The MIC and the MCID of the POSAS 2.0

Knowing the minimal important change (MIC) and the minimal clinically important difference (MCID) is crucial to determine if a POSAS 2.0 score represents a clinically relevant change or difference. These results were published in the journal Burns in 2024.

A prospective study with 127 patients to determine the MIC and MCID

The aim of this study was to explore the MIC and MCID of POSAS version 2.0. This prospective study included 127 patients with deep dermal burns requiring split skin grafting, with a mean age of 44 years (range 0–87) and a total body surface area burned of 10% (range 0.5–55). POSAS 2.0 data were obtained for one burn scar area at three, six, and twelve months post-grafting. At the second and third visits, patients rated the degree of clinical change in scar quality compared to the previous visit. At twelve months, they completed the POSAS 2.0 for a second burn scar area and rated the degree of clinical difference between the two scar areas. Two anchor-based methods were used to determine the MIC and MCID.

Results

MIC values of the patient POSAS ranged from −0.59 to −0.29 between three and six months and from −0.75 to −0.38 between six and twelve months. MCID values ranged from −0.39 to −0.08. These results suggest that patients consider minor differences (less than 0.75 on the 1–10 scale) in POSAS 2.0 scores as clinically important changes in scar quality. MCID values can be used to evaluate the effects of burn treatment and to perform sample-size calculations.

Legemate CM, Middelkoop E, Carrière ME, van Zuijlen PPM, van Baar ME, van der Vlies CH. (2024). The minimal important change (MIC) and minimal clinically important difference (MCID) of the patient and observer scar assessment scale (POSAS) 2.0. Burns. https://doi.org/10.1016/j.burns.2024.05.022