A 10-item short form of the Patient Benefit Index Standard version (PBI-S) may be effective for measuring overall patient-relevant benefits in psoriasis, according to findings from a study in the British Journal of Dermatology.
The 10-item short version (PBI-S-10) is based on the validated 25-item PBI-S questionnaire.
Researchers used data from the German Psoriasis Registry PsoBest (n=4164) and the cross-sectional PsoHealth4 study on psoriasis care (n=1185).
The items in the short version included average importance rating, correlation with the PBI-S total score, percentage of missing values, inter-item correlations, floor/ceiling effects, and clinical relevance. The criterion validity of the short form was assessed according to its association with the long form.
Patients in the PsoBest database had a mean age of 48.6 years (58.6% men) and were diagnosed with psoriasis an average of 18.4 years. Patients in the PsoHealth4 database had a mean age of 50.9 years (53.3% men) and were diagnosed with psoriasis an average of 20.8 years.
The total score yielded from the 10 selected items had excellent agreement with the corresponding score on the long form in the PsoBest and PsoHealth4 databases (intra-class correlation [ICC] =0.958/0.940; r=0.973/0.945, respectively), and internal consistency was good in both databases (0.794/0.816, respectively), according to the study authors.
Among the PsoBest participants, the PBI-S-10 correlated with changes in Dermatology Life Quality Index (DLQI), Psoriasis Area and Severity Index (PASI), Patient Body Surface Area (PBSA), and patients’ global assessment of disease severity, which indicates convergent validity. Known-groups validity was demonstrated by strong effects regarding the PBI-S-10 in patients who achieved vs those who did not achieve a DLQI of 0, and between patients who achieved and those who did not achieve PASI-75.
For the PsoHealth4 group, correlations between PBI-S-10 and DLQI, PBSA, PASI, and physicians’ global assessment of disease severity also supported convergent validity. The participants who received more potent treatment had higher PBI-S-10 total scores.
The researchers noted that their study comprised only patients from Germany and patient partners were not included. In addition, responses to single items of a questionnaire may be affected by the content and number of the other items.
“We recommend use of the PBI-S-10 in clinical studies that focus on overall patient-relevant benefit from psoriasis treatment, and for shared decision-making if time does not allow for usage of the long form,” concluded the study authors. “However, in clinical practice, a more differentiated assessment of patient needs including all 25 items of the PBI-S may be advisable in order to align the treatment to all those goals relevant to the person.”
Disclosure: A study authors is a license holder of the Patient Benefit Index.
Please see the original reference for a full list of authors’ disclosures.
Blome C, von Stülpnagel CC, Augustin M, et al. Measuring patient-relevant benefits in psoriasis with the Patient Benefit Index: development and preliminary validation of a 10-item short form. Br J Dermatol. Published online April 5, 2022. doi:10.1111/bjd.21593