VALIDATION OF A HARMONIZED SPANISH VERSION OF THE IPSS - EVIDENCE OF EQUIVALENCE WITH THE ORIGINAL AMERICAN SCALE

Objectives. To validate the use in Spain of a linguistically harmonize d Spanish version of the International Prostate Symptom Score (IPSS Sp ), and to compare it with the original American scale (IPSS Am). Metho ds. Validity and reliability were studied in 59 patients with benign p rostatichyperplasia (BPH) (age >50 years) and 68 control subjects with out BPH (age 18 to 49 years). Construct validity was assessed by corre lating IPSS Sp scores with the EuroQol-5D (EQ-5D), the Psychological G eneral Well-Being Index (PGWBI), and item 8 (quality of life) of the I PSS, Discriminatory power was assessed by calculating the area under t he receiver operating characteristic (ROC) curve. Reliability was eval uated using the test-retest method, and internal consistency was asses sed using Cronbach's alpha. Sensitivity to change was expressed as the effect size in preintervention versus postintervention scores in 26 a dditional patients with BPH (age >50 years) who underwent transurethra l resection of the prostate. Results. Correlations of the IPSS Sp were -0.07 to 0.36 with EQ dimensions; -0.29 with the EQ visual analogue s cale score; 0.14 to 0.41 with PGWBI dimensions; and 0.72 with item 8 o f the IPSS, ROC area was 0.95 +/- 0.02 (standard error). Using a cutof f point of 7, sensitivity was 83% and specificity was 98%. Test-retest reliability was 0.92 and Cronbach's alpha was 0.79. Mean preoperative and postoperative IPSS So scores were 25.56 and 8.48, respectively (P < 0.001). Overall effect size was 2.52. These results are similar to those of the original American scale. Conclusions. This Spanish transl ation of the IPSS is valid, reliable, and sensitive to clinical change and has demonstrated equivalent psychometric properties to the origin al American instrument. Scores obtained with the two instruments can t herefore be reliably compared and aggregated when statistically approp riate. UROLOGY 52: 614-620, 1998, (C) 1998, Elsevier Science Inc. All rights reserved.