Introduction: Intermittent claudication is the most common symptom of peripheral arterial disease, with impaired walking ability due to pain in the legs and with negative effects on quality of life as well as a high risk for cardiovascular events. The first line of treatment is secondary prevention, including smoking cessation, walking exercise and best medical therapy with the purpose of reducing claudication symptoms, of slowing down the progression of the atherosclerotic process and of preventing cardiovascular events. However, there is a deficiency in evidence-based systematic care regarding secondary prevention for these patients. Accordingly, new ways to support patients with intermittent claudication to adhere to treatment is needed. Further, knowledge about patients’ requisite resources for managing their disease are important to be able to improve the care of patients with intermittent claudication. Therefore, the overall aim of this thesis is to explore illness perception and associated factors for adherence to secondary prevention treatment for patients with IC. A further aim is to test and evaluate a web-based application as support for secondary prevention in patients with IC.

Methods: Study I was a systematic review of current research in illness perception. The data were analysed deductively using the common-sense model, as well as inductively with conventional content analysis. In study II, health literacy was evaluated in patients with intermittent claudication regarding clinical characteristics, demographics, self-efficacy and quality of life. The method was a cross-sectional multicentre questionnaire study. In total, 158 patients were included. Study III aimed to compare illness perceptions, health literacy, self efficacy, adherence to treatment, and quality of life in patients with intermittent claudication. It was a longitudinal cohort multicentre questionnaire study where the participants from study II (n=158) were followed up after 6 (n=133) and 12 months (n=128). Descriptive and inferential statistics were used in studies II-IV. Study IV was a randomised controlled pilot trial which aimed to evaluate the usability of a web-based application and its effect on secondary prevention outcomes. Patients’ experiences of using the application were collected through focus group interviews and analysed with thematic analysis. In total, 34 patients were included. For three months, the intervention group (n=18) reported information in the application about physical activity, smoking, medication therapy, blood pressure, pain after activity, and quality of life.

Results: In study I, the findings showed a lack of understanding of the symptoms, the cause and the chronic nature of the disease. The beliefs about control and cures varied from awareness of the positive effects of physical activity to the belief that walking would not have any effect, but instead make patients’ situations worse. There was fear that the disease would progress, leading to increased dependency and a lack of control. The experienced consequences showed that living with the disease meant a process of adaptation to patients’ new situations. According to study II, 52.5 % of the participants had insufficient levels of health literacy. Insufficient levels were more frequent among patients living alone compared to co-habitants. Patients with a university degree reported a significantly higher ability to access and understand health-related information. Further, patients with sufficient health literacy reported significantly higher selfefficacy and quality of life, and were more physically active than patients with insufficient health literacy. According to study III, women reported higher illness coherence and higher emotional representations compared to men. The believed cause for one’s disease reported most often was smoking, followed by age, genetics and “no idea”. Patients with sufficient health literacy reported less consequences and lower emotional representations of the disease. They also reported higher self-efficacy and higher quality of life than patients with insufficient health literacy. Quality of life increased between baseline and 12 months, but there were no differences in self-efficacy. In study IV, the results showed a non-significant trend towards increased walking distance and an improved mean change in ankle-brachial index in the intervention group compared to the control group. Patients in the intervention group also had an improved quality of life between baseline and follow-up, and reported higher levels than in the control group, in which no improvement was found. The focus group interviews identified three major themes, focussed on describing a process whereby the usability factors of the application led to the feeling of having a helping hand which further worked as a promoter of self-care and control.

Conclusion: Illness perception, health literacy and self-efficacy are factors influencing self-management in patients with IC and should be addressed to beable to improve adherence to secondary prevention. The positive results from the pilot study indicate that the web-based application might be beneficial for patients with IC in giving support to adherence to secondary prevention treatment and that a further study at a larger scale could be valuable.