The Influence of Health Literacy and Health Numeracy on Weight Loss Outcomes Following Bariatric Surgery.

ABSTRACT

BACKGROUND: Although cognitive functioning and health literacy are related to weight loss 1year following bariatric surgery, the influence of health numeracy (i.e., health-related mathematical abilities) is unknown. In addition, further research is needed to examine the impact of all these factors on longer-term weight loss outcomes to determine if they influence the ability to maintain weight loss. SETTING: Single bariatric center. METHODS: Patients (N = 567) who underwent bariatric surgery from 2014-2017 completed a brief survey including current weight. Retrospective chart reviews were conducted to gather information from the presurgical evaluation including weight, body mass index (BMI), health literacy, health numeracy and score on a cognitive screener. RESULTS: Among participants in the weight loss period (< 2 years postsurgery), health literacy, health numeracy and cognitive functioning were not related to change in BMI (ΔBMI), percent total weight loss (%TWL) or percent excess weight loss (%EWL). However, for participants in the weight maintenance period (2-4 years postsurgery), higher health literacy scores were related to greater change in ΔBMI, and higher health numeracy scores were related to greater ΔBMI, %TWL, and %EWL. DISCUSSION: Although health literacy and health numeracy did not predict weight loss outcomes for those in the initial weight loss period, they were related to weight outcomes for participants in the weight maintenance period. This suggests that health literacy and health numeracy may play a role in facilitating longer-term weight maintenance among patients who undergo bariatric surgery. Clinicians conducting presurgical psychosocial evaluations should consider routinely screening for health literacy and health numeracy.