An Analysis and Evaluation of the Information-Motivation-Behavioral Skills (IMB) Model for Antiretroviral Therapy

Abstract

We use Fawcett and DeSanto-Madeya's framework to critique Fisher and Fisher's information-motivation-behavioral skills model and determine its usefulness and applicability for nursing. Our analysis and evaluation show that the model is a parsimonious and useful situation-specific theory for guiding nursing research and practice because it shows good fit with the nursing context, has social and theoretical significance, and exhibits empirical and pragmatic adequacy. More consistency in using terms referring to each concept would help to improve the model's internal consistency. The model's testability could also be improved by measuring health outcomes (eg, viral load or CD4 count) in future research.

GLOBALLY, more than 37 million people are living with HIV,1 and widespread use of antiretroviral therapy (ART) has increased survival2,3 and reduced HIV transmission4–6 among HIV-positive individuals. In many settings, however, adherence to ART is inadequate to achieve these goals. A recent meta-analysis of 85 studies revealed that, on average, 62% of HIV-positive patients reported adequate ART adherence7 and adherence varies widely (27% and 80%) across populations and geographic settings.8 To better address ART adherence, scientists and clinicians require suitable theoretical frameworks to guide intervention development, testing, and evaluation.

The information-motivation-behavioral skills (IMB) model was developed by Fisher and Fisher9 to understand, predict, and promote HIV-preventive behaviors such as ART adherence, consistent condom use, and intravenous drug use. In 2006, the IMB model was revised to incorporate ART adherence as an important HIV prevention behavior.10 As shown in the Figure, the IMB model has 3 core components: information, motivation, and behavioral skills.9,10 Information refers to comprehensive and accurate information about both the virus and its prevention and treatment and includes such information as medication instructions and what to do when you miss a dose.9,10 Motivation refers to a patient's goals and reasons for pursuing goals and includes support that they receive (or not) from caregivers and others.9,10 Behavioral skills refer to cognitive-motor skills for routine pill taking as well as social and interpersonal skills to integrate treatment into daily life.9,10

Figure.

The information-motivation-behavioral skills model of highly active antiretroviral therapy adherence. From Fisher et al.10^(p465) Used with permission.

According to the IMB model,9,10 patients can achieve higher levels of medication adherence when they have adequate knowledge of HIV and ART, possess high levels of personal and social motivation, and receive coaching to help them incorporate medication taking into their daily routines. In the model, the influences of knowledge and motivation on medication adherence are posited to be fully mediated by a patient's behavioral skills for ART self-management.9,10 Finally, Fisher and colleagues9,10 theorize that personal factors such as mental illness, homelessness, and drug dependency can moderate the influences of knowledge, motivation, and behavioral skills on ART self-management. For example, patients with substance use disorders may have more difficulty in translating personal knowledge into routines that are compatible with daily pill taking. Originally developed to address HIV medication adherence, the model has been applied to evaluate and predict condom use,11 pre-exposure prophylaxis use,12 and other behavioral outcomes13 in the HIV context.

The ongoing interest in the IMB model reflects its usefulness and applicability for developing, testing, and evaluating interventions to increase ART adherence,14 including those led by nurses.15 However, theories borrowed from other disciplines, such as the IMB model, should be critiqued for their usefulness and applicability in nursing before being used in nursing research and clinical practice.16–18 The theory critique process is important because it can help determine a theory's empirical appropriateness for employment in nursing research, education, administration, and practice.19 Critique can help, moreover, to identify which concepts and propositions within a theory could be refined to better suit the nursing discipline.17–19

Despite some use of the IMB model in nursing studies,20–23 the IMB model has never been formally critiqued to determine its usefulness and applicability for nursing research and practice. The purpose of this article is to critique the IMB model and examine its usefulness and applicability to nursing by employing a critique methodology proposed by Fawcett and DeSanto-Madeya.24,25

Statements of Significance

What is known or assumed to be true about this topic?

• Successful HIV treatment and prevention depend on high levels of adherence to prescribed antiretroviral therapy (ART).

• According to Fisher and Fisher's information-motivation-behavioral skills (IMB) model (1992), successful behavior change is predicated on patients having the requisite information, motivation, and behavioral skills to correctly carry out an HIV prevention behavior. The model has been widely used, tested, and validated in the HIV context to evaluate the effects of behavioral interventions on reduction of HIV transmission risk, and it was revised in 2006 to include ART adherence as a prevention behavior.

• Although it has been tested in several populations and settings, the IMB model has not been evaluated for its value as a nursing theory.

What this article adds:

• We used Fawcett and DeSanto-Madeya's framework to critique the IMB model and determine its usefulness and applicability for nursing.

• We examined 17 studies using the IMB model in diverse HIV populations to investigate the model's testability and empirical adequacy.

• We found the IMB model to be consistent with the nursing metaparadigm and applicable for use in nursing research and practice involving ART adherence.

• The IMB model demonstrates good context, social and theoretical significance, and parsimony as well as empirical and pragmatic adequacy. However, the model's semantic consistency and testability should be improved in future studies.

• Neither objective biological indicators of ART adherence nor subjective health was measured in the reviewed studies, leaving knowledge gaps to be filled in future research.

• Nurse researchers can employ the IMB model to clarify information, motivation, behavioral skills, and other moderating factors that are important for a given HIV population. Nurses can then apply the research findings to tailor ART adherence enhancement interventions for target groups or individual patients.

METHODS

Fawcett and DeSanto-Madeya's25 framework for critiquing nursing theory includes 2 main steps: analysis and evaluation. Analysis refers to objective and nonjudgmental description of a theory by scrutinizing its scope, context, and content as presented by the developers.25 Evaluation involves reaching a judgment about the extent to which a theory satisfies 6 criteria: significance, internal consistency, parsimony, testability, empirical adequacy, and pragmatic adequacy.25

To evaluate the IMB model's testability and empirical adequacy, we searched for studies that could serve as sources of information about the model's use in research. Using the search terms “antiretroviral therapy,” “information motivation behavioral skills model,” and “medication adherence,” we searched 5 databases for such sources: PubMed, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Psychological Information Database (PsycINFO), the Excerpta Medica Database (EMBASE), and Google Scholar. The initial search yielded 123 studies that applied the 1992 or 2006 version of the IMB model in the context of ART adherence. After excluding 59 duplicates, we screened the titles and abstracts of the remaining studies, and 37 potentially useful studies were selected for review in full-text form. Studies that employed the IMB model to only a small degree or that did not measure its concepts were excluded (n = 20), and 17 articles were chosen to support this critique.

RESULT

Analysis of the IMB model

Theory scope

A theory's scope refers to its breadth or degree of abstraction. In that regard, a theory can be classified as “grand,” “middle-range,” or “situation-specific” depending on its degree of specificity, the measurability of its concepts and propositions, and its applicability to provide a framework for nursing practice.25,26 In general, grand theories are broad in scope, nonspecific, and abstract, whereas middle-range theories are more specific, and their concepts and propositions are measurable.25 Situation-specific theories have the most limited scope and the lowest level of abstraction, as they focus on specific phenomena or are limited to specific populations or to particular fields of practice.26

Although the authors of the IMB model of ART adherence did not explicitly define its scope, the model meets the definition of a situation-specific theory because (a) it focuses specifically on ART adherence behavior, (b) its concepts directly inform measurable variables, (c) its specific propositions can be tested empirically, and (d) it can be used to guide nursing practice.

Theory context

Analyzing a theory's context involves examination of its inclusion of nursing metaparadigm concepts and propositions, philosophical claims, and worldview as well as the conceptual models from which the theory was derived and the antecedent knowledge used in theory development.25

Nursing metaparadigm

A metaparadigm describes the global concepts of a discipline, and the nursing metaparadigm has 4 concepts: human beings, environment, health, and nursing.27

Although the IMB model did not originate in the nursing discipline, all 4 concepts of the nursing metaparadigm were implied throughout the model. The concepts of human beings and the environment were implied by the definition of social motivation as “the individual's perceptions of social support from significant others for adhering to a regimen and motivation to comply with significant others.” Accordingly, the “human beings” concept was reflected in the form of HIV-infected individuals who are receiving ART regimens, and “environment” consisted of those human beings' “significant others.” “Environment” was also incorporated in the model through Fisher et al's10 definition of moderating factors affecting adherence (Table 1); that is, they considered the individual's living situation, whether stable or unstable, as an important environmental factor that can influence the effects of the model's key constructs on adherence behavior. In addition, the concept of “health” was addressed through Fisher and colleagues' definition of health outcomes, as shown in Table 1.

Table 1. IMB Model Concepts and Propositions.

Concept	Nonrelational Proposition	Relational Proposition
Adherence information	Specific information relevant to ART adherence, such as information about the specific medications of a regimen, correct ART utilization, and adequate adherence; side effects and drug interactions; heuristics that permit relatively automatic and cognitively effortless adherence decision-making; and implicit theories that require cognitive effort to be applied to adherence decision-making10	“Adherence information ... [is] fundamental determinants of adherence [behavior]”10(p463) “Adherence information ...work primarily through adherence behavioral skills to influence behavior”10(p464) “[In complicated situations,] the [adherence] information may have direct effects on adherence behavior”10(p464)
Adherence motivation	“An individual's motivation to adhere to HAART is based on his or her personal and social motivation to adhere to therapy”10(p464)	“Adherence motivation is an additional fundamental determinant of HAART adherence”10(p467) “Adherence motivation work primarily through adherence behavioral skills to influence behavior”10(p464) “[In complicated situations,] the [adherence] motivation may have direct effects on adherence behavior”10(p464)
Personal motivation	“The individual's attitudes toward adhering to his or her regimen. [These are] based on his or her beliefs about the outcomes of HAART adherence (or nonadherence) and evaluations of these outcomes”10(p464)	“[High personal motivation is] assumed to be associated with greater adherence to therapy”10(p464)
Social motivation	“An individual's perceptions of social support from significant others for adhering to his or her regimen and the individual's motivation to comply with these significant others”10(p464)	“[High social motivation is] assumed to be associated with greater adherence to therapy”10(p464)
Adherence behavioral skills	“An individual's objective abilities and perceived self-efficacy concerning the performance of the complex sequence of behaviors that are involved in adhering to HAART”10(p464)	“[There is] a direct relation between HAART adherence behavioral skills and HAART adherence behavior”10(p467)
Adherence behavior	“Proper dosing (percentage of ART medication pills taken over the number prescribed), optimal adherence (95% or greater adherence to dosing requirements of all ART medications), and adherence levels over time”10(p465)	“Adherence [behavior] is generally associated with favorable health outcomes”10(p468)
Health outcomes	An individual's physical health and subjective health outcomes related to ART adherence, such as viral load, CD4 count, drug resistance, and quality of life10	“Individual health outcomes ... [influence] individuals' future HAART adherence via a feedback loop that affects the individual's future levels of adherence information, motivation, behavioral skills and subsequent adherence behavior and health outcomes”10(p464)
Moderating factors affecting adherence	Situational and individual characteristics such as degree of psychological health, stable or unstable living situation, ease of access to medication and medical services, and chemical dependency status10	“[Moderating factors affecting adherence may] influence the relation of IMB constructs with adherence behavior, and...the degree of moderation depends on the level or intensity of the moderator”10(p468)

Abbreviations: ART, antiretroviral therapy; CD4, cluster of differentiation 4; HAART, highly active antiretroviral therapy; IMB, information-motivation-behavioral skills.

As psychologists, Fisher et al9,10 did not explicitly address nursing in the IMB model's context. However, the model has been used to guide the development, implementation, and evaluation of model-based interventions to promote ART adherence.13 Therefore, it is reasonable to view the IMB model-based actions, processes, and interventions that nurses perform or participate in as reflecting the metaparadigm's nursing concept. On the whole, the IMB model of ART adherence incorporates the fundamental concepts of the nursing metaparadigm.

Philosophical claims and worldview

Philosophical claims reflect values and beliefs about nursing and the human-environment relationship.25 In this regard, Fawcett28 proposed 3 worldviews: reaction, reciprocal interaction, and simultaneous action.

Although the IMB model does not make any explicit philosophical claims, the model's view of human behavior as dynamic and influenced through interaction with the environment is consistent with Fawcett's28 description of the reciprocal interaction worldview as emphasizing the influence of housing, social support, and access to affordable health care services on health-promoting behaviors. For example, homelessness and incarceration have been repeatedly shown to undermine the life stability needed for long-term medication adherence.29 Thus, the worldview implied by the IMB model bears strong resemblance to and is consistent with earlier nursing worldviews emphasizing human-environment (reciprocal) interactions.

Conceptual model and antecedent knowledge

Fawcett and DeSanto-Madeya25 stated that theory development is guided by a conceptual model that is more abstract than the theory itself. Therefore, as part of theory analysis, they called for examination of the conceptual model a theory was derived from and the antecedent knowledge from nursing and adjunctive disciplines used in the theory's development.

No conceptual model or antecedent knowledge from the nursing discipline was used as a basis for developing the IMB model's core concepts or relationships.9,10,30 However, Fisher and colleagues30 stated that the model draws on the social cognitive theory,31 theory of reasoned action,32 and health belief model,33 all of which show strong parallels to 2 nursing-specific conceptual models: Neuman's system model and Orem's self-care deficit nursing theory (SCDNT). Within Neuman's model,34 the central goal of nursing is to promote optimal patient wellness by retaining, attaining, or maintaining the stability of life. With HIV, ART adherence plays a role in primary (retaining), secondary (attaining), and tertiary (maintaining) disease prevention. Likewise, the IMB model's emphasis on knowledge, motivation, and behavioral skills as prerequisites for ART adherence strongly resembles the SCDNT's35 emphasis on the patient's role in and abilities for disease self-management. With its conceptual origins in theories that acknowledge the nestedness of human behavior in social interaction, the IMB model meets Fawcett and DeSanto-Madeya's criterion for a theory having a clear conceptual foundation.

Theory content

A theory's content is expressed through its concepts and propositions. Concepts are the special vocabulary of a theory that illustrate mental images of a phenomenon. Propositions are classified as either nonrelational propositions describing concepts' definitions or relational propositions expressing the relationships linking concepts. Theory content can be analyzed by comprehensively examining all the concepts and propositions in the theory.

The IMB model published in 1992 had 4 concepts (adherence information, adherence motivation, adherence behavioral skills, and adherence behavior) and 2 subconcepts (personal and social motivation). Two additional concepts (health outcomes and moderating factors affecting adherence) were included in the IMB model of ART adherence in 2006 (Figure). The model's nonrelational and relational propositions are presented in Table 1.

Evaluation of the IMB model

Significance

Fawcett and DeSanto-Madeya25 defined 2 types of significance: social and theoretical. Socially significant theories have a beneficial impact on society, such as enhancing public health. Theoretically significant theories enhance the ability to make new discoveries that enhance nursing science.

The IMB model is socially significant because it can be used to understand ART adherence behavior. This model can be used in practice to help HIV-infected individuals to change their ART adherence behavior, potentially reducing viral load, HIV transmission, and mortality. Moreover, the IMB model exhibits theoretical importance because it advances nursing knowledge by expanding understanding of ART adherence behavior. Nurses can use this knowledge as a foundation for generating interventions to promote ART adherence behavior.

Internal consistency

Assessing a theory's internal consistency involves evaluating the congruence of all theory elements, including philosophical claims, conceptual models, concepts, and propositions. Additionally, evaluation of the theory's semantic clarity and consistency as well as the structural consistency of the theory's propositions is required in this step.25 No philosophical claims or conceptual models were explicitly identified for the IMB model; however, its implied worldview of reciprocal interaction and the antecedent knowledge used in its development are congruent with the model's concepts and propositions.

The IMB model displays semantic clarity because explicit descriptions of all its concepts were provided (Table 1). However, it lacks semantic consistency because many different terms were used to refer to the same concepts. For example, Fisher et al10 presented the term “adherence information” in their conceptual diagram, but this term was used interchangeably with “adherence-related information” and “information” in their descriptive text. This pattern of semantic inconsistency was also identified for the concepts of “adherence motivation” and “adherence behavioral skills.” Other inconsistently used terms included “moderator factors affecting adherence,” as this concept was also referred to as “moderator variables.”10

No contradictions were found among the theory propositions, which supported the structural consistency of the IMB model. However, the theorists should have clearly defined the relationship between the concepts “adherence information” and “adherence motivation” shown in the conceptual diagram.10 In the diagram, these concepts are connected by a 2-headed arrow (Figure), yet no explanation of this bidirectional relationship was provided in the text. In conclusion, the IMB model has some limitations in semantic consistency and structural consistency that detract from its overall internal consistency.

Parsimony

Fawcett and DeSanto-Madeya25 defined parsimony as the clarity and conciseness of a theory. Specifically, parsimony is achieved when a theory clearly explains the phenomena of interest using only the necessary concepts and propositions. The IMB model is concise without oversimplification; adherence behavior is clearly defined using 6 key concepts, 2 subconcepts, and 7 relational propositions.

Testability

The testability of a theory is determined by assessing whether its concepts can be measured by reliable and valid instruments.25 To evaluate the testability of the IMB model, a systematic review was performed to examine studies that measured the IMB concepts and propositions (see Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A67). Despite the existence of valid and reliable instruments for the concept of health outcomes, none of the reviewed studies measured this concept.

The primary concepts of interest in the reviewed studies were adherence behavior, adherence information, adherence motivation, and adherence behavioral skills, and adherence behavior was measured as a primary outcome. Most studies used self-report measures for adherence behavior; participants reported the number of missed medication doses or the number of doses taken for particular recall periods using a single-item questionnaire or complex multi-item measures. Unfortunately, none of the reviewed studies reported the validity and reliability of self-report measures of this concept (see Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A67).

The concepts of adherence information, adherence motivation, and adherence behavioral skills were measured using the Life Windows IMB-ART-Adherence Questionnaire (LW-IMB-AAQ) or questionnaires developed by the researchers. Some researchers used the full 33-item LW-IMB-AAQ,22,36–38 whereas in other cases, only selected items from this questionnaire were used. For example, Hawkins et al39 selected 20 items from the LW-IMB-AAQ and an additional 2 items from the literature to investigate differences in psychological and behavioral variables between episodes of ART adherence and nonadherence in adolescence.

The internal consistency reliability of the LW-IMB-AAQ was reported in some reviewed studies. When these data were available (see Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A67), internal consistency reliability (Cronbach's α coefficients) ranged from 0.54 to 0.98, 0.74 to 0.87, and 0.71 to 0.92 for instruments that measured adherence information, adherence motivation, and adherence behavioral skills, respectively. Notably, half the reviewed studies using the LW-IMB-AAQ reported Cronbach's α coefficients below the acceptable value of 0.70 for items measuring adherence information.22,38,40

For instruments developed by researchers, internal consistency reliability was adequate or poor.41–45 For example, Cronbach's α coefficients above 0.80 were reported for adherence information, adherence motivation, and adherence behavioral skills in Ameri et al's41 study, as shown in Supplemental Digital Content Table 2 (available at: http://links.lww.com/ANS/A67). In contrast, poor Cronbach's α values of 0.52 and 0.35 were reported for measurements of adherence motivation and adherence behavioral skills, respectively, in Amico et al's42 study.

The concept of moderating factors affecting adherence was measured using valid and reliable instruments. For example, Horvath and colleagues37 assessed depressive symptoms using the 10-item Center for Epidemiologic Studies-Depression Scale (α = .88), perceived stress using the Perceived Stress Scale (α = .88), life chaos using the Life Chaos Scale (α = .77), and alcohol use using the standard Alcohol Use Disorders Identification Test. Drug use was also assessed through participants' self-reporting of the number of times they had used illicit substances.

In summary, the overall testability of the IMB model is considered to be moderate. Evidence of its testability is weakened by the reviewed studies' lack of measurement of the health outcomes concept and the poor internal consistency reliability of some instruments used to measure the concepts of adherence information, adherence motivation, and adherence behavioral skills.

Empirical adequacy

A theory has empirical adequacy when research findings support its theoretical assertions.25 As shown in Supplemental Digital Content Table 2 (available at: http://links.lww.com/ANS/A67), both quantitative and qualitative methodologies have been used with different types of data analysis techniques in studies applying the IMB model.

Adherence information

The reviewed studies partially support the relational proposition in which adherence information is a key predictor of adherence behavior. Regression analyses performed in 3 studies showed that adherence information significantly predicted ART adherence behavior.36,40,44 For example, Gordon et al's36 study found that the accuracy of information significantly predicted optimal adherence in the early phase of ART. Furthermore, Movahed et al's46 quantitative study reported that lack of information in various dimensions (such as taking medication regularly, drug interaction, and drug side effects and management) was one of the main sources of nonadherence behavior. However, contrasting findings were reported by 2 other studies.38,39 In one such study, no correlation was found between adherence information and adherence behavior among people living with HIV who received ART in Mexico.38 In the other study, when the researchers compared adherent and nonadherent episodes of young people living with HIV who received ART, no significant differences in adherence information were identified.39

Adherence motivation

The IMB model proposes that adherence motivation is another fundamental determinant of ART adherence behavior. Some empirical evidence supported this proposition, but some did not. For example, Pomeroy et al44 reported that motivation was a significant predictor of ART adherence due to subjects' perceived vulnerability (ie, beliefs that they would be able to control their HIV with the treatment and that it would help them live longer). Also, lack of motivation was found to be one of the main sources of ART nonadherence in Movahed et al's study.46 However, motivation neither predicted nor correlated with ART adherence behavior in other studies,38,40 and in the early phase of ART, motivation did not significantly predict optimal ART adherence.36

The IMB model further proposes that individuals' adherence motivation is based on personal and social motivation; higher personal and social motivation is assumed to be associated with greater adherence to ART. Few reviewed studies tested this proposition, and their findings were inconsistent. Specifically, Hawkins et al39 found that social motivation significantly differed between nonadherent and adherent episodes, but no significant differences were found for personal motivation. Similarly, a qualitative study reported that motivation was not drawn from internal resources and was primarily social; perceived support from peer relationships was an important driver of adherence motivation.47

Adherence behavioral skills

Fisher and colleagues10 asserted that adherence behavioral skills directly influenced adherence behavior (Figure), and the empirical findings consistently supported this relational proposition. All the reviewed studies employing structural equation modeling (SEM)21,42,45,48,49 reported that behavioral skills had a significant direct effect on adherence behavior. In other studies, behavioral skills significantly predicted ART adherence behavior40 and correlated with both adherence in the last week and the last time a dose was missed in the past 3 months.38 Qualitative research46,50 also supported the proposition. Notably, however, adherence behavioral skills did not predict adherence behavior in the early phase of ART.36

Adherence behavior

The IMB model asserts that adherence behavior is directly linked with health outcomes (Figure). However, no reviewed studies tested this relationship, as none measured the health outcomes concept. Thus, after establishing the testability of this concept, further studies will be needed to evaluate the health outcomes proposition proposed by the model.

Mediational assertion

The major mediational assertion of the IMB model is that adherence information and adherence motivation influence adherence behavior through adherence behavioral skills (Figure). Various studies tested this assertion using SEM analysis, and the findings of 3 studies42,45,48 consistently supported the relationships among these concepts. For example, Amico et al42 found that both information and motivation had significant direct effects on adherence behavioral skills, which then significantly affected adherence behavior. Partial support for the mediational assertion was also reported in Kalichman et al's43 study. Their results indicated that adherence motivation had a direct effect on adherence behavioral skills, which then significantly influenced adherence behavior; however, adherence information showed neither direct nor indirect effects on adherence behavioral skills or adherence behavior.

Another IMB model assertion is that, in certain situations, the model's relationships may be moderated by factors affecting ART adherence (Figure). In support of this assertion, Horvath et al37 found that the effects of adherence information on adherence behavioral skills and on adherence behavior differed between drug and nondrug users (see Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A67). However, because the concept of moderating factors affecting adherence was only broadly defined by Fisher and colleagues, further research is needed to examine other situations or characteristics mentioned in the model as potential moderating factors for model relationships.

Additionally, research findings supported the last 2 assertions of the IMB model. These assertions maintained that the strength and specific content of adherence information, adherence motivation, and adherence behavioral skills might vary across populations, cultures, and adherence behaviors of interest. For instance, information, motivation, and behavioral skills explained ART adherence behavior at different variances (17%-52%), depending on the study participants and countries.42,44,45,48 Furthermore, Movahed et al46 reported that different genders showed different levels of skill in managing and minimizing ART side effects. In addition, Rongkavilit et al51 asserted that the model's definition of adherence motivation needed to be revised for the Thai context to capture the social support and responsibility emphasized in family relationships and in the core values of Buddhism.

Pragmatic adequacy

The final step in theory evaluation is to determine a theory's usefulness, or pragmatic adequacy. This determination involves assessing education or special training required to apply the theory and its real-world application, feasibility of implementation, legality in nursing practice, compatibility with expectations of nursing practice, and favorable outcomes.25

Required education or special training

Although the IMB model is relatively clear and concise, a full understanding of the theory's contents is required before applying it in practice. Nurses will need sufficient education on the model's concepts and propositions to select the appropriate measurements for each concept.

Real-world application

The IMB model has been used to guide many studies of ART adherence with different populations in multiple countries (see Supplemental Digital Content Table 2 available at: http://links.lww.com/ANS/A67). The model has supported identification of determinants of ART adherence; delineation of the relationships among them; and intervention development, implementation, and evaluation.10 Therefore, the model has demonstrated its applicability for initiatives to improve public health.

Feasibility of implementation

The feasibility of implementing a theory can be determined by evaluating the availability of both the personnel and resources needed for carrying out theory-based activities.25 Although multiple resources are required, past studies have established that implementation of IMB model-based interventions and activities is both reasonable and feasible. Nurse knowledge of the IMB model is key to performing these activities, and thus, as noted above, nurses require education about the model's concepts, propositions, and application.

Legality

The ease of translating the IMB model into research and practice was a concern during its development.10 Most of the IMB model's concepts can be measured using questionnaires, and thus nurses have the ability to implement and measure the effectiveness of theory-based practical activities. However, objective measurement of health outcomes may be challenging. For example, when subjects with HIV have to provide blood samples to determine their viral load and CD4+ counts, nurse researchers must design their studies to protect this confidential information.

Compatibility with expectations for nursing practice

Theory application should be compatible with public and health care system expectations for nursing practice in the HIV context.25 IMB model-based activities can focus on promoting ART adherence by providing patients with accurate knowledge about their medication regimens, enhancing patient motivation to adhere to ART prescriptions, and strengthening the important skills needed by patients to perform adherence behaviors. These objectives are compatible with public and health care system expectations of nurses providing HIV treatment because ART adherence is a prerequisite for positive health outcomes among patients.

Favorable outcomes

IMB model-based practical activities may produce favorable patient health outcomes such as improvement in ART adherence.14 The model's suitability for understanding and predicting ART adherence has been noted by various researchers.42,44,45,48 However, the efficacy of model application in promoting ART adherence remains uncertain, as both successes43,52 and failures22 of IMB model-based interventions have been reported.

IMPLICATIONS FOR NURSING

Our theoretical critique of the IMB model showed that the model is appropriate for guiding nurse-led ART research and adherence programs because the model has social and theoretical significance, exhibits both empirical and pragmatic adequacy, and is parsimonious. However, several model-related limitations should be addressed in future studies, including the inadequate internal consistency reliability of the LW-IMB-AAQ for measuring the concept of adherence information and the varying internal consistency reliability of model-based measures developed by researchers. Most importantly, there is a lack of data on how research guided by the IMB model has improved health in people living with HIV because researchers have measured neither objective biological indicators of ART adherence (eg, viral load and CD4 count) nor subjective health (eg, quality of life). Moreover, with respect to semantic consistency, the terms of each model concept need to be used consistently to avoid confusion and ensure appropriate application of the theory in research and practice.

Moreover, our analysis and evaluation suggest that the IMB model is empirically adequate for describing and explaining ART adherence and that it can be considered a shared theory that promotes development of further knowledge to guide nursing practice. Nurse researchers and practitioners alike can use the IMB model to clarify the information, motivation, behavioral skills, and moderating factors that are important to regimen adherence in HIV-infected groups or individuals of interest. Based on this information, nurses can then tailor adherence enhancement interventions for a target group or individual patient. Additionally, the IMB model supports understanding of the complexity of ART adherence behavior by considering moderating factors such as individuals' characteristics and their specific situations. Thus, the model lends itself to cross-cultural research and may be helpful in assessing social-cultural determinants of health behaviors.

Furthermore, nurses can improve the use of the IMB model for studying ART adherence by directly addressing some of the model-related limitations. For example, when research on ART adherence has been conducted in other fields, researchers have failed to measure health indicators, presumably because it was not feasible to access patients' medical records or to collect and analyze blood samples. In contrast, nurse researchers are in an excellent position to collect objective data on health indicators among HIV-infected individuals. In turn, nursing studies can generate findings that will be useful for either supporting or strengthening the IMB model. Finally, we should acknowledge that some nursing scientists have challenged the concept of medication “adherence” or “compliance” as coercive or patriarchal.53,54 These scientists have suggested replacing this concept with “negotiated collaboration” or “goal attainment” to highlight the patient's individual autonomy and ability to set medication-taking goals.53,54 Resolution of this debate lies beyond the scope of this article.

CONCLUSION

Based on Fawcett and DeSanto-Madeya's framework for analyzing and evaluating nursing theory, the IMB model was found to be useful and applicable for nursing research and practice in the context of ART adherence. Despite the complexity of ART adherence behavior, the model concisely presents all the main determinants of adherence in its theoretical concepts. Also, the IMB model offers nursing researchers a broader perspective on ART adherence behavior by considering moderating factors that appear to explain this behavior in different populations. Although the IMB model is fully applicable in nursing research and practice, its usefulness in a given ART context depends on the instruments chosen to measure each concept. Therefore, as indicated by our evaluation of the model's testability and empirical and pragmatic adequacy, nursing researchers should carefully define the variables associated with each concept and select optimal measures for them. Additionally, to achieve meaningful research outcomes using the IMB model, nursing researchers require a comprehensive understanding of its concepts, propositions, and previous applications.

Supplementary Material

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