Determinants of active self-care behaviour of insulin treated patients with diabetes: Implications for diabetes education

0277-9536/9053.00+ 0.00 Copyright p 1990Pergamon Press plc

Sot. Si. Med. Vol. 30. No. 5, pp. 605-615. 1990 Printed in Great Britain. All rights reserved

DETERMINANTS OF ACTIVE SELF-CARE BEHAVIOUR OF INSULIN TREATED PATIENTS WITH DIABETES: IMPLICATIONS FOR DIABETES EDUCATION INGE DE WBBRDT,” ADRIAAN PH. VISSER,~GERJO KOK’ and ED A. VAN DER VEEN’ ‘Department of Endocrinology, Free University Hospital. 1007 MB Amsterdam, ?Department of Health Economics and ‘Health Education Department, University of Limburg, 6200 MD Maastricht, The Netherlands

Abstract-The most important aim of diabetes education is to alter the self-care behaviour of patients with diabetes. In order to change their behaviour its determinants must be known. The pretest of a multicentre evaluation study with 558 participating insulin treated patients with diabetes was analysed to test the usefulness of the attitude-behaviour theory of Fishbein & Ajzen in explaining and possibly changing diabetes related active self-care behaviour. The theory of Fishbein & Ajzen is based on the assumption that human behaviour is reasoned behaviour. The theory views a person’s intention as the immediate determinant of action. Determinants of intention are attitude and social norm. The results showed that the attitude was the most important determinant of active self-care, while a sufficient level of knowledge and a low orientation on the powerful others health locus of control scale were prerequisites for a positive attitude. The influence of the social environment was detrimental; although people tried to motivate patients to active self-care, they could not provide any real help in performing this desired behaviour. According to the results of this study, diabetes education should first aim at improving the level of knowledge and the health locus of control of the patients and second, at a positive attitude to active self-care. It is necessary to educate the social environment to create a more supportive atmosphere for the patient with diabetes. Key aprdsdiabetes

education, attitude-behaviour

theories, self-care behaviour, Fishbein & Ajzen

INTRODUCTION A great deal of attention has been paid to diabetes education in the past decade. The behavioural approach has been mentioned as promising [l], while changing the behaviour of patients with diabetes is considered to be the most important aim of diabetes education. Active self-care should consist of: performing home blood glucose monitoring (HBGM), variation of nutrition to daily needs, insulin dose adjustments to actual needs and taking exercise regularly [2-4]. More active self-care behaviour would result in better metabolic control, higher quality of life and lower costs of therapy 151. In order to influence and change health behaviour, its determinants must be known. Social science has developed theories explaining health behaviour in general. Studies on the usefulness of the Health Belief Model for the explanation of health behaviour generally yielded conflicting results [6]. Some studies [7,8] evaluated the value of the Health Belief Model in explaining diabetes related health behaviour. The results of these studies were very divergent. In a previous article (91 we proposed the theory of Fishbein & Ajzen [lo] as a guideline for the explanation and change of diabetes related health behaviour as well as for the development of diabetes education programmes. The theory of Fishbein & Ajzen (Fig. 1) *Address correspondence to: Inge de Weerdt. Department of Endocrinology, Free University Hospital, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. 605

is based on the assumption that human behaviour is reasoned behaviour. Consistent with this view, the theory views a person’s intention as the immediate determinant of action. According to the theory a person’s intention is a function of two basic determinants: attitude and social norm. In the theory of Fishbein & Ajzen, attitudes are a function of beliefs. A person who believes that performing a given behaviour will lead to mostly positive outcomes will hold a favourable attitude towards performing the behaviour, whereas a person who believes that this behaviour will lead to mostly negative outcomes will hold an unfavourable attitude. An attitude consists of several relevant (or salient) beliefs (b) about whether the behaviour results in specific consequences (e.g. “home blood glucose monitoring (HBGM) results in better metabolic control”) and corresponding evaluations (e) of these consequences (being in better metabolic control is good). The attitude can be assessed by multiplying the beliefs by the corresponding evaluations, and adding up the products (Att = Zi bi * ei). According to Fishbein & Ajzen a person’s social norm is his or her perception of whether the majority of significant others think that the person should or should not perform the behaviour in question. The social norm is determined by several normative beliefs (nb)-which are perceived expectations of specific reference persons (e.g. my partner wants me to perform HBGM)-and by the person’s motivation to comply (mc) with these expectations (e.g. with regard to HBGM, I do what my partner wants me to do). Just as the attitude, the

606

1%~

DE

WEERDTet

al

external variables

knowledge

--

anxiety

_----_-_-_-_-+

I behaviour

control

Fig. I. The theory of Fishbein & Ajzen for diabetes related health behaviour. social norm can be assessed by multiplying the normative beliefs by the motivations to comply, and adding up the products (SN = Z, nbi * mci). The theory of Fishbein % Ajzen also considers external variables such as personality traits and demographic variables. These external variables may influence the attitude and social norm a person holds or the relative importance he attaches to attitudinal and normative considerations. Previously published studies [6] showed that possibly relevant external variables for diabetes related health behaviour are: level of knowledge of diabetes, level of anxiety, health locus of control and demographic variables (age, general education level). The value of this theory in explaining diabetes related health behaviour has not been studied thoroughly. We found one study (81 that examined the usefulness of the theory of Fishbein & Ajzen to explain diet compliance of patients with diabetes. In this study the social norm was found to be the strongest predictor of behavioural intention. However, the value of this study is limited because of the small number of participating patients and a poorly constructed questionnaire. The validity of this theory has been proved several times for other kinds of health behaviour [12-141. As a contribution to validating this theory for diabetes related health behaviour, this paper presents the results of the analyses of the pretest (the test before education) of a multicentre diabetes education study. The main aim of this multicentre study is to evaluate an education programme for insulin treated patients with diabetes. The object of this part of the study is to determine the value of the theory of Fishbein & Ajzen in understanding and explaining active self-care behaviour of insulin treated patients with diabetes. The study has a cross-sectional design. Therefore the results will only give information about the relation between the variables and not about the causality between the variables. SUBJECTS AND METHODS

Subjects

The study was conducted in IS randomly selected hospitals spread geographically over the Netherlands.

The diabetologist of each hospital randomly recruited 40-50 patients with diabetes by giving the first 40-50 patients who came to the clinic a leaflet about the study and a request to participate. Criteria for inclusion were: age between I8 and 6.5years, insulin dependency of over 6 months, not pregnant and able to understand and speak the Dutch language. The participating diabetologists recruited 625 patients with diabetes. A total of 558 patients (89%) aged between 18 and 65 years and with a mean age of 44years (SD = 15.3 yr) participated in the study. The mean duration of diabetes was 12.7years (SD = 9.6 yr), mean duration of the use of insulin 10.6 years (SD = 10.2 yr). There was an equal distribution over both sexes. No significant differences were found between the participants and the non-participants as to age, gender, duration of diabetes and insulin use. Since the results of the pretest of an evaluation study have been used for this study, we also analysed the differences between patients in the experimental and control groups. We could not find significant differences between the patients of the experimental and control groups as to any variable assessed. Methods

Fishbein & Ajzen [IO] have written very explicit directives for developing the appropriate questionnaire to test the usefulness of their model. A wrong interpretation of these directives or ignorance will end up in misleading results. In accordance with these directives, care has to be taken to maintain a similar level of specificity (with respect to the target, setting and time of the activity) in the wording of attitude, social norm, intention and behaviour. Attitude, social norm and intention must be assessed on the same specific level as behaviour. When studying the behaviour ‘HBGM regularly’, attitude, social norm and intention to HBGM regularly should be assessed. Active self-care was considered as consisting of four behavioural elements, i.e. HBGM regularly, adjusting the insulin dose to actual needs, varying the amount and timing of meals according to daily needs and taking exercise regularly. Following the directives of Fishbein & Ajzen, the model was tested and analysed for its usefulness for

Behavioural determinants each of the four behavioural elements of active self-care. Attitude to active self-care was not one assessment but consisted of four different questionnaires. i.e. four questionnaires to’ assess (1) attitude to HBGM regularly, (2) attitude to adjusting the insulin dose to actual needs, (3) attitude to varying the amount and timing of meals to daily needs and (4) the attitude to taking exercise regularly. The same procedure was followed for assessing social norm, intention and level of active self-care behaviour. In the following the design and content of the assessment methods for each variable will be explained in more detail. Attitude and social norm. In accordance with the directives of Fishbein & Ajzen, firstly 28 insulin treated patients with diabetes were interviewed about the four aspects of active self-care behaviour: regular HBGM, adapting the size and timing of meals to daily needs. adapting the insulin dose to daily needs and taking regular exercise. The aim was to elicit salient beliefs (b) and salient normatire befiefs (nb) about the four behavioural elements. For eliciting the salient beliefs of HBGM, the following questions were asked: explaining

-What do you believe are the advantages and disadvantages of HBGM regularly? -What else do you associate with HBGM regularly? The respondent was asked to list briefly the beliefs that came to mind. The same procedure was followed for the other three behavioural elements. To elicit salient normative beliefs, similar questions for each behavioural element were asked. The following questions are examples of the questions for eliciting salient normative beliefs of HBGM: -Are there groups or people who would approve or disapprove of you performing HBGM regularly? -Are there any other groups or people who come to mind when you think about HBGM regularly? Based on the results of these interviews, and still following the directives of Fishbein & Ajzen, a questionnaire was constructed. In this questionnaire respondents were asked to evaluate each of the outcomes (beliefs) and to indicate subjective probabilities that their performance of the behaviour would lead to each of the outcomes. The strength of each belief was measured by means of a bipolar scale, such as: “If I perform blood tests more regularly I can regulate my blood sugar better”: likely unlikely. (5) (4) (2) (3) (1) The evaluation of these outcomes was indicated in terms of positive and negative scores, such as: “regulating my blood sugars better is”: negative C-2) (-1) (0) (1) (2)

positive.

The same procedure was followed for the normative beliefs and the motivations to comply. An example of a question to measure the normative belief is: “does

of active self-care

607

your partner think that you should perform HBGM regularly?’ Scores ranged from + 2 (yes, certainly) to -2 (definitely not). For the motivation to comply, patients were asked to indicate how much they cared about opinions of reference persons [scores: very much (6) to nothing (0)]. To find the most important salient beliefs and normative beliefs that should be included in the final version, 50 randomly recruited patients were asked to complete the developed questionnaire. This procedure resulted in 14 salient beliefs for variation of nutrition, 9 for exercise, 8 for HBGM and 8 for self-devised variations in the insulin dose. A corresponding number of evaluations (e) for each behavioural element was included in the questionnaire. For each behavioural element 9 normatice beliefs (nb) and 9 motivations to comply (mc) were measured. The most important reference persons appeared to be the partner, house-mates, family, children, friends, physician, dietitian, colleagues and fellow patients with diabetes. Intention. The intention to behaviour was measured for each behavioural element by one single question, e.g. “Do you intend to perform HBGM regularly in the near future?“; scores from +2 (yes, certainly) to -2 (definitely not). Lecef of behariour. Level of active self-care behaviour was assessed by general questions about the frequency of the 4 behavioural elements of active self-care and a few questions to obtain more detailed information. A higher score means a higher level of active self-care behaviour. External cariables. For assessing level of knowledge we used a multiple choice questionnaire consisting of 30 items covering general aspects of diabetes, HBGM, adjustments of insulin dose and nutrition and injection technique. The questionnaire was designed using previously developed validated questionnaires of Dunn (151, Casparie [I61 and Visser [ 171. Questions derived from the questionnaire of Dunn were translated and adjusted to the Dutch situation. Using this method content validity should be guaranteed. Questions covering urine control were replaced by questions about HBGM of Casparie [I61 and Visser [ 171. The first version of the developed knowledge scale was tested on comprehensibility at the out-patient clinic of the Free University Hospital in Amsterdam. Consecutively, 30 randomly recruited patients with diabetes completed the second adjusted version of this knowledge scale to test the difficulty and discrimination validity of each item. To test the reliability (construct validity), the next and final version of the questionnaire was completed by 55 randomly recruited insulin treated patients with diabetes. The questionnaire proved to be highly reliable (Cronbath’s II = 0.89). Other indications for a high construct validity were a Pearson correlation coefficient of -0.36 between level of knowledge and age, and a correlation coefficient of 0.28 between knowledge and occupational status. These results corresponded with the findings of Dunn and his analysis of the DKNscales [ 151and confirmed our earlier findings that the developed questionnaire was reliable. Scores for level of knowledge could range from 0 (all answers wrong) to 30 (all answers right).

608

INGE DE WEERDTer

To assess lerel of anxiety we used the Dutch validated version [I81 of the State Trait Anxiety Inventory (STAI) [l9]. This questionnaire consists of two forms: one form to assess level of trait anxief~ (a personality characteristic) and one form to assess level of stare anxiery. In this study, level of state anxiety was assessed. The reliability of the questionnaire to assess level of state anxiety proved to be high in this study as well (Cronbach’s z = 0.93). The questionnaire consists of 20 statements, IO statements representing high anxiety feelings and IO statements representing low anxiety feelings. Each statement requires a response on a four point-scale. Scores for level of state anxiety could range from 20 (low anxiety) to 80 (high anxiety). Health focus of control is a multidimensional construct consisting of three dimensions [20]: -Internal health locus of control (IHLC): the extent to which patients perceive their own behaviour as responsible for their health (diabetes control). -Powerful others health locus of control (PHLC): the extent to which patients perceive powerful other people, i.e. the physician, as responsible for their health (diabetes control). -Chance health locus of control (CHLC): the extent to which patients perceive chance factors (fate, luck, etc.) as responsible for their health (diabetes control). According to Halfens [2l] the predictive value of a disease specific health locus of control measure, in patients with a specific disease, is higher than the predictive value of the general health locus of control measure. For this reason, we applied the Dutch version [22] of the health locus of control scale of Wallston & Wallston [ZO]for diabetes. Each subscale (IHLC, PHLC and CHLC) consists of six statements that require a response to an agree-disagree, six-point Likert-type scale. A high score on each scale means a high orientation on the subscale in question. Scores for each scale could range from 6 (low) to 36 (high). To determine the multidimensional character of the developed questionnaire, principal component analysis was performed. This analysis reported the following eigenvalues for the first three factors: 4.76, 2.48 and 1.04. Respectively, these factors explained 57.5, 30.0 and 12.5% of total variance. The results of the varimax rotated factor analysis showed that the designed questionnaire consists of three main factors (IHLC, PHLC and CHLC) and that all items correlated highly to the right proposed factor. The reliability scores (Cronbach’s a) for the three subscales (IHLC: r = 0.80; PHLC: z = 0.84; CHLC: z = 0.84) showed that each subscale had a high internal consistency. Results of both analyses combined gave sufficient evidence that a reliable questionnaire for assessing diabetes health locus of control was developed. Demographic data

The questionnaire also covered relevant demographic data: age, gender, educational level [scale: I (low)-8 (high)]. occupational status [scale: I (low) -5 (high)]; relevant aspects of diabetes therapy and diabetes related complications.

al.

Metabolic control

For the quality of metabolic control, a blood sample was taken to assess HbAI% (Pierce GlycoTest; upper normal range: 6.5%). Hb.AI% is a measure for level of metabolic control of the previous 6-8 weeks. To standardise the data collection as much as possible, patients were asked to come to the outpatient clinic of the local hospital in groups of 10-15. Immediate control of the completed questionnaire reduced the occurrence of missing data. All data were processed twice to prevent mistakes as much as possible and all blood samples were analysed at the same laboratory. Statistics

The Statistical Package for the Social Sciences (SPSS [23]) was used for the statistical analyses. Following the directives of Fishbein & Ajzen, hierarchical multiple regression analyses were performed to test the usefulness of their theory. The predictive value of intention, attitude, social norm and the external variables to behaviour were determined stepwise, with intention implemented in the first and attitude and social norm in the second step. The predictive value of the external variables was tested in the third step. Only those external variables were entered that had a significant linear correlation with behaviour. If one of the external variables was of significant predictive value for the behaviour, the results will comprise the partial correlation coefficient (controlled for the influence of intention. attitude and social norm) of the external variable to behaviour. The predictive value of attitude and social norm to intention was also analysed using a multiple regression analysis, with intention as the dependent variable and attitude and social norm entered on the first step. For each behavioural element patients were divided into two groups: more active and less active patients. This grouping was based on the scores on the reported level of behaviour for each of the four behavioural elements. For HBGM regularly the less active patients were defined as patients not performing HBGM. For nutrition less active patients were defined as patients who reported to adhere to their diet very strictly. For the behavioural element selfdevised adjustments of insulin dose, the group of less active patients consisted of patients never making these self-devised adjustments. Less active patients with respect to regular exercise reported to take exercise never or seldom. Two-tailed t-tests were used to compare these groups on the beliefs, the evaluation of beliefs, the normative beliefs, the motivations to comply and the external variables. Analysis of variance (ANOVA) was used if indicated. RESL’LTS

Since no linear correlations were found between all four behavioural elements, the results of the analyses of the usefulness of the theory of Fishbein & Ajzen for explaining active self-care behaviour will be presented for each behavioural element of active-

Behavioural

determinants

r-.31

609

of active self-care

(rP=.27)

___----____---_____---------

V pomrful

I

social norm

others r-.18 of __*

health locus

r-.48

cc&r01

I

I

r-O.00 (rP-. -------=---+

I -----__________--__

-I r- -.Zl

(rP- -.21)

Fig. 2. The theory of Fishbein & Ajzen for HBGM

and intention) between social norm and behaviour. It seems as if the environment has a positive influence on the intention to active self-care, but that did not lead to the desired behaviour.

self-care separately. We only found a significant correlation between HBGM and adjustments of insulin dose (r = 0.36, P < 0.001) and between variation of nutrition and adjustments of insulin dose (r = 0.24, P -C0.001). Firstly the results of the multiple regression analysis will be presented, followed by the results of the comparison of the less active and more active patients and their scores on beliefs, evaluation of beliefs, normative beliefs, motivations to comply and external variables.

Comparison of less active and more active patients concerning HBGM. Of the participants, 60.4% re-

Home blood glucose monitoring Correlations between the variables of the theory of Fishbein & Ajzen. Figure 2 shows the correlations

between the variables of the theory of Fishbein & Ajzen for HBGM regularly. As can be seen from this figure, for HBGM ‘level of knowledge’ and ‘powerful others health locus of control’ are important external variables having a significant partial correlation with behaviour. Level of anxiety had no significant linear relationship with behaviour. This variable was therefore not included in the multiple regression analysis. A multiple correlation coefficient (R) of 0.57 was found of attitude and social norm, to intention. Attitude and social norm are almost equally important for determining intention. There was a relatively low correlation coefficient of 0.53 between intention and behaviour. This might be due to the negative partial correlation coefficient (= correlation coefficient when correcting for the influence of attitude Table

1. Mea”

scores of active

(AP)

and “on-active

patients

ported that they performed HBGM, but only a small percentage (19.1%) performed HBGM regularly (more than once a week). Extra blood glucose tests were performed during holidays, illness, exercise and dinner parties. In Table 1 the mean scores on the beliefs and the evaluation of beliefs concerning HBGM of the inactive (not performing HBGM) and the active patients are presented. As can be seen from this table the active patients believed that HBGM had positive personal advantages more than did the non-active patients. For the active patients, HBGM results in better metabolic control, more certainty, more adequate adjustments of nutrition, insulin and exercise, better communication with the physician and improved awareness of glycaemic control. In contrast to the non-active patients, the active patients felt that more stress is not a consequence of HBGM. The evaluation of the consequences of HBGM by the active patients was also more positive, except the evaluation of more stress. No significant differences between both groups were found for their scores on the social norm. The active patients were more motivated to comply with their partner, house-mates, family, physician,

(NAP)

on kliefs

(b),

evaluation

I. 2.

Better metabolic More certainty

control

NAP

AP

NAP

AP

NAP

3.69 3.71

I.51 1.50

0.88 0.90

6.55 6.49

3.60 3.61 4.15

Improved

4.32

3.89

1.59

1.00

6.98

More

adequate

adjustments

of nutrition

4.04

3.63

I .22

0.76

5.13

3.01

5.

More

adequate

adjustments

of insulin

4.04

3.60

1.33

0.90

5.65

3.44

6. 7.

More adequate adjustments Better communication with

of exercise the physician

3.82 3.63

3.47 3.33

I.13 I .28

0.73 0.92

4.55 4.93

2.80 3.28

More

differences

Ranges

control

AP 4.22 4.25

3.

8.

of glycaemic

HBGM

b*e

4.

All

awareness

(e) and b c e concerning

Evaluations

Beliefs Co”xque”ces

regularly.

stress

of scores:

(products).

2.41

between

active

beliefs:

and

I (very

non-active unlikely)

patients to 5 (very

were

significant

likely);

3.04

-1.15

at P < 0.001.

evaluations:

-2

(very

except

-0.77 l

negative)

- 2.39

-2.17.

= not significant. to

+2

(very

positive);

b

l

e: -10

lo + 10

610

INGE DE WEERDTet al.

1--------.r=.38r-.28 levelof __* attitude klKWledp

;

4 r-.58

b.43~Yz@+

r-.30

1 powerful others r-.12 healthlocusof--_, control

social norm

I r-.36 -__---r-.01 (rp--28)

I

L _----------------

r-.37

(r,-.28)

Fig. 3. The theory of Fishbein & Ajzen for variation of nutrition.

dietitian and fellow patients with diabetes. But this did not result in a more positive social norm because they did not perceive positive pressure to perform the behaviour. The scores on the normative beliefs were rather neutral. With respect to the external variables, it appears that for HBGM, the more active patients were younger (P < O.OOl), had a higher social status (P < 0.05), a higher educational level (P < 0.01) greater knowledge of diabetes (P < 0.05) and had lower scores on the PHLC-scale (P < 0.001). ANOVA showed that out of the external variables, powerful others health locus of control was the main discriminative variable (P < 0.001). Variation of nutrition Correlations between the variables of Fishbein & &en. The correlations between the variables of Fishbein & Ajzen for variation of nutrition are given in Fig. 3. This figure is almost identical to the theory of Fishbein & Ajzen for HBGM regularly. Level of knowledge and powerful others health locus of control are important external variables. A multiple correlation coefficient (I?) of 0.43 was found of attitude and social norm, to intention. The almost equal influence of attitude and social norm on

intention was also found in the results for HBGM. This is also valid for the relatively low correlation coefficient (0.52) of intention to behaviour, which might be due to the negative partial correlation coefficient between social norm and behaviour. Comparison of active and non-active patients concerning variation of nutrition. For nutrition, 50.2% of the patients reported that they varied their diet regularly (active patients); 33.6% reported that they always ate at the same time, while 20.9% of the patients always consumed the same amount of food. Only a small percentage of the participants (5.0%) reported no fixed amounts of food and no fixed eating times. Most of the participants used the exchange list to vary their diets. Non-active patients were defined as patients who reported that they adhered to their diet very strictly (49.8% of the participants). In Table 2 the scores of the active and non-active patients on the beliefs and the evaluation of the beliefs of variation of nutrition are given. The more active patients believed that variation of nutrition results in more feelings of freedom and easier adjustment to many situations. They also felt the consequences of variation of nutrition, such as not eating the proper amount of carbohydrates, gaining weight and being more out of metabolic control more often

Table 2. Mean scores of active (AP) and non-active patients (NAP) on beliefs (b), evaluations (c) and b Beliefs Consequences

AP

NAP

I. 2. 3. 4. 5. 6. 7. 8. 9. IO. I I. 12. 13. 14.

3.06 3.85 3.64 3.88 3.79 2.79 2.97 3.49 3.34 3.25 2.72 2.69 2.87 3.10

2.89 3.4s 3.73 3.76 3.5s: 3.27. 2.93 3.33 3.19 3.21 2.95: 3.06’ 2.89 3.02

Having the possibility to eat everything Having more feelings of freedom More often performing blood tests Eating more tasty Easier adjustments in many situations Eating the right amount of carbohydrates Eating hcalthicr Having a more normal way of life Having more dinner parties Easier cooking Gaining weight Being more often out of metabolic control Cheaper food Having less feelings of guilt

l

e concerning variation of nutrition

Evaluations AP 1.01 I .27 0.60 I .oa I.17 0.83 1.18 I .23 0.40 0.60 - I .23 -1.56 0.04 0.53

b*e

NAP

AP

0.72 I .03* 0.65 0.83’ I .02t 0.87 I .29 1.13 0.19: 0.50 - I .os: - I .29* 0.11 0.57

3.35 5.13 2.60 4.33 4.54 2.34 3.94 4.36 I.51 2.17 -3.28 -4.06 0.27 I .72

NAP 2.30 3.77’ 2.44 3.39t 3.79) 2.76 3.51 3.82t 0.87: I .70 -3.10 - 3.97 0.58 I .a5

lP
tP<0.0l;:P<0.05. Range of scores:beliefs: I (very unlikely) to 5 (very likely); evaluations: -2 (very negative) to +2 (very positive); b

l

e: - 10 to + 10 (Products).

Behavioural determinants

of active self-care

lP.51

611

($-.rs)

----------------m-J r-.49

(rp--43)

Fig. 4. The theory of Fishbein & Ajzen for self-devised adjustments of insulin dose.

to be less negative. several

evaluations

Both groups also differed on (possibility to eat everything,

more feelings of freedom, enjoying their food more, easier adjustment to many situations, possibility for more dinner parties, gaining weight and being out of metabolic control more often). No significant differences were found for the scores on the social norm. Taking into account the scores on the normative beliefs and the motivations to comply, the active patients were less motivated to comply with the important reference persons (children, physician and dietitian). However, these differences were not enough to cause a significant difference in the scores on the social norm. As to the external variables the more active patients were younger (P < O.OOl), had a higher occupational status (P < 0.05), a higher general educational level (P c O.OOl),a higher level of knowledge of diabetes (P < 0.5) and lower scores on the PHLCscale (P < 0.001). ANOVA showed that out of these external variables powerful others health locus of control was the main discriminative variable (P < 0.001). Self-devised

adjustments

of insulin dose

Correlations between the variables of Fishbein & Ajzen. The theory of Fishbein & Ajzen for self-

devised adjustments of insulin dose is given in Fig. 4. Level of knowledge and powerful others health locus of control are important external variables, but these variables only have a significant correlation with the attitude. The multiple correlation coefficient (0.52) of attitude and social norm to intention is comparable Table 3. Mean scores of active (AP) and non-active

patients (NAP)

to the results of the behavioural elements HBGM and variation of nutrition. The correlation coefficient between attitude and intention is higher than the correlation coefficient of intention to behaviour is relatively low. For self-devised adjustments of insulin dose no significant partial correlation coefficient (rp = - 0.06) of social norm to intention was found. Comparison of active and non-active patients concerning self-devised adjustments of insulin dose. Of the

participants, 45.8% reported that they never made self-devised adjustments of the insulin dose (nonactive patients). Active patients are defined as those making self-devised adjustments of insulin dose; 47.0% sometimes adjusted their insulin doses and only 7.2% regularly did so. Upper range of blood glucose level for adjusting the insulin dose varied from 10 to 25 mmol/l (mean = 14.2 f 6.2 mmol/l). Lower range varied from 2 to 6 mmol/l (mean = 3.1 + 1.9 mmol/l). These values show that some patients do not have sufficient knowledge for an appropriate adjustment of the insulin dose. The mean scores of the active and non-active patients on the beliefs and the evaluations of these beliefs are outlined in Table 3. The results showed that the active patients perceived better metabolic control, more self-confidence and improved wellbeing as personal advantage of this behaviour. They perceived fewer negative consequences of the behaviour: making mistakes, feelings of fear and danger and not having sufficient knowledge. The active patients also evaluated the positive consequences more positively.

on beliefs (b), evaluations (e) and b dose Beliefs

AP

NAP

::

4.26 4.27

3.71. 3.72.

1.51 1.52

3.89 4.21 2.11 2.10 2.65 2.21

3.62. 3.66, 3.10’ 3.03. 3.77’ 3.31’

1.35

3. 4. 5. 6. 7. 8.

e concerning adjustments of insulin

Evaluations

Conxaucnca To control diabetes blood betterbetter regulate sugars More self-confidence Feeling better Being afraid of something Making mistakes Not having sufficient knowledge Something dangerous

l

AP

I .49 -0.98 -1.09 -1.16 -1.04

NAP

b*e AP

NAP

0.99. 1.02.

6.6 6.65I

4.04. 3.97.

1.09* 1.17’ -0.67’ -0.81’ -o.a4* -0x2t

5.67 6.43 - I .80 -2.40 -3.32 -2.72

4.22’ 4.57’ -1.99 -2.07 -2.91 -2.19

lP < 0.001; tP
612

INGE DE WEERDTet al.

r-.67

-----------___ r-.04 (rp--27) Fig. 5. The theory of Fishbein

As to the social norm the active patients perceived a higher social norm and felt more pressure to adapt their insulin dose if necessary. Scores of the active patients on all normative beliefs and the motivations to comply were significantly higher (P < 0.05). As the external variables: active patients were younger (P < O.OOl), had a higher occupational status (P < O.OOl), a higher general educational level (P < O.OOl), a higher level of knowledge of diabetes (P < 0.05) and lower scores on the PHLCscale (P < 0.001). No significant differences between the active and non-active patients were found as to age and occupational status. Main discriminative variable was powerful others health locus of control (P < 0.001). Regular exercise Correlations between the variables of Fkhbein & Ajzen. The theory of Fishbein & Ajzen for regular

exercise is outlined in Fig. 5. Main difference between this figure and the corresponding figures for the other three behavioural elements was found in the external variables. For regular exercise only level of knowledge was found to have a linear correlation coefficient, but not a significant partial correlation coefficient with behaviour. Another important difference was found in the multiple correlation coefficient of attitude and social norm to intention. This correlation coefficient is much lower than the coefficients found for the other three elements of active self-care. The correlation coefficient of intention to behaviour is higher (0.67). Just as for the elements HBGM and variation of nutrition, for regular exercise a negative

SC Ajzen

for regular exercise.

partial correlation coefficient of social norm to behaviour was found. Comparison between active and non-active patients concerning regular exercise. Of the participants,

19.4% reported taking no exercise at all and 16.5% reported seldom taking regular exercise. Only 15.0% of the participants took more than 5 hr of exercise a week. Cycling and walking were the most common forms of exercising. According to our definition, active patients are patients taking regular exercise (at least once a week; =64% of the patients). The non-active patients are those patients who never or seldom take regular exercise (36% of the patients). The scores of both groups on the beliefs and the evaluation of these beliefs are outlined in Table 4. The more active patients had significantly higher scores on 7 out of 9 beliefs. The active patients also evaluated most of these beliefs more positively. Only the belief “not knowing how your body will react” was evaluated more negatively by the more active patients. Despite the significantly higher scores of the active patients on the motivation to comply (P -E 0.05) no significant differences between both groups were found in their scores on the social norm. As to the external variables, the more active patients had a significantly higher general educational level (P < 0.001) and significantly lower scores on the PHLC-scale (P c 0.05). The general educational level was the main discriminative variable (P c 0.01). Correlation between active sel/care and metabolic control. To study whether active self-care had a

positive effect on metabolic control, Pearson correla-

Table 4. Mean scores of active (AP) and non-active patients (NAP) on beliefs (b), evaluations (e) and b l c concerning regular exercise Reliefs

Evaluations

b*e

Consequences

AP

NAP

AP

I. 2. 3. 4. 5. 6. 7. 8.

3.88 4.12 3.91 3.52 3.49 3.01 3.45

3.60. 3.81’ 3.54. 3.30t 3.283 3.257 3.41

1.19 1.41 1.14 1.19 I .27 -1.00 0.98

I.Olt 1.17. 0.91 l 1.12 l.II$ -0.92 0.78t

4.84 5.98 4.65 4.36 4.67 -2.95 3.57

3.83’ 4.64. 3.36. 3.82+ 3.76t -2.92 2.81.

2.97 2.80

2.87 2.23.

0.86 -1.03

0.78 -0.80t

2.66 -2.73

2.27 -2.46

9.

More feelings of freedom Feeling more fit Getting more satisfaction A better regulation of blood sugars Less having the idea to be sick Having a bigger chance on a hypo reaction Having more social contacts Receiving more understanding from social environment Not knowing how your body will react

AP

NAP

NAP

lP
l

e: - 10 to + IO(products).

Behavioural determinants of active self-care tion coefficients were computed between the four behavioural elements and HbA 1%. Only HBGM had a significant correlation with HbAl% (r = - 0.16, P < 0.001). Multiple regression analysis showed that, of all diabetes therapy related variables, the frequency of HBGM was the best predictor of metabolic control. ANOVA (covatiates: age and duration of diabetes) showed that patients performing HBGM regularly had a mean HbAl% of 8.9%, compared to the non-active patients’ mean of 9.5%. DISCUSSION AND IMPLICATIONS FOR DIABETES EDUCATION

The theory of Fishbein & Ajzen gives valuable information for explaining active self-care behaviour of adult insulin treated patients with diabetes. Active self-care was considered to consist of four behavioural elements: HBGM regularly, self-devised adjustments of insulin dose, adapting the timing and size of meals to daily needs and taking exercise regularly. In the theory of Fishbein & Ajzen, the immediate determinant of each behavioural element of active self-care is intention, which is determined by attitude to and social norm on active self-care. Attitude is the most important variable for explaining active selfcare behaviour. Active patients, with respect to the four behavioural elements of active self-care, had a more positive attitude compared to the non-active patients. Other studies [6, 71 have also found a positive relationship between attitude and self-care behaviour. However, since different kinds of attitude were assessed, the results are hardly comparable. Most of the studies focussed on the health beliefs of the Health Belief Model; others focussed on attitude to diabetes [24] or on the emotional component of attitude to diabetes [25]. For HBGM, variation of nutrition and regular exercise, the social norm had a positive influence on intention, but a negative partial correlation coefficient with behaviour. We assume that the social environment tries to stimulate patients to activate self-care without knowing how to provide real help. Other studies [26,271 found different results. Schafer [27] concluded that higher perceived levels of nonsupportive family behaviour were related to reduced regimen adherence and poor metabolic control. An important difference between this study and our study is the kind of behaviour assessed: regimen adherence vs active self-care. It seems as if the social environment is not familiar with new strategies in diabetes therapy, that give patients with diabetes more opportunities to live their lives as normally as possible. At the same time, a patient with diabetes feels pressure from the social environment to behave like a normal, healthy person without receiving any help in this. The theory of Fishbein & Ajzen also considers external variables that can influence the attitude or social norm. They are considered as prerequisites. Prerequisite for a positive attitude to all behavioural elements was a sufficient level of knowledge and, for a positive attitude to HBGM variation of nutrition and self-devised adjustments of insulin dose, a low orientation on the powerful others health locus of control

613

scale is required as well. Previous studies [28-311 found a significant relationship between health locus of control and self-care behaviour. Others [15,28,29,32,33] found a correlation between level of knowledge and metabolic control. Although our theoretical concept is different, these results correspond with our findings. The results of the studies mentioned suggest that an internal health locus of control and a sufficient level of knowledge are prerequisites for a high level of self-care and or good metabolic control. Lockington [34] recently suggested that a minimum (threshold) level of knowledge is necessary above which other factors, including attitudes and motivation, are likely to be of much greater importance. This suggestion corresponds with our premises and results. According to the theory of Fishbein & Ajzen, a more powerful others health locus of control and a sufficient level of knowledge are prerequisites for a positive attitude to active self-care, while a positive attitude is considered as the most important determinant of self-care behaviour. In our opinion, a theoretical concept such as the theory of Fishbein & Ajzen gives a deeper understanding of the feasibility of changing the behaviour under study. Recently Ajzen [35] suggested adding another variable to the model of Fishbein & Ajzen: behavioural control. This variable is similar to the variable selfefficacy derived from the social learning theory of Bandura [36]. Self-efficacy expresses the degree to which persons perceive themselves capable of performing a certain behaviour. This variable should be added to the model on the same level as the attitude and social norm. In our study we did not assess this variable. Maybe the studied behaviour could be better explained if we had taken this variable into account as well [37]. However, we did assess the external variable powerful others diabetes health locus of control. This variable is a bit similar to the variable self-efficacy, while it expresses the degree of helplessness of a patient. A high partial correlation coefficient was found between this PHLC-scale and behaviour. This means that the influence of this variable on behaviour is not completely mediated by attitude and social norm and that the powerful others health locus of control has a direct influence on behaviour. Similar results were found for level of knowledge which supports the previous findings, that adding a .third variable (together with social norm and attitude) to the theory of Fishbein & Ajzen, possibly could enlarge its predictive value for diabetes related health behaviour. Future research should find out if the factor self-efficacy is of significant value for the explanation of active self-care behaviour of patients with diabetes. In the introduction of this article we already referred to the cross-sectional design of this study. Attitude, social norm, intention and behaviour were assessed at the same time. The results give therefore only evidence for the relation between the variables and for the explanation and not for the prediction of the behaviour studied. We have no reason to believe that the low correlation coefficient between intention and behaviour is due to this cross-sectional design. Most research on the usefulness of the theory of Fishbein & Ajzen had

614

INGEDE WEERDTer al.

a cross-sectional design and found stronger relations between intention and behaviour [12,13]. A recent study with a longitudinal design reported a much lower correlation coefficient between intention and behaviour [38]. We therefore believe that the crosssectional design of this study cannot explain the low correlation coefficient between intention and behaviour. From the results we can develop general profiles for the active and the non-active patients with diabetes as to the four behavioural elements of active self-care. Active patients generally have lower scores on the powerful others health locus of control scale, which coincides with a higher level of knowledge of diabetes, a lower age, a higher social status and a higher educational level. They perceive more personal advantages in active self-care, while they are not bothered by opinions of important persons in their social environment. Non-active patients generally have higher scores on the powerful others health locus of control scale, which coincides with a lower level of knowledge of diabetes, a higher age and a lower social status. For the level of active self-care behaviour, the opinion of the social environment is more important than their own personal attitude. The variable HBGM correlated best with metabolic control. Patients who performed HBGM were in better metabolic control than non-active patients. Similar results have been found in other studies [39,40], although the amount of evidence is relatively small. Other studies could not show any improvement of metabolic control during HBGM [41,42]. Future research should probably focus more on the relationship between the quality of the behaviour performed and metabolic control rather than the frequency of the behaviour. Implications for diabetes education

For diabetes education, it is most important to adopt the content and method to the individual characteristics of the patient. Health locus of control is one such individual characteristic. Patients who are more externally controlled rely for a great deal upon the opinions of important others such as the educator and the physician for their health. They need very explicit guidelines about how to perform active selfcare and will never make self-reliant variations to adjust these guidelines to daily fluctuations. Diabetes education must be very structured in nature and strong guidance of the patient is necessary. Less guidance is necessary for less externally controlled patients. The active participation by these patients in their own therapy is very common. They also actively look for more information about their disease. Since these patients do not like strong guidance, diabetes education should consist of democratic co-operation between patient and educator. In both cases, diabetes education should aim to improve the level of active self-care behaviour. Since attitude is the best predictive variable of this behaviour, education should focus on improving it. A sufficient level of knowledge and a low orientation on the powerful others health locus of control are considered prerequisites for a positive attitude. The first

step of education must therefore consist in providing knowledge and trying to improve patients’ health locus of control by changing an external health locus of control into a more internal one. Since in our study, level of knowledge was highly related to powerful others health locus of control, one might expect that improving knowledge would have a positive effect. However, some discussion is possible about the feasibility of changing health locus of control, and whether education alone can change it. Generally, it may be stated that the health and illness specific locus of control are more subject to change than the general locus of control [21]. The evaluation of education programmes must demonstrate this. In the United States, some training programmes 1431 especially developed to change an external health locus of control into an internal one are available. The usefulness of these programmes for diabetes education is unknown, The second step in education should consist in improving the attitude to active self-care. This is possible by stressing the relevant beliefs that patients hold about active self-care. For HBGM, it is important to stress that performing the desired behaviour can result in better metabolic control, more certainty, more adequate adjustments of nutrition, insulin and exercise, better communication with the physician and improved awareness of glycaemic control. The importance of negative consequences (for HBGM: more stress) must be diminished. The same method is also useful to influence the attitude to the other three behavioural elements of active self-care. By attempting to increase the importance of positive consequences and decreasing the importance of negative consequences, the cost-benefit analysis a person makes before he decides to engage in a certain behaviour will be influenced positively. Lastly, it is important to educate the social environment, since it seems that they lack knowledge to provide the patient any real help. Information of all aspects of diabetes therapy should be provided to those people in the social environment who are actively involved in the daily life of the patient with diabetes. Since the patient also seems to meet misunderstanding from other parts of society, it might be worthwhile to use the mass media for educating the social environment in its broadest context. would like to thank Paul Uitewaal, Okke de Weerdt, Taeke Spinder, Jan Jaap Spijkstra, Roe1 Rexwinkel, Irene Visser and Marie-Gabrielle Leijdekker for their enormous support in gathering and processing the data. We are also very thankful for the generous co-operation of all health care workers of the 15 participating hospitals and their patients. We gratefully acknowledge the financial support of Stichting DiaAcknowledgements-We

betes Fonds Foundation).

Nederland

(Dutch

Diabetes

Research

REFERENCES

. Dunn S. M. Reactions

to educational techniques: coping strategies for diabetes and learning. Diabetic Med. 3, 419-429,

1986.

Behavioural determinants of active self-care 2. Assal J. P., Muhlhauser I.. Pernet A., Gfeller R., Jorgens V. and Berger M. Patient education as the basis for diabetes care in clinical practice and research. Diabetologia

28, 602-613,

1985.

3. Padgett D., Mumford E., Hynes M. and Carter R. Meta-analysis of the effects of educational and psychosocial interventions on management of diabetes mellitus. J. c/in. Epidem. 10, 1007-1030, 1988. 4. Weerdt de I. Diabetes educatie: theorie en praktijk. Ned. Tijhchr.

Die&en

2, 3740,

1988.

5. Berger M. Evaluation of a teaching and treatment programme for type I diabetic patients. Diabetes Educafor 10. 36-38, 1984. 6. Janz N. K. and Becker M. H. The health model: a decade later. Hlrh Educ. Q. 11, l-47, 1984. 7. Bloom Cerkoney K. A. and Hart L. K. The relationship between the health belief model and compliance of persons with diabetes mellitus. Diabetes Care 2, 594-598,

1980.

8. Harris R. and Linn M. W. Health beliefs, compliance and control of diabetes mellitus. South. med. J. 2, 162-166,

1985.

9. Weerdt de I., Visser A. P. and Van der Veen E. A. Attitude behaviour theories and diabetes education programmes. Patienr Educ. Counsel. 14, 3-19, 1989. IO. Ajzen I. and Fishbein M. Undersranding Arrirudes and Predicting Social Rehariour. Prentice Hall, Englewood Cliffs, N.J., 1980. II. Shenkel R. J., Rogers J. P., Perfetto G. and Levin R. A. Importance of ‘significant others’ in predicting cooperation with diabetic regimen. Inr. J. Psychiaf. Med. 15, 1499155, 1986.

12. De Vries H. and Kok G. J. From determinants of smoking behaviour to the implications for a prevention programme. Hlrh Educ. Res. 1, 85-94, 1986. 13. Kok G. J. and Siero S. Tin recycling: awareness, comprehension, attitude, intention and behaviour. J. Econ. Psvchiat.

6, 157-173.

1985.

14. Cook M. P., Lonnsburg J. W. and Fontenelle G. A. An application of Fishbein & Ajzen’s attitude-subjective norm model to the study of drug use. J. Sot. Psychol. 11, 193-201, 1980.

IS. Dunn S. M., Bryson J. M., Hoskins P. L., Alford J. B., Handelsman D. J. and Turtle J. R. Development of the diabetes knowledge (DKN) scales: forms DKNA, DKNB and DKNC. Diabetes Care 7. 36-41. 1984. 16. Casparie A. F. and Elving L. D. Voorlichting aan diabetespatienten en toetsing van hun kennis: een kwestie van voortdurende zorg. Medisch Contact 40, 429-431,

1985.

17. Visser A. P., Van den Boogaard P. R. and Van der Veen E. A. Participatie van diabeten: betrokkenheid bij de DVN en gesprekgroepen. Medisch Conracr 40, 1502-1504,

1985.

18. Van der Ploeg H. M. Validatie van de Zelf-beoordelings Vragenlijst (een nederlandstalige bewerking van de Spielberger State-Trait Anxiety Inventory). Ned. Tijdschr. Psychol.

35, 243-249,

1980.

19. Spielberger C. D., Gorsuch R. L. and Lushene R. E. STAI

Manual for

the Slare-Trait

Anxiety

Imemory.

Consulting Psychologist Press, Palo Alto, Calif., 1970. 20. Wallston K. A., Wallston B. S. and Devellis R. Development of the multidimensional health locus of control (MHLC) scales. Hlrh Educ. Monow. 160-169. 1978. 21. Halfens ‘R. and Visser A. P. De beheersingsorientatie van gezonheid en ziekte. 7. Sot. Gezondheid. 66, 397-398,

1988.

22. Halfens R. J. G. Locus of control: de beheersingsorien-

tatie in relatie tot ziekte-en gezondheidsgedrag. Academic thesis, Maastricht. 1985. 23. Nie N. H., Hadlai Hull C., Jenkins J. G., Steinbrenner K. and Bent D. H. SPSS: Statistical Package for the Social Sciences. McGraw-Hill, New York, 1975.

61.5

24. Lockington T. J., Meadows K. A. and Wise P. H. Compliant behaviour: relationship to attitudes and control in diabetic patients. Diabetic Med. 4, 5661, 1987. 25. Dunn S. M., Smartt H. H., Beeney L. J. and Turtle J. R. Measurement of emotional adjustment in diabetic patients: validity and reliability of ATT39. Diabetes Care 9, 480-489,

1986.

26. Schwartz L. S., Springer J., Flaherty J. A. and Kiani R. The role of recent life events and social support in the control of diabetes. Gen. Hosp. Psychiaf. 8, 212-216. 1986.

27. Schafer L. C., McCaul K. D. and Glasgow R. E. Supportive and nonsupportive family behaviors: relationships to adherence and metabolic control in persons with type I diabetes. Diabetes Care 9, 179-185, 1986. 28. Peyrot M. and McMurry J. F. Psychosocial factors in diabetes control: adjustment of insulin-treated adults. Psychosom.

Med. 6, 542-557.

1985.

29. Korhonen T., Huttunen J. K., Aro A.. lhalainen 0.. Majander H., Siitonen 0.. Uusitupa M. and Pyorola K. A controlled trial on the effects of patient education in the treatment of insulin-dependent diabetes. Diaberes Care 6, 256-261,

1983.

30. Schlenk E. A. and Hart K. L. Relationship between health locus of control, health value, and social support and compliance of persons with diabetes. Diaberes Cure 7, 566-574,

1984.

31. Alogna M. Perception of severity of disease and health locus of control in compliant and noncompliant diabetic patients. Diabefes Care 3, 533-534, 1980. 32. Watts F. N. Behavioural aspects of the management of diabetes mellitus: education, self-care and metabolic control. Rehau. Res. Ther. 18, 171-180, 1980. 33. Assal J. P., Muehlhauser I., Pernet A., Gfeller R., Joergens V. and Berger M. Patient education as the basis for diabetes care in clinical practice and research. Diabetologia

28, 602-613,

1985.

_

34. Lockington T. J., Farrant S., Meadows K. A.. Dowlatshahi D. and Wise P. H. Knowledge profile and control in diabetic patients. Diabetic Med. 5, 381-386. 1988. 35. Aizen I. and Madden T. J. Prediction of goal directed behavior: attitudes, intentions and perceived behavioral control. J. exp. Sot. Psychol. 22, 453-474. 1986. 36. Bandura A. Self-efficacy: toward a unifying theory of behavior change. Psychol. Rev. 84, 191-215, 1977. 37. De Vries H., Dijkstra M. and Kuhlman P. Self-efficacy: the third factor besides attitude and subjective norm as a predictor of behavioural intention. Hlrh Educ. Res. 3, 273-282,

1988.

38. De Vries H. Smoking prevention in Dutch adolescents. Academic thesis, University of Limburg. Maastricht, 1989. 39. Terent A., Hagfall 0. and Cederholm U. The effect of education and self-monitoring of blood glucose and glycosylated hemoglobin in type I diabetes. Acra med. stand. 217, 47-53, 1985. 40. Sonksen P. H. Home monitoring

of blood-glucose, method for improving diabetic control. Lancer i, 729-732, 1978. 41. Worth R., Home P. D., Johnston D. G., Anderson J.. Asworth L.. Burrin J. M., Appleton D., Binder C. and Alberti K. G. M. M. Intensive attention improves glycaemic control in insulin-dependent diabetes without further advantage from home blood glucose monitoring: results of a controlled trial. Er. med. J. 285, 1233-1240, 1982. 42. Mazze R. S., Pasmantier

R., Murphy J. A. and Shamoon H. Self-monitoring of capillary blood glucose: changing the performance of individuals with diabetes.

Diabetes Care 8, 207-212, 1985. 43. Wallston B. S. and Wallston K. A. Locus of control and health: a review of literature. Hlrh Educ. Monogr. 6, 107-I 17, 1978.