Evaluation of an instrument to assess the needs of men diagnosed with prostate carcinoma: an assessment of the validity and reliability of a self-administered questionnaire developed to measure the needs experienced by men diagnosed with prostate carcinoma.
BACKGROUND
This study was conducted to evaluate a self-administered questionnaire developed to measure the needs experienced by men diagnosed with prostate carcinoma (the Prostate Cancer Needs Questionnaire [PCNQv1.1]). The PCNQv1.1 was constructed in two parts. Part 1 measures the needs at diagnosis and initial treatment and Part 2 measures current needs.


METHODS
A random sample of 650 men diagnosed with prostate carcinoma who were being treated by a urologist of the Hunter Urology Group in Newcastle, New South Wales, Australia, were invited to participate in the study. They were sent by post the self-administered PCNQv1.1. Completed questionnaires were received from 385 men. Information provided on 100 additional men was considered ineligible.


RESULTS
The principal components method of factor analysis with varimax orthogonal rotation identified eight factors with eigenvalues greater than 1, which accounted for 61.7% of the variance in Part 1 of the PCNQv1.1. Likewise, six factors were identified in Part 2, which accounted for 63.5% of the variance. Internal reliability coefficients (Cronbach alpha) were adequate for identified factors with values ranging from 0.70 to 0.88 for Part 1 and from 0.71 to 0.87 for Part 2. Test-retest reliability was acceptable with intraclass correlation coefficients ranging from 0.61 to 0.78 for Part 1 and from 0.60 to 0.82 for Part 2.


CONCLUSIONS
These results suggest that the PCNQv1.1 is a valid and reliable instrument to assess the needs experienced by men diagnosed with prostate carcinoma.
Duke
Janine M
JM
Centre for Clinical Epidemiology and Biostatistics, The University of Newcastle, Royal Newcastle Hospital, Newcastle, NSW, Australia. jduke@cceb.newcastle.edu.au
Treloar
Carla J
CJ
Byles
Julie E
JE
D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000523:psychology*; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires