Temporal Relationship Between Insulin Resistance and Lipid Accumulation After Bariatric Surgery: a Multicenter Cohort Study

Purpose Insulin resistance (IR) is closely associated with lipid accumulation. Here, we investigated the temporal relationship between the two conditions after bariatric surgery. Materials and Methods In total, 409 participants were enrolled from three bariatric centers in China from 2009 to 2018. We evaluated whether baseline IR (proxied by homeostasis model assessment of insulin resistance (HOMA-IR)) and lipid accumulation (proxied by visceral adiposity index (VAI) and lipid accumulation product (LAP)) were associated with follow-up IR and lipid accumulation (3 months postoperatively) using linear regression models. We then conducted a cross-lagged panel analysis model to simultaneously examine the bidirectional relationship between IR and lipid accumulation. Results Multivariable linear regression analyses showed that baseline HOMA-IR was associated with follow-up VAI ( β = 0.430, 95% CI: 0.082–0.778, p = 0.016) and LAP ( β = 0.070, 95% CI: 0.010–0.130, p = 0.022). There was no relationship between baseline lipid accumulation and follow-up IR. Further cross-lagged panel analyses indicated that the path coefficient from baseline HOMA-IR to follow-up VAI ( β 2 = 0.145, p = 0.003) was significantly greater than the coefficient from baseline VAI to follow-up HOMA-IR ( β 1 = − 0.013, p = 0.777). Similarly, the path coefficient from baseline HOMA-IR to follow-up LAP ( β 2 = 0.141, p = 0.003) was significantly greater than the coefficient from baseline LAP to follow-up HOMA-IR ( β 1 = 0.041, p = 0.391). Conclusion Our study demonstrated a unidirectional relationship from HOMA-IR to VAI and LAP, suggesting that the change in IR may precede lipid accumulation after surgery. Graphical Abstract