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 (ß = 0.430, 95% CI: 0.082-0.778, p = 0.016) and LAP (ß = 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 (ß2 = 0.145, p = 0.003) was significantly greater than the coefficient from baseline VAI to follow-up HOMA-IR (ß1 = - 0.013, p = 0.777). Similarly, the path coefficient from baseline HOMA-IR to follow-up LAP (ß2 = 0.141, p = 0.003) was significantly greater than the coefficient from baseline LAP to follow-up HOMA-IR (ß1 = 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.