The relationship between subclinical hypothyroidism and diabetic retinopathy in elderly type 2 diabetic patients / 中华老年医学杂志

ABSTRACT

Objective To investigate the relationship between subclinical hypothyroidism (SCH) and diabetic retinopathy (DR) in elderly type 2 diabetic patients.Methods 1170 hospitalized patients with type 2 diabetes mellitus were enrolled in our study.After identified by systematic sampling,all the elderly patients received examinations of thyroid function,biochemical indexes,steamed bread meal test and C-peptide releasing test.The serious degree of DR was observed through digital fundus photography and ophthalmofundoscope.The relationship between SCH and DR was analyzed.Results All the subjects were divided into two subgroups:euthyroid group(TSH≤4mU/L)and subclinical hypothyroidism (SCH) group (mild SCH group,TSH ＞4～10 mU/L; serious SCH group,TSH＞10 mU/L).Free thyroxine (FT4) was significantly lower in SCH group than in euthyroid group[(13.91±2.17) pmol/L vs.(16.55±2.81)pmol/L,P＜0.001].The levels of basal (CP0) and post glucose-challenge (CP1-3) C-peptide were significantly higher in SCH group than in euthyroid group (P0-3 value:0.001,0.012,0.004,0.001).There were significant differences in the progress of diabetic retinopathy between SCH and euthyroid groups (retinopathy-L,P=0.018; retinopathy-R P=0.013).Conclusions Elderly type 2 diabetic patients with SCH have a higher incidence of diabetic retinopathy (DR).The elevated FT4 level and decreased basal C-peptide level are probably the main reasons.