Background Despite many reports on the anabolic effects of insulin on connective tissue and cartilage metabolism in diabetes, data relating to the effect of insulin therapy in the progression of osteoarthritis (OA) is sparse.
Objectives To investigate whether radiographic changes in knee OA in Type 2 diabetes mellitus (T2DM) patients on insulin treatment differed from those not on insulin.
Methods A cross-sectional study was performed in 311 subjects (211 T2DM patients and 100 control subjects without diabetes), screened over a period of one year in a hospital-based setting. Patients were categorized into three groups, T2DM patients not on insulin (G1, n=99), T2DM patients on insulin (G2, n=112) and non-diabetic control group (G3, n=100). Plain X-ray of knee was used to assess the changes of knee OA and graded using Kellegren-Lawrence (K-L) scale and the Osteoarthritis Research Society International (OARSI) Atlas grading scale.
Results A total of 622 knee X-rays were evaluated. A highly significant association (p<0.001) was observed for OARSI-Joint Space Narrowing (JSN) as well as for osteophyte formation between the three groups. Comparing G2 and G3, highly significant association (p<0.001) was retained for JSN and for osteophyte formation. Comparing G1 and G2, though there was no association (p>0.05) for JSN, significantly lesser osteophytes formation were noted in T2DM G2 patients compared to T2DM G1 patients (11.7% vs. 19.7%, p=0.02). Multivariate logistic regression analysis showed that T2DM G2 group had less osteophyte formation than both G1 T2DM group and G3 control group, (odds ratio =0.294, p<0.008 and odds ratio =0.098, p<0.001, respectively) after inclusion of confounders such as age, gender and BMI.
Conclusions Our findings suggest that insulin therapy might retard the radiographic osteophytes formation in T2DM patients with OA knee. Further longitudinal prospective studies are needed to explore the significance of these observations.
Disclosure of Interest None declared