Abstract P162: The Baseline Ankle Brachial Index (ABI), but Not Change in the ABI, is Associated With 11-Year Change in the SF-36: The San Diego Population Study (SDPS)

Abstract

Background: Lower extremity peripheral artery disease (PAD) affects approximately 9 million people in the US. Less well-recognized is that PAD, even when asymptomatic, is associated with decreased functional status and quality of life. Previous studies have largely examined associations of the ankle brachial index (ABI) and quality of life in participants with PAD. To our knowledge no studies have examined the impact of ABI and change in ABI on change in quality of life in a population-based setting. Methods: The SDPS is a population-based prospective study that evaluated non-Hispanic White, African-American, Hispanic and Asian men and women for lower extremity PAD at two examinations approximately 11 years apart. Participants completed the SF-36 questionnaire, and 802 participants had ABI and SF-36 data available at both examinations. Analyses were restricted to these participants who also had a baseline ABI<1.4. Growth curve models were used to assess the associations of baseline ABI and change in the ABI with change in the SF-36 physical component score (PCS) and mental component score (MCS) over time. Change in the ABI was defined as (follow-up ABI - baseline ABI)/baseline ABI. Results: Participants were on average 57±9 years of age at baseline, and 69±9 at follow-up. At baseline, nearly 2 percent had ABI≤0.90, and the mean±SD ABI was 1.12±0.10. After adjustment for age, sex, race/ethnicity, BMI, ever smoking, physical activity, hypertension, diabetes, and dyslipidemia, each SD lower baseline ABI was significantly associated with an average change of -0.63 points (95% CI (-0.10, -1.17), p=0.02) on the PCS. This association was marginally significant for the MCS (-0.54 points (0.14, 1.22), p=0.12). Lower baseline ABI was also associated with negative change in two SF-36 subscales, physical functioning (p=0.02) and vitality (p=0.01). Change in the ABI over 11 years was not associated with change in the MCS (p=0.97) or PCS (p=0.41). Results were similar when excluding participants with ABI≤0.90. Conclusions: A lower ABI at baseline is associated with a significantly worse physical functioning quality of life approximately 11 years later. However change in the ABI was not significantly associated with change in quality of life over this time period. Additional studies are warranted in larger samples, especially to confirm the lack of findings for change in ABI.