A Short Primer on the Reporting of Patient-Reported Outcome Measures in Clinical Studies

Patient-reported outcome measures (PROMs) offer valuable insights into patients’ health, symptoms, functional status, and overall well-being from the patient’s perspective. These measures have become central to orthopaedic outcomes research and are now expected in many foot and ankle studies. The integration of PROMs into clinical research has increased significantly, highlighting the need for rigorous methodologic reporting to ensure transparency, reproducibility, and comparability of findings across studies. Reviews assessing health-related quality of life outcomes in clinical trials found varying, but generally suboptimal, methodologic reporting.^1,11 Guidelines and checklists have been developed to standardize the incorporation of PROMs in trial protocols and reporting of PRO data.^{3-6 ,8,9,15,16} In particular, the Consolidated Standards of Reporting Trials (CONSORT) PRO extension reporting guideline was developed to promote transparent and comprehensive reporting of PRO results in clinical trials.^3,4 However, despite these efforts, gaps and deficiencies in the methodologic reporting of PROMs persist.^{2,7,10,12,13,14} The following key aspects of methodologic reporting, aligned with the CONSORT PRO extension, provide essential guidance for authors and reviewers. Although the guideline was created for clinical trials, its general principles can be applied to observational studies to improve methodologic rigor and outcome interpretation.

1. Identification of PROMs in Study Design: The PROM should be explicitly identified in the abstract as well as in the Materials & Methods as either a primary or secondary outcome. Clearly stating its role ensures transparency in study design and enables appropriate interpretation of findings.

2. Rationale and Hypothesis for PROM Assessment: The background and justification for using the PROM should be provided, detailing how the selected PROM aligns with the study objectives. Additionally, authors should state the PROM hypothesis and specify relevant domains assessed, if applicable. For example, the objective of a study may be to examine the impact of an intervention on patient-reported pain and function 1 year post-intervention, as measured using a visual analog scale (VAS) and the Foot and Ankle Ability Measure (FAAM). The stated hypothesis specifies that patients undergoing the intervention will report a clinically meaningful reduction in pain (≥10 points on VAS) and improved function (≥10.8 points on the activities of daily living [ADL] subscale of the FAAM) at 1 year postoperatively. (Note: MCIDs provided are for illustrative purposes and will vary depending on the population.) Authors should refrain from selecting multiple outcome measures for the same outcome, such as multiple patient-reported measures of pain or physical function, unless clearly needed for the study’s goal.

3. Description of PROM: A brief description of the PROM(s) included in the study should be provided, including information on structure (eg, number of items, any subscales) and scoring (ie, possible range of scores, whether higher or lower scores indicate worse outcomes). Any modification(s) to the PROM, including changes to wording, scoring, or administration method, should be described and justified, as these may affect validity.

4. Selection of PROMs: The choice of a PROM should be justified based on its measurement properties, including validity, reliability, and responsiveness. Evidence supporting the instrument’s measurement properties and interpretation guidelines should be provided or cited if available, ideally in the target population. The person completing the PROM (ie, the patient or a proxy) and methods of data collection (eg, paper, electronic, telephone) should also be explicitly stated. The length and complexity of PROM instruments should also be considered, as excessive response burden may reduce patient compliance, increase missing data, and compromise data quality.

5. Sample Size: When a PROM is the primary study outcome, a sample size calculation should be provided to ensure adequate statistical power. This will be based on the established minimum clinically important difference (MCID) for the PROM. In the absence of a relevant MCID, the expected mean difference between groups and the standard deviation can be estimated from prior studies or pilot data. If an a priori sample size calculation was not conducted, authors should supply sufficient data for readers to independently perform a post-hoc power analysis. For exploratory, descriptive, or pilot studies, a sample size calculation may not be necessary; however, the study research question and objectives should be framed accordingly, and the sample size should be sufficient to provide meaningful insights. For underpowered studies (incl. pilot studies), the limitations should provide details on the necessary number of subjects the study would need to ensure adequate power.

6. Statistical Considerations

a) Multiple Outcomes: When analyzing studies with multiple scales or subscales (eg, SF-36), researchers should prespecify a single primary outcome and limit significance testing at α = .05 to that outcome. Secondary outcomes should be clearly labeled as exploratory, and if multiple outcomes are tested, appropriate statistical corrections (eg, Benjamini-Hochberg or Bonferroni) must be applied to control for false positives. Selective reporting of only the most significant results is not acceptable; all outcomes and their statistical methods should be transparently reported to ensure scientific integrity.

b) Handling Missing Data: Missing data in PROMs is common and can introduce bias. Statistical approaches for dealing with missing data should be explicitly stated, such as imputation methods or sensitivity analyses.

c) Baseline and Outcome Data: Studies should summarize baseline PRO data for each group and report the number of participants contributing data at each time point for each analysis. For every primary and secondary outcome, results should be reported for each group, including the estimated effect size (eg, mean differences, Cohen d, odds ratios) and its precision (eg, 95% CI), presented for each domain (in the case of multidimensional PROMs) and time point.

• 7. Limitations and generalizability: The discussion should address the limitations of the PRO data and consider its generalizability to other populations or clinical settings. This may include an explanation for why patients were excluded from analyses, potential reasons for why data are missing, and any implications for clinical practice.

• 8. Interpretation of Outcomes: PRO data should be considered in conjunction with clinical outcomes to provide a comprehensive understanding of a treatment’s effect. This dual interpretation—combining patient experience with objective clinical data—enhances both internal and external validity. Statistical significance alone does not guarantee that a result is meaningful to patients. Authors should use established interpretive thresholds, such as the minimum clinically important difference (MCID) or patient acceptable symptom state (PASS), to determine whether changes are clinically relevant. When available, these thresholds help translate numeric score changes into real-world implications for patient well-being. Importantly, authors should report both the average change in PROM scores and the proportion of patients who meet or exceed the MCID. For example, if both groups improve, but 70% of patients in group A and only 40% in group B exceed the MCID, this suggests a more clinically relevant benefit in group A, even if the mean difference appears modest. As MCIDs can vary by population and context, authors should cite the source of the threshold used and interpret findings cautiously.

Careful integration of patient-reported outcome measures, combined with accurate and detailed methodologic reporting, is essential for maintaining the integrity of clinical research. Adopting rigorous reporting practices will strengthen the validity, transparency, and impact of studies that use PROMs, ensuring that even underpowered studies make a constructive contribution to the literature. Future efforts should focus on improving adherence to these standards and addressing existing gaps in PROM methodology.