Impact of screening

It was hypothesised that, since the different methods of offering screening would result in different uptake rates and they would offer different 'types' of screening, the subsequent impact of screening would be affected. However, although there were wide differences in uptake rates of the three groups and they did offer different 'types' of screening, the method of offering screening had little effect on overall impact.

The only difference shown between methods of offering screening was for intention to smoke less at one week following screening. Using smokers only in this analyses it was found that those screened opportunistically had the highest intention to smoke less. Further analyses showed that those patients who attended the clinic were the least likely to be smokers compared to the

opportunistic group and the non-attenders. So smokers were less likely to attend if invited to a screening clinic. Previous studies have shown that those who were least likely to attend for screening for cancer (Seydal et al, 1990) and for CHD risk factors (Worksite study, see Chapter 2) perceived themselves as more susceptible to disease. It may be that smokers perceive their susceptibility to be higher than average and thus avoid screening. Alternatively they may anticipate a more aversive screening consultation and avoid it for that reason. It seems that smokers avoid screening clinics and therefore opportunistic screening is a better way of reaching smokers.

Knowledge and satisfaction did not act as mediators between method of offering screening and impact as predicted. Nevertheless it is important to note that the ‘number correct’ component of knowledge predicted some aspects of impact, especially intention to change. The other aspects of knowledge, i.e. the number of misconceptions and number of uncertainties, did not affect impact which suggests that it is the amount of correct knowledge that was important - the amount of uncertainty and misconceptions the subjects had were less relevant in this study. Overall, it seems to have been relevant to divide the knowledge scoring in this way. Satisfaction, on the other hand was not related to any of the outcome variables. This suggests that responding to advice about risk factors and

behaviour change does not depend on satisfaction with the consultation and may be a different process from adherence to medical advice which has been found to be related to satisfaction (Ley, 1988). The lack of group differences shown for satisfaction and knowledge could suggest a ceiling effect. This might be expected as the subjects are all consulters and may thus be generally satisfied with the services at the health centre and have a good knowledge of lifestyle risk factors. The satisfaction results do seem to support this suggestion as the average score was 45.5 out of a possible 55. However, knowledge scores averaged 7.5 out of

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11 which may suggest some room for knowledge improvement which screening did not seem to effect. The result for knowledge was that screening did not predict knowledge but knowledge predicted impact. From an applied perspective this suggests that screening outcomes may be improved by designing interventions to increase knowledge of risk factors during the screening process.

4.5.2.1 Effects of screening per se

The assumption that screening per se would make a difference to outcome such that those screened would be more likely to have intentions, to try and to manage to change their health behaviours was hardly supported. Those patients who were screened (both at the clinic and opportunistically) were more hkely than those who were not screened to intend (at both assessments), to try and to manage to take more exercise. There was, however, no effect of screening on intention, trying or managing to do any of the other behaviours measured, although all tended to be enhanced by screening. This may account for the main finding that neither the Letter invitation nor the Opportunistic methods had any overall advantage over the Personal invitation method even though their uptake rates were higher. If screening per se has little effect on the outcomes measured in this study, then it is not surprising that the methods which allowed more people to be screened did not show better overall screening outcomes. However, the second follow-up in the current study was only three months following screening and it is possible that screened patients would still be receiving advice from the GP or practice nurse which might have an impact at a later stage. Nonetheless, the impact would probably be affected by the type of advice given. Michie et al

(1995) found that the type of feedback following screening affected the extent of behaviour change and Johnston (1995) argues that such feedback should be informed by current theory and evidence on factors influencing behaviour change. Unfortunately, information regarding the feedback given to patients was not available in this study. Further research on the behavioural impact of screening should investigate this issue in more detail.

Another possible reason for the lack of differences between those screened and those not screened is that patients may not have taken any advice seriously.

Previous research by Rastam et al (1988) showed that 30% of their sample regarded their screening results as unimportant.

It is interesting however that those screened did have a higher intention, tried more and managed to exercise more. This may be because those who are screened are more likely to have tried to exercise more before screening which may just continue following screening. It is also possible that taking more exercise is 'easier' for those who are screened if they are given a barrage of advice at their appointment and decide to choose one thing to do. This may be especially true considering the questionnaire item used which did not measure the extent of exercise by which they were increasing, but was simply a dichotomous question as to whether or not they had taken more exercise. Exercise also differs from all the other behaviours in the sense that it requires taking up a positive (health

enhancing) behaviour as opposed to giving up a negative behaviour (e.g. eating less fat, smoking less, etc.). It may be easier for people to find the motivation to take up a positive behaviour than give up a negative behaviour. Or, exercise may have been stressed in the screening appointment due to a particular need for an increase in physical activity within the screened group, or because it was a priority of the health professionals involved.

4.5.2.2 Clinic vs. opportunistic screening

The underlying assumption that type of screening (i.e. clinic vs. opportunistic) would affect screening outcomes held true at least to some extent. The clinic method was certainly more effective for motivation to eat less fat and salt and for changing people's behaviour in terms of eating less fat and taking more exercise. However looking back at the main results comparing the three methods of offering screening, the two clinic/invitation groups did not have better overall outcomes than the opportunistic group, so this beneficial effect of the clinic is obviously not enough to overcome the low screening uptake rates.

More of the smokers screened opportunisticallv intended (at time 1) to smoke less than smokers screened at the clinic. This may account for the main finding, in the comparison of the three different methods of offering screening, of an advantage

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OXCHECK study (1994) which was mentioned in Chapter 1 (Section 1.2.4.2) also showed that clinics run by Practice Nurses were not successful in getting smokers to stop smoking. This finding could be because smokers are less likely to attend clinics (which was found in this study) but if they do attend, they may be unusually resistant to change smoking behaviour. Perhaps they are attending due to some other motivation such as desire to avoid medical disapproval as outlined in anticipated decision regret theory (Tmystra, 1989). These data suggest that not only was opportunistic screening a better way of reaching smokers as discussed above but that the opportunistic screening process itself may have been a more effective way of persuading smokers to smoke less. It may be that smoking is the salient message that GPs manage to convey in an opportunistic consultation. In fact, the supposed disadvantage of opportunistic screening allowing for such a short time might actually be its advantage. It may enable GPs to prioritise the most important behaviour needing changed which may make that particular behaviour more salient for the patient and easier to cope with than a list of possible changes.

4.5.2.3 Managing without trying

As noted in the results section, it was evident that some people seem to have managed to change certain behaviours without trying. This indicates that some health behaviours may be easier to change than others, perhaps due to

circumstantial changes. For example, a change in employment could result in an increase in exercise, without the need for trying to change their exercise behaviour on the individual’s part. Or a change in diet could occur due to a partner deciding to make a change to what is eaten in the household. It is however important to note that smoking less and losing weight were not able to be achieved without trying which may indicate that these behaviours always require a more cognitive effort on the part of the individual.