馬辰星,康向輝(綜述),張景義(審校)
(河北聯(lián)合大學(xué)附屬開灤總醫(yī)院 a.內(nèi)分泌科, b.口腔科, 河北 唐山 063000)
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下調(diào)空腹血糖截點(diǎn)對(duì)早期診斷糖尿病的價(jià)值
馬辰星a△,康向輝b(綜述),張景義a※(審校)
(河北聯(lián)合大學(xué)附屬開灤總醫(yī)院 a.內(nèi)分泌科, b.口腔科, 河北 唐山 063000)
摘要:近年來(lái),糖尿病發(fā)病率逐年上升,且發(fā)病年齡有逐年下降的趨勢(shì)??崭寡窃\斷糖尿病具有快速、經(jīng)濟(jì)、簡(jiǎn)便和易被受檢者接受的特點(diǎn),一直被臨床廣泛應(yīng)用。目前,世界衛(wèi)生組織制訂的空腹血糖診斷糖尿病標(biāo)準(zhǔn)依然偏高,導(dǎo)致漏診率很高。選擇一個(gè)合理的早期診斷糖尿病的空腹血糖截點(diǎn)成為研究的熱點(diǎn)問(wèn)題。該文就近年來(lái)國(guó)內(nèi)外文獻(xiàn)對(duì)空腹血糖與糖尿病并發(fā)癥的關(guān)系,以及下調(diào)空腹血糖截點(diǎn)對(duì)早期診斷糖尿病的價(jià)值進(jìn)行了綜述。
關(guān)鍵詞:糖尿?。豢崭寡?;截點(diǎn);早期診斷
1965年,對(duì)Pima印第安人的研究顯示,空腹血糖和葡萄糖負(fù)荷后2 h血糖(PG 2 h)呈雙峰曲線,奠定了糖尿病的診斷標(biāo)準(zhǔn)[1];1979年,美國(guó)國(guó)家糖尿病數(shù)據(jù)組制訂并發(fā)表了糖尿病診斷標(biāo)準(zhǔn)及分型[2];世界衛(wèi)生組織于1980年對(duì)美國(guó)國(guó)家糖尿病數(shù)據(jù)組診斷標(biāo)準(zhǔn)進(jìn)行適當(dāng)修改后并予以采納;1985年,世界衛(wèi)生組織將診斷標(biāo)準(zhǔn)進(jìn)行修訂,并得到廣泛認(rèn)可和應(yīng)用[3]。經(jīng)過(guò)十多年的臨床應(yīng)用后,許多研究發(fā)現(xiàn)空腹血糖≥7.8 mmol/L與PG 2 h≥11.1 mmol/L在糖尿病診斷中缺乏良好的一致性;Pima印第安人等4項(xiàng)流行病學(xué)研究資料表明,以PG 2 h≥11.1 mmol/L為糖尿病診斷的金標(biāo)準(zhǔn),那么最匹配的空腹血糖截點(diǎn)應(yīng)在6.7~7.0 mmol/L[4~7]。因此,1997年美國(guó)糖尿病協(xié)會(huì)提出空腹血糖診斷截點(diǎn)應(yīng)該下調(diào)至7.0 mmol/L;1999年世界衛(wèi)生組織正式采納該建議,形成當(dāng)今仍在沿用的診斷標(biāo)準(zhǔn)[8]。雖然該標(biāo)準(zhǔn)將空腹血糖僅下調(diào)了0.8 mmol/L,但卻能使20%的患者免于漏診,具有劃時(shí)代的臨床意義。現(xiàn)就空腹血糖與糖尿病并發(fā)癥關(guān)系的研究進(jìn)行予以綜述。
1空腹血糖與血管并發(fā)癥
糖尿病的診斷標(biāo)準(zhǔn)是依據(jù)糖尿病性血管病變的發(fā)生率制訂的[1,4]。因此,空腹血糖與糖尿病性血管并發(fā)癥之間存在一定的相關(guān)性。糖尿病微血管并發(fā)癥(視網(wǎng)膜病變、腎病等)是致殘和降低糖尿病患者生活質(zhì)量的主要危險(xiǎn)因素之一,而80%的2型糖尿病患者死于糖尿病大血管并發(fā)癥——心血管疾病[9]。早期診斷糖尿病、積極控制血糖對(duì)延緩糖尿病慢性并發(fā)癥具有重要意義,并能真正降低糖尿病血管并發(fā)癥的致殘率和病死率。
1.1空腹血糖與心血管疾病一方面,心血管并發(fā)癥是導(dǎo)致糖尿病死亡的重要原因之一[10];另一方面,糖尿病又是心血管疾病重要的獨(dú)立危險(xiǎn)因素[11]。眾所周知,三酰甘油是預(yù)測(cè)冠狀動(dòng)脈粥樣硬化性心臟病(冠心病)的重要指標(biāo),有研究顯示, 空腹血糖和空腹三酰甘油呈正相關(guān),并且是餐后三酰甘油的一個(gè)重要預(yù)測(cè)指標(biāo)[12]。因此,再次印證空腹血糖是冠心病的獨(dú)立危險(xiǎn)因素。另有研究顯示,即使正常人群和空腹血糖增高但未達(dá)到7.0 mmol/L 的人群,心血管疾病的發(fā)生風(fēng)險(xiǎn)與空腹血糖升高也呈線性正相關(guān)[13-14]。另外,一項(xiàng)涉及70萬(wàn)非糖尿患者、102個(gè)前瞻性研究的薈萃分析結(jié)果表明,空腹血糖與心血管疾病的發(fā)生風(fēng)險(xiǎn)均呈現(xiàn)一個(gè)溫和的非線性增加趨勢(shì)[15]。不但糖尿病早期空腹血糖的增高能夠增加心血管疾病病死率[16],而且糖尿病的病程與心血管病死率也呈顯著正相關(guān)[15]。盡早篩查空腹血糖、早期使血糖控制達(dá)標(biāo),并盡早干預(yù)生活方式,對(duì)減少心血管疾病的發(fā)生更有意義[17]。
1.2空腹血糖與視網(wǎng)膜病變糖尿病性視網(wǎng)膜病變(diabetic retinopathy, DR)是一種可早期診斷的致盲性眼病。雖然DR發(fā)病率很高,但知曉率卻很低,就診率更低,晚期治療效果不理想,造成了高致盲率,從而給患者帶來(lái)極大痛苦。我國(guó)40歲以上糖尿病患者中DR的患病率約為37%[18];而2005年至2008年,美國(guó)≥40歲的成年人DR的患病率約為28.5%[19];在非洲糖尿病患者中DR的患病率為30.2%~31.6%[20]。當(dāng)糖尿病患者血糖達(dá)到一定閾值時(shí),容易發(fā)生微血管并發(fā)癥,從而使DR的發(fā)生風(fēng)險(xiǎn)顯著增加。Tapp等[21]從澳大利亞隨機(jī)選擇42個(gè)地區(qū)且年齡≥25歲的成年人,進(jìn)行視網(wǎng)膜病變的評(píng)估,得出結(jié)論:當(dāng)空腹血糖>6.6 mmol/L,DR的患病率已經(jīng)呈現(xiàn)上升趨勢(shì);當(dāng)空腹血糖>7.1 mmol/L,DR的患病率上升趨勢(shì)更加顯著。Colagiuri等[22]對(duì)來(lái)自5個(gè)國(guó)家9項(xiàng)研究的44 623例患者(年齡20~79歲)的可分級(jí)視網(wǎng)膜照片數(shù)據(jù)匯集進(jìn)行了分析,建議糖尿病的空腹血糖診斷截點(diǎn)應(yīng)下降為6.5 mmol/L。東亞人口中唯一使用眼科檢查的糖尿病研究表明,最佳診斷糖尿病的空腹血糖截點(diǎn)應(yīng)為 6.4 mmol/L[23]。
1.3空腹血糖與糖尿病腎病糖尿病性腎病是糖尿病最嚴(yán)重的并發(fā)癥之一,在我國(guó),終末期腎病患者中糖尿病腎病約占15%。眾所周知,尿微量白蛋白是糖尿病早期腎臟損害的靈敏指標(biāo),也是判斷糖尿病性腎病預(yù)后的重要指標(biāo)。Tapp等[21]對(duì)某研究人群進(jìn)行了微量白蛋白尿的評(píng)估,結(jié)果表明空腹血糖>6.6 mmol/L,糖尿病性腎病的患病率明顯上升。
2空腹血糖與PG 2 h
許多研究均顯示,空腹血糖與PG 2 h呈線性正相關(guān)[4,24-25]。如果以PG 2 h≥11.1 mmol/L為糖尿病診斷的金標(biāo)準(zhǔn), 那么最匹配的空腹血糖截點(diǎn)為6.4 mmol/L[23]和6.8 mmol/L[4], 均<7.0 mmol/L。也就是說(shuō),通過(guò)空腹血糖可大概估計(jì)其PG 2 h血糖情況。然而,食物血糖生成指數(shù)的差異和個(gè)人飲食結(jié)構(gòu)的不同,可對(duì)PG 2 h造成不同的影響[26-27],致使單純測(cè)量PG 2 h值將導(dǎo)致較大的測(cè)量誤差。另外,PG 2 h也存在測(cè)量不方便、不易被人群接受等缺點(diǎn),所以PG 2 h不適合作為篩查糖尿病的首要方法??崭寡菧y(cè)量方便、經(jīng)濟(jì)、易被廣大人群接受,并且混雜因素容易控制,不存在飲食差異對(duì)血糖測(cè)量結(jié)果的干擾,結(jié)果更快速、可靠。因此,空腹血糖比PG 2 h更適合作為早期篩查及診斷糖尿病的首要手段。
3空腹血糖與糖化血紅蛋白
目前,空腹血糖與糖化血紅蛋白在糖尿病篩查及診斷意義方面的研究,均以空腹血糖≥7.0 mmol/L為標(biāo)準(zhǔn),得出糖化血紅蛋白診斷糖尿病等效于甚至優(yōu)于空腹血糖的結(jié)果[28-29]。類似研究未闡述血紅蛋白病、溶血性疾病或其他與紅細(xì)胞壽命縮短等對(duì)糖化血紅蛋白的測(cè)定結(jié)果會(huì)產(chǎn)生何種影響[30-31]。
4空腹血糖截點(diǎn)的爭(zhēng)議
雖然空腹血糖≥7.0 mmol/L作為診斷糖尿病的截點(diǎn)在全世界范圍內(nèi)廣泛使用,但這個(gè)截點(diǎn)仍然不完美,有許多的受檢者漏診。Pima印第安人和美國(guó)國(guó)家健康及營(yíng)養(yǎng)調(diào)查研究Ⅲ發(fā)現(xiàn),空腹血糖最佳診斷截點(diǎn)為6.8 mmol/L和6.7 mmol/L[4,7]。近年來(lái),一些學(xué)者認(rèn)為,1999年世界衛(wèi)生組織空腹血糖診斷標(biāo)準(zhǔn)空腹血糖≥7.0 mmol/L偏高,空腹血糖診斷截點(diǎn)降至6.5 mmol/L更為合理[22]。日本久山研究表明,東亞人診斷糖尿病的空腹血糖最佳截點(diǎn)為6.4 mmol/L[23]。韓國(guó)一項(xiàng)研究顯示,診斷糖尿病的空腹血糖最佳截點(diǎn)是6.1 mmol/L[32]。澳大利亞的研究表明,雖然空腹血糖>6.6 mmol/L,DR的患病率就已經(jīng)有了較明顯地上升,但當(dāng)空腹血糖>7.1 mmol/L后,DR的患病率才呈現(xiàn)顯著上升趨勢(shì)[21]。同樣,我國(guó)北京市的一項(xiàng)橫斷面研究也顯示了同樣結(jié)果,空腹血糖>6.6 mmol/L,DR患病率有所上升,當(dāng)空腹血糖>7.2 mmol/L后,DR的患病率急劇上升[33]。這兩項(xiàng)研究均認(rèn)為,當(dāng)前世界衛(wèi)生組織的診斷截點(diǎn)是合理的。
5小結(jié)
近年來(lái),中國(guó)的糖尿病患病率大幅增加,有很多患者沒(méi)有被及時(shí)發(fā)現(xiàn),人群中未確診的糖尿病患者人數(shù)眾多,估計(jì)可達(dá)到總患病人數(shù)的50%[34]。糖尿病患者在出現(xiàn)臨床癥狀以前有較長(zhǎng)的臨床前期階段,而一旦診斷為糖尿病,一部分患者已經(jīng)合并了糖尿病慢性并發(fā)癥。目前,甚至有使用現(xiàn)有的醫(yī)療計(jì)劃數(shù)據(jù),開發(fā)和驗(yàn)證識(shí)別2型糖尿病高危個(gè)體的預(yù)測(cè)方程的研究項(xiàng)目[35]。可見,全世界范圍內(nèi)對(duì)糖尿病非常重視,糖尿病需要早期篩查、診斷,盡早使血糖控制達(dá)標(biāo),從而延緩并發(fā)癥的發(fā)生和發(fā)展。因此,如何選擇一個(gè)合理的空腹血糖診斷截點(diǎn),從而更有效地早期診斷糖尿病成為值得進(jìn)一步探討的問(wèn)題。
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Study on the Value of Down-regulating the Cut-off Point of Fasting Blood Glucose in Early Diagnosis of Diabetes
MAChen-xinga,KANGXiang-huib,ZHANGJing-yia.
(a.DepartmentofEndocrinology,b.DepartmentofStomatology,KailuanGeneralHospitalAffiliatedtoHebeiUnitedUniversity,Tangshan063000,China)
Abstract:In recent years,the incidence of diabetes has been increasing year by year,and the age of onset has a downward trend.Detection of fasting blood glucose has been widely used in clinical to diagnose diabetes due to its characteristics of fast,economical,simple,and easily accepted.Currently,the WHO diagnostic criteria of fasting blood glucose for diabetes remains high,which leads to high rate of misdiagnosis,so choosing a reasonable cut-off point of fasting blood glucose for early diagnosis of diabetes has become a hot research spot.Here is to make a review of relationship between fasting blood glucose and diabetes complications,and the value of down-regulating the cut-off point of fasting blood glucose in early diagnosis of diabetes basing on recent literatures worldwide.
Key words:Diabetes mellitus; Fasting blood glucose; Cut-off point; Early diagnosis
收稿日期:2014-03-19修回日期:2014-07-30編輯:鄭雪
doi:10.3969/j.issn.1006-2084.2015.07.043
中圖分類號(hào):R587.1
文獻(xiàn)標(biāo)識(shí)碼:A
文章編號(hào):1006-2084(2015)07-1263-03