Factors related to spontaneous changes in fat intake and physical activity after coronary angioplasty

Patients who have had the minimally invasive percutaneous coronary intervention (PCI) to treat blocked coronary arteries are less likely to make lifestyle changes than other patients with coronary heart disease (CHD). Protection motivation theory (PMT) is a useful theory to understand behaviour change. This longitudinal study used an extended protection motivation theory (PMTplus) model that also included an emotional appraisal variable, namely, distress regarding a future cardiac event, to understand predictors of behaviour change after PCI. The current study had two aims; firstly to investigate change over time in health behaviours (saturated fat intake and walking frequency) and PMTplus measures for patients who have had a first PCI and secondly to identify which PMTplus measures predicted change in health behaviours in these patients. Structured telephone interviews were conducted with 216 consecutive PCI patients shortly after hospital discharge and again six months later. PMTplus measures were completed at both time-points, along with measures of saturated fat intake and frequency of walking. The first aim of the study was addressed through the use of mixed model ANOVA with repeated measures to test for effects of the independent variables of cardiac rehabilitation (CR) attendance, diagnostic group membership and time on the PMTplus dependent variables and the two health behaviour measures. Results showed a significant main effect for time and no significant interaction effects for all PMTplus variables, with the exception of exercise self efficacy. Walking frequency also showed a significant main effect for time. While there was no significant main effect for time for either exercise self efficacy or saturated fat intake, a significant interaction was evident between time and CR attendance for these variables. The second aim of the study was addressed through the use of two separate hierarchical regression analyses using change in PMTplus measures to predict change in walking and saturated fat intake. The PMTplus model explained 23% of the variance in change in walking over time. Increased walking was predicted by younger age, self efficacy and distress. The PMTplus model also explained 17% of the variance in change in saturated fat intake over time. Change in saturated fat intake was predicted by vulnerability and distress. This study identified PMTplus as a promising theoretical framework to understand behaviour change in this patient group.