만성폐쇄성폐질환환자에서우울과불안심리평가 이화여자대학교의과대학내과학교실, 호흡기내과류연주, 천은미, 심윤수, 이진화 Depression and Anxiety in Outpatients with Chronic Obstructive Pulmonary Disease Yon Ju Ryu, M.D., Eun Mi Chun, M.D., Yun Su Sim, M.D., Jin Hwa Lee, M.D. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, College of Medicine, Ewha Womans University, Seoul, Korea Background: Patients with chronic obstructive pulmonary disease (COPD) have often been reported to suffer from depression and anxiety possibly due to the exacerbation, hospitalization and mortality of COPD. However,scarce data are available in Korea. This study assessed degree of depression and anxiety, and evaluated the factors associated with depressive symptoms in COPD. Methods: The cross-sectional data on the lung function measurements, smoking behavior, body mass index (BMI), age, gender, depressive symptoms using Beck Depression Inventory (BDI) and anxiety using the State-Trait Anxiety Inventory (STAI) were evaluated in 72 outpatients with COPD and 50 controls without underling lung diseases from September, 2005 to October, 2006 in the Ewha medical center. Results: 1) The age, body mass index (BMI) and serum albumin levels were similar in the patients and controls. The BDI scores (16(0-37) vs. 12(1-30), p=0.001) and the prevalence of depression (36% vs. 6%, p<0.0001) were higher in the COPD patients than in the controls. In the COPD group, the prevalence of depression increased with increasing GOLD stage (p=0.008). The prevalence was 18%(4/22), in mild cases, 30%(6/20) in moderate cases, 52%(13/25) in severe cases and 60%(3/5) in very severe cases. 2) The SAI and TAI scores were higher in the COPD patients (44(20-67) and 47(20-66)) than in the healthy controls (39(26-65) and 44(33-90)). There were a significant correlation between the depression and anxiety scores (p<0.001). 3) A lower BMI, lower postbronchodilator FEV 1, current smoking behavior and severity of COPD were univariately associated with the depressive group in COPD, 4) while multivariate logistic analysis revealed only the severe-to-very severe group (OR 3.9, 95% CI 1.2 to 12.9) to be independently associated with depressive symptoms. Conclusion: COPD is strongly associated with depression and anxiety. Therfore, screening for psychological problems in COPD patients is essential, particularly in patients with severe-to-very severe COPD. (Tuberc Respir Dis 2007; 62: 11-18) Key word: Depression, Anxiety, Severity, Chronic obstructive pulmonary disease. 서 만성폐쇄성폐질환 (Chronic Obstructive Pulmonary Disease, COPD) 은적절한치료에도진행하여완치가불가능하고, 전세계적으로 2020년에는 3번째로중요 론 Address for correspondence: Eun Mi Chun, M.D. Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Dongdaemun Hospital, Ewha Womans University, College of Medicine, Jongno 6-ga, Jongno-Ku, Seoul, Republic of Korea, Phone : (02) 760-5053, Fax : (02) 760-5193, E-mail: cem@ewha.ac.kr Received: Sep. 29. 2006 Accepted: Dec. 14. 2006 한사망원인으로예측되며 1, 최근보고에의하면국내유병률이 45세성인이상에서 17.2% 이상인중요한질환이다 2. COPD 환자들은점진적인폐기능의손상으로인한활동의제한과기능상실을겪게됨에따라자아존중감이저하되고우울에빠지게되어기본적인일상생활및삶의질과안위에영향을주며전반적인삶의만족에부정적인영향을미치게된다. 또한, COPD 환자에서치료의장기화에따르는삶의질의저하는우울증및불안장애등의발생가능성을높게하고치료경과 3,4 및사망률에도 5,6 영향을주는것으로보고되고있다. 국내외에서 COPD의조기진단과예방, 치료면에서의연구는활발하게진행되고있으나, COPD 환자군에서우울과불안장애의유병률 7-10, 사회심리학 11
YJ Ryu et al: Depression and anxiety in COPD 적인차원에서의치료접근이부족한실정이며 11, 국내 COPD 환자를대상으로시행한우울과불안심리평가는거의없다 12. 우울증의선별검사방법으로지금까지여러방법이제시되고있으나이중환자스스로보고하는방법이사용하기편리하며, Beck Depression Inventory (BDI) 는 1961년 13 제안된이래지금까지구미에서가장널리사용되고있는우울증검사도구중의하나이다. COPD 환자를대상으로한연구들도보고되었고 7-9, 1986년한홍무등은이를번안하여신뢰도와타당도를인정받았다 14. Light 등은중등증이상의 COPD 환자를대상으로하여 BDI와 State-Trait Anxiety Inventory (STAT) 15 를이용한설문조사에서우울증의빈도가 42% 로높았고, 환자군에서우울과불안심리는상관관계가높다고보고하였다 7. 또한, 최근에는 COPD환자에서의우울과불안심리의위험인자를찾아서조기에정신심리상태를진단하려는노력을하고있다 16-18. 따라서, 본연구에서는외래로추적중인 COPD환자를대상으로실제임상에서 BDI와 STAT를이용하여우울과불안심리를평가하고, 중증도에따른차이와우울증의위험인자를밝혀서치료과정에서우울증의조기진단으로환자가겪을수있는불안심리등정신사회적인문제점을해결하는데기여하고자하였다. 대상및방법 1. 연구대상 2005년 9월부터 2006년 8월까지이화여자대학교부속병원호흡기내과외래로내원하여 COPD로치료받고있는환자를대상으로하였다. 본연구에서는 COPD 환자의정의및중증도분류를 NHLBI/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) Workshop Summary 19 에나온국제지침기준을적용하였고, 폐기능검사결과는설문시기에급성호흡곤란의악화소견이없고안정된상태에서시행한검사결과를이용하였다. 성별과나이, 흡 연력과영양상태측정을위한체질량지수 (Body Mass Index, BMI(kg/m 2 ), albumin(g/dl) 을조사하였다. 대상환자군을중증도에따라비교하였는데, GOLD병기에따라 Stage 0을제외한 4군으로분류하였고, 폐기능검사를시행해서기관지확장제에대한 FEV 1 의호전이 200ml이상이면서 12% 이상기저치보다증가하는가역성을보이는경우와, 기존의정신질환의병력이있거나, 설문및검사를하기힘들며자발적동의를하지않은환자는대상에서제외하였다. 대조군은같은기간동안본원종합검진센터및호흡기내과외래에호흡기검진을위해내원후시행한문진에서호흡기증상이없고기저호흡기질환이나정신질환의병력이없으면서, 이학적검사및흉부방사선촬영과기관지확장제가역성검사를포함한폐기능검사에서정상이었고설문조사에자발적동의를하였던 50명을대상으로하였다. 2. 연구방법 1) 우울검사우울증에관한조사는국내에서타당도와신뢰도가검정된한글판 Beck Depression Inventory (BDI) 14 설문지를이용해서시행하였다. 한글판 BDI는우울의정서적, 인지적, 동기적, 생리적증상영역을포함하는총 21개의항목으로이루어져있고, 각항목에는우울증점수가가장낮은 0점에서 3점까지로구성되어있으며전체점수의범위는 0점에서 63점의범위내에있게된다. Beck이제시한 BDI점수분류기준은 0~9 점까지는우울하지않은상태, 10~15까지는가벼운우울상태, 16~23점까지는중한우울상태, 24~63점은심한우울상태라하였고 20, 15점이상을기준으로우울증으로진단하여보고한연구도있으나 7,9, 본연구에서는한국인을대상으로한자료를바탕으로한글판 BDI에서제시한 21점을우울증의진단기준으로사용하였다 14. 검사절차는검사자가피검자에게각문항을읽어주고그중에서자신을가장잘나타내는하나를고르도록해서그것을검사자가기록하도록하였다. 피검자도검사자와동일한설문지를배부받고그것을눈 12
Tuberculosis and Respiratory Diseases Vol. 62. No.1, Jan. 2007 으로읽도록하였고본연구에서는검사자가지시문 을읽어주고피검자가답하는방법을이해하는가를확인한뒤, 피검자스스로가각개별문항의설문에답하도록하였다. 2) 불안검사상태불안 (State Anxiety) 이란염려나긴장으로발생된즉각적인정서상태로즉, 현재발생된상황에따라변하는정서상태이며, 특성불안 (Trait Anxiety) 이란객관적으로위협적이지않은상황을위협적으로느끼는것으로후천적으로습득되어성격화된행동경향을말한다 15. 본연구에서는 Spielberger 가제작한 State-Trait Anxiety Inventory (STAT) 15 를한국상황에맞게번안하여표준화된검사도구를사용하였다 21. 이검사는상태불안을측정하는 20문항과특성불안을측정하는 20문항으로총 40문항으로구성되어있고각문항은 4점척도로구성되어있다. 개인이얻을수있는점수범위는상태불안과특성불안이각각 20점에서 80점으로점수가높을수록불안수준이높은것을의미하며, Spielberger 는일반인구에서평균 50 점, 표준편차 10으로보고하였으나 15, 불안장애를진단하는정해진절단점은없다. 검사절차는상기우울검사와같게시행하였다. 3. 통계분석통계처리는 SPSS for Windows 13.0 통계프로그램을이용하였고, p 값이 0.05보다작은경우에통계적으로유의한차이가있다고판단하였다. 연속변수인경우에환자군과대조군간의, 혹은환자군내의중증도에따른여러변수에대한비교는 student t-test, 혹은 Mann-Whitney U test를이용하여비교하였고, 명목변수에서는 Pearson chi-square test 혹은 Fisher's exact test, linear by linear association를이용하여분석하였다. 환자군내에서우울증여부에따라통계적으로두군간차이를보였던변수들에대해다변량로지스틱회귀분석을시행하였고, 환자군내에서우울증의위험요인비차비 (odds ratio) 와 95% 신뢰구간을산출하였다. 결과 1. 대상환자및대조군의특성대상환자군은총 72명으로 GOLD병기중증도분류상경증 22명, 중등증 20명, 중증 25명, 심한중증이 5 Table 1. Demographic and clinical characteristics in general population and patients with chronic obstructive pulmonary disease (COPD), grouped according to Global Initiative for Chronic Obstructive Lung Disease staging. Variables Control (n=50) Mild-to-moderate (n=42) COPD Severe-to-very severe (n=30) Total (n=72) p value * Age, years 63±9 67±9 65±12 66±9 0.055 Male sex 20 39 29 68 < 0.001 Body mass index (BMI, kg/m 2 ) 23.8±3.2 23.5±2.9 21.6±2.8 # 22.7±3.0 0.084 Smoking history Never smoker Ex-smoker Current smoker Post-bronchodilator FEV 1, %pred FEV 1/FVC ratio 41 8 1 106.3±15.6 79.7±6.0 0 26 16 80.2±16.2 75.0±16.5 0 21 9 0 47 25 36.8±7.2 # 38.5±7.7 # 62.1±25.3 50.6±13.3 < 0.001 < 0.001 < 0.001 Albumin, g/dl 4.2±0.4 4.1±0.5 4.1±0.4 4.1±0.5 0.990 Values are expressed as means±sd, medians (ranges) or frequencies (%). * : When compared between COPD and general population. # p value<0.05 when compared between mild-to-moderate and severe-to-very severe group of COPD 13
YJ Ryu et al: Depression and anxiety in COPD 명이었다. 환자군에서남자가 94% 로대조군에서 40% 에비해남자의분포가높았고 (p<0.001), 두군간의평균연령은대조군 63세, 환자군 66세의고령으로통계적으로유의한차이를보이지않았다. 환자군과대조군간에체질량지수는유의한차이가없었으며, 환자군내에서는중증이상의환자군이중등증이하의환자군에비해유의하게낮았다 (p=0.011). 혈청알부민수치도대조군에서 4.2±0.4g/dl로환자군의 4.1±0.5g/ dl과비교하여차이를보이지않았다. 대조군의흡연력은과거흡연력과현재흡연력을합하여 18%(9/50) 이었고기관지확장제사용후 FEV 1 의예측치는 106.3±15.6% 로측정되었다 (Table 1). 2. 우울과불안심리비교분석우울심리평가에서 BDI점수의중간값이환자군 16(0-37), 대조군 12(1-30) 으로환자군에서유의하게높은우울증점수를보였으며 (p=0.001), COPD 환자군내에서중증도별로분류하여보았을때경중등증환자군보다중증이상의환자군에서유의하게높았다 (p=0.01). BDI점수 21점을기준으로우울증진단시에환자군에서 36% 로대조군의 6% 에비해우울증의빈도가월등히높았다 (p<0.0001). 환자군을중증도별로 4군으로분류했을때경증군 18%(4/22), 중등증군 30%(6/20), 중증군 52%(13/25), 심한중증군 60% (3/5) 로우울증의빈도가질환의중증도가높아질수 록높았고 (p=0.008), 중증이상의환자군에서 53% (16/30) 으로경증및중등증군 24%(10/42) 에비해서유의하게높았다 (p=0.01) (Table 2). 불안심리평가에서상태불안과특성불안이환자군에서각각 44(20-67) 와 47(20-66) 로대조군의 39 (26-65), 44(33-90) 에비해각각유의하게높았다 (p=0.005, p=0.022) (Table 2). Spielberger 가 15 상태불안과특성불안점수에서각각일반인구의평균점수로보고한 50점보다높은수치를보인경우는, 환자군에서대조군에비해상태불안은약 7배로높았고 (p=0.006), 특성불안은약 4배로높은빈도를보였다 (p=0.013) (data not shown). 환자군에서중증도별로비교시에중증이상의환자군에서중등증이하의환자군에비해상태불안과 (p<0.0001) 특성불안점수 (p=0.001) 모두유의하게높았다 (Table 2). 3. COPD 환자군에서우울증의위험인자분석환자군을대상으로우울증점수에서 21점을기준으로 14 우울집단과비우울집단으로이분하여임상적특성을비교하였다. 두군간에연령과성별의차이는없었으나, 체질량지수가우울집단에서유의하게낮았다 (p=0.013). 흡연력의비교에서흡연갑년의차이는보이지않았으나, 우울집단에서현재흡연자가 50% (13/26) 로비우울집단의 26%(12/46) 에비해유의하게높았다 (p=0.041). 우울집단에서기관지확장제사용후 Table 2. Psychological status of depression and anxiety in general population and patients with chronic obstructive pulmonary disease (COPD), grouped according to Global Initiative for Chronic Obstructive Lung Disease staging. Variables Beck Depression Inventry (BDI) Total score BDI 21 State-Trait Anxiety Inventory (STAI) State anxiety score Trait anxiety score Control (n=50) 12(1-30) 3(6%) 39(26-65) 44(33-90) Mild-to-moderate (n=42) 14(3-34) 10(24%) 42(26-63) 46(32-66) COPD Severe-to-very severe (n=30) 21(0-37)# 16(53%)# 48(20-67)# 50(20-62)# Values are expressed as means±sd, medians (ranges) or frequencies (%). *: When compared between COPD and general population. # p value<0.05 when compared between mild-to-moderate and severe-to-very severe group of COPD Total (n=72) 16(0-37) 26(36%) 44(20-67) 47(20-66) p value * 0.001 <0.0001 0.005 0.022 14
Tuberculosis and Respiratory Diseases Vol. 62. No.1, Jan. 2007 Table 3. Clinical characteristics of patients with chronic obstructive lung disease (COPD) with or without depression by the BDI scoring. Variables BDI < 21 (n=46) BDI 21 (n=26) Total (n=72) p value Age, years Male sex Body Mass Index (kg/m 2 ) Smoking, packyears Current smoker Post-bronchodilator FEV 1, %pred COPD stage Mild Moderate Severe Very severe State anxiety score Trait anxiety score 66±10 44(96) 23.3±2.7 40±20 12(26) 68.8±24.3 18(40) 14(30) 12(26) 2(4) 42(20-56) 45(20-58) Values are expressed as means±sd, medians (ranges) or frequencies (%). 66±7 24(92) 21.5±3.3 42±17 13(50) 50.4±22.9 4(15) 6(23) 13(50) 3(12) 50(31-67) 51(37-66) 66±9 68 22.7±3.0 40±19 25(35) 62.1±25.3 22(30) 20(28) 25(35) 5(7) 44(20-67) 47(20-66) 0.769 0.616 0.013 0.593 0.041 0.002 0.008 <0.001 0.001 Table 4. Predictive factors of depression in patients with chronic obstructive lung disease (COPD). Variables Odds ratio (95% CI) p value Age, year Male sex Body Mass Index (kg/m 2 ) Current smoker COPD severity Severe-to-very severe 1.000 (0.935-1.070) 0.703 (0.065-7.570) 0.893 (0.718-1111) 3.191 (0.993-10.261) 3.898 (1.166-12.895) 0.993 0.771 0.311 0.051 0.027 FEV 1 의예측치가유의하게낮았고 (p=0.002), 높은중증도를보였다 (p=0.008). 상태불안과특성불안점수모두우울집단에서비우울집단에비해유의하게높은불안수치를보였다 (Table 3). 우울증의요인분석을위해서다변량로지스틱회귀분석을이용하여연령과성을통제한상태에서, 우울증관련변수로 (Table 3) 환자의체질량지수, 현재흡연여부, COPD 질환의중증도를분석하였다. 중증이상의 COPD 환자는그렇지않은환자에비해우울증이있을확률이 4배정도로유의하게높았고 (p=0.027), 현재흡연중인환자인경우에는약 3배로높은경향을보였다 (p=0.051). 고찰우울증과불안장애는삶의질을떨어뜨리고잠재적으로는치명적일수있는질병이며만성질환에서흔하게동반되어나타난다. COPD는만성질환중에서 정신행동학적으로크게영향을받는질환중하나로일반인구에비해우울증이흔해서 16-42% 7-10,22,23, 불안장애는 2-50% 로알려져있으며 3,7,23 COPD환자들중우울증으로진단된경우, 이중 37% 는동시에불안심리도높음이보고되었다 22. 본연구에서도전체대상환자들의 36% 가우울집단에포함되었고이들은비우울집단에비해서불안심리정도도높았다. COPD 는지속적으로관리가요구되며완치가불가능한만성적질환으로서금연과투약및흡입치료등지속적인노력과반복적인급성악화등으로많은정신적갈등을겪게된다. 또한, 우울증및공황장애의치료제로사용되는항정신성약물이심한중증의 COPD환자치료에효과를보인연구결과들은호흡병태생리와우울및불안등의정신심리학적관련성을보고하고있다 24-26. 임상적으로우울증이있는 COPD환자에서는치료에대한순응도가떨어지고불량한치료예후와사망률증가에관련됨이보고되었다 3-6. 따라서 COPD환자 15
YJ Ryu et al: Depression and anxiety in COPD 의치료중우울및불안장애의조기진단을통해치료순응도개선과정신과적인협진으로증상의개선을도모할수있을것으로생각된다. 본연구에서사용한선별검사도구들은 13,15 세계적으로널리사용되면서국내실정에맞게표준화되어있는자기보고형평가도구로서 14,21, 우울증과불안장애를선별해내는것이숙련된임상가의정확한진단을대신할수는없으나, 정신과의사가아니더라도우울증여부나불안정도를쉽게평가할수있고실시와채점이쉽고경제적이다. 또한이미국외에서는 COPD 환자들에서 BDI와 STAI를이용한우울등과불안장애연구가보고되었다 7-9,15. COPD 환자의우울증에영향을미치는여러인자를이해하는것이우울증을빨리진단하고치료할수있게하며호흡재활치료의결과를좋게할수있다. 우울증을유발하는요인은생물학적및신체적요인, 심리학적요인, 환경적요인등이복합적으로작용하여유발된다. 본연구의제한점으로교육이나경제적수준, 사회적지위, 결혼상태등의요인들을배제해서사회경제적수준의영향을알수없었고, 불안장애의유병률은파악하지못해서다른연구와불안장애의유병률을파악하지는못했다. 그러나불안점수가대조군에비해유의하게높았으며, 현재발생된상황에따라변하는일시적일수있는상태불안과함께, 후천적으로습득되어성격화된특성불안점수도높았음을알수있었다. 본연구에서도우울증이있는환자의경우불안점수가유의하게높아기존의연구결과와 비슷했고 7,22 우울증과관련된요인으로환자의체질 량지수와현재흡연력, 폐기능에따른중증도분류가있었으나, 독립적위험인자는 COPD 병기의높은중증도로분석되었다. COPD의중증도별로우울증빈도를분석한연구에서 Wagena 등은 9 중증이상의 COPD 환자들이 37% 로경중등증군의 22% 보다높은빈도를보고하였고, van Manen 등의 18 연구에서는차이가크진않으나중증인경우가 25% 로경중등증군 20% 보다약간높았다. 본연구에서는경중등증환자에서 24%, 중증이상에서 53% 로뚜렷하게중증군에서우울증빈도가높았고, 유일한우울증의위험요인이었다. COPD 환자군에서우울증과불안장애를함께연구한 결과에서 17,27 우울과불안의위험요인으로서여성, 현재흡연력, GOLD병기의높은중증도가보고되었고, 또한 COPD환자의우울증의위험요인을조사한연구에서는 16,18 여성, 중증의병기, 25이상의체질량지수를보고하였다. 이러한요인들이 COPD 환자의삶의질을감소시키며우울증과불안장애를증가시키는것으로알려져있고, 본연구결과와크게다르지않았다. 본연구결과는외래치료중인 COPD 환자군에서의우울증의빈도와불안심리정도가 COPD를포함한기존의폐질환이없는대조군에비해높으며, 특히같은환자군에서도중증도가높은환자들에서우울증과불안점수가높아서중증일수록우울및불안장애의진단과관리가필요함을보여주었다. 또한현재흡연중인 COPD 환자에서우울증의빈도가높은경향을보여흡연환자를대상으로적극적인금연과정신심리학적접근의필요성을다시한번부각시켰다. COPD환자에서조기에우울증및불안장애를평가하고위험요인을분석하여, 치료과정에서기존의흡입및투약치료와함께정신심리치료의조기개입을병행하여치료효과를증진시키는데기여할수있을것으로생각되며 28,29, 추후의연구에서는간단한선별검사를이용하여진단한우울증및불안장애의치료가실제로임상에서 COPD 환자의예후및삶의질에어떤영향을미치는지후향적인평가가필요할것으로사료된다. 요약연구배경 : 만성폐쇄성폐질환 (chronic obstructive pulmonary disease, COPD) 환자군에서우울증및불안장애의유병률이높고, 이는치료경과및사망률에도영향을주는것으로알려져있다. 저자들은국내연구가미비한 COPD 환자들의우울과불안심리에대한평가를하고자하였다. 방법 : 2005년 9월부터 2006년 8월까지이화의료원호흡기내과에서외래치료중인 72명의 COPD환자와정상대조군 50명에서 Beck Depression Inventory (BDI) 와 State-Trait Anxiety Inventory (STAI) 로설문조사를시행하였고, 임상기록을분석하였다. 결과 : 1) 연령과체질량지수, 혈청알부민수치는 16
Tuberculosis and Respiratory Diseases Vol. 62. No.1, Jan. 2007 환자군과대조군간의유의한차이를보이지않았다 (p>0.05). 우울심리는 BDI점수가환자군 16(0-37), 대조군 12(1-30) 으로환자군에서유의하게높았고 (p=0.001), 21점이상의우울집단은환자군이 36% 로대조군 6% 에비해많았다 (p<0.0001). 환자군에서는경증군 18%(4/22), 중등증군 30%(6/20), 중증군 52%(13/25), 심한중증군 60%(3/5) 로중증일수록빈도가높았다 (p=0.008). 2) 불안심리는환자군에서 SAI 점수 44(20-67), TAI점수 47(20-66) 로각각대조군 39(26-65), 44(33-90) 보다유의하게높았다 (p=0.005, p=0.022). 환자군에서 BDI와 STAI 점수는상관관계를보였고 (p<0.001), 우울집단에서불안점수가유의하게높았다. 3) COPD환자군에서우울집단은비우울집단보다체질량지수, 기관지확장제후 FEV 1 의예측치가유의하게낮았고, 현재흡연자의비율과중증도, STAI점수가유의하게높았다 (p<0.05). 4) 연령과성별을통제한다변량로지스틱회귀분석상 95% 신뢰구간으로비차비는체질량지수 0.9(p=0.311), 현재흡연자 3.2(p=0.051), 중증군이상 3.9로 (p=0.027), 중증이상의중증도가유일한우울증발생의독립적위험요인이었다. 결론 : COPD환자군에서우울증과불안심리가흔하게관찰되며, 체질량지수, 폐기능, 현재흡연력이우울관련요인으로특히중증도가높을수록우울증과불안장애의관리가필요함을보여주었다. 참고문헌 1. Murray CJ, Lopez AD. Alternative projections of mortality and disability by cause 1990-2020: Global Burden of Disease Study. Lancet 1997;349:1498-504. 2. Kim DS, Kim YS, Jung KS, Chang JH, Lim CM, Lee JH, et al. Prevalence of chronic obstructive pulmonary disease in Korea: a population-based spirometry survey. Am J Respir Crit Care Med 2005;172:842-7. 3. Dahlen I, Janson C. Anxiety and depression are related to the outcome of emergency treatment in patients with obstructive pulmonary disease. Chest 2002;122:1633-7. 4. Gudmundsson G, Gislason T, Janson C, Lindberg E, Hallin R, Ulrik CS, et al. Risk factors for rehospitalisation in COPD: role of health status, anxiety and depression. Eur Respir J 2005;26:414-9. 5. Crockett AJ, Cranston JM, Moss JR, Alpers JH. The impact of anxiety, depression and living alone in chronic obstructive pulmonary disease. Qual Life Res 2002;11:309-16. 6. Stage KB, Middelboe T, Pisinger C. Depression and chronic obstructive pulmonary disease (COPD): impact on survival. Acta Psychiatr Scand 2005;111: 320-3. 7. Light RW, Merrill EJ, Despars JA, Gordon GH, Mutalipassi LR. Prevalence of depression and anxiety in patients with COPD: relationship to functional capacity. Chest 1985;87:35-8. 8. Kunik ME, Roundy K, Veazey C, Souchek J, Richardson P, Wray NP, et al. Surprisingly high prevalence of anxiety and depression in chronic breathing disorders. Chest 2005;127:1205-11. 9. Wagena EJ, Arrindell WA, Wouters EF, van Schayck CP. Are patients with COPD psychologically distressed? Eur Respir J 2005;26:242-8. 10. van Ede L, Yzermans CJ, Brouwer HJ. Prevalence of depression in patients with chronic obstructive pulmonary disease: a systematic review. Thorax 1999;54: 688-92. 11. Borson S, Claypoole K, McDonald GJ. Depression and chronic obstructive pulmonary disease: treatment trials. Semin Clin Neuropsychiatry 1998;3:115-30. 12. Chung KH, Kim JH, Hah ES, Kim SJ, Lee KJ, Lee SH, et al. Frequency and clinical characteristics of depression and anxiety disorder in COPD patients. Tuberc Respir Dis 2005;59(Suppl 2):62. 13. Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory for measuring depression. Arch Gen Psychiatry 1961;4:561-71. 14. Han HM, Yum TH, Shin YW, Kim KH, Yoon DJ, Chung KJ. A standardization study of back depression inventory in Korea. Neuropsychiatry 1986;25:487-98. 15. Spielberger CD, Gorsuch RL, Lushene RE. State-trait anxiety inventory for adults(form x). CA: Consulting Psychologistspress 1970. 16. Chavannes NH, Huibers MJ, Schermer TR, Hendriks A, van Weel C, Wouters EF, et al. Associations of depressive symptoms with gender, body mass index and dyspnea in primary care COPD patients. Fam Pract 2005;22:604-7. 17. Gudmundsson G, Gislason T, Janson C, Lindberg E, Suppli Ulrik C, Brondum E, et al. Depression, anxiety and health status after hospitalisation for COPD: a multicentre study in the Nordic countries. Respir Med 2006;100:87-93. 18. van Manen JG, Bindels PJ, Dekker FW, Ijzermans CJ, van der Zee JS, Schade E. Risk of depression in 17
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