Identifying determinants of medication adherence following myocardial infarction using the Theoretical Domains Framework and the Health Action Process Approach

Figures & data

Table 1. Important belief statements by domain.

Theoretical domain	Belief statements
Beliefs about Consequences	“I am certain the medications will keep my heart healthy”
	“I am concerned about side effects of the medications”
Memory/Attention/Decision Processes	“I occasionally forget to take my medications”
	“I find that reminders help ensure I take my medications”
Behavioural Regulation	“I use a pill organizer to keep track of whether I’ve taken my medications”
Social Influence	“I take medication because my healthcare providers recommend it”
	“My family encourage me to take my medication”
Social/Professional Role and Identity	“I did not take medications consistently before my heart attack”
	“Taking medication does not fit who I am as a person”

Table 2. Means, standard deviations and comparison results at each time point post-MI.

	0–2 weeks (n = 50)	3–12 weeks (n = 51)	13–24 weeks (n = 50)	25–36 weeks (n = 50)	p
Age	67.26 (11.14)	65.04 (11.21)	68.55 (13.78)	69.82 (10.48)	.21
Sex (% women)	34%	47%	40%	34%	.48
Adherence (MMAS-8)	7.62 (.69)	7.45 (1.06)	7.07 (1.12)	7.39 (.99)	.04
Intention	4.46 (.48)	4.34 (.47)	4.33 (.51)	4.23 (.42)	.12
Self-efficacy	4.15 (.49)	4.13 (.39)	4.11 (.43)	4.14 (.42)	.96
Outcome Expectations	4.12 (.60)	4.15 (.60)	3.92 (.57)	4.00 (.54)	.16
Risk Perceptions	3.69 (.99)	3.69 (1.02)	3.33 (.94)	3.60 (.97)	.19
Social Support	3.35 (1.04)	3.43 (1.02)	3.05 (.93)	3.11 (.93)	.16
Action Planning	4.21 (.59)	4.11 (.59)	4.19 (.60)	4.13 (.34)	.75
Coping Planning	4.06 (.87)	4.18 (.55)	4.05 (.74)	4.06 (.60)	.77

Note: MMAS-8 scaled from 0 to 8. All other scales 1–5. All p values based on one-way ANOVA with Tukey post hoc tests, except sex, which is based on a test.

* p < .05

** p < .01.

Table 3. Means, standard deviations and bivariate correlations (N = 201).

	1	2	3	4	5	6	7	8	9	10
1. Adherence	7.38 (.99)
2. Intention	.05	4.34 (.48)
3. Self-efficacy	.16*	.58**	4.13 (.43)
4. Outcome expectancies	.01	.37**	.32**	4.05 (.58)
5. Risk perceptions	−.01	.14	.07	.10	3.68 (.97)
6. Social support	.15*	.04	.03	.19**	.15*	3.24 (.98)
7. Action planning	.22**	.51**	.48**	.26**	.07	.07	4.16 (.54)
8. Coping planning	.06	.40**	.39**	.28**	.09	.10	.38**	4.09 (.69)
9. Sex	.06	.06	.12	−.07	−.12	−.06	−.08	.10	34% women
10. Age	.15*	−.05	.02	.02	−.31**	.04	.05	.03	.04	67.65 (11.75)
Cronbach’s alpha	.60	.94	.76	.77	.86	.70	.80	.74	–	–

* p < .05

** p < .01.

Table 4. Testing predictors of Intention and medication adherence.

					95%CI B
Predictors of Intention	B	SE	β	p	Lower	Upper
Outcome Expectations	.16	.05	.20	<.01	.06	.26
Self-efficacy	.56	.07	.50	<.01	.43	.69
Risk Perceptions	.03	.03	.07	.26	−.03	.09
Social Support	−.02	.03	−.04	.54	−.07	.04
Time Since MI	−.05	.02	−.13	.03	−.10	−.01
Sex	.02	.06	.02	.74	−.09	.13
Age	.00	.00	−.03	.61	−.01	.00
Predictors of Adherence
Intention	−.31	.19	−.15	.10	−.68	.06
Self-efficacy	−.39	.42	−.17	.35	−1.22	.44
Social Support	.15	.07	.15	.03	.01	.29
Action Planning	1.26	.36	.68	<.01	.54	1.97
Coping Planning	−.10	.11	−.07	.36	−.32	.12
Time Since MI	−.12	.06	−.14	.05	−.24	.00
SE × Time Since MI	.31	.16	.35	.05	−.01	.62
AP × Time Since MI	−.37	.15	−.49	.01	−.67	−.08
Sex	.13	.14	.07	.34	−.14	.41
Age	.01	.01	.14	.05	.00	.02

Figure 1. Bootstrapped mediation of relationship between intention and behaviour via action planning.

Table 5. Mapping the Theoretical Domains Framework to the Health Action Process Approach.

Theoretical Domains Framework Domains	Health Action Process Approach constructs
Knowledge	–
Skills	–
*Social/Professional Role and Identity	–
Beliefs about Capabilities	#Self-efficacy
*Beliefs about Consequences	#Outcome Expectancies; Risk Perceptions
Reinforcement	–
Optimism	–
Intention	Intention
Goals	Intention
*Memory, Attention and Decision Processes	–
Environmental Context and Resources	Barriers and Resources
*Social Influences	%Social Support; Action Control
Emotion	Risk Perceptions; Outcome Expectations
*Behavioural Regulation	%Action Planning, Coping Planning, Action Control

*  = identified as important in interviews in Study 1.

#  = identified as predictors of adherence intention in Study 2.

%  = identified as predictors of adherence behaviour in Study 2.