Validating the Reliability and Clinical Relevance of a Nasolabial Fold Photonumeric Scale

• Published in: Journal of drugs in dermatology Vol. 23; no. 1; p. 1319
• Main Authors: Lorenc, Z Paul, Smith, Stacy, Bass, Lawrence S, Bank, David, Weiss, Robert, Canfield, Doug, D'Alessandro, Brian M, Cramer, Lisa M
• Format: Journal Article
• Language: English
• Published: United States 01.01.2024
• ISSN: 1545-9616
• DOI: 10.36849/JDD.7316

The use of tissue fillers to treat age-related deepening of the nasolabial fold (NLF) has increased and become the standard clinical approach, creating a need for evidence-based, objective evaluation for pre- and post-procedure assessment of the NLF. A 5-point rating scale was developed to assess the NLF, specifically the presence of depression and shadowing. Live validation of the scale was performed with a total of 73 participants representing the full range of NLF severities. Physicians board-certified in a core aesthetic specialty (3 trained raters) performed the scale validation over 2 rounds, 2 weeks apart. Training was carried out, and test-retest reliability was quantitated through the determination of intra- and inter-rater reliability by percentage of agreement, weighted kappa statistic with 95% confidence interval (CI), and intraclass correlation coefficient with 95% CI. To evaluate the clinical relevance of a 1-grade difference, rater assessments of 90 photo pairs were compared with previous designations of clinically different or not clinically different. The NLF scale achieved near-perfect intra- and inter-rater reliability when utilized by trained raters to assess a diverse group of live participants. Furthermore, clinically relevant differences between grades were established, and a 1-point difference was detectable by trained evaluators using the NLF scale. The clinically relevant and highly reliable validated NLF scale provides a standardized grading system with a user-friendly design for objectively assessing NLF in clinical practice and as a research tool for clinical approval studies of new aesthetic products and technologies. J Drugs Dermatol. 2024;23(1):1284-1291. doi:10.36849/JDD.7316.