What are the factors contributing to failure in improvement of subjective symptoms following silodosin administration in patients with benign prostatic hyperplasia? Investigation using a pressure-flow study.

AIMS

To investigate the factors responsible for failure in improvement of subjective symptoms following silodosin treatment on the basis of findings of a pressure-flow study (PFS).

METHODS

A post hoc analysis of a prospective study to investigate the efficacy of silodosin in patients with BPH was conducted, and 104 patients were analyzed. The patients were administered silodosin 8 mg/day for 4 weeks. At the baseline and after treatment, subjective symptoms were evaluated using the IPSS and OABSS. A PFS was conducted to measure storage and voiding function. The patients were divided into two groups: good responders (GR), patients with 25% or more improvement in IPSS, and poor responders (PR), <25% improvement. The clinical and objective findings for the two groups were compared.

RESULTS

The mean IPSS and OABSS significantly improved in GR, but no significant improvement was observed in PR. PFS analysis revealed that all voiding and storage function parameters improved significantly in GR. Although PR showed a significant improvement in the voiding function parameters, it did not show significant changes in the storage function. Involuntary detrusor contraction (IDC) resolved in 68.6% of the patients in GR and in only 30% of the patients in PR, thereby showing a significant difference in the remedial effect between the two groups.

CONCLUSIONS

The findings suggest that insufficient improvement in storage function is a contributing factor to the failure in improvement of subjective symptoms after silodosin treatment in patients with BPH.