Recombinant human nerve growth factor in the treatment of interstitial cystitis: preliminary results

Interventions for treating people with symptoms of bladder pain syndrome: a network meta-analysis

BACKGROUND

Bladder pain syndrome (BPS), which includes the condition of interstitial cystitis, is a poorly understood clinical condition for which patients present with varying symptoms. Management of BPS is challenging for both patients and practitioners. At present, there is no universally accepted diagnosis and diverse causes have been proposed. This is reflected in wide-ranging treatment options, used alone or in combination, with limited evidence. A network meta-analysis (NMA) simultaneously comparing multiple treatments may help to determine the best treatment options for patients with BPS.

OBJECTIVES

To conduct a network meta-analysis to assess the effects of interventions for treating people with symptoms of bladder pain syndrome (BPS).

SEARCH METHODS

We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL, in the Cochrane Library), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and handsearched journals and conference proceedings (searched 11 May 2018) and the reference lists of relevant articles. We conducted a further search on 5 June 2019, which yielded four small studies that were screened for eligibility but were not incorporated into the review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of interventions for treating adults with BPS. All types of interventions (including conservative, pharmacological and surgical) were eligible.

DATA COLLECTION AND ANALYSIS

We assessed the risk of bias of included studies using Cochrane's 'Risk of bias' tool. Primary outcomes were the number of people cured or improved, pain, frequency and nocturia. For each outcome, random-effects NMA models were fitted using WinBUGS 1.4. We monitored median odds ratios (ORs) for binary outcomes and mean differences (MDs) for continuous outcomes with 95% credible intervals (Crls). We compared results of the NMA with direct evidence from pairwise meta-analysis of head-to-head trials. We used the CINeMA tool to assess the certainty of evidence for selected treatment categories.

MAIN RESULTS

We included 81 RCTs involving 4674 people with a median of 38 participants (range 10 to 369) per RCT. Most trials compared treatment against control; few trials compared two active treatments. There were 65 different active treatments, and some comparisons were informed by direct evidence from only one trial. To simplify, treatments were grouped into 31 treatment categories by mode of action. Most studies were judged to have unclear or high risk of bias for most domains, particularly for selection and detection bias. Overall, the NMA suggested that six (proportion cured/improved), one (pain), one (frequency) and zero (nocturia) treatment categories were effective compared with control, but there was great uncertainty around estimates of effect. Due to the large number of intervention comparisons in this review, we focus on three interventions: antidepressants, pentosan polysulfate (PPS) and neuromuscular blockade. We selected these interventions on the basis that they are given 'strong recommendations' in the EAU Guidelines for management of BPS (EAU Guidelines 2019). We found very low-certainty evidence suggesting that antidepressants were associated with greater likelihood of cure or improvement compared with control (OR 5.91, 95% CrI 1.12 to 37.56), but it was uncertain whether they reduced pain (MD -1.27, 95% CrI -3.25 to 0.71; low-certainty evidence), daytime frequency (MD -2.41, 95% CrI -6.85 to 2.05; very low-certainty evidence) or nocturia (MD 0.01, 95% CrI -2.53 to 2.50; very low-certainty evidence). There was no evidence that PPS had improved cure/improvement rates (OR 0.14, 95% CrI 0.40 to 3.35; very low-certainty evidence) or reduced pain (MD 0.42, 95% CrI -1.04 to 1.91; low-certainty evidence), frequency (MD -0.37, 95% CrI -5.00 to 3.44; very low-certainty evidence) or nocturia (MD -1.20, 95% CrI -3.62 to 1.28; very low-certainty evidence). There was evidence that neuromuscular blockade resulted in greater cure or improvement (OR 5.80, 95% CrI 2.08 to 18.30) but no evidence that it improved pain (MD -0.33, 95% CrI -1.71 to 1.03), frequency (MD -0.91, 95% CrI -3.24, 1.29) or nocturia (MD -0.04, 95% CrI -1.35 to 1.27). The certainty of this evidence was always very low.

AUTHORS' CONCLUSIONS

We are uncertain whether some treatments may be effective in treating patients with BPS because the certainty of evidence was generally low or very low. Data were available for a relatively large number of trials, but most had small sample sizes and effects of treatments often could not be estimated with precision. An NMA was successfully conducted, but limited numbers of small trials for each treatment category hampered our ability to fully exploit the advantages of this analysis. Larger, more focused trials are needed to improve the current evidence base.

[Specific treatments for painful bladder syndrome]

INTRODUCTION

Painful bladder syndrome is defined as chronic pelvic pain present for more than 6 months, causing discomfort perceived as being related to the bladder and accompanied by a persistent and strong urge to urinate or urinary frequency. The purpose of this article is to review the treatment of painful bladder syndrome.

MATERIAL AND METHODS

A comprehensive review of the literature was performed by searching PUBMED for articles on specific treatments for painful bladder syndrome.

RESULTS

Many treatments have been proposed for the management of painful bladder syndrome: local intravesical treatments (glucosaminoglycan [pentosan polysulfate], dimethylsulfoxide [DMSO], heparin, bacillus Calmette-Guérin [BCG], anticholinergic agents [oxybutynin, etc.] or oral treatments [glucosaminoglycan (pentosan polysulfate), antihistamines, antidepressants, immunosuppressives, etc.]) with an action on the pathophysiology of this syndrome. The efficacy of these various treatments has been limited, with trials based on small numbers of patients and not always conducted according to a randomized, prospective design. Other salvage treatments (neuromodulation, botulinum toxin, surgery, etc.) have also been reported with limited efficacy, but allowing salvage of treatment failures.

CONCLUSION

The therapeutic management of painful bladder syndrome is complex. The large number of proposed treatment modalities present a limited efficacy with discordant results from one study to another making comparisons and analyses difficult.

Intravesical treatments for painful bladder syndrome/ interstitial cystitis

BACKGROUND

Painful Bladder Syndrome/Interstitial Cystitis (PBS/IC) occurs predominantly in women. It is a poorly-understood condition with symptoms of bladder pain, urinary frequency, urgency and nocturia. Treatments for PBS/IC include dietary/lifestyle interventions, oral medication, intravesical instillations and, in some cases, surgery. Success rates are generally modest and there is little consensus as to the best form of treatment for this condition.

OBJECTIVES

To assess the effectiveness of intravesical treatment for PBS/IC.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group specialised trials register (30 May 2006) as well as reference lists of all selected trials. Recognised researchers in the field were contacted for any additional relevant material.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials were included in the review if they had recruited participants with a clinical diagnosis of PBS/IC and if at least one arm of the trial was treatment with an intravesical preparation. Outcome measures were pre-determined, the primary ones being the effect on pain and bladder capacity. Others included symptomatic response to treatment, quality-of-life assessment, economic factors and adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial eligibility and quality, then extracted relevant data from the studies.

MAIN RESULTS

Nine eligible trials were identified - six parallel group, one incomplete cross-over and two cross-over trials - with a total of 616 participants. Six trials compared an 'active' instillation with placebo instillation, two compared different types of instillation, and one was a comparison of an instillation plus bladder training versus bladder training alone. Altogether, the review included trials of six different types of intravesical instillation: Resiniferatoxin, Dimethyl sulfoxide, BCG, pentosanpolysulphate, oxybutin, and alkalinisation of urine pH. Confidence intervals were generally wide. Resiniferatoxin was not associated with sustained differences in the review outcomes reported but pain during instillation and withdrawal from treatment was significantly more common. The data available about Dimethyl sulfoxide (DMSO) were very limited but with no apparent differences from placebo. Groups treated with BCG tended to report less pain and fewer general symptoms. Although adverse events were commonly reported, these were no more common after BCG than after placebo instillation. The few data about Pentosanpolysulphate tended to favour the actively treated, but with wide confidence intervals; there was little information about adverse events. Oxybutinin instillation was associated with increased bladder capacity, reduced frequency, improved quality of life scores and fewer drop-outs. Alkalinisation of urine pH did not make any clear difference, but with potentially wide confidence intervals.

AUTHORS' CONCLUSIONS

Overall, the evidence base for treating PBS/IC using intravesical preparations is limited and the potential for meta-analysis reduced by variation in the outcome measures used. The quality of trial reports was mixed and in some cases this precluded any meaningful data extraction. BCG and oxybutin are reasonably well-tolerated and evidence is most promising for these. Resiniferatoxin showed no evidence of effect for most outcomes and caused pain, which reduced treatment compliance. There is little evidence for the other treatments included in this review. Randomised controlled trials are still needed and study design should incorporate outcomes that are most relevant to these with PBS/IC and should be standardised.

Targets for therapy of the painful bladder

Interstitial cystitis is an elusive disorder. Without a defining etiology and distinctive pathophysiology, diagnosis is made on an exclusionary basis. Treatment strategies for the disease vary, as do estimates of its prevalence. Nevertheless, advances are being made in understanding this disease. Basic research is helping to define rational treatment approaches for interstitial cystitis, and new therapies based on the findings of such research are being developed. This article reviews the theories of the etiology of interstitial cystitis and reviews the evidence for clinical effectiveness of various treatments.