Determinants of Physical Activity in Chronic Kidney Disease Patients: An Examination of the Theory of Planned Behaviour

Abstract

<p> Physical activity improves physical and psychological functioning in patients with chronic kidney disease (CKD). However, no studies have investigated the determinants of physical activity in the CKD population. The purpose of the study was to evaluate the utility of the Theory of Planned Behaviour (TPB) for understanding physical activity in the CKD population. A secondary purpose of this study was to examine alternate conceptualizations of the subjective norm construct within the TPB framework. We hypothesized that attitude, subjective norm (injunctive and descriptive norms), perceived behavioural control (PBC), and social support would predict intention to engage in physical activity and that both intention and PBC would predict physical activity behaviour.</p> <p> Participants (52 male, 28 female, mean age = 68.43 (13.21)) were recruited from nephrologists' clinics and were all predialysis (mean serum creatinine = 310.55 (148.75) μmol/L). Participants completed a questionnaire assessing attitude, subjective norm, PBC, and social support. One week later, participants were phoned for a follow-up interview to assess their physical activity during the preceding week.</p> <p> In a regression model, 61% of the variance in intention to perform physical activity was explained, with PBC (β=.69,p<.001) emerging as the sole significant predictor, while attitude (β=.17, p=.10), subjective norm (β=.02, p=.89), informational support from family (β=-.10,p=.33), and informational support from doctors (β=-.05, p=.54) were non-significant predictors. In a regression model to explain physical activity, 28% of the variance in physical activity was explained, with intention emerging as a significant predictor (β=.53, p=.02), but not PBC (β=.18, p=.29).</p> <p> The hypotheses were only partially supported, as PBC emerged as a significant predictor of physical activity intention, while attitude, subjective norm, and social support did not. Furthermore, intention, but not PBC, predicted physical activity behaviour. These results demonstrate the utility of the TPB for explaining physical activity in the CKD population. Additional research is required to clarify if targeting PBC may be an effective means for intervention to increase physical activity in the CKD population.</p>