A CASE CONTROL STUDY TO EVALUATE THYROID DYSFUNCTION AS A RISK FACTOR FOR DIABETIC RETINOPATHY IN TYPE 2 DIABETES MELLITUS.

Corresponding Author:
Dr. Subbaiah Vasan Chandrakumar,
Eye Department Op. No. 50,
Govt. Rajaji Hospital, No. 1, Panagal Road,
Madurai-625020, Tamilnadu.
E-mail: eyedrck@gmail.com

ABSTRACT

This is a Case Control Study that was conducted among 100 Type 2 DM (Diabetes Mellitus) patients who attended the OP and the wards of Ophthalmology Department at Government Rajaji Hospital, Madurai, to assess the prevalence of thyroid dysfunction among Type 2 DM patients and whether thyroid dysfunction is associated with increased risk of retinopathy in Type 2 diabetes patients. Patients diagnosed with Type 2 DM on treatment for more than 5 years of diabetes mellitus and over 12 years of age were taken up for this study. Patients with known history of thyroid disorder, patients on drugs known to affect thyroid function like lithium, amiodarone, oral contraceptive pills, etc., pregnant mothers, systolic blood pressure more than 150 mm of Hg and diastolic more than 90 mm of Hg, with nephropathy and those patients for whom fundus examination was not possible, patients not consenting for this study were excluded from this study. Data and blood samples will be collected from subjects and serum shall be extracted for thyroid profile. All the study patients will undergo a detailed ocular examination for grading of Diabetic Retinopathy (DR) as per the Early Treatment Diabetic Retinopathy Study (ETDRS) guidelines.

RESULTS

Odds Ratio (OR) for determining association between risk factor and disease was 5.06, with an upper 95% Confidence Limit of 15.051 and a lower confidence limit of 1.703, which means the odds of a diabetic patient with thyroid dysfunction (subclinical and overt hypothyroidism) developing retinopathy is 5.06 times that of a diabetic patient without thyroid dysfunction. According to this study the prevalence of thyroid dysfunction among the 100 Type 2 Diabetes Mellitus patients studied was 23% with the most common problem being Subclinical Hypothyroidism (SCH) at 21% among the study population followed by overt hypothyroidism at 2%. As expected the prevalence of thyroid dysfunction³ among females (32%) was much more than among males (14%), the odds ratio being 5.06. Chi-Square statistic applied to our data revealed P-value of <0.005.

CONCLUSION

Our study showed a significant association between subclinical and overt hypothyroidism with development of diabetic retinopathy in this study population.

KEYWORDS

Hypothyroidism, Diabetic Retinopathy, Type 2 Diabetes Mellitus.