Study design, materials and methods
A systematic search was performed by PRISMA checklist. The electronic databases including PubMed and the Cochrane library were checked until 2021 using keywords: “pentosan polysulfate”, “bladder pain syndrome”, “interstitial cystitis”, also, bibliography of relevant papers were checked.
Selection criteria:
Inclusion: Patients with a confirmed diagnosis of BPS/IC and cystoscopy criteria - petechial hemorrhages or Hunner’s lesions. Study design-randomized controlled trials(RCT). Exclusion: hypersensitivity, pregnancy, lactation, oral therapy for BPS/IC in the period 1 month before the study and abstracts or unpublished papers.
Data collection:2 reviewers independently assessed the quality of the trials and extracted the data. The risk of bias was assessed by Rob 2(The Cochrane collaboration)tool.
Results
Initial database search has found 186 articles according to relevant keywords. Also, references of relevant studies were checked to find appropriate ones that will match our inclusion and exclusion criteria. We have found 6 RCT for qualitative synthesis and 4 of them involving 329 patients were included in meta-analysis which was done by Rev.Man 5.4 software. Based on our meta-analysis, treatment group had better effects on symptoms (P=0.003).
Bade et al. (1997) conducted a double-blind placebo-controlled study in which 10 patients received intravesical PPS (300 mg in 50 mL of 0.9% sodium chloride) applied twice a week for 3 months and the other 10 patients received a placebo. The urodynamic bladder capacity showed a statistically significant increase in patients treated with PPS (P=0.047). Overall Rob2 risk of bias: some concerns.
Davis et al.(2008) compared 41 patients with IC. At week 18 all groups showed improvement in overall condition: treatment group-18/21 and placebo-18/20(p=0.6).Overall Rob2:low.
Holm-Bentzen et al.(1987)compared 105 patients using 2 separate protocols with different inclusion criteria. Outcome measures were identified separately according to most common symptoms.PPS had no clinically significant effect in patients with IC. Overall Rob2:high.
Mulholland et al.(1990)compared 110 patients, after 3 months 28% of PPS patients vs.13% of placebo patients evaluated themselves as more than slightly improved(p=0.04).PPS was significantly more effective. Overall Rob2:high.
Parsons et al.(1993)compared 148 patients, after 3 months 24 of 74 PPS group vs. 12 of 74 placebo patients evaluated themselves as 50% overall improved relative to the condition at the beginning of the study(p = 0.01). Overall Rob2:some concerns.
Sant et al.(2003) randomized 121 patients(62 received PPS, 59-placebo).11 of 62-PPS group and 20 of 59 in the placebo group responded to treatment. Overall Rob2:low
Interpretation of results
Based on our meta-analysis, pentosan polysulfate has shown more efficiency in comparison with placebo RR = 1.54, 95% Cl: 1.16 to 2.05, P = 0.003. The heterogeneity for this comparison was 84%.