OBJECTIVE: To compare the response to I-PSS according to its mode of administration (by the doctor versus self-assessment). METHODS: 388 patients were included during the 3 months following a diagnosis of benign prostatic hyperplasia. The general practitioner completed the I-PSS and gave an I-PSS questionnaire to the patient to be completed at home and returned in a reply-paid envelope to the data entry centre. The Bland & Altman method was used to visualize individual differences and to quantify the bias between the two modes of evaluation. RESULTS: The doctor overestimated the I-PSS by an average of 1.3 points [95% CI: 0.9-1.7]. In 42% of patients, these individual differences were 3 points or more. Significant overestimation was confirmed at 6, 12 and 18 months of follow-up. CONCLUSION: A significant bias was demonstrated according to the mode of administration of the I-PSS. We therefore recommend that the same mode of administration should be maintained during clinical trials.
OBJECTIVE: To compare the response to I-PSS according to its mode of administration (by the doctor versus self-assessment). METHODS: 388 patients were included during the 3 months following a diagnosis of benign prostatic hyperplasia. The general practitioner completed the I-PSS and gave an I-PSS questionnaire to the patient to be completed at home and returned in a reply-paid envelope to the data entry centre. The Bland & Altman method was used to visualize individual differences and to quantify the bias between the two modes of evaluation. RESULTS: The doctor overestimated the I-PSS by an average of 1.3 points [95% CI: 0.9-1.7]. In 42% of patients, these individual differences were 3 points or more. Significant overestimation was confirmed at 6, 12 and 18 months of follow-up. CONCLUSION: A significant bias was demonstrated according to the mode of administration of the I-PSS. We therefore recommend that the same mode of administration should be maintained during clinical trials.