Exploratory factor analysis: strategies used by patients to promote health.

Strategies used by patients to promote health (SUPPH) was used to measure self-care self-efficacy in patients with cancer. The objectives of this study were (1) to determine the extent to which self-efficacy theory explained the factor structure of the SUPPH and (2) to determine the relationship of demographic data with factors of the SUPPH. Subjects were diagnosed with prostate cancer (PCa) and treated with either: (a) radical prostatectomy, (b) intensity modulated radiation therapy (IMRT) + radioactive seed implantation, or (c) IMRT + high dose rate. Subjects completed a demographic questionnaire and the SUPPH. Exploratory factor analysis of the SUPPH was performed using a varimax rotation. Subjects (n = 265) were predominately white and averaged 68 years of age. The model explained 81.3% of the total sum of eigenvalues. Two factors of the SUPPH were identified: physiological efficacy information and performance efficacy information. Younger subjects who were fully employed and earning more money had significantly higher performance self-efficacy than older subjects who were working part time and earning less money. Results are congruent with Bandura's (1997) description of self-efficacy. Use of the SUPPH may facilitate research validating Bandura's (1997) assertion that an individual's self-efficacy is related to quality of life (QOL) during chronic illness. Additional research focusing on self-efficacy and PCa patients' QOL may lead to efficacy enhancing interventions that will improve QOL of patients with PCa.