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 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. Methods: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. Results: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. Conclusions: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.