Era's Lucknow Medical College And Hospital

EVALUATION OF MACULAR THICKNESS IN TYPE -2 DIABETICS ON PIOGLITAZONE

ABSTRACT

Thiazolidinediones are oral hypoglycemic drugs that have been recently used for patients of type 2 diabetes. Review of literature shows that their side effect of systemic fluid retention aggravates diabetic macular edema. This research work was designed to see the effect of Thiazolidinediones (Pioglitazone) on early diabetic retinopathy. Optical Coherence Tomography (OCT) was used to measure average and central foveal thickness. 122 consecutive eyes of metabolically stable Type 2 diabetes were taken up for study and followed for three months who fulfilled the exclusion criteria. Patients were divided in two groups. Group one included patients with no diabetic retinopathy. Group two included patient with mild / moderate retinopathy without macular edema. As group two was further randomized into two subgroups. First subgroup received standard systemic medical therapy for diabetes and second subgroup received 30mg Pioglitazone in addition to standard treatment. All subjects underwent complete ocular systemic examination including Optical Coherence Tomography (OCT) at baseline, 6 weeks and 3 months. In this study, there was increase in central foveal thickness and average cube thickness in both the subgroups on Pioglitazone. Pioglitazone therapy is related to statistically significant increase in macular thickness at three month follow up. Optical Coherence Tomography (OCT) is an important tool for picking up subclinical changes in macular thickness that do not reflect in visual acuity.

Key Words: Hypoglycemic, Diabetes, Macular edema, Retinopathy, OCT.

Introduction

At least 171 million people worldwide suffer from diabetes and this is estimated to be doubled by 2030 (WHO) (1.) Most common cause of visual impairment in diabetic retinopathy (DR) is because of macular edema.

Optical Coherence Tomography (OCT) is a new investigative tool for quantification and classifying macular edema. (2,3) By measuring thickness it aids in early detection of macular edema and also in serial follow ups of patients on treatment..

Hee et al. (4) showed that with OCT measurements in diabetics, the mean macular thickness was larger in all regions for eyes with Non Proliferative Diabetic Retinopathy (NPDR) or PDR compared with the normal eye. The difference was most significant in average and central foveal thickness.

The therapy for diabetes mellitus mainly includes Diet, exercise, life style and pharmacological management.

Rosiglitazone and Pioglitazone have been evaluated in clinical trial in patients of type-2 Diabetes mellitus. Both these drugs have a beneficiary role in diabetic retinopathy by reducing hyperglycemia it tends to lower the progression of diabetic retinopathy this is in contradiction to what its side effect of systemic fluid retention may have (systemic fluid retention can aggravate diabetic macular edema. Review of literature provided instances of aggravation of diabetic macular edema attributed to use of this class of medicine. (5,6,7,8,9,10.) This study was designed to see the effect of pioglitazone on early diabetic retinopathy.

MATERIAl AND METHoDS

A prospective study was conducted between Sept. 2009 to May 2010 on 122 consecutive eyes of 66 patients, who had metabolically stable Type 2 diabetes mellitus (DM) attending diabetic clinic run by Department of Medicine (who fulfilled exclusion criteria). Only those patients who completed their 3 months follow up were included. Exclusion criteria were:

(1) Patients receiving Glitazones before enrolment into the study. (2) Any Intraocular surgery or recent pseudophakia (<3 months). (3) Any ocular disease (except early cataract).

(4) Hazy ocular media that occluded Fundus imaging. (5) Hypertension with edema. The two groups were further randomized into two subgroups. First subgroup (Subgroup A) received the standard systemic medical therapy for diabetes. The second subgroup (Subgroup B) received 30mg of Pioglitazone in addition to standard treatment. A detailed history of all patients were taken. Ocular examination included Best Corrected Visual Activity (BCVA) on ETDRS Chart. Anterior segment examination and applanation tonometry was done.  Fundus examination by 90 D lens central 50º fundus photography were taken. Fundus Fluorescein Angiography (FFA) was done, if required. Macula was studied by optical coherence Tomography using Cirrus HD – OCT (Carl Zeiss Meditee, Dubling CA) Scanning protocol was 512 x 128 combo, and the retinal thickness was measured in microns (μ). Retinal maps were analysed  for  all patients  and average cube thickness  and  Central foveal retinal thickness was measured. Weight was measured. Patients were examined 

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