | 10,921,244 | 10,446,157 | 96 |
GooglePlay_US_Medical | 5378 | 3180 | 59 | 900,476 | 852,068 | 95 |
a Apps, the total number of apps in each specified combination of store, region, and category.
b Sum of user ratings, the total number of ratings received from app users.
c Sum of user ratings, free, the total number of ratings received for free apps.
The repository also contains information of the most popular apps from the GooglePlay in the United States. For the GooglePlay, the Web pages only list the most popular or the newest released apps in each category based on their release dates and daily user usage. Since the GooglePlay Web pages are updated daily, to get a comprehensive list of all the apps, we collected the app IDs available on the GooglePlay with our crawling program every day from July 24 to December 6, 2014, and combined the results to get a list of 14,817 unique app IDs. We then excluded the inactive apps that are no longer available on the GooglePlay. In addition, as we did for the AppStore, we also excluded the apps with their primary category other than HEALTH_AND_FITNESS or MEDICAL. Finally, we obtained a list of 12,272 totally unique apps, including 6894 and 5378 apps in the subcategories of HEALTH_AND_FITNESS and MEDICAL, respectively.
According to
Based on the release date information of each app included in our repository, we can analyze the trend of mHealth apps available in the AppStore. We plotted the number of apps released in each quarter since the third quarter of 2008 (
The trend of the number of released mHealth apps in the Apple App Store (AppStore). 2008Q3: third quarter of year 2008. BR: Brazil; CN: China; JP: Japan; RU: Russia; US: United States.
The mHealthApps repository allows us to analyze thousands of apps in the market systematically and efficiently, and can be utilized to provide an overview of the trends for mHealth apps. The repository is scheduled to be updated quarterly. Detailed information of all these apps can be freely requested from the repository website [
It is noted that our study has some limitations. First, the category of each app is submitted by the app’s owner and approved by the app store. Therefore, the accuracy of app categorization is beyond our control. Additional strategy based on nature language processing would be necessary to ensure all the apps included in our repository are health-related. Second, we only retrieved mHealth apps from the two most established system platforms, the iOS (AppStore) and the Android (GooglePlay), there are also apps from other platforms, such as the Windows Phone Store [
Zip flat file with array format for AppStore Health & Fitness apps in United States.
Zip flat file with array format for AppStore Health & Fitness apps in China.
Zip flat file with array format for AppStore Health & Fitness apps in Japan.
Zip flat file with array format for AppStore Health & Fitness apps in Brazil.
Zip flat file with array format for AppStore Health & Fitness apps in Russia.
Zip flat file with array format for AppStore Medical apps in United States.
Zip flat file with array format for AppStore Medical apps in China.
Zip flat file with array format for AppStore Medical apps in Japan.
Zip flat file with array format for AppStore Medical apps in Brazil.
Zip flat file with array format for AppStore Medical apps in Russia.
Zip flat file with array format for GooglePlay Health & Fitness apps in United States.
Zip flat file with array format for GooglePlay Medical apps in United States.
Disclaimer.
app program interface
apps
Apple App Store
Brazil
China
Google Play Store
identity
Japan
JavaScript Object Notation
mobile health
Russia
This work is supported in part by National Institutes of Health grant R01 LM010022 and the seed grant from the University of Texas Health Science Center at Houston.
Disclaimer: According to the Terms of Use by Apple (https://www.apple.com/legal/internet-services/terms/site.html) and the GooglePlay (https://play.google.com/intl/en_us/about/play-terms.html), we claim our work is exclusively for research and non-commercial informational purpose. To comply with the websites Terms of Use by Apple and GooglePlay, we now restrict the public anonymous access to the complete data repository. Instead, the URL link for downloading the most updated dataset will only be sent to the users upon request, and is limited for personal and non-commercial use only. When sending your request, please indicate your school or institute, the version you need, and use the subject such as “Request mHealthApps 2014 Q4 version” with an email to: komunling@gmail.com, or Yin.liu@uth.tmc.edu.
WX and YL conceived of the idea and wrote the paper. WX performed the derivations, implemented the algorithm, and prepared the data.
None declared.