The use and reporting of cluster analysis in health psychology: a review.

PURPOSE: Cluster analysis is a collection of relatively simple descriptive statistical techniques with potential value in health psychology, addressing both theoretical and practical problems. There are many methods of cluster analysis from which to choose, with no clear guidelines to aid researchers. In the absence of guidelines it is likely that methods already reported by published researchers will be adopted, and so clear reporting of statistical methodology, while always important, is particularly crucial with cluster analysis. The aim of this review is to describe and evaluate the reporting of cluster analysis in health psychology publications. METHODS: Electronic searches of 18 health psychology journals identified 59 articles using cluster analysis published between 1984 and 2002. Articles were submitted to systematic evaluation against published criteria for the reporting of cluster analysis. RESULTS: Just 27% of the papers reviewed met all five criteria, although 61% met at least four. Details of the similarity measure and the computer program used were most frequently omitted. Furthermore, while researchers usually reported the procedures employed to determine the number of clusters and to validate the clusters, these procedures were often lacking in rigour, and were reported in insufficient detail for replication. CONCLUSIONS: The reporting of cluster analysis was found to be generally unsatisfactory, with many studies failing to provide enough information to allow replication or the evaluation of the quality of the research. Clear guidelines for conducting and reporting cluster analyses in health psychology are needed.

Symptom experiences, symptom attributions, and causal attributions in patients following first-time myocardial infarction.

We examined symptom experiences, symptom attributions, and causal attributions reported by patients hospitalized for a first-time myocardial infarction (MI). We also explored the roles of symptoms, negative affect, and risk factors in promoting stress and other causal attributions. Patients (N = 65) completed measures of symptom experiences and attributions, perceived causes of their MI, state and trait negative affect, and risk factors. Patients attributed most of their symptoms to the heart condition, although rates varied from 48% (headaches) to 97% (nausea). The most common causal attribution was stress, followed by high cholesterol, heredity, fat consumption, and hypertension. Stress attributions were positively associated with state anxiety and specific, stress-related symptoms (e.g., fatigue and breathlessness). Anxious mood and stress-related symptoms appear to enhance the plausibility of stress as a cause of MI. Risk factors were moderately correlated with associated causal attributions. For many patients, however, attributions to hypertension, cholesterol, and family history of heart disease were discordant with their clinical data. Causal attributions remained stable over the subsequent 6 months.

Doubts about necessity and concerns about adverse effects: identifying the types of beliefs that are associated with non-adherence to HAART.

This cross-sectional study assessed beliefs about highly active antiretroviral therapy (HAART) and their association with reported adherence to HAART among 109 HIV-positive patients receiving HAART while attending an ambulatory care clinic in Brighton, UK. Patients' beliefs about the necessity for and concerns about HAART and their adherence to it were assessed using validated questionnaires. There was considerable variation in beliefs and reported adherence. A quarter of participants reported low adherence to HAART and this was related to concerns about adverse effects as well as to the way in which each individual balanced concerns against perceptions of necessity. Patients were significantly more likely to report low adherence rates if their concerns were high relative to their perceptions of personal need for HAART. Patients with higher CD4 counts were significantly more likely to hold a view of HAART in which perceptions of necessity were higher relative to their concerns about adverse effects. CD4 was not related to reported adherence. A comparison of most recent viral load results between high and low adherence group identified differences in the predicted direction but these were not statistically significant. These preliminary findings suggest that patients' perceptions of HAART are important determinants of adherence with implications for future research and clinical practice.

Changing illness perceptions after myocardial infarction: an early intervention randomized controlled trial.

OBJECTIVE: This study was designed to examine whether a brief hospital intervention designed to alter patients' perceptions about their myocardial infarction (MI) would result in a better recovery and reduced disability. DESIGN: In a prospective randomized study, 65 consecutive patients with their first MI aged were assigned to receive an intervention designed to alter their perceptions about their MI or usual care from rehabilitation nurses. Patients were assessed in hospital before and after the intervention and at 3 months after discharge from hospital. RESULTS: The intervention caused significant positive changes in patients' views of their MI. Patients in the intervention group also reported they were better prepared for leaving hospital (p<.05) and subsequently returned to work at a significantly faster rate than the control group (p<.05). At the 3-month follow-up, patients in the intervention group reported a significantly lower rate of angina symptoms than control subjects (14.3 vs. 39.3, p<.03). There was no significant differences in rehabilitation attendance between the two groups. CONCLUSIONS: An in-hospital intervention designed to change patients' illness perceptions can result in improved functional outcome after MI.