In case you missed it this month, Apple's "Special Event" devoted significant attention to health care innovation. It even brought onstage a doctor associated with a new app that lets clinicians view patients' appointment schedules and see vital signs, such as heart rates, via the Apple Watch.

This new AirStrip app has plenty of company. A search of the term "mobile health" in the Apple App Store produces 22,755 programs that purport to do everything from consolidating personal health records to triaging symptoms. One app can even turn a smartphone into a medical device designed to diagnose patients with sleep apnea when a single-lead electrocardiograph (ECG) is connected to the phone.

Most apps are intended for use by consumers. But there are also those intended for clinical use by health care providers, assisting with assessment and decisionmaking. Increasingly, they offer real-time care monitoring, allowing users to share health data with a doctor from a smartphone. Some apps even allow doctors to virtually assess, diagnose and treat patients without ever having them leave home.

Historically, and by its very nature, medicine tends to require in-person contact. The patient tends to defer to the doctor's knowledge and judgment. Medical mobile apps alter this relationship by empowering patients with information and personal statistics. The patient might now come to an appointment with ideas on treatment options — and want to take a more active role in treatment by utilizing the tools in their app.

This shift has pros and cons. On the one hand, the ease and convenience of mobile health apps increase patient engagement. Clinicians can use apps to improve decisionmaking based on concrete long-term data methodically tracked and sent directly to them. Apps could also lead to increased efficiency.

On the other hand, patients may second-guess physicians, place blind faith in an app, or forgo necessary in-person treatment. The use of apps might also undermine long-term doctor-patient relationships.

Mobile medical apps aren't cure-alls, and physicians who recommend or even discuss such apps with patients should be cautious. Concerns include the effect on the doctor-patient relationship, the accuracy and function of the app, and data privacy.

Mobile health apps can have all the hallmarks of legitimacy — availability in the app store, a well-designed logo, a catchy name. However, there's no vetting process by trained medical professionals for mobile medical apps. Although apps must meet specific criteria before acceptance into, for example, the Apple App Store, the review only validates compliance with content guidelines. The accuracy of the data or function of the app is not reviewed or validated. Nor is there an easy way for an end user to qualitatively evaluate an app.

Furthermore, mobile medical apps are not required to disclose information sources or limitations. Even if a user were inclined to actually locate and read the lengthy terms and conditions, there's no way to determine if the app was created with the involvement of a medical professional. To the contrary, the fine print on the app's privacy policy and terms will likely include language warning the end user that the app is "not a substitution for consultations with qualified health care professionals who are familiar with an individual's medical needs." Thus, the physician continues to be liable for patients' care.

Despite some calls for regulation of mobile medical apps, governmental review and regulation is limited. The Food and Drug Administration has announced that it will only evaluate mobile medical device apps that are complex in nature, such as controlling delivery of insulin to a pump; serving as a de facto medical device like a glucometer; or using patient-specific information to create a diagnosis or recommend treatment. The FDA will not, as a general rule, evaluate apps deemed to pose less risk, such as those that inform or assist patients in managing their disease without providing treatment suggestions, or apps that help patients track or organize health information.

Privacy is another concern. While traditional health care providers are bound by the strict requirements for protecting the confidentiality of patient data under HIPAA, mobile medical apps are not. App privacy policies will typically include vague privacy terms and ultimately disavow any responsibility for data security. For example, one policy says: "To ensure that your information is secure, we have in place commercially suitable physical, electronic, and managerial procedures. Nevertheless, the transmission of information via the Internet is not completely secure and we cannot guarantee the security of data sent to use."

Additionally, the app is likely to collect, in the words of one policy, "location data, IP address, dates and times of access, which pages you view, information about your illnesses, symptoms, diagnoses, time of incidence of the illness or symptoms, and information regarding the relationships you have with people and or locations." The app may also reserve the right to "disclose your information to third parties" without any word on who those third parties might be.

Ultimately, patients should keep in mind that mobile medical apps are largely unregulated, unverified and not subject to same legal requirements as health care providers. So don't delete your doctor's phone number just yet.