Replication and extension of dietary adherence as a predictor of suboptimal weight-loss outcomes in postbariatric patients. Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery Wakayama, L., Nameth, K., Adler, S., Safer, D. L. 2018

Abstract

BACKGROUND: Sarwer et al. found that poor dietary adherence at 6 months postoperatively predicted lower weight loss.OBJECTIVES: To replicate and extend these findings.SETTING: University bariatric clinic.METHODS: Fifty-four adults (72% female; age 51.1 ± 11.3 yr; mean body mass index [BMI]?=?43.8 ± 7.4 kg/m2; 53.7%?=?Roux-en-Y gastric bypass, 42.6%?=?laparoscopic sleeve gastrectomy, and 3.7%?=?gastric banding) were identified as low or high dietary adherers following the method of Sarwer et al. Patients self-reported dietary adherence with a 9-point Likert scale. Splitting the group at the median, low adherers scored <7 and high dietary adherers =7. BMI, percentage excess weight loss (%EWL), and percentage total weight loss (%TWL) were prospectively assessed at 12, 24, and 36 months. Two-tailed independent t tests and Cohen's d effect sizes were used to compare between-group outcomes.RESULTS: BMI did not differ between low (n?=?24) and high (n?=?30) dietary adherers at 6 months after surgery. At 12 months, the BMI of low (n?=?17) adheres was significantly higher (34.1 ± 4.61 versus 30.3 ± 3.90 kg/m2, P?=?.006, d?=?0.90) than that of high (n?=?25) adherers, with significantly less %EWL (49.0 ± 24% versus 70.7 ± 21.5%; P?=?.004; d?=?0.95) and %TWL (20.7 ± 11.5% versus 28.9 ± 10.5, P?=?.02, d = 0.74). At 24 months, BMI remained significantly higher for low (n?=?12) versus high (n?=?10) adherers (33.7 ± 4.77 versus 29.7 ± 3.82 kg/m2, P?=?.045, d?=?0.92), but %EWL and %TWL were not significantly different, despite large effect sizes. At 36 months, moderate effects supported continued higher BMIs and lower %EWL and %TWL for low (n?=?5) versus high (n?=?8) adherers. Attrition from follow-up was 22.2% (12 mo), 59.3% (24 mo), and 75.9% (36 mo). Post hoc analyses revealed no impact of baseline characteristics on low follow-up rates except younger age (at 1 yr).CONCLUSIONS: Findings that 6-month postoperative dietary adherence predicts 12-month BMI, %EWL, and %TWL were replicated. Medium to large effects suggest findings extend to 24 and 36 months, with low follow-up rates likely affecting statistical significance.

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