Development of a New Patient-reported Outcome Measure to Evaluate Treatments for Acne and Acne Scarring: The ACNE-Q

A.F. Klassen; S. Lipner; M. O'Malley; N.M. Longmire; S.J. Cano; T. Breitkopf; C. Rae; Y.L. Zhang; A.L. Pusic


The British Journal of Dermatology. 2019;181(6):1207-1215. 

In This Article


In clinical trials of treatments for acne and acne scarring, psychosocial distress is an important outcome. But cosmetic appearance is also important to patients. Measuring appearance as a concept separate from psychosocial distress has been largely overlooked in existing acne-specific PROMs. Therefore, the ACNE-Q represents the first acne-specific PROM to provide a set of scales for patients to report how their skin, acne and acne scars look. These concepts are important to include in clinical trials of treatments to improve or clear acne, prevent and improve acne scarring, or prevent future outbreaks. Appearance is highly subjective and therefore requires self-report.

In our development and psychometric study, the ACNE-Q scales showed reliability and validity, and measured a clinical hierarchy for each concept. Targeting is critical in scales designed for use in clinical trials. Participants need to fit on the scale and have room to move up or down the scale as their outcomes change with treatment. Our scales had minimal floor and ceiling effects and the vast majority of participants scored inside the range of measurement for each scale.

The ACNE-Q differs from other available acne-specific PROMs by comprehensively addressing appearance (of facial skin, face, chest and back acne, and acne scars) in addition to appearance-related distress and symptoms. Only the five-item SCARS scale covers the appearance construct in depth by including items asking about coverage, number, size, depth and visibility of acne scars.[13] The ACNE-Q scar scale covers these issues, and also includes items that ask about the appearance of scars in different scenarios (e.g. in photos, under a bright light, up close), as well as difference in colour between the skin and scar. The ACNE-Q also measures appearance-related distress, which is important because it has been found that acne has a negative impact on psychosocial function.[32] In a recent systematic review that examined the effect of acne treatment on HRQoL,[2] 37 studies were identified that used a variety of instruments, including both generic and disease-specific ones. The Dermatology Life Quality Index (DLQI), a dermatology-specific measure (not acne-specific), was the most utilized measure included in 15 studies, and the most commonly used generic measure was the Short Form 36 (SF-36), included in three studies.[2] The DLQI has 10 items that address symptoms, feelings, leisure, work/school, personal relationships and treatment.[33] The generic SF-36 has 36 items that measure eight concepts: physical functioning; role – physical; bodily pain; mental health; role – emotional; social functioning; vitality; and general health perceptions.[34,35] Neither of these two commonly used PROMs ask about appearance. ACNE-Q covers items missing in generic measures, as well as additional items and constructs not found in dermatology-specific instruments, helping to better compare PROs in clinical trials.

A strength of our study was our patient-oriented approach as we engaged patients and healthcare providers at each stage of the instrument development process. Our approach to developing PROMs emphasizes content validity, the most important measurement property,[23] in order to create scales that cover patient concerns. Input from people with acne/acne scars was crucial in the design and refinement of the ACNE-Q scales, as patients' stories were used to identify and develop themes that were shaped into scales and items. Furthermore, we used a modern psychometric approach in the development of the ACNE-Q. An advantage of RMT analysis is that scales where the data fit the requirements of the Rasch model have interval-level measurement, which means that it is mathematically sound to compare measurement outcomes over time.[22] Only one other acne-specific instrument – the Acne Symptom and Impact Scale[11] – used a RMT approach. Another strength of our study was the recruitment of participants from two countries and different settings (i.e. hospital and community dermatology clinics).

A limitation of our study was that the ACNE-Q was developed in North America only. Use of the ACNE-Q in other countries would require cultural and/or linguistic validation studies to ensure the scales are acceptable and relevant to patients in other contexts. Another limitation is that our sample of patients with back and chest acne was small, as was the number of participants who completed the TRT reliability study. Future research is called for to examine TRT reliability in a larger sample. Finally, our study did not include a clinical variable of the severity of participants' acne or acne scars.

As PROM data are increasingly used worldwide in clinical practice, research and quality-improvement initiatives, the ACNE-Q provides the dermatology community with a rigorously developed instrument to complement other clinical outcome assessment tools. The next step of research is to examine responsiveness of ACNE-Q scales to measuring clinical change in treatment studies.