Wide variations are present in outcomes and outcome measures reporting across randomised control trials (RCT) on surgical managements for pelvic organ prolapse (POP) resulting in research heterogeneity (1). These variations create barriers to the synthesis of primary research and high-quality meta-analyses on surgical efficacy and safety. 

The primary aim of this systematic review was to identify variations in outcome and outcome measure selection, collection and reporting within RCTs evaluating laparoscopic or robotic surgical techniques for the management of POP. Furthermore, we performed an assessment of the methodological quality and the quality of outcome reporting for each of those trials. The underlying objective is the development of Core Outcome Sets (COS) and Core Outcome measure Sets (COMS) in order to harmonise future research and increase comparability amongst studies. While the process of development of COS/COMS is in progress, we aim to propose interim COS which can be utilised.

A systematic literature search conducted in January 2021 identified RCTs from the following databases: EMBASE, Cochrane Central Register of Controlled Trials, PubMed and MEDLINE. The following Medical Subject Headings (MeSH) terms were used: “laparoscopic”, “laparoscopic surgery”, “robotic”, “minimally invasive”, “pelvic organ prolapse”, “prolapse”.  All RCTs published in English from inception to 2021 including adult female participants were included. Non-randomised control trials, reviews and retrospective studies were excluded. The titles and abstracts from the literature search were screened and if they met the inclusion criteria, full texts were scrutinised for eligibility. Any disagreements over the inclusion of particular trials were resolved through consensus meetings among the researchers. In addition, snowballing and hand searches were conducted. Consequently, eligible trials had their study characteristics extracted. These included number of participants, date of publication, interventions, primary and secondary outcomes and outcome measures. This systematic review was reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement (2). 

Each RCT had the methodological quality and outcome reporting quality assessed by two researchers independently, using JADAD and MOMENT scoring respectively. Any trials with discrepancies on either score were re-assessed independently by a third researcher. Studies which scored 4 or over in either parameter were classified as high-quality studies. 

InCites Journal Citation Reports (Clarivate Analytics, 2020) was used to obtain the journal impact factor for the specific year each trial was published in the particular journal. All these data were input into a database. The primary and secondary outcomes were categorised into domains based on the outcome’s definition. Consequently, these domains were grouped into themes in accordance with the COMET Handbook recommendations. Finally, Spearman’s Rho (IBM SPSS ®, version 25.0) was used to assess the associations between the MOMENT scores and various other variables. These included the JADAD score, year of publication and journal impact factor.

The MeSH terms yielded a total of 6867 studies across the various databases. Following the application of limits which were previously mentioned, 443 RCTs were identified and consequently screened. Forty full text studies were assessed, and 20 trials met the inclusion criteria. Figure 1 graphically represents the results of the literature search and the screening process. The 20 trials were included in the systematic review and had a total of 1761 female participants.

Seven of 20 trials (35%) included more than 100 participants, 17 of 20 studies (85%) enrolled more than 50 women and 3 of 20 trials (15%) included 30 participants or less in their study.  75 different outcomes were identified. The outcomes were grouped into 12 different domains which were subsequently categorised into the following 4 themes: “adverse events”, “clinical effectiveness”, “cost effectiveness” and “life impact”. The most frequently reported outcomes were operative time (13/20 [65%]), postoperative pain (9/20 [45%]), quality of life (9/20 [45%]), blood loss (8/20 [40%]), anatomical success (8/20 [40%]) and length of hospital stay (7/20 [35%]). The largest outcome domain was “intraoperative technical outcomes and observations” which is categorised into the “adverse events” theme. This domain contains 11 different outcomes and the most frequently reported is blood loss (8/20 [40%]). 

The 52 different outcome measures reported were divided into the following 6 categories: “examination”, “imagining”, “objective measures”, “perception of symptoms” and “quality of life”. The most frequently reported outcome measures were Pelvic Organ Prolapse Quantification system (POP-Q) (16/20 [80%]) for the evaluation of surgical treatment effectiveness, Visual analogue scale (9/20 [45%]), Pelvic Floor Distress Inventory (PFDI) (8/20 [40%]) and Patient Global Impression of Improvement (PGI-I) (7/20 [35%]). Quality of life was the largest category with 25 different outcome measures, PGI-I being the most frequently reported one. Outcomes relating to success or failure were defined differently throughout the trials, some reported success defined only anatomically, whereas some trials included patient satisfaction as a factor. 

Outcome reporting quality assessment using MOMENT criteria scored a mean of 5.10. All studies included stated their primary outcome and defined it for reproducible measures. Sixteen out of twenty (80%) studies clearly stated the secondary outcomes. Methodological quality assessment using JADAD scored a mean of 3.85.  All 20/20 (100%) of studies were described as randomised but only (18/20 [90%]) had an appropriate method of randomisation. In addition, only (10/20 [50%]) of studies were blinded and utilised an adequate blinding technique. 

The most common publishing journal was the International Urogynaecology Journal with (5/20 [25%]) studies. The highest journal impact factor was 17.298 for a trial published in 2018 in the European Urology and the lowest Journal impact factor being 1.392 for Female Pelvic Medicine and Reconstructive Surgery in 2017.

A wide variety of outcomes and outcome measures were reported by the identified RCTs. The results highlight the tendency of trials to focus on intraoperative data and complications such as blood loss and operative time. Various outcomes were underreported, these include cost (4/20 [20%]), sexual function (2/20 [10%]) and cosmetic outcome of the wound (1/20 [5%]). Some trials mention sexual health as an outcome but do not provide the outcome measure used. 
Statistical analysis using Spearman’s Rho highlighted the absence of correlation between journal impact factor and MOMENT scores as well as between MOMENT and JADAD scores. 

The variations observed were similar to variations in other trials on pelvic floor research. These variations could be due to preferences of the research groups or variations in clinical practice and relevant priorities or to different professional, training and specialisation backgrounds of researchers.

Most trials focused on the efficacy of the surgical procedures and the impact they have on the quality of life of the woman, however, many fail to report outcomes related to cost, sexual health and cosmetic outcome of the wound. This is due to the lack of harmonisation and standardisation of a minimum of outcomes when conducting RCTs. Based on the results we recommend the use of an interim set of the 3 most frequently reported outcomes in each domain as illustrated in Figure 2. Consequently, we aim to proceed to Delphi surveys as part of the process we undertake for the development of COS in line with the COMET guidelines (3).

de Mattos Lourenco MBBCH TR, Pergialiotis V, Durnea C, Elfituri MBBCH A, Haddad JM, Betschart C, et al. A systematic review on reporting outcomes and outcome measures in trials on synthetic mesh procedures for pelvic organ prolapse: Urgent action is needed to improve quality of research |. 2018;3:4.
Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. Vol. 372, The BMJ. BMJ Publishing Group; 2021.
Williamson PR, Altman DG, Bagley H, Barnes KL, Blazeby JM, Brookes ST, et al. The COMET Handbook: Version 1.0. Vol. 18, Trials. BioMed Central Ltd.; 2017. p. 1–50.