Normative data and clinically significant effect sizes for single-item numerical linear analogue self-assessment (LASA) scales

Background: Single-item assessments have been the most often-used measures in National Cancer Institute (NCI) cancer control clinical trials, but normative data are not available. Our objective was to examine the normative data and clinically significant effect sizes for single-item numerical linear analogue self-assessment (LASA) scale for overall quality of life (QOL). Methods: We analyzed baseline data from 36 clinical trials and 6 observational studies with various populations, including healthy volunteers, cancer trial patients (patients with advanced incurable cancer or patients receiving treatment with curative intent) and hospice patients as well as their caregivers. The overall QOL LASA was rated 0 (as bad as it can be) to 10 (as good as it can be). We calculated the summary statistics and the proportion of patients reporting a clinically meaningful deficit (CMD) of a score equal to 5 or less on the 0-10 scale. Results: In total, for the collective sample of 9,295 individuals, the average overall QOL reported was 7.39 (SD = 2.11) with a markedly skewed distribution with roughly 17% reporting a score of 5 or below indicating a clinically significant deficit in overall QOL. Hospice patients report a much worse average score of 5.7 upon entry to hospice; hospice caregivers average 7.4. Cancer patients vary within these two extremes with most patients averaging in the 7's on the 0-10 scale (range, 0 to 10 p-value < 0.0001). Men and women's QOL distributions were virtually identical (with average of 7.6 vs. 7.5, p-value = 0.046). Overall QOL was weakly related to performance status with a Spearman correlation coefficient of -0.29 (p-value < 0.0001). Overall QOL was related to tumor response (p-value = 0.0094), i.e. patients with a full or partial response reported a CMD in 11.4% of cases compared to 14.4% among those with stable disease and 18.5% among those with disease progression. Data missingness was high for performance status and tumor response associations. Conclusions: This study provides the normative data for cancer patients and healthy volunteers for overall QOL using the LASA. These can serve as benchmarks for future studies and inform clinical practice decision-making.