Using the health action process approach to predict and improve health outcomes in individuals with type 2 diabetes mellitus

Figures & data

Table 1 Correlation between baseline HAPA variables and healthy eating

	Expectancy	Intention	SE task	SE coping	SE recovery	Planning	Healthy eating
Risk	0.505**	0.406**	0.355**	0.260*	0.299**	0.159	0.120
Expectancy		0.514**	0.535**	0.432**	0.385**	0.272*	0.102
Intention			0.700**	0.648**	0.424**	0.458**	−0.014
SE task				0.808**	0.561**	0.520**	0.097
SE coping					0.615**	0.577**	0.142
SE recovery						0.415**	0.134
Planning							0.191

Notes:

* P<0.05

** P<0.01.

Abbreviations: SE, self-efficacy; HAPA, health action process approach.

Table 2 Hierarchical regressions predicting health outcomes at follow up, from baseline control and HAPA variables

	Diabetes distress	Healthy eating	BMI	Waist	Blood glucose	Systolic BP	Diastolic BP	Cholesterol	Triglycerides	HDL	LDL
		β	β	β	β	β	β	β	β	β	β
Step 1: controls a
ΔR ^2	0.064	0.020	0.237**	0.274**	0.125	0.141	0.137	0.188*	0.072	0.253**	0.080
Age	−0.133	0.062	−0.341*	−0.229	−0.295*	−0.038	−0.365**	−0.114	−0.172	0.256	−0.254
Sex	0.059	0.081	−0.012	−0.419**	−0.059	−0.299*	−0.048	0.369**	0.069	0.424**	0.193
Education	−0.120	−0.039	−0.107	−0.165	−0.083	−0.166	−0.019	0.016	−0.015	−0.012	0.013
Marital status	0.077	0.017	−0.236*	−0.194	0.232	0.120	0.195	−0.250*	−0.054	−0.090	−0.133
Exercise	0.051	−0.035	−0.287*	−0.336**	−0.167	−0.268*	−0.208	0.033	−0.302*	0.193	0.095
Step 2: HAPA
ΔR ^2	0.167	0.126	0.166*	0.073	0.085	0.151	0.122	0.094	0.084	0.116	0.126
Risk	0.199	0.238	0.308*	0.221	0.155	0.365**	0.149	−0.161	−0.065	−0.102	−0.095
Expectancy	0.301	−0.221	−0.044	−0.179	−0.076	−0.120	0.097	−0.235	−0.065	−0.025	−0.267
Intention	0.036	0.176	0.247	0.332	−0.300	−0.251	−0.433*	0.207	0.264	−0.034	−0.069
SE task	−0.632**	−0.237	−0.300	−0.098	−0.045	0.137	−0.062	0.054	−0.374	0.330	0.173
SE cope	0.322	−0.086	0.266	−0.016	0.470*	0.016	0.368	−0.104	0.133	−0.492*	0.055
SE recovery	0.091	0.252	0.348*	−0.117	−0.106	−0.029	−0.181	0.112	−0.105	0.361*	0.061
Planning	−0.115	0.150	0.135	−0.049	−0.053	0.219	0.244	0.110	<0.001	0.032	0.226
Total R ^2	0.231	0.146	0.403**	0.347**	0.209	0.291*	0.260	0.282*	0.156	0.369**	0.207

Notes: Standardized regression coefficients (β) are from step 2

* P<0.05

** P<0.01.

a Control variables were “dummy” coded as follows: sex (male =0, female =1); education (high school or less =0, further education =1), marital status (single =0, married =1).

Abbreviations: BMI, body mass index; BP, blood pressure; Waist, waist circumference; HAPA, health action process approach; SE, self-efficacy; HDL, high density lipoprotein; LDL, low density lipoprotein.

Table 3 ANCOVA analysis of the healthy eating intervention on change in outcome and HAPA variables

Variable group	Variable name	F	P	Partial η ^2
Outcome variables	Diabetes distress	0.84	0.36	0.011+
	Healthy eating	0.04	0.84	0.001
	BMI	0.58	0.45	0.008
	Waist circumference	1.82	0.18	0.030+
	Blood glucose level	0.26	0.61	0.004
	Blood pressure, systolic	0.92	0.34	0.013+
	Blood pressure, diastolic	0.00	0.10	0.000
	Cholesterol: total	2.28	0.14	0.030+
	Triglycerides	1.48	0.23	0.020+
	HDL (“good cholesterol”)	0.04	0.85	0.000
	LDL (“bad cholesterol”)	0.11	0.74	0.002
Process variables	Risk	0.01	0.93	0.000
	Expectancy	1.09	0.50	0.015+
	Intention	0.96	0.33	0.013+
	Self-efficacy task	0.99	0.32	0.014+
	Self-efficacy coping	0.25	0.62	0.003
	Self-efficacy recovery	1.00	0.83	0.001
	Planning	0.98	0.24	0.020+

Notes: Age and baseline levels of outcome variables were controlled for;

+ small effect size (partial η ²=0.010–0.060).

Abbreviations: ANCOVA, analysis of covariance; BMI, body mass index; HAPA, health action process approach.