Effect of mode of administration on I-PSS scores in a large BPH patient population

The International Prostate Symptoms Score (I-PSS) was designed to be self-administered to patients with benign prostatic hyperplasia. This study tested for a possible mode of administration effect on the I-PSS and assessed the reliability of the I-PSS over time when modes of administration varied.

Benign prostatic hyperplasia patients over 50 years of age were recruited at 52 Spanish centres. The I-PSS was administered on two occasions 1 month apart. Patients were sequentially classified into groups A-D according to the mode of administration (S = self-administered, I = interview administered) at the two visits (A = S-S, B = S-I, C = I-S, and D = I-I). The intraclass correlation coefficient was used to assess test-retest reliability, and multiple regression analysis was used to test the effects of the mode of administration and the visit number on I-PSS scores.

926 patients (mean age 66 years) were evaluated. The mean I-PSSs symptoms score at visit 1 in groups A-D were, respectively, 13.19, 13.57, 12.06, and 12.29. Multiple regression analysis between-group scores were 0.93 points higher when the I-PSS was self-administered and 1.98 points lower at the second visit. The intraclass correlation coefficients were: group A = 0.77, group B = 0.70, group C = 0.67, and group D = 0.76.

Interview administration of the I-PSS results in slightly lower scores. The reliability is higher when the same mode of administration is used at two recurrent visits.