Objective: To evaluate changes in bladder capacity and potassium sensitivity after glycosaminoglycan (GAG) substitution therapy.
Material and methods: The study population comprised two groups of female patients with bladder pain syndrome/interstitial cystitis (BPS/IC): responders (those with symptom improvement) and non-responders (those without symptom improvement) after a 10-week period of intravesical, episodic, weekly, GAG substitution therapy. A total of 27 volunteers with increased pre-therapeutic potassium sensitivity were enrolled in the study and re-evaluated using the modified comparative potassium test (maximal bladder capacity with a saline solution versus a 0.2 M KCl solution) following intravesical GAG substitution therapy.
Results: In the 13 responders, the average maximal bladder capacity increased by 17% with the saline solution and by 101.5% with the 0.2 M KCl solution. In the 14 non-responders, post-therapeutic average maximal bladder capacity was decreased by 35% with the saline solution and remained relatively unchanged after instillation with a 0.2 M KCl solution.
Conclusion: These data demonstrate that in patients who respond symptomatically to intravesical GAG substitution therapy, cystometric bladder capacity is increased, whereas non-responders experience a decrease in bladder capacity.