The Internet Intervention Patient Adherence Scale for Guided Internet-Delivered Behavioral Interventions: Development and Psychometric Evaluation

Patient adherence is defined as the degree to which a patient follows a given health care intervention or medical advice. In medicine good adherence would be e.g. if a patient takes medication or follows dietary advice according to the prescription. In psychological and behavioral treatments the usual way of measuring adherence has been to record attendance to therapy sessions or to which degree the patient has completed homework exercises.

Now that psychological and behavioral treatments are developed as e-health formats, delivered via the internet on apps or web-portals, adherence has been increasingly difficult to measure. Simply, when therapists do not see patients at the office, it makes it much harder to make an assessment of how engaged the patient is in the treatment.

And why would it be important to assess how much a patient adheres to treatment? Well, for clinicians, and researchers, it is vital to know how their patients are doing, because usually there is a correlation between how engaged you are in a treatment and the effect that you will get of that treatment. If a patient is sub-optimally engaged in a treatment, we would like to know it, in order to either give more support, or change to another treatment that is better suited for that person’s needs.

Within e-health one popular approach to measure patient adherence has been to count how many modules patients have completed or how many times patients have logged in. This has been practical and easy to measure, but it turns out that these numbers often do not tell us much about patient engagement and even less how much of an effect patients will yield from the treatments.

As there has not been any, to our knowledge, reliable way to measure patient adherence in e-health and internet-delivered interventions, me and my colleagues at Karolinska and CAP Research Center in Stockholm started to develop a new instrument some years ago. After some discussions and testing, and then some more testing, we came up with the internet intervention Patient Adherence Scale, short iiPAS.

The iiPAS is a brief, 5 item questionnaire, filled out by online therapists or clinicians. It assesses how much a patient is following the formal schedule of an e-health intervention (e.g. completed exercises and work pace) but also how much the patient actually is using the strategies that he or she has been working with in treatment.

Our evaluation of the iiPAS shows that it correlates nicely and significantly not only with objective indicators of engagement (nr of logins, competed chapters and written characters) but also with the clinical effect of the internet treatments that were given.

All in all, we believe that the iiPAS is a useful tool for clinicians and researchers in the e-health and internet interventions field and can help us to measure patient adherence in a reliable way. The iiPAS could therefore be used to make clinical decisions, help to further improve new interventions and get a generally better understanding of patient adherence within the context of internet treatments.

To read more about the iiPAS, you can access the full evaluation HERE including a copy of the scale in English and Swedish. Requests regarding use, modification or translation of the iiPAS can be sent to me at

Reference: Lenhard F, Mitsell K, Jolstedt M, Vigerland S, Wahlund T, Nord M, Bjureberg J, Sahlin H, Andrén P, Aspvall K, Melin K, Mataix-Cols D, Serlachius E, Högström J. The Internet Intervention Patient Adherence Scale for Guided Internet-Delivered Behavioral Interventions: Development and Psychometric Evaluation. J Med Internet Res 2019;21(10):e13602. DOI: 10.2196/13602. PMID: 31573901

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