Technology is affecting all aspects of health care systems. With the introduction of electronic health records (EHRs), patients are now able to access their medical records through patient portals, or personal health records (PHRs). Tethered patient portals or PHRs are connected to the EHR operated by the health care provider or organization and typically contain information about patient’s health records such as allergies, immunizations, medication, and upcoming appointments [1]. Some patient portals can also include information such as genetic data, preventative or customized medical advice [1], or offer functionalities such as ordering repeat prescriptions, messaging health care providers, and sharing health care record [2].

Patient portals are generally offered through the primary care providers, but can also be offered in hospital care, or during acute care [3]. The technology provides some benefits to patients and the health care system. For the health care system, portals may contribute to reducing phone call and visits [4], reducing emergency department visits [5], reducing hospital readmissions, improving the quality and efficiency of the health care system [6,7], and reducing health care service utilization in the long run and improving adherence to medical appointments [8]. For the patient, the use of patient portal may contribute to assisting in medical decision making [9], improving health care outcomes [6,10], improving adherence [11], improving patient- or person-centered care [4], improving patient satisfaction and increasing patient safety [12], and improving disease management and prevention [6,7]. In addition, patient portal functionalities such as viewing medical record may improve the relationship between patients and their providers [13]. Patient portals also make it possible to connect different emerging technologies such as wearable devices and mobile health (mHealth) technologies and collect the information in the patient record [14].

Although patient portals are associated with benefits to patients’ health and to the health care system, there are no definitive explanations about how they contribute to improved outcomes. A theoretical framework depicting how a patient portal access could improve health and health care quality experience is illustrated in Figure 1 using findings of qualitative studies. The benefits are often explained through the use of specific functionalities of the portal. For example, patients’ access to the health record with visit notes gives them ability to revisit their notes, which in turn improves their compliance with the care plan set out by the doctor [15,16] and also increases their confidence [17,18]. At the same time, access to the health record or test results gives the patients the chance to instantly and continuously review their record, increasing their knowledge about their condition [15] and improving their communication with the health care provider through increased ability to discuss their health care condition [15,16,18]. Other functionalities of patient portals such as e-messaging or secure messaging and patient education can improve patients’ involvement in their care [15] and their knowledge about their disease [19], respectively. Patients’ ability to refill medication through the portal allows them to efficiently refill medication, reducing the time they spend without medication, and as a consequence may improve their adherence and compliance with medication regime [17,20].

When reviewing patient portal studies it is important to consider possible sources of bias. Patient portal studies are often subject to bias due to the complex mechanisms involved between technology use and outcomes. Uptake usually varies between patients and often only registration on the portal is accounted for in studies. For example, while a meta-analysis reported a mean adoption rate of 51% (95% CI 42%-62%) from 40 studies about patient portals [21], a patient portal for laboratory results viewing with additional functionality of e-messaging received only 8.91% views out of the 208,635 tests released through the portal [22]. Second, registration or access to the portal does not guarantee use of the portal. A study among 301 patients with asthma reported that patients rarely used the patient portal on a regular basis and only about one-half used the portal in general [23]. In addition, studies cannot possibly take into account all of the interventions/factors other than the patient portal that may contribute to the patient outcomes [23].

Health care systems around the world are adopting patient portals [11,24,25]. In England, the National Health Service (NHS) made patient portals universally available in all general practices since 2015 [26]. The outcomes of the introduction of patient portals in England are yet to be examined, but before any outcomes can be expected, there needs to be an uptake of the technology by patients. Most published systematic reviews about patient portals focused on health outcome [11,24,25], patient experience outcomes such as patient engagement [27] or patient satisfaction [12], facilitators and barriers of use [21], and impact on quality [7]. However, most of these systematic reviews are now outdated due to the increased number of studies about patient portals in the last 1-2 years. Some reviews focused on patient portal adoption by a patient subgroup such as patients with diabetes [6,10], or cancer [2]. One meta-analysis reported patient portal adoption stratified by study setting (controlled versus real-world) but did not report patient portal functionalities of the included studies [21].

Although a number of published systematic reviews about patient portals are available, there are currently no reviews, that we know of, that focus on patient portal functionalities. When describing the outcomes, contextual factors such as the health care setting, patient type, and the functionalities of the patient portal should be considered as much as possible. Research reporting patient portal outcomes can provide valuable evidence if the context and the patient portal functionalities are clearly described and specified [6], because the context could contribute to the success of the technology. In addition, because patient portal adoption can generally be higher among patients with chronic diseases [28], the literature focused on studying the patient portal mostly by patient subpopulations such as those with diabetes or hypertension [17]. It is, therefore, essential to report user characteristics and contextual factors when considering patient portals.

There are a number of systematic review protocols of ongoing reviews about patient portals. Ammenwerth et al. [29] are planning to report patient portal outcomes based on the functionalities of the portal in which they will compare patient portals with access to the EHR alone with portals that have additional functionalities. However, the review will only include randomized controlled trials and cluster randomized controlled trials. Other upcoming reviews are examining patient portal user expectations [30]. An upcoming review by Petrovskaya et al. [31] plans to report patient and health care outcomes as a result of using patient portals among others; however, this will be an umbrella review and will only include other systematic reviews. Some other upcoming reviews will only focus on specific diseases such as diabetes, multiple sclerosis, and lower limb arthroplasty [32], or on one functionality of the patient portals (ie, having access to the medical record) [33], or will report only specific health care outcomes such as no-show appointments and emergency visits [34].

The aim of this systematic review is to synthesize the evidence on health and health care quality outcomes associated with patient portal use among adult (18 years or older) patients.

The review research questions are as follows:

All research questions will be stratified by country, disease type, and health care system model.

This systematic review is ongoing. The software searches started in September 2019. Data abstraction and data synthesis are expected to be completed by the end of June 2020. The review is anticipated to be completed by the end of June 2020. We are planning to disseminate the forthcoming systematic review in a peer-reviewed journal.