Objective: To compare the Danish Prostatic Symptom Score (DAN-PSS) with the International Prostatic Symptom Score (IPSS). Madsen-Iversen and Boyarsky symptom indexes in a clinical setting, and to evaluate the potential significance of any differences in information obtained from these questionnaires.
Patients and methods: The study comprised two substudies: in the first, 205 patients with lower urinary tract symptoms (LUTS) suggestive of bladder outlet obstruction (BOO), a Madsen-Iversen score > 6 and a maximum flow rate of < 10 mL/s were randomized to receive either placebo or alfuzosin in a double-blind study of 16 weeks. The symptoms were assessed using the Madsen-Iversen, DAN-PSS and the IPSS questionnaires. In the second, 138 patients with LUTS suggestive of BOO were selected for treatment with transurethral microwave thermotherapy (TUMT, 52 degrees C for 60 min, microwave energy 200 kJ) and their symptoms assessed using the Boyarsky and the DAN-PSS questionnaires. Patients were then followed for one year. Rank correlation coefficients and regression lines were calculated using Spearman's non-parametric test. The relative changes, i.e. responsiveness, calculated for the DAN-PSS, IPSS and Boyarsky indexes were compared pairwise using the Wilcoxon-Pratt test.
Results: The DAN-PSS, IPSS and Madsen-Iversen indexes were correlated on a pairwise basis. The DAN-PSS and IPSS indexes have significant construct validity in terms of correlation with the Madsen-Iversen system (Spearman's correlation coefficient, rs = 0.51 and rs = 0.45, respectively). The DAN-PSS and the IPSS indexes were correlated (rs = 0.61). The DAN-PSS was more sensitive than the IPSS to changes after pharmacological treatment, with scores decreasing 70% and 29% (P < 0.05), respectively, after treatment with an alpha-blocker for 4 months, and 50% and 29% (P < 0.05), respectively, after 4 months on placebo treatment. Finally, the responsiveness of the Boyarsky and DAN-PSS indexes to TUMT showed that the DAN-PSS system was significantly more responsive than the Boyarsky index, with scores decreasing 57% and 15% (P < 0.05), respectively, after one year.
Conclusions: The DAN-PSS index is more sensitive than the IPSS, Madsen-Iversen and Boyarsky symptom indexes, incorporates important outcome events, includes a patient-weighting of each symptom, thereby reflecting better the patients' global assessment of outcome.