Validity and Reliability of the Dutch Adaptation of the Actinic Keratosis Quality of Life Questionnaire (AKQoL).

BACKGROUND

The Actinic Keratosis Quality of Life Questionnaire (AKQoL) is a disease-specific instrument to measure the impact of actinic keratosis (AK) on patients' lives.

OBJECTIVE

To validate and test the psychometric properties of the AKQoL translated into the Dutch language (AKQoL-NL).

METHODS

All new patients ≥50 years of age with untreated AK in a university medical center and a general hospital between August 2014 and August 2015 were eligible. The AKQoL was obtained and repeated after 2 weeks. The feasibility was tested by missing responses and response distribution. The internal consistency reliability of each domain was investigated with the Cronbach alpha, and test-retest reliability and validity with the Spearman correlation coefficient. AKQoL scores were compared to the Skindex-17 for convergent validity and to the Groningen Frailty Indicator scores for divergent validity.

RESULTS

A total of 153 of 190 eligible patients consented to participate. Feasibility analysis showed that none of the items missed ≥10% of responses but 5 of the 9 items showed floor effect. The AKQoL subscales showed a moderate internal consistency (Cronbach α = 0.235-0.468) and an excellent test-retest reliability (interclass correlation coefficient = 0.997-1). The AKQoL correlated poorly with the symptom component and moderately with the psychosocial component of the Skindex-17 (ρ = -0.015 to 0.346 and 0.324 to 0.501, respectively), which is less than expected. The AKQoL scored poorly in both of the Groningen Frailty Indicator (GFI) components (ρ = -0.97 to 0.12 and 0.185 to 0.276, respectively), as expected.

CONCLUSION

The AKQoL-NL is a feasible, moderately valid, and moderately reliable health-related quality of life questionnaire.