History and Objectives: Long term treatment of Thalassemic major is by regular blood transfusion and infusion of an Iron chelator. The treatment is cumbersome and expensive and compliance may be low. Diabetic mellitus is well known side of chronic or acute Iron toxicity. Relationship between compliance and emergence diabetes mellitus is investigated among patients referred to the Bou-Ali Sina hospital in 1997.

Materials and Methods: A case control study was carried out. Control group consisted of Thalassemic patients with normal glucose tolerance test and case group was Thalassemic patients with diabetes mellitus. 2 groups were matched for age, sex, severity of Thalassemia (Age of diagnosis, age of transfusion and degree of dependence to the transfusion), social-economic class and infection to chronic hepatitis C. Results were obtained from patient’s record. Body mass index was calculated from height and weight. All patients were from Mazandaran province and have no record of diabetes mellitus in their first-degree relatives. Compliance was assessed by a suggested system and classified. On the basis of this system, compliance was classified as good, fair and poor and compared in the control and case group. Results were analyzed by Chi-square method and odds ratio for estimation relative risk was determined.

Results: Two control and case groups were similar on the basis of the above-mentioned criteria. Classification of compliance for the last year was similar but results for the last five years indicated that 79% of non-diabetic patients had good or fair compliance (Score of 4 or better) whereas on 29% of diabetic patients had similar score. The differences were significant statistically (P<0.01) and the odds ratio shows that poor compliance to treatment increase risk of diabetic mellitus 3 fold.

Conclusion: Lack of compliance or in availability of treatment, especially to the Iron chelation, increases the risk of diabetes mellitus among Thalassemic major patients. Therefore, patients should be encouraged to follow their treatment closely.