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Obesity and type 2 diabetes (T2DM) are considered risk factors for complications following total hip arthroplasty (THA). How these risk factors separately or in combination influence the risk of reoperation due to periprosthetic joint infection (PJI) or all-cause reoperation is not fully known. We sought to investigate the 2-year risk of reoperation following THA due to osteoarthritis (OA) among people with and without the metabolic risk factors, T2DM and obesity. We linked all patients with THA registered during 2008–2019 in the Swedish Hip Arthroplasty Register (SHAR) to the National Diabetes Register. The risk of reoperation was analysed by applying Kaplan–Meier (KM) and multivariable Cox regression analyses. Subgroup analyses were performed to explore the effect modification by obesity. After THA exclusions (such as bilateral THA observations and other diagnoses than OA) there were 14,512 individuals identified with T2DM and 116,579 without. The primary outcome was reoperation due to PJI within two years after THA. The secondary outcome was reoperation due to any cause within two years after THA. 2-year 1–KM reoperation estimate for reoperation due to PJI was 1.69% with 95% confidence interval (95%CI) 1.47–1.90 among individuals with T2DM and 1.02% (95%CI 0.96–1.08) among those without T2DM. The 1–KM reoperation estimate for reoperation due to any cause was 2.67% (95%CI 2.40–2.94) for the T2DM group, and 1.99% (95%CI 1.91–2.07) for non-T2DM. However, adjusted for Body Mass Index (BMI), T2DM was not a statistically significant risk factor (infection-related reoperation: adjusted hazard ratio (aHR) 1.1 with 95% confidence interval (95%CI) 0.9–1.3; all-cause reoperation: aHR 1.0, 95%CI 0.9–1.2). In the BMI subgroup analyses, T2DM associated increased risk of reoperation due to PJI was limited to normal/underweight individuals (aHR 1.6 95%CI 1.1–2.4). In the subgroups with overweight or obesity, T2DM was neither associated with increased risk of all-cause reoperation nor reoperation due to PJI. Overall, T2DM is not an independent risk factor for reoperation when adjusted for BMI. However, T2DM constitutes a minor risk factor in individuals of normal/underweight. Risk of reoperation was more strongly associated with BMI rather than T2DM, suggesting that the additional risk observed in obese patients is likely influenced by multiple interrelated factors beyond T2DM alone.