Is a Longer Recall Period Better? A Study of EQ-5D-5L With a “1-Week” Recall Period in the General Population

OBJECTIVES: We compared psychometric properties of two EQ-5D-5L versions differing in recall period (today vs. 1 week) in the Singaporean general population.

METHODS: Online surveys were completed by Singaporean participants aged≥15 years(N=592) at two timepoints. Participants completed standard EQ-5D-5L with “today” (T) as the recall period and reported demographic and health characteristics at baseline, and completed modified EQ-5D-5L with recall period of “1 week” (1W) and WHOQOL-BREF 3-15 days after baseline. We compared the ceiling effects, dimensional agreement (Cohen’s kappa, k), agreement with EQ Index and EQ VAS scores (paired t-test, ICC, and Cohen’s d), convergent validity between the two recall periods. For known-groups validity, Index and VAS was compared between individuals with/without disability and chronic disease and individuals with different alcohol consumption and physical activity status.

RESULTS: The ceiling effect were 43.24% (T) and 45.10% (1W). Dimensional agreement (k) between the two versions ranged from 0.38 (Usual activities) to 0.61 (Anxiety/depression). Index (p=0.149; d=-0.05; ICC=0.69) and VAS (p=0.608; d=0.02; ICC=0.45) for both versions were similar. The correlations of EQ-5D physical health dimensions with WHOQOL-BREF physical scores for T/1W were -0.45/-0.43 (mobility), -0.11/-0.37 (self-care), -0.38/-0.46 (usual activities), and -0.42/-0.39 (pain/discomfort). The correlations between the anxiety/depression dimension and WHOQOL-BREF psychological scores were -0.61 (T) and -0.68 (1W). The correlations of Index and VAS with WHOQOL-BREF physical scores for T/1W were 0.59/0.60 and 0.64/0.54; and with WHOQOL-BREF psychological scores for T/1W were 0.44/0.46 and 0.56/0.39, respectively. T/1W-generated Index and VAS differed expectedly by the presence of disability (d_Index=-1.64/-1.10; d_VAS=-0.77/-0.56) and chronic disease (d_Index=-0.65/-0.62; d_VAS=-0.54/-0.51), and levels of physical activity (d_Index=-0.45/-0.45; d_VAS=-0.58/-0.51). The Index and VAS were similar between binge and non-binge drinkers (ps>0.05) for both versions.

CONCLUSIONS: EQ-5D-5L with 1-week recall period exhibited similar psychometric properties as the standard EQ-5D-5L with “today” as the recall period in the Singaporean general population.