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

Objectives:The International Prostate Symptoms Score (I-PSS) was designed t o 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 administratio n varied. Methods: Benign prostatic hyperplasia patients over 50 years of age were re cruited at 52 Spanish centres. The I-PSS was administered on two occasions 1 month apart. Patients were sequentially classified into groups A-D accord ing to the mode of administration (S self-administered, I = interview admin istered) at the two visits (A = S-S, B = S-I, C = I-S, and D I-I). The intr aclass correlation coefficient was used to assess test-retest reliability, and multiple regression analysis was used to test the effects of the mode o f administration and the visit number on I-PSS scores. Results: 926 patients (mean age 66 years) were evaluated. The mean I-PSSs s ymptoms 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 a t 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. Conclusions: Interview administration of the I-PSS results in slightly lowe r scores. The reliability is higher when the same mode of administration is used at two recurrent visits. Copyright (C) 2001 S. Karger AG, Basel.