Effects Of Type 2 Diabetes Mellitus On Pulmonary Function And Quality Of Life In Patients With Chronic Obstructive Pulmonary Disease

Objective:A cross-sectional study was conducted on the effect of type 2 diabetes mellitus（T₂DM）on the patient’s pulmonary function in chronic obstructive pulmonary disease（COPD）.We measured the pulmonary function,improved score of the British Medical Research Council Respiratory Disorder scale（m MRC）,score of the chronic obstructive pulmonary disease assessment test（CAT）and acute exacerbation of chronic obstructive pulmonary disease（AECOPD）times in the previous year between simple COPD patients and COPD patients with diabetes,We evaluated the effect of T₂DM on pulmonary function and quality of life in patients with COPD.Methods:A total of 124 patients who were hospitalized in the second affiliated hospital of dalian medical university from September 2018 to February 2020 were included in the study and were divided into COPD group and without COPD group.Basic clinical information of all research subjects including gender,age,height and smoking history,tobacco consumption and so on were collected.Fasting plasma glucose（FPG）and hemoglobin A1c(Hb A_1C)were performed in fasting blood.All patients underwent pulmonary function test.Collect lung function parameters including vital capacity（VC）,forced vital capacity（FVC）,forced expiratory volume in 1 second（FEV₁）,the ratio of FEV1 to FVC（FEV1/FVC）,peak expiratory flow（PEF）,maximal mid-expiratory flow（MMEF）,total airways resistance（R tot）,residual capacity（RV）,total lung capacity（TLC）and the ratio of residual volume to total lung volume（RV/TLC）.Except FEV₁/FVC,RV/TLC and both PEF and MMEF only recorded the percentage of the measured value to the predicted value（%pred）,all the other pulmonary function parameters recorded both the measured value and the percentage of the measured value to the predicted value.Then,according to whether it is complicated with T₂DM or not,the patients were divided into simple COPD group,COPD with T₂DM group,T₂DM group and healthy control group.The differences of pulmonary function both between simple COPD group and COPD with T₂DM group and between T₂DM group and healthy control group stratificated by sex were observed respectively.The differences of m MRC score,CAT score and AECOPD times in the previous year between the simple COPD group and the COPD with T₂DM group were also compared in the COPD group.In addition,the correlation between FPG and pulmonary function parameters was performed.All the above data were analyzed by SPSS 21.0 statistical software,and P<0.05 was statistically significant.Results:In patients without COPD group,no matter male or female,there was no significant difference in age,height,weight,BMI,smoking history and tobacco consumption between the T₂DM group and the healthy control group（P>0.05）.The FPG,Hb A_1Cand the prevalence of hypertension in the T₂DM group were significantly higher than those in the healthy control group（P<0.05）.In the female group,none of the patients had a history of smoking,VC,percentage of predicted VC,FVC,percentage of predicted FVC,percentage of predicted FEV₁,TLC and percentage of predicted TLC were significantly lower in T₂DM group compared to the healthy control group（P<0.05）.In the male group,compared with the healthy control group,the T₂DM group had lower VC,percentage of predicted VC,FVC,percentage of predicted FVC,FEV₁,percentage of predicted FEV₁and percentage of predicted MMEF,and had higher RV and RV/TLC（P<0.05）.Then,the male group was divided into smoking group and never smoking group.In the male patients with smoking history,compared with the healthy control group,the T₂DM group had lower VC,percentage of predicted VC,FVC,percentage of predicted FVC,FEV₁and percentage of predicted FEV₁,and had higher RV and percentage of predicted RV/TLC（P<0.05）.Compared with healthy controls,T₂DM group had lower percentage of predicted VC,percentage of predicted FVC,percentage of predicted FEV₁and percentage of predicted MMEF in male patients with never smoking history（P<0.05）.In the patients without COPD group,FPG was negatively correlated with multiple pulmonary function parameters（percentage of predicted VC:r=-0.550,P<0.001,percentage of predicted FVC:r=-0.491,P<0.001,percentage of predicted FEV₁:r=-0.403,P=0.001,percentage of predicted TLC:r=-0.291,P=0.016）.This negative correlation still exists when all the individuals without COPD stratificated by gender.In the patients with COPD group,no matter male or female,there was no significant difference in age,height,weight,body mass index（BMI）,smoking history and tobacco consumption between COPD patients with T₂DM and simple COPD patients.In female group,COPD patients with T₂DM had higher FPG compared to the simple COPD patients（P<0.05）.In male group,COPD patients with T₂DM had higher FPG and HBA_1Ccompared to the simple COPD patients（P<0.05）.There was no significant difference in pulmonary function,m MRC score,CAT score and AECOPD times in the previous between the COPD patients with T₂DM and the simple COPD patients in GOLD-undefined（P>0.05）.Among COPD case subjects（GOLD1–4）,compared to the simple COPD patients,GOLD stages 2 patients with T₂DM had lower VC,percentage of predicted VC,FVC,percentage of predicted FVC,FEV₁,percentage of predicted FEV₁and percentage of predicted PEF,and had higher R tot and percentage of predicted R tot（P<0.05）.However,there was no significant difference in pulmonary function among other COPD groups.FPG was positively correlated with percentage of predicted Rtot（r=0.317,P=0.017）.Conclusion:Patients with T₂DM may have restrictive ventilatory dysfunction.The GOLD stages 2 patients with T₂DM had worse pulmonary function compared to the COPD patients without T₂DM.But,there is no effect of T₂DM on the quality of life of patients with COPD.