Systematic Review
Gynecology
Variation in outcome reporting in endometriosis trials: a systematic review

https://doi.org/10.1016/j.ajog.2015.12.039Get rights and content

Objective

We reviewed the outcomes and outcome measures reported in randomized controlled trials and their relationship with methodological quality, year of publication, commercial funding, and journal impact factor.

Data Sources

We searched the following sources: (1) Cochrane Central Register of Controlled Trials, (2) Embase, and (3) MEDLINE from inception to November 2014.

Study Eligibility

We included all randomized controlled trials evaluating a surgical intervention with or without a medical adjuvant therapy for the treatment of endometriosis symptoms.

Study Design

Two authors independently selected trials, assessed methodological quality (Jadad score; range, 1-5), outcome reporting quality (Management of Otitis Media with Effusion in Cleft Palate criteria; range, 1-6), year of publication, impact factor in the year of publication, and commercial funding (yes or no). Univariate and bivariate analyses were performed using Spearman Rh and Mann-Whitney U tests. We used a multivariate linear regression model to assess relationship associations between outcome reporting quality and other variables.

Results

There were 54 randomized controlled trials (5427 participants), which reported 164 outcomes and 113 outcome measures. The 3 most commonly reported primary outcomes were dysmenorrhea (10 outcome measures; 23 trials), dyspareunia (11 outcome measures; 21 trials), and pregnancy (3 outcome measures; 26 trials). The median quality of outcome reporting was 3 (interquartile range 4–2) and methodological quality 3 (interquartile range 5–2). Multivariate linear regression demonstrated a relationship between outcome reporting quality with methodological quality (β = 0.325; P = .038) and year of publication (β = 0.067; P = .040). No relationship was demonstrated between outcome reporting quality with journal impact factor (Rho = 0.190; P = .212) or commercial funding (P = .370).

Conclusion

Variation in outcome reporting within published endometriosis trials prohibits comparison, combination, and synthesis of data. This limits the usefulness of research to inform clinical practice, enhance patient care, and improve patient outcomes. In the absence of a core outcome set for endometriosis we recommend the use of the 3 most common pain (dysmenorrhea, dyspareunia, and pelvic pain) and subfertility (pregnancy, miscarriage, and live birth) outcomes. International consensus among stakeholders is needed to establish a core outcome set for endometriosis trials.

Section snippets

Sources

A protocol with explicitly defined objectives, criteria for study selection, and approaches assessing outcome selection was developed. The systematic review was registered with the Core Outcome Measures in Effectiveness Trials Initiative Register4 and conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.5

A comprehensive and systematic literature review was undertaken searching the Cochrane Central Register of Controlled Trials (CENTRAL),

Results

The search strategy identified 1570 titles and abstracts. We screened 1409 titles and abstracts following the exclusion of 161 duplicate records (Figure 1). We included 54 RCTs9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62 (Table 1). The included trials collected and reported 164 outcomes and 113 outcome measures (Table 2).

Summary

In this study, there was outcome reporting heterogeneity. The most common comparable outcome (dysmenorrhea) and measurement tool assessed (visual analog scale from 1 to 10) were reported infrequently.

There was a relationship between the quality of outcomes reported and the quality of a study, but there was not an association with journal impact factor at publication in a multivariable analysis. The RCTs included were from an international setting with different patient populations. This meant

Acknowledgment

We thank Dr Javier Zamora (Queen Mary University of London, United Kingdom) for his advice regarding data analysis and interpretation.

International Collaboration to Harmonize Outcomes and Measures for Endometriosis Steering Group: Dr James M N Duffy (Balliol College, University of Oxford, Oxford, United Kingdom); Cindy Farquhar (Department of Obstetrics & Gynecology, University of Auckland, Auckland, New Zealand); Dr Martin Hirsch (Women's Health Research Unit, Queen Mary University of London,

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    The authors report no conflict of interest.

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