Hypothesis / aims of study
Variations in patient-reported outcomes (PROs) in trials on postpartum women with perineal trauma during childbirth have been reported. There is also inconsistency in the use of PROMs (1). Content validity of a measurement instrument is an essential property as it is a measure of the degree to which an instrument’s content accurately reflects the construct being measured (2). Inappropriate use of PROMs may affect clinical guidance and practice, the quality of research and possibly lead to research waste.
This systematic review aimed to evaluate the content validity of the most widely used PROMs measuring PROs amongst women who have experienced childbirth perineal trauma. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology were applied (2). This study is part of a wider project of CHORUS (International Collaboration for Harmonizing Outcomes, Research and Standards in Urogynaecology and Women’s Health).
Study design, materials and methods
The search strategy was based on a previous systematic review evaluating randomised controlled trials reporting PROs and PROMs in evaluating the effectiveness of interventions in childbirth perineal trauma. From this systematic review we obtained information on the measurement instruments and applied similar Medical Subject Heading (MeSH) terms related to childbirth perineal trauma (1). Search terms and filters proposed by Terwee et al. were also included (3).
EMBASE, MEDLINE and PsychInfo databases were searched from inception to December 2021. Google scholar was also inspected (search date 28th December 2021) through hand-searching on content validity of PROMs. Additional limits such as ‘adults’, ‘human’ and ‘female’ were also specified to further focus the search to relevant papers. The inclusion criteria included perineal trauma of any degree acquired during childbirth, availability of the full text of the original paper and publication in the English language irrespective of the format in which they were presented. Studies concerned with the cross-cultural adaptation of a PROM or articles regarding the PROM of interest with a translation in the English language that have undertaken a pilot study of the adapted PROM were also included if available.
Assessment of the content validity of each PROM was fulfilled using the methodological COSMIN guidelines which outline three key steps: evaluation of the quality of the PROM development, evaluation of the quality of content validity studies on the PROM, if available and evaluation of the content validity of the PROM reflecting the reviewer’s interpretation.
Results
A total of 10,827 papers were identified from the keyword searches. Application of the additional limits removed 10,464 papers. A further 61 papers were excluded after deduplication narrowing the final screening to 302 papers. The titles of these papers were screened and checked against the inclusion criteria, but none were found to be eligible. Figure 1 shows a PRISMA flow diagram of the studies captured.
The five most used PROMs in childbirth perineal trauma have been identified as the visual analogue scale (VAS) 0-10, the visual analogue scale (VAS) 0-100mm, the Cleveland Incontinence Clinic Score (also known as the Wexner scale), the McGill Pain Questionnaire (MPQ) and the Fecal Incontinence Quality of Life Scale (FIQoL).
The full texts of the development studies for the Cleveland Incontinence Clinic Scale, the McGill Pain Questionnaire and the Fecal Incontinence Quality of Life Scale were reviewed. However, the development and validation studies for the VAS 0-10 and VAS 0-100mm instruments could not be identified.
The overall quality of the development studies was inadequate for all PROMs. This was determined on the basis that all PROM designs and their pilot studies were of inadequate quality and altogether accompanied by very low quality of evidence.
No content validity studies surrounding the topic of childbirth perineal trauma was found.
Only one PROM (Fecal Incontinence Quality of Life Scale) gave a clear but broad description of the target population for which it was developed. Cognitive interviews were not undertaken for any of the PROMs, but pilot studies were performed in the development stage of two PROMs. It is unknown how the patients communicated their feedback on the relevance, comprehensibility, and comprehensiveness of the PROM items as recordings, interview guides or verbatim transcriptions were not reported. Thus, their concept elicitation was inadequate.
Interpretation of results
This review demonstrates gaps in evidence around the content validity of the most used PROMs in women experiencing childbirth perineal tears, as no content validity studies were identified. There is no evidence of patient participation in the development process of PROMs. Future PROM developers should include patient involvement in constructing items relevant to the population of interest and follow appropriate methodological principles to accurately gauge relevance, comprehensiveness, and comprehensibility in the validation process of a PROM.