The clinical analysis of glycemic control and changes of pulmonary diffusion capacity in elderly type 2 diabetes

Abstract

Objective To investigate the effect of blood glucose level on pulmonary diffusion capacity in elderly patients with type 2 diabetes and its clinical significance. Methods Totally 132 older adults with type 2 diabetes were enrolled in this study. According to blood glucose level, the patients were divided into well-controlled group (n=57) and poor-controlled group (n=75). Additionally, 52 age-matched non-diabetic healthy subjects were selected as control group. Levels of fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), fasting insulin (FINS) and 2-hour postprandial glucose (2h PG) in the diabetic patients were detected, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The patients with type 2 diabetes underwent urinary albumin excretion rate (UAER) detection, fundus examination and nerve conduction velocity test. pulmonary ventilation, diffusion of the lungs for carbon monoxide (DLCO) and DLCO corrected by alveolar volume (DLCO/VA) were examined in all subjects. Results Levels of FBG, 2h PG, HbA1c and HOMA-IR were higher in poor-controlled group than in good glycemicwell-controlled group (all P 0.05). DLCO and DLCO/VA were lower in diabetic groups than in the control group(all P<0. 05). DLCO and DLCO/VA in poor-controlled group were lower than those in well controlled group (both P<0.05). DLCO and DLCO/VA were lower in patients with microangiopathy score≥2 than those without microangiopathy (both P<0.05). Multiple liner regression analysis showed that DCLO and DLCO/VA were negatively correlated with HbA1c, HOMA-IR, duration of diabetes and microangiopathy (r=-2.51, -2.35, -2.42, -2.37, -2.41, -2.52, -2.47, -2.36, all P<0.05). Conclusions The pulmonary diffusion capacity is significantly impaired in elderly patients with type 2 diabetes. Pulmonary diffusion capacity is negatively correlated with the blood glucose level. The lung may be one of the target organs of type 2 diabetes mellitus. Key words: Respiratory function tests; Diabetes mellitus, type 2; Insulin; Diabetic angiopathies