Questionnaires may be reliable in assessing psoriasis prevalence
Patient-completed psoriasis questionnaires showed response agreement over time, while atopic dermatitis questionnaires had inconsistent responses, according to a study.
“While registry studies may enable examination of a large number of individuals, several countries do not have consistent collection of health care data in registries,” Lea K. Nymand, MSc, of the department of dermatology at Bispebjerg Hospital, University of Copenhagen, and colleagues wrote. “Therefore, for questionnaire-based studies, a self-reported non-dermatologist-physician or dermatologist diagnosis is often applied to estimate the disease prevalence.”
A nationwide population-based cohort study surveyed 2,333 participants in Denmark who responded to a psoriasis questionnaire in 2018 and again in 2020 and 2,312 subjects who responded to an AD questionnaire in both 2018 and 2020.
In the psoriasis questionnaire, 2,107 participants reported never having psoriasis at both time points, 143 reported having or having had psoriasis at both times, 39 reported having or having had psoriasis in 2018 but not in 2020, and 44 reported having or having had psoriasis in 2020 but not in 2018.
In the AD survey 2,036 subjects reported never having AD at both time points, 88 reported having or having had AD at both times points, 101 reported having or having AD in 2018 but not in 2020, and 87 reported having or having had AD in 2020 but not in 2018.
There was a 96.4% agreement in psoriasis history and 95.3% agreement for psoriasis divided by diagnosis type. The AD agreement was 91.9% for any history and 91.1% for different types of diagnoses.
The agreement was substantial for reporting history of psoriasis ( = 0.7558) but only moderate for AD ( = 0.4395).
“This cohort study found considerable agreement between individual participant responses over time when asked about a history of psoriasis,” the authors wrote. “For a history of atopic dermatitis, the individual participant responses were less consistent and suggest that, in adults, using a reported history of atopic dermatitis will confer considerable risk of bias and misclassification.”