Utility estimations of health states of older Australian women with atrial fibrillation using SF-6D

Abstract

Purpose

To estimate SF-6D utility scores for older women with atrial fibrillation (AF); calculate and compare mean utility scores for women with AF with various demographic, health behaviours, and clinical characteristics; and develop a multivariable regression model to determine factors associated with SF-6D utility scores.

Methods

This study evaluated N = 1432 women diagnosed with AF from 2000 to 2015 of the old cohort (born 1921–26) of the Australian Longitudinal Study on Women’s Health (ALSWH) who remained alive for at least 12 months post first recorded AF diagnosis. Self-reported data on demographics, health behaviours, health conditions, and SF-36 were obtained from the ALSWH surveys, corresponding to within three years of the date of the first record of AF diagnosis. Linked Pharmaceutical Benefits Scheme (PBS) data determined the use of oral anticoagulants and comorbid conditions, included in CHA₂DS₂-VA (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes, Stroke or TIA, Vascular disease and Age 65–74 years) score calculation, were assessed using state-based hospital admissions data. Utility scores were calculated for every woman from their SF-36 responses using the SF-6D algorithm with Australian population norms. Mean utility scores were then calculated for women with various demographic, health behaviours, and clinical characteristics. Ordinary Least Square (OLS) regression modelling was performed to determine factors associated with these utility scores. Two different scenarios were used for the analysis: (1) complete-case, for women with complete data on all the SF-36 items required to estimate SF-6D (N = 584 women), and (2) Multiple Imputation (MI) for missing data, applied to missing values on SF-36 items (N = 1432 women). MI scenario was included to gauge the potential bias when using complete data only.

Results

The mean health utility was estimated to be 0.638 ± 0.119 for the complete dataset and 0.642 ± 0.120 for the dataset where missing values were handled using MI. Using the MI technique, living in regional and remote areas ($\beta = 0.016 \pm 0.007$) and the use of oral anticoagulants ($\beta = 0.021 \pm 0.007)$ were positively associated with health utility compared to living in major cities and no use of anticoagulants, respectively. Difficulty to manage on available income $\left( {\beta = -\,0.027 \pm 0.009} \right)$, no/low physical activity $\left( {\beta = -\,0.069 \pm 0.011} \right)$, disability $\left( {\beta = -\,0.097 \pm 0.008} \right)$, history of stroke ($\beta = -\,0.025 \pm 0.013)$ and history of arthritis $\left( {\beta = -\,0.024 \pm 0.007} \right)$ were negatively associated with health utility.

Conclusion

This study presents health utility estimates for older women with AF. These estimates can be used in future clinical and economic research. The study also highlights better health utilities for women living in regional and remote areas, which requires further exploration.