ACTIVE INGREDIENTS
4.5 DESIGNING TAILORED INTERVENTIONS .1 Overview
4.5.3 Methods
The design of tailored and adaptive interventions rests on a lucid understanding of the health problem (as delineated in the theory of the problem) and of the features of the interventions (as delineated in the theory of implementation and the theory of change) developed to address the problem. Knowledge of the health problem is necessary for identifying the variables on which to tailor the intervention, and knowledge of the intervention provides directions for specifying its features that can be tailored, how and when. This information is then combined to generate the algorithm that guides the tailoring process.
4.5.3.1 Identification of Variables for Tailoring
Logic, empirical evidence, clinical experience, and the theory of the problem are sources for the identification of variables serving as the foundation for tailoring the intervention design and delivery. The theory of the problem is most informative. It describes variations in the experience of the health problem by specifying the possible range of the problem’s indicators, level of severity, duration, and determinants. Varia- tions in the experience of the problem within a particular context and time, suggests the need for tailoring. The theory proposes variables that account for the variation in the experience of the problem. These include clients’ personal characteristics and life circumstances or contextual factors, and are considered for tailoring (Lei et al., 2012).
For example, clients with insomnia may exhibit some but not all health behaviors asso- ciated with insomnia and may have different sleep habits that perpetuate insomnia.
Accordingly, these behaviors are considered for tailoring of the sleep hygiene compo- nent and behavioral intervention for insomnia as suggested by Manber et al. (2012).
The theory of the problem proposes that clients’ personal characteristics and life cir- cumstances influence their engagement in the intervention and enactment of treatment recommendations, and subsequently achievement of the desired changes; these are also considered for tailoring. Examples include: level of health literacy, computer skills, comorbid conditions and concurrent treatments, beliefs or explanatory model of the health problem, expectations regarding the potential benefit of and level of motivation for the intervention (e.g. Beck et al., 2010; Cohen et al., 2015), work place requirements and availability of resources required for applying the treatment recommendations.
The theory of the problem, in combination with expert consultation, points to the salient variables that form the foundation for tailoring. These have been referred to as the tailoring variables. The tailoring variables should be clearly defined at the
4.5 Designing Tailored Interventions
89
conceptual and operational levels. These definitions inform the selection of reliable and valid instruments to measure them. Assessment of the variables is the first step in the tailoring process. Furthermore, awareness of how the variables influence the experience of the health problem and/or the application of the treatment recommen- dations gives directions for specifying what features of the intervention to tailor, how and when.
4.5.3.2 Identification of Intervention Features for Tailoring
Tailoring may involve (1) the selection and provision of different interventions or components of an intervention, to be consistent with the clients’ experience of the health problem and the tailoring variables; (2) modification of an intervention’s com- ponents, mode or dose of delivery, at one or more points in time during the treatment period to account for clients’ response to treatment; and (3) provision of additional nonspecific components to support clients in the application of the treatment recom- mendations. The goal of tailoring is to enhance the responsiveness of the interven- tion to the client’s experiences.
Selection of Different Interventions or Components
The first form of tailoring demands the availability of different interventions (e.g.
medication, herbal therapies, cognitive behavioral therapy for insomnia) or different components of an intervention (e.g. education and cognitive restructuring as compo- nents of cognitive therapy; stimulus control therapy, sleep restriction therapy and relaxation therapy as components of behavioral therapy for insomnia). The list of interventions and components is generated from relevant theories, or empirical and experiential evidence. Specific interventions or components are selected and deliv- ered in a manner that is consistent or responsive to the salient tailoring variables, assessed at one point in time; the time point is usually baseline or prior to interven- tion delivery for tailored interventions, or at predetermined time points or intervals (e.g. weekly) during the treatment period for adaptive interventions. For example, clients may vary in their beliefs or explanatory model of depression and are offered interventions that correspond with their beliefs. Clients who believe in biological causes of depression are offered medications (e.g. antidepressants) and those who view depression as resulting from life stress are offered psychotherapy. Clients with insomnia may experience different perpetuating factors; they are given different com- ponents of cognitive behavioral therapy. As suggested by Espie et al. (1989), clients experiencing physiological arousal are provided relaxation therapy; those presenting with cognitive arousal are provided paradoxical intention to reduce performance anx- iety; and those having poor sleep habits are provided stimulus control therapy.
Alternatively, tailoring may be achieved in what has been called stepped care.
This is represented with a sequential delivery of the health intervention’s compo- nents. The sequential delivery begins with the component that is relevant to the most salient client’s experience of the health problem, with subsequent components selected based on client’s response (i.e. reported improvement in the problem) fol- lowing completion of the first component, as is done in adaptive interventions. For example, clients with insomnia are exposed to sleep education and sleep hygiene in the first week of treatment to address misconceptions about sleep and health behav- iors known to perpetuate insomnia; those showing no improvement in their sleep quantity and quality are then exposed to relaxation or a behavioral therapy to manage arousal and poor sleep habits.
Modification of Intervention
The second form of tailoring requires the capacity to modify the intervention compo- nents and/or the mode and dose of intervention delivery to fit the clients’ experi- ences. The modification is carefully done to minimize major deviation from the specific components that characterize the intervention’s active ingredients; the specific components are responsible for initiating the mechanism of action and the intervention’s effectiveness in improving the health problem. The combination of theoretical, empirical, and experiential approaches is useful in specifying what mod- ifications can be done, how and when. The following illustrates modifications to the sleep education and sleep hygiene components that can be made to match the char- acteristics of clients without jeopardizing their integrity and potential effectiveness:
(1) clients with full-time employment involving long working hours and sedentary activities are encouraged to explore work-related activities that can be performed at the level to be counted toward daily recommendations for physical activity, and to find “a buddy system” comprising coworkers to promote engagement in physical activity within the work setting (e.g. taking a walk at lunch break); (2) clients with high general and computer literacy, busy schedule, and transportation or travel diffi- culty are offered the two components in the form of web-based modules to review at their convenience; (3) clients showing a good understanding and ability to apply the recommended sleep hygiene techniques, and reporting improvement in their sleep quantity and quality may be offered the option to not attend later intervention sessions (i.e. reduced dose) that involve face-to-face group discussion of barriers to implementation of the recommended techniques and of strategies to mitigate the barriers.
Additional Components
The third form of tailoring involves the procurement of additional nonspecific components to support clients facing challenges during the intervention period, such as those with low motivation to engage or adhere to treatment recommendations and/or those with less-than-optimal improvement in the health problem. For instance, clients with low motivation to initiate and continue treatment may require additional counseling or support from the therapist; motivational techniques can be used in this instance.
The identification of the intervention’s features that can be tailored and the spec- ification of how the features can be modified inform the development of the algorithm to guide the delivery of tailored interventions.
4.5.3.3 Development of Algorithm
The algorithm is the essence of tailored and adaptive interventions. It consists of a set of decision rules that link or match the tailoring variables with the intervention fea- tures to enable the customization of the intervention. The decision rules reflect the logic that underpins the customization, that is, the selection of interventions, specific and nonspecific components, mode of delivery, and dose that are appropriate, consis- tent or responsive, correspond or match clients’ experiences of or levels on the tai- loring variables. The rules are operationalized in “if-then” statements (Golsteijn et al., 2017), which take the form of: “If the client presents with a particular variable at a specified level, then this intervention, component (i.e., content, activity, treatment recommendation), mode, or dose is recommended.”
4.5 Designing Tailored Interventions
91
The way in which decision rules are stated is comparable for tailored and adaptive interventions; however, the type of tailoring variables and the timing for decision- making vary. For tailored interventions, tailoring variables (e.g. experience of the health problem) are assessed at baseline, prior to the intervention delivery. The results of the assessment inform the decision of what intervention to select or what feature of the intervention is to be modified and how. The selected intervention option or the modified intervention feature is provided to the client throughout the treatment period. For adaptive interventions, the same process is followed to select the appropriate intervention or the modified intervention feature to which clients are exposed for a predetermined time period (e.g. one week). Concurrently, clients report on the experience of the problem and adherence to treatment. Toward the end of this predetermined time period, clients’ reports are analyzed to determine their response to the intervention (i.e. level of improvement in the experience of the health problem) and adherence to treatment. Clients’ responses and adherence become the client characteristics for further customization, whereby other interventions, components, additional support, or higher dose are provided (Hekler et al., 2018; Lei et al., 2012;
Lagoa et al., 2014).
The decision rules can be (1) simple, where the customization is done for one feature of the intervention on the basis of one tailoring variable, or (2) complex, where the tailoring is done for two or more features of the intervention, on the basis of two or more tailoring variables and at two or more time points. In the latter case, principles of control system engineering have been used to develop adaptive interventions (for detail, refer to Deshpande et al., 2014; Lagoa et al., 2014; Rivera et al., 2007).
To ensure their replicability and utility in informing interventionists or health professionals in delivering tailored or adaptive interventions, the decision rules should make explicit:
1. The tailoring variables: The variables should be clearly labeled and defined at the conceptual and operational levels.
2. The instruments measuring the variables: The instruments or measures should be described in terms of the attributes of the tailoring variable cap- tured, the scoring procedure (i.e. how the total score is calculated to quantify the clients’ level on the variable), and the interpretation of the score (e.g.
cutoff score indicating presence or absence, or range of scores indicating dif- ferent levels, of the variable).
3. The time at which assessment of the tailoring variables is conducted.
4. The set of possible interventions or components that could be offered through a range of modes and at different dose level: These should be clearly identified and described. The way in which the intervention features are modified and how should be clearly delineated.
5. The decision rules: The rules that link the tailoring variable and the level at which each variable is experienced (as represented by the cutoff or range of scores) with the corresponding intervention, component, or modified inter- vention features should be lucidly presented (Lei et al., 2012).
The algorithm must be reviewed by a panel of experts (researchers, health pro- fessionals, and clients) for precision, utility, and clarity. The experts review (1) the tailoring variables for relevance as the basis for customization; (2) the instrument for measuring the variables for content validity and accuracy of score interpretation;
(3) the appropriateness of the time points for assessing the variables; (4) the set of interventions, components, and modified features for relevance, feasibility, and effec- tiveness in addressing the unique experience of the health problem; and (5) the decision rules for clarity and accuracy. The experts engage in a discussion of what part to change and how in order to clarify or refine the algorithm.