Chronic obstructive pulmonary disease (COPD) is, and will remain, a global health problem as far as we can prognosticate. In the developed world (in contrast to the other big killers: coronary artery disease, cancer and cerebrovascular accident) COPD has the dubious honour of maintaining unabated and continued growth1,2。Because the transfer of wealth from more developed to lesser developed countries is associated with a shift in the health pattern of those societies to resemble that of the richer ones, it is only reasonable to expect similar changes in the causes of death over time in the most populated parts of our globe. The completion of spirometrically defined surveys in different parts of the world, through the PLATINO project in Latin America3以及阻塞性肺病(BOLD)倡议的负担4, have provided a cross-sectional picture of the state of the world with regard to COPD, which can be summarised as follows: COPD is highly prevalent, its prevalence varies by regions, and whether it is due to cigarette smoking or environmental exposure COPD is consistently under-diagnosed, under-treated and its research under-funded. There is no epidemiologically sound longitudinal follow-up of populations that can provide an accurate picture of the success, or failure, of the efforts that over the past decades have been made to prevent and treat COPD.
While estimates based on data modelling present a very bleak picture of the effect of COPD on society2, this issue of theEuropean Respiratory Journal首次提供来自两个不同时间点的两个不同横截面研究的一些数据,旨在确定欧洲不同地区COPD的患病率5,6。作为我的永久乐观主义者,两项研究的结果向我表明,玻璃杯已经满了一半,并且有谨慎的理由。
The first of the two studies was conducted in Spain and reported by Sorianoet al.5。This group re-analysed the data of two cross-sectional population-based studies conducted 10 yrs apart. The first one, the IBERPOC study (n = 4,030), was conducted in 1997, and the second, the EPI-SCAN study (n = 3,802), was completed in 2007. Poorly reversible airflow obstruction compatible with COPD for the two studies was defined according to the old European Respiratory Society (ERS) definitions. The estimated COPD prevalence in the population 40–69 yrs of age dropped from 9.1% (95% CI 8.1–10.2) in 1997 to 4.5% (95% CI 2.4–6.6), a hard to believe 50.4% decline. In addition, using the Global Initiative for Chronic Obstructive Lung Disease/American Thoracic Society/ERS staging system the authors documented that the distribution of COPD prevalence by severity also changed from 38.3% mild, 39.7% moderate and 22% severe in 1997 to 85.6% mild, 13% moderate and 1.4% severe in 2007; and in the 40–69 yr EPI-SCAN sub-sample to 84.3% mild, 15% moderate and 0.7% severe. In addition, the under-diagnosis was reduced from 78% to 73% (nonsignificant) and under-treatment from 81% to 54% (p<0.05) within this 10-yr epoch. Unfortunately, the proportion of subjects reporting being smokers had increased from 25% to 29% over the 10 yrs, but the total pack years of smoking had decreased from an average of 36 to 25 pack-yrs.
The second of the studies was completed in Finland and reported by Vasankariet al.6。They compared the prevalence rates and the potential determinants of COPD in two population surveys performed 20 yrs apart. The first one, conducted in 1978–1980, included 6,364 subjects with acceptable spirometry aged 30–74 yrs. The second survey, conducted 20 yrs later (2000–2001), included 5,495 participants of similar age groups. Airway obstruction was defined as ratio of forced expiratory volume in 1 s (FEV1) to forced vital capacity below the lower limit of normal, and staged for severity on the basis of FEV1%的预测。的年龄调整患病率of obstruction were rather similar in both surveys in males (4.7%versus4.3%;p = 0.25),但在后一种调查中,女性的调查几乎明显更高(2.2%versus3.1%;p = 0.06)。1978 - 1980年的COPD II期或更高率为3.9%,男性为3.6%(男性为P = 0.36),女性分别为1.4%和1.5%(P = 0.93)。总体而言,在相似的基于人群的相似调查相距20年之间,COPD阶段II – IV的患病率没有显着差异。在这项研究中,吸烟者的比例从38%显着下降到34%。对与气流限制有关的因素的评估包括年龄,吸烟,低体重指数(BMI),低教育水平,哮喘和结核病病史。
The two studies are far from perfect in that they were not planned and conducted under a longitudinal follow-up design, no bronchodilators were used in the Finnish study, different spirometers were used in the Spanish study and the definition of obstruction and predictive values differed not only in the two studies but also in between the surveys at the two sites. In spite of that, the findings provide information that appears common to both studies. First, the prevalence of COPD appears to be stabilising or even decreasing. Unfortunately, this is clearly the case for males while it is alarming that it is not true for females. Secondly, most of the detected cases represent patients in the milder stages, where the gain of primary and secondary prevention and the response to treatment may be greatest. Thirdly, the basic anthropometrics of the two populations had changed over time. In both countries, the height increased by 3 cm, the BMI was higher and, at least in the study where it was evaluated (the Finnish study), the history of previous tuberculosis was significantly lower. Perhaps a better overall health status in the new generations will make environmental challenges easier to bear. An interesting positive finding reported in the Spanish study is that the more severe cases are being diagnosed and treated. Perhaps the efforts directed at diagnosing and treating COPD is beginning to bear fruit.
What can we learn, and where do we go from here? The two studies highlight the difficulties in comparing repeated cross-sectional surveys of spirometry in populations. This difficult task is made even more difficult if the surveys are not conducted under the same overall plan and with similar techniques and basic tools. In addition, studies need to be well supported by granting agencies, in order to have better chances of objective success. The titanic efforts of PLATINO3and BOLD4and their undisputably impressive results are due to a group of dedicated researchers primarily funded by industry. Contrast this to the wealth of information that has been generated by well-funded and manned studies, such as that of the Framingham cohort, which has been provided significant public funds over decades7。Similar efforts in the area of COPD should reap the same benefits. Such an endeavour would improve COPD outcomes in the same way that the knowledge gained from the continued follow-up of the Framingham cohorts has resulted in improved outcomes in cardiovascular diseases. The two studies reported in this issue of theEuropean Respiratory Journal提供我们可以谨慎乐观的论点。在过去的二十年中,在大多数发达国家的空气中进行了决定性的努力,并打击诸如结核病之类的疾病,可能导致气流阻塞恶化。在西方世界中,吸烟流行率正在下降,并且在利用全面方法来对抗烟草使用的社会中,例如在美国,患病率的历史低位为20%8。这条路漫长而充满障碍,但这些西班牙和芬兰研究的结果可能表明,对于COPD,隧道尽头有一丝光线。让我们保持希望,继续与这个顽固的杀手抗争。
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