Exploring the relation between the EQ-5D-5L pain/discomfort and pain and itching in a sample of burn patients

BACKGROUND: The EQ-5D domain pain/discomfort (PD) uses one item to capture pain and other aspects of discomfort, like itching. This study explored how pain, itching and the EQ-5D-5L PD domain relate to each other in a sample of burn patients. METHODS: Adult burn patients completed the EQ-5D-5L and the Patient and Observer Scar Assessment Scale (POSAS) 5–7 years after sustaining their injury. The POSAS includes a separate pain and an itching item. Spearman’s correlation coefficient established the association between the EQ-5D-5L PD and the POSAS pain and itching item. With multivariable regression analysis the linear association between the POSAS pain and itching item and EQ-5D-5L PD domain was tested. RESULTS: Data from 245 patients were included. Mean EQ-5D-5L index value was 0.87 and 39.2% reported at least slight problems on the EQ-5D-5L PD domain. Most patients gave corresponding answers on the EQ-5D-5L PD domain and on the POSAS pain (73%) and itching (70%) item. Spearman correlation coefficients of the EQ-5D-5L PD domain with the POSAS pain and itching were 0.468 (p < 0.001) and 0.473 (p < 0.001), respectively. Among respondents with pain and without itching and respondents with itching and without pain, Spearman correlation coefficients were 0.585 (p = 0.076) and 0.408 (p = 0.001), respectively. POSAS pain (unstandardized Beta = 0.14) and POSAS itching (unstandardized Beta = 0.08) were significantly associated with EQ-5D-5L PD domain (p < 0.001). CONCLUSIONS: Our findings indicate that, in a sample of burn patients, pain and itching are captured by the broader EQ-5D-5L PD domain. The EQ-5D-5L PD domain can thus be used to assess pain and itching in relation to HRQL, but the POSAS pain and itching items are more sensitive. The EQ-5D-5L is, however, no replacement of the POSAS when the POSAS is used for its primary aim; assessment of scar quality. TRIAL REGISTRATION: Netherlands Trial Register (NTR6407).