Changes of bone mineral density of patients with chronic obstructive pulmonary disease and analysis of the related factors / 中国医师进修杂志

ABSTRACT

Objective To study the relationship between chronic obstructive pulmonary disease (COPD) and osteoporosis by measuring the bone mineral density (BMD),lung function,blood gas analysis,calcium ion,high sensitive C reactive protein (hs-CRP) and the quality of life.Methods BMD measuring was performed by ultrasound dry bone densitometer in 32 patients with COPD (COPD group) and 35 healthy controls (control group).The ultrasonic transmission speed (SOS),SOS T,fracture risk factor (OSI) and bone strength (TI) were measured at the sites of the left calcaneus.COPD group was divided into three groups according to lung function,3 cases of mild,14 cases of moderate and 15 cases of severe.According to the level of BMD,there were another three groups,3 cases with normal BMD,24 cases with lower BMD,and 5 cases with osteoporosis.According to the history of systemic glucocorticoid application,COPD group was divided into two groups,10 cases with glucocorticoid application and 22 cases without glucocorticoid application.The levels of BMD between COPD group and control group were compared,and the correlation between BMD and lung function,blood gas analysis,calcium ion,hs-CRP and the quality of life in patients with COPD was analyzed.Results COPD group had lower BMD than that in control group (P ＜ 0.05).In COPD group,the severe patients had lower BMD than the moderate patients (P ＜ 0.05),and the severe patients had only lower SOS than the mild patients(P ＜ 0.05),but there was no statistic significant difference in BMD between the moderate and mild patients(P ＞ 0.05).According to the level of BMD,the osteoporosis patients had lower arterial oxygen tension (PaO2) and higher hs-CRP and COPD assessment test (CAT) than the normal BMD and lower BMD patients,and the lower BMD patients had lower PaO2 and higher CAT than the normal BMD patients (P ＜ 0.05),but there was no statistic significant difference in calcium ion among them(P ＞ 0.05).According to the history of systemic glucocorticoid application,the patients with glucocorticoid application had lower level of BMD than the other patients (P ＜ 0.05).SOS,SOS T,OSI and TI was correlated with one second forced expiratory volume percent predicted (FEV1％) (r =0.389,0.262,-0.295,0.265; P＜0.05),also correlated with PaO2 (r =0.391,0.100,-0.374,0.122;P＜0.05),and also correlated with CAT (r =-0.659,-0.463,0.175,-0.178 ; P ＜ 0.05).There was only a negative correlation between SOS and hs-CRP (r =-0.390,P ＜ 0.05).Further in Logistic regression analysis,the results showed that both PaO2 and FEV1％ were the risk factors of BMD reduction.Conclusions Patients with COPD have lower BMD than their peers of healthy.The reduction of blood oxygen pressure and lung function are the risk factors of BMD reduction.There is a conjecture that the reduced BMD is correlated with chronic inflammation in patients with COPD.