Despite the fact that diabetes individuals are often associated with a higher risk of bone fracture, our previous research demonstrated that Diabetic ketosis (DK) or ketoacidosis (DKA) induced significant alterations in bone biomarkers. It is unknown whether there is a difference in bone metabolism between obese and non-obese diabetic populations while they are in DK or DKA; hence the current study will investigate this further to aid in the prognosis and prediction of bone fracture risk in patients with different BMIs. We categorized patients into four groups based on their BMI utilizing data from our hospital's medical record system from 2018 to 2020 in the Department of Endocrinology: obese DK or DKA patients (OB+DK/DKA, n=41), non-obese DK or DKA patients (DK/DKA, n=201), obese type 2 diabetes patients without DK or DKA (OB+T2D, n=93), and patients with type 2 diabetes only (T2D only, n=304). The comparisons were made on glycosylated hemoglobin (HbA1c), body mass index (BMI), fasting plasma C-peptide (FPCP), and plasma lipids, in addition to bone metabolism indicators such as total 25-OH-VitD3 (25-OH-VitD3), N-terminal middle molecular fragment of osteocalcin (NMID), -C terminal cross-linking telopeptide of type 1 collagen (-CTX), parathyroid hormone (PTH), and blood calcium (Ca2+). The OB+DK/DKA group had a lower average age (p<0.05) than the DK/DKA group, while the DK/DKA group had a significantly lower FPCP (p<0.05). The 25-OH-VitD3 levels of DK/DKA patients were considerably lower than those of the T2D-only group (p< 0.05). In contrast, NMID and Ca2+ levels were significantly lower than those of non-ketosis or acidosis patients (p<0.05), and PTH levels in the DK/DKA group were significantly lower than those of OB+ T2D patients (p<0.05). In contrast, the β-CTX of the DK or DKA group (OB+DK/DKA and DK+DKA) was significantly greater than that of the non-DK or DKA group (p<0.05), although there was no significant difference in blood phosphorus between OB+DK/DKA and DK/ DKA (p>0.05). The levels of thyroid-stimulating hormone (TSH) and free T4 (FT4) did not differ significantly among the four groups (p>0.05); however, the levels of total T3 (TT3), T4 (TT4), and free T3 (FT3) were significantly lower in the DK/DKA group (p<0.05); the ratio of TT3 to TT4 (TT3/TT4) was significantly decreased in the DK/DKA group, whereas the ratio of FT3/FT4 was significantly lower (p<0.05). Obese patients with DK or DKA have a younger onset age, superior pancreatic function, and better blood glucose management than non-obese patients with DK/DKA. Despite having higher bone absorption signals than non-DK/DKA patients, OB+DK/DKA patients have stronger bone formation markers than non-obese DK/DKA patients, according to a recent study. Changes in markers of bone metabolism may be linked to non-thyroidal illness syndrome in cases of DK or DKA.