Outcomes for symptomatic non-obstructed individuals and individuals with mild (GOLD stage 1) COPD in a population based cohort

BACKGROUND

We aimed to study the adverse outcomes of symptomatic and asymptomatic non-obstructed individuals and those with mild COPD longitudinally in participants from three Latin-American cities.

METHODS

Two population-based surveys of adults with spirometry were conducted for these same individuals with a 5- to 9-year interval. We evaluated the impact of respiratory symptoms (cough, phlegm, wheezing or dyspnea) in non-obstructed individuals, and among those classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 1, COPD on exacerbation frequency, mortality and FEV1 decline, compared with asymptomatic individuals without airflow obstruction or restriction.

RESULTS

Non-obstructed symptomatic individuals had a marginal increased risk of mortality (HR 1.3; 95% CI 0.9-1.94), increased FEV1 decline (-4.5 mL/year; 95% CI -8.6, -0.4) and increased risk of 2+ exacerbations in the previous year (OR 2.6; 95% CI 1.2-6.5). Individuals with GOLD stage 1 had a marginal increase in mortality (HR 1.5; 95% CI 0.93-2.3) but a non-significant impact on FEV1 decline or exacerbations compared with non-obstructed individuals.

CONCLUSIONS

The presence of respiratory symptoms in non-obstructed individuals was a predictor of mortality, lung-function decline and exacerbations, whereas the impact of GOLD stage 1 was mild and inconsistent. Respiratory symptoms were associated with asthma, current smoking, and the report of heart disease. Spirometric case-finding and treatment should target individuals with moderate-to-severe airflow obstruction and those with restriction, the groups with consistent increased mortality.

Lung function decline in subjects with and without COPD in a population-based cohort in Latin-America

BACKGROUND

Lung-function decline is one of the possible mechanisms leading to Chronic Obstructive Pulmonary Disease (COPD).

METHODS

We analyzed data obtained from two population-based surveys of adults (n = 2026) conducted in the same individuals 5-9 years (y) after their baseline examination in three Latin-American cities. Post BronchoDilator (postBD) FEV1 decline in mL/y, as %predicted/y (%P/y) and % of baseline/y (%B/y) was calculated and the influence of age, gender, BMI, baseline lung function, BD response, exacerbations rate evaluated using multivariate models.

RESULTS

Expressed in ml/y, the mean annual postBD FEV1 decline was 27 mL (0.22%P, 1.32%B) in patients with baseline COPD and 36 (0.14%P, 1.36%B) in those without. Faster decline (in mL/y) was associated with higher baseline lung function, with significant response to bronchodilators, older age and smoking at baseline, also in women with chronic cough and phlegm, or ≥2 respiratory exacerbations in the previous year, and in men with asthma.

CONCLUSIONS

Lung function decline in a population-based cohort did not differ in obstructed and non-obstructed individuals, it was proportional to baseline FEV1, and was higher in smokers, elderly, and women with respiratory symptoms.

Assessment of five different guideline indication criteria for spirometry, including modified GOLD criteria, in order to detect COPD: data from 5,315 subjects in the PLATINO study

BACKGROUND

Spirometry is the gold standard for diagnosing chronic obstructive pulmonary disease (COPD). Although there are a number of different guideline criteria for deciding who should be selected for spirometric screening, to date it is not known which criteria are the best based on sensitivity and specificity.

AIMS

Firstly, to evaluate the proportion of subjects in the PLATINO Study that would be recommended for spirometry testing according to Global initiative for Obstructive Lung Disease (GOLD)-modified, American College of Chest Physicians (ACCP), National Lung Health Education Program (NLHEP), GOLD and American Thoracic Society/European Respiratory Society (ATS/ERS) criteria. Secondly, we aimed to compare the sensitivity, specificity, and positive predictive and negative predictive values, of these five different criteria.

METHODS

Data from the PLATINO study included information on respiratory symptoms, smoking and previous spirometry testing. The GOLD-modified spirometry indication criteria are based on three positive answers out of five questions: the presence of cough, phlegm in the morning, dyspnoea, age over 40 years and smoking status.

RESULTS

Data from 5,315 subjects were reviewed. Fewer people had an indication for spirometry (41.3%) according to the GOLD-modified criteria, and more people had an indication for spirometry (80.4%) by the GOLD and ATS/ERS criteria. A low percentage had previously had spirometry performed: GOLD-modified (14.5%); ACCP (13.2%); NLHEP (12.6%); and GOLD and ATS/ERS (12.3%). The GOLD-modified criteria showed the least sensitivity (54.9) and the highest specificity (61.0) for detecting COPD, whereas GOLD and ATS/ERS criteria showed the highest sensitivity (87.9) and the least specificity (20.8).

CONCLUSION

There is a considerable difference in the indication for spirometry according to the five different guideline criteria. The GOLD-modified criteria recruit less people with the greatest sum of sensitivity and specificity.

FEV1 is a better predictor of mortality than FVC: the PLATINO cohort study

OBJECTIVE

To determine whether the presence of chronic obstructive lung disease (COPD) and reduction of lung function parameters were predictors of mortality in a cohort.

MATERIALS/PATIENTS AND METHODS

Population based cohorts were followed in Montevideo, Santiago and Sao Paulo during 5, 6 and 9 years, respectively. Outcomes included all-cause, cardiovascular, respiratory and cancer mortality; exposures were COPD, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Cox regression was used for analyses. Sensitivity, specificity, positive and negative predictive values, receiver operator characteristics curves and Youden's index were calculated.

RESULTS

Main causes of death were cardiovascular, respiratory and cancer. Baseline COPD was associated with overall mortality (HR = 1.43 for FEV1/FVC<LLN; 2.01 for GOLD 2-4; 1.46 for GOLD 1-4; 1.50 for FEV1/FEV6 <LLN). For cardiovascular mortality, significant associations were found with GOLD 2-4 (HR = 2.68) and with GOLD 1-4 (HR = 1.78) for both genders together (not among women). Low FEV1 was risk for overall and respiratory mortality (both genders combined). FVC was not associated with overall mortality. For most COPD criteria sensitivity was low and specificity high. The area under the curve for FEV1 was greater than for FVC for overall and cardiovascular mortality.

ANSWER TO THE QUESTION

COPD and low FEV1 are important predictors for overall and cardiovascular mortality in Latin America.

Increased risk of exacerbation and hospitalization in subjects with an overlap phenotype: COPD-asthma

BACKGROUND

Several COPD phenotypes have been described; the COPD-asthma overlap is one of the most recognized. The aim of this study was to evaluate the prevalence of three subgroups (asthma, COPD, and COPD-asthma overlap) in the Latin American Project for the Investigation of Obstructive Lung Disease (PLATINO) study population, to describe their main characteristics, and to determine the association of the COPD-asthma overlap group with exacerbations, hospitalizations, limitations due to physical health, and perception of general health status (GHS).

METHODS

The PLATINO study is a multicenter population-based survey carried out in five Latin American cities. Outcomes were self-reported exacerbations (defined by deterioration of breathing symptoms that affected usual daily activities or caused missed work), hospitalizations due to exacerbations, physical health limitations, and patients' perception of their GHS obtained by questionnaire. Subjects were classified in three specific groups: COPD--a postbronchodilator (post-BD) FEV₁/FVC ratio of < 0.70; asthma--presence of wheezing in the last year and a minimum post-BD increase in FEV₁ or FVC of 12% and 200 mL; and overlap COPD-asthma--the combination of the two.

RESULTS

Out of 5,044 subjects, 767 were classified as having COPD (12%), asthma (1.7%), and COPD-asthma overlap (1.8%). Subjects with COPD-asthma overlap had more respiratory symptoms, had worse lung function, used more respiratory medication, had more hospitalization and exacerbations, and had worse GHS. After adjusting for confounders, the COPD-asthma overlap was associated with higher risks for exacerbations (prevalence ratio [PR], 2.11; 95% CI, 1.08-4.12), hospitalizations (PR, 4.11; 95% CI, 1.45-11.67), and worse GHS (PR, 1.47; 95% CI, 1.18-1.85) compared with those with COPD.

CONCLUSIONS

The coexisting COPD-asthma phenotype is possibly associated with increased disease severity.

A population-based cohort study on chronic obstructive pulmonary disease in Latin America: methods and preliminary results. The PLATINO Study Phase II

BACKGROUND

The PLATINO baseline study, conducted from 2003-2005 in five Latin American cities (São Paulo, Mexico City, Montevideo, Santiago, Caracas), showed a high prevalence of chronic obstructive pulmonary disease (COPD).

METHODS/DESIGN

A follow-up study was conducted in three out of the five centers (Montevideo, Santiago, and São Paulo) after a period of 5, 6 and 9years, respectively, aimed at verifying the stability of the COPD diagnosis over time, the evolution of the disease in terms of survival, morbidity and respiratory function, and the analyses of inflammatory and genetic biomarkers in the blood. Some questions were added to the original questionnaire and death certificates were obtained from the national official registries.

RESULTS

The fieldwork has been concluded in the three centers. From the original samples in the PLATINO study phasei, we were able to locate and interview 85.6% of patients in Montevideo, 84.7% in Santiago and 77.7% in São Paulo. Individuals who could not be located had higher education levels in Brazil, and were more likely to be current smokers in Santiago and São Paulo than in Montevideo. The overall quality of spirometries was ≥80% according to American Thoracic Society criteria. The number of deaths was 71 (Montevideo), 95 (Santiago) and 135 (São Paulo), with death certificates obtained from the national mortality registries for 76.1%, 88.3% and 91.8% of cases in Montevideo, Santiago and São Paulo, respectively.

CONCLUSIONS

This study shows that is possible to perform population-based longitudinal studies in Latin American with high follow-up rates and high-quality spirometry data. The adequacy of national mortality registries varies among centers in Latin America.

Reliability of FEV1/FEV6 to diagnose airflow obstruction compared with FEV1/FVC: the PLATINO longitudinal study

QUESTION

A 6-second spirometry test is easier than full exhalations. We compared the reliability of the ratio of the Forced expiratory volume in 1 second/Forced expiratory volume in 6 seconds (FEV₁/FEV₆) to the ratio of the FEV₁/Forced vital capacity (FEV₁/FVC) for the detection of airway obstruction.

METHODS

The PLATINO population-based survey in individuals aged 40 years and over designed to estimate the prevalence of post-Bronchodilator airway obstruction repeated for the same study participants after 5–9 years in three Latin-American cities.

RESULTS

Using the FEV₁/FVC<Lower limit of normal (LLN) index, COPD prevalence apparently changed from 9.8 to 13.2% in Montevideo, from 9.7 to 6.0% in São Paulo and from 8.5 to 6.6% in Santiago, despite only slight declines in smoking prevalence (from 30.8% to 24.3%). These changes were associated with differences in Forced expiratory time (FET) between the two surveys. In contrast, by using the FEV₁/FEV₆ to define airway obstruction, the changes in prevalence were smaller: 9.7 to 10.6% in Montevideo, 8.6 to 9.0% in São Paulo, and 7.5 to 7.9% in Santiago. Changes in the prevalence of COPD with criteria based on FEV₁/FVC correlated strongly with changes in the FET of the tests (R² 0.92) unlike the prevalence based on a low FEV₁/FEV₆ (R² = 0.40).

CONCLUSION

The FEV₁/FEV₆ is a more reliable index than FEV₁/FVC because FVC varies with the duration of the forced exhalation. Reporting FET and FEV₁/FEV₆<LLN helps to understand differences in prevalence of COPD obtained from FEV₁/FVC-derived indices.

Comorbidities and health status in individuals with and without COPD in five Latin American cities: the PLATINO study

INTRODUCTION

Comorbidities are common in patients with chronic obstructive pulmonary disease (COPD), and have a significant impact on health status and prognosis. The PLATINO study provides data on self-reported comorbidities and perceived health status in COPD subjects.

METHODS

PLATINO is a population-based study on COPD prevalence in five Latin American cities. COPD diagnosis was defined by GOLD criteria (FEV1/FVC<.70 post-bronchodilator). Information was collected on the following comorbidities: heart disease, hypertension, diabetes, cerebrovascular disease, peptic ulcer and asthma. Health status was evaluated using the SF-12 questionnaire, derived from the question: «In general, would you say your health is excellent, very good, good, fair or poor?». A simple comorbidity score was calculated by adding the total number of comorbid conditions.

RESULTS

Of a total population of 5314individuals, 759 had COPD. Reported comorbidities by decreasing frequency were: any cardiovascular disease, hypertension, peptic ulcer, heart disease, diabetes, cerebrovascular disease, asthma and lung cancer. COPD patients had a higher comorbidity score and prevalence of lung cancer (P<.0001) and asthma (P<.0001), as well as a higher tendency to have hypertension (P=.0652) and cerebrovascular disease (P=.0750). Factors associated with comorbidities were age, body mass index (BMI) and female gender. The number of comorbidities increased as the health status deteriorated.

CONCLUSIONS

In the PLATINO population-based study, COPD individuals had an increased number of comorbidities. Age, female gender and higher BMI were the factors associated with comorbidity in these patients. Comorbid conditions were associated with impaired health status, independently of the COPD status.

Perceptions of short and long sleep duration and comorbid conditions: the PLATINO study

OBJECTIVES

We aimed to describe the distribution of self-reported sleep duration in adults over the age of 40 years and to analyze the associated risk factors, comorbid conditions, and quality of life (QoL).

METHODS

Our study was constructed as a cross-sectional population-based study and is part of the PLATINO (Spanish acronym for the Latin American Project for Research in Pulmonary Obstruction) study. It includes data from Mexico City (Mexico), Montevideo (Uruguay), Santiago (Chile), and Caracas (Venezuela). Data from 4533 individuals were analyzed using a single questionnaire entitled, PLATINO, which was designed to collect data on self-reported sleep symptoms. Spirometry also was performed in accordance with international standards. All statistical analyses took the study design into consideration with adjustments for each city.

RESULTS

The prevalence of subjects who reported sleeping <7h was 38.4%, ≥ 7 to <9h was 51.4%, and ≥ 9h was 10.2%. In the multivariate analysis, individuals with shorter sleep duration had higher frequencies of insomnia, increased forced expiratory volume in one second in liters and percentage/forced vital capacity in liters (FEV1/FVC) of predicted ratios, and a higher presence of coughing and phlegm. The main risk factor associated with longer duration of sleep was the number of comorbidities.

CONCLUSIONS

Self-reported sleep duration discriminated among groups that differed in sleep-related symptoms, respiratory symptoms, QoL and comorbid conditions.

Airflow obstruction in never smokers in five Latin American cities: the PLATINO study

BACKGROUND

Although chronic obstructive pulmonary disease (COPD) is mostly related to tobacco smoking, a variable proportion of COPD occurs in never smokers. We investigated differences between COPD in never smokers compared with smokers and subjects without COPD.

METHODS

PLATINO is a cross-sectional population-based study of five Latin American cities. COPD was defined as postbronchodilator FEV(1)/FVC <0.70 and FEV(1) <80% of predicted values.

RESULTS

Among 5,315 subjects studied, 2278 were never smokers and 3036 were ever smokers. COPD was observed in 3.5% of never smokers and in 7.5% of ever smokers. Never smokers with COPD were most likely older and reported a medical diagnosis of asthma or previous tuberculosis. Underdiagnosis was as common in obstructed patients who never smoked as in ever smokers.

CONCLUSIONS

Never smokers comprised 26% of all individuals with airflow obstruction. Obstruction was associated with female gender, older age and a diagnosis of asthma or tuberculosis.

Paid employment in subjects with and without chronic obstructive pulmonary disease in five Latin American cities: the PLATINO study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a costly condition that frequently causes permanent work disabilities. Little information exists regarding the impact of COPD on work force participation and the indirect costs of the disease in developing countries.

OBJECTIVE

To examine the frequency of paid employment and factors influencing it in a Latin-American population-based study.

METHODS

Post-bronchodilator FEV(1)/FVC < 0.70 (forced expiratory volume in 1 s/forced vital capacity) was used to define COPD. Information regarding paid work was assessed by the question 'At any time in the past year, have you worked for payment?'

RESULTS

Interviews were conducted with 5571 subjects; 5314 (759 COPD and 4554 non-COPD) subjects underwent spirometry. Among the COPD subjects, 41.8% reported having paid work vs. 57.1% of non-COPD (P < 0.0001). The number of months with paid work was reduced in COPD patients (10.5 ± 0.17 vs. 10.9 ± 0.06, P < 0.05). The main factors associated with having paid work in COPD patients were male sex (OR 0.33, 95%CI 0.23-0.47), higher education level (OR 1.05, 95%CI 1.01-1.09) and younger age (OR 0.90, 95%CI 0.88-0.92). COPD was not a significant contributor to employment (OR 0.83, 95%CI 0.69-1.00, P = 0.054) in the entire population.

CONCLUSIONS

Although the proportion of persons with paid work is lower in COPD, having COPD appears not to have a significant impact on obtaining paid employment in the overall population of developing countries.

Prevalence of smoking and incidence of initiation in the Latin American adult population: the PLATINO study

Background

The PLATINO project was launched in 2002 in order to study the prevalence of chronic obstructive pulmonary disease (COPD) in Latin America. Because smoking is the main risk factor for COPD, detailed data on it were obtained. The aim of this paper was to evaluate the prevalence of smoking and incidence of initiation among middle-aged and older adults (40 years or older). Special emphasis was given to the association between smoking and schooling.

Methods

PLATINO is a multicenter study comprising five cross-sectional population-based surveys of approximately 1,000 individuals per site in Sao Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay) and Caracas (Venezuela). The outcome variable was smoking status (never, former or current). Current smokers were those who reported to smoke within the previous 30 days. Former smokers were those who reported to quit smoking more than 30 days before the survey. Using information on year of birth and age of smoking onset and quitting, a retrospective cohort analysis was carried out. Smoking prevalence at each period was defined as the number of subjects who started to smoke during the period plus those who were already smokers at the beginning of the period, divided by the total number of subjects. Incidence of smoking initiation was calculated as the number of subjects who started to smoke during the period divided by the number of non-smokers at its beginning. The independent variables included were sex, age and schooling.

Results

Non-response rates ranged from 11.1% to 26.8%. The prevalence of smoking ranged from 23.9% (95%CI 21.3; 26.6) in Sao Paulo to 38.5% (95%CI 35.7; 41.2) in Santiago. Males and middle-aged adults were more likely to smoke in all sites. After adjustment for age, schooling was not associated with smoking. Using retrospective cohort analysis, it was possible to detect that the highest prevalence of smoking is found between 20–29 years, while the highest incidence is found between 10–19 years. Age of smoking onset tended to decline over time among females.

Conclusion

The prevalence of smoking varied considerably across sites, but was lower among countries with national anti-smoking campaigns.

[Wheezing phenotypes from birth to adolescence: a cohort study in Pelotas, Brazil, 1993-2004]

OBJECTIVE

To study the prevalence of wheezing patterns and their associations with independent variables.

METHODS

Cohort study of live births in 1993 in Pelotas, Brazil. A systematic subsample (20%) of the original cohort was evaluated at 6 months, 12 months and 4 years. At 10-12 years, 87.5% of the original cohort was contacted. Wheezing was categorized: transient, wheezing at 4 years but not at 10-12; persistent, wheezing at all evaluations; late-onset, wheezing at 10-12 years. Independent variables were analyzed: gender; skin color; family income; smoking/asthma during pregnancy; breastfeeding; respiratory infection/diarrhea (during the 1st year); family members with asthma/allergy (at 4 years and at 10-12); physician-diagnosed rhinitis/eczema (at 10-12 years).

RESULTS

The subsample comprised 897 adolescents. Wheezing patterns were expressed as prevalence (95% CI): transient, 43.9% (40.7-47.2); persistent, 6.4% (4.8-8.0); and late-onset, 3.3% (2.2-4.5). The transient pattern was more common in children from low-income families, children breastfed for less time, children with a history of respiratory infections (during the 1st year) and children with asthma in the family (at 4 years). The persistent pattern was almost twice as common in males, in children whose mothers had asthma during pregnancy, in children with respiratory infections (during the 1st year) and in children with asthma in the family (at 4 and 10-12 years). The late-onset pattern was more prevalent among those with asthma in the family (at 10-12 years) and those diagnosed with rhinitis (at 10-12 years), being less prevalent among those reporting respiratory infections (during the 1st year) and those diagnosed with eczema (at 10-12 years).

CONCLUSIONS

Knowledge of the associations of wheezing patterns allows us to adopt preventive and therapeutic measures.

Frequency of self-reported COPD exacerbation and airflow obstruction in five Latin American cities: the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar (PLATINO) study

BACKGROUND

Recurrent exacerbations are common in COPD patients. Limited information exists regarding exacerbation frequency in COPD patients from epidemiologic studies. We examined the frequency of self-reported exacerbations and the factors influencing exacerbation frequency among COPD patients in a population-based study conducted in Latin America.

METHODS

We used a post-bronchodilator FEV(1)/FVC ratio of < 0.70 to define COPD. Exacerbation was self-reported and defined by symptoms (deterioration of breathing symptoms that affected usual daily activities or caused missed work).

RESULTS

Spirometry was performed in 5,314 subjects. There were 759 subjects with airflow limitation; of these, 18.2% reported ever having had an exacerbation, 7.9% reported having an exacerbation, and 6.2% reported having an exacerbation requiring at least a doctor visit within the past year. The proportion of individuals with an exacerbation significantly increased by Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, from 4.2% in stage 1 to 28.9% in stages 3 and 4. The self-reported exacerbation rate was 0.58 exacerbations per year. The rate of exacerbations requiring at least a doctor visit and length of stay in hospital due to exacerbations also increased as COPD severity progressed. The factors associated with having an exacerbation in the past year were dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and disease severity of GOLD stages 3 and 4.

CONCLUSIONS

The proportion of individuals with airflow limitation and self-reported exacerbation increases as the disease severity progresses. Dyspnea, prior asthma diagnosis, receiving any respiratory therapy, and more severe obstruction were significantly associated with having an exacerbation in the past year.

Pericardial tamponade in a patient with polymyalgia rheumatica

We report a patient who developed pericarditis and pericardial tamponade coinciding with polymyalgia rheumatica onset. Our patient did not show any clinical sign of vasculitis; temporal artery biopsies were negative for giant cell arteritis. Pericardial biopsy in our case shows inflammatory perivascular lymphocytary infiltrates thus we believe pericardial effusion has an inflammatory-immunologic origin. Cardiac manifestations are exceptional in polymyalgia rheumatica, though it should be considered in the differential diagnosis in patients with pericarditis over 50 years. The recognition of this uncommon manifestation is very important due to the good response to corticosteroid treatment.

Prevalence of sleep related symptoms in four Latin American cities

STUDY OBJECTIVES

to estimate the prevalence of the most common sleep related symptoms (SRS) in the metropolitan areas of Mexico City, Montevideo (Uruguay), Santiago (Chile), and Caracas (Venezuela).

METHODS

The study consisted of a multistage cluster sampling of adults aged > or = 40 years living in metropolitan areas. All participants completed a questionnaire on sleep related symptoms. Simplified respiratory polygraphy during sleep was conducted on 188 subjects from Mexico City. Obstructive sleep apnea syndrome was defined as Epworth Sleepiness Scale score > or = 11 and respiratory disturbance index (RDI) > or = 15 events/h; a cut-off of 15 was chosen because of its high sensitivity and specificity in association with the portable monitor used in the study.

RESULTS

The study included 4,533 subjects (1,062 in Mexico City, 941 in Montevideo, 1,173 in Santiago, and 1,357 in Caracas). Snoring was reported by 60.2% (95% CI 58.8% to 61.6%), excessive daytime sleepiness by 16.4% (15.3% to 17.5%), observed apneas by 12.3% (11.4% to 13.3%), insomnia by 34.7% (33.3% to 36%), sedative use by 15.1% (14.1% to 16.2%), daytime napping by 29.2% (27.7% to 30.6%), and a combination of snoring, sleepiness, and observed apneas by 3.4% (2.9% to 4%). Men had a higher frequency of snoring and daytime napping, whereas women reported more insomnia and sedative use. Prevalence of OSAS varied from 2.9% among subjects who denied snoring, excessive daytime sleepiness, and observed apneas, to 23.5% among those reporting these 3 symptoms.

CONCLUSIONS

A high prevalence of sleep related symptoms and undiagnosed obstructive sleep apnea in Latin America was observed.

[Treatment of chronic obstructive pulmonary disease in 5 Latin American cities: the PLATINO study]

OBJECTIVE

PLATINO project is a population-based study designed to determine the prevalence of chronic obstructive pulmonary disease (COPD) in São Paulo, Brazil; Mexico City, Mexico; Montevideo, Uruguay; Santiago de Chile, Chile; and Caracas, Venezuela. The objective of this portion of PLATINO was to describe preventive and pharmacological treatment of COPD patients and factors associated with such treatment.

PATIENTS AND METHODS

Eligible subjects completed a questionnaire and underwent postbronchodilator spirometry.

RESULTS

Of the total of 5529 individuals who answered items referring to treatment, 758 had COPD (ratio of postbronchodilator forced expiratory volume in 1 second to forced vital capacity of <0.7), and 86 of them had been previously diagnosed by a physician. Among all COPD patients, only half of smokers or former smokers had been advised to quit and 24.7% had received some type of respiratory medication. Only 13.5% had used inhaled corticosteroids, and those were the patients with the most severe disease. In the group of patients who had a previous medical diagnosis of COPD, 69% of the smokers or former smokers had been advised to quit by a physician and 75.6% had received respiratory medication in the preceding year: 43% reported having used inhaled medication and 36% had used bronchodilators. Rates of vaccination against influenza and the use of mucolytic drugs and inhalers varied from one health care facility to another. All drug prescriptions were based on previous spirometry.

CONCLUSIONS

Spirometry emerged not only as a diagnostic tool, but also as a factor associated with treatment, against a background of uneven use of available health care resources in these 5 Latin American cities.

Worldwide burden of COPD in high- and low-income countries. Part II. Burden of chronic obstructive lung disease in Latin America: the PLATINO study

SETTING

Five Latin American cities: São Paulo, Brazil; Mexico City, Mexico; Montevideo, Uruguay; Santiago, Chile; Caracas, Venezuela.

OBJECTIVE

To describe the burden of chronic obstructive pulmonary disease (COPD) in Latin America.

DESIGN

This is a multicentre study. Post-bronchodilator spirometry was used and the main outcome measure was FEV(1)/FVC < 0.7 (fixed ratio criterion). Global Obstructive Lung Disease (GOLD) stages were also analysed.

RESULTS

The combined population aged > or =40 years in the five countries included in the study was approximately 85.3 million. Of these, it was estimated that 12.2 million have airflow obstruction, which corresponds to our prevalence estimate of 14.3%. The proportion of subjects in Stages II-IV of the GOLD classification was 5.6%. Risk factors presenting the highest aetiological fractions for COPD were age, current smoking, indoor exposure to coal and exposure to dust in the workplace. Smoking, the modifiable factor with the strongest aetiological fraction for COPD, affects 29.2% of adults aged > or =40 years in these cities, corresponding to approximately 25 million smokers in this age group.

CONCLUSION

Prevention of smoking and exposure to pollutants, such as coal and dust, are the interventions most likely to succeed against COPD in Latin America. The information obtained by a collaborative study has been vast and encouraging for other similar studies.

Use of respiratory medication in five Latin American cities: The PLATINO study

BACKGROUND

There is scanty information regarding respiratory medication prescription pattern in Latin America. We examined the use of bronchodilators and corticosteroids in a population-based study conducted in five Latin American cities.

METHODS

Medication use was derived from questions regarding the use of medication "to help breathing" within the previous 12 months, type of medicine, and frequency of use. To minimize the possibility of overdiagnosis, we used postbronchodilator FEV(1)/FVC<0.70 plus FEV(1)<80% as the definition of obstruction.

RESULTS

Interviews were completed in 5571 subjects from 6711 eligible individuals, and spirometry was performed in 5314 subjects. There were 360 (6.5%) treated subjects and 5211 not treated. Treated subjects were more likely to be older, women, unemployed, have higher tobacco consumption, higher body mass index, higher FEV(1) reversibility and airway obstruction. They were also more likely to report prior spirometry, prior diagnosis of COPD, asthma or tuberculosis, and more respiratory symptoms. Over half of treated subjects had neither obstruction nor FEV(1) reversibility, and approximately 30% reported no prior diagnosis of asthma or COPD. Prior respiratory diagnoses and wheezing were more strongly associated with treatment than objective measures of airway obstruction.

CONCLUSIONS

The use of bronchodilators and/or corticosteroids is common in the general population aged 40 years or older, with over one-half of treated subjects using them without being obstructed.

Chronic obstructive pulmonary disease and body mass index in five Latin America cities: the PLATINO study

BACKGROUND

The body mass index (BMI) is a prognostic factor for chronic obstructive pulmonary disease (COPD). Despite its importance, little information is available regarding BMI alteration in COPD from a population-based study. We examined characteristics by BMI categories in the total and COPD populations in five Latin-American cities, and explored the factors influencing BMI in COPD.

METHODS

COPD was defined as a postbronchodilator forced expiratory volume in the first second/forced vital capacity (FEV(1)/FVC) <0.70. BMI was categorized as underweight (< 20 kg/m(2)), normal weight (20-24.9 kg/m(2)), overweight (25.0-29.9 kg/m(2)), and obese (> or = 30.0 kg/m(2)).

RESULTS

Interviews were completed in 5571 subjects from 6711 eligible individuals, and spirometry was performed in 5314 subjects. There were 759 subjects with COPD and 4555 without COPD. Compared with the non-COPD group, there was a higher proportion of COPD subjects in the underweight and normal weight categories, and a lower proportion in the obese category. Over one-half COPD subjects had BMI over 25 kg/m(2). No differences in BMI strata among countries were found in COPD subjects. Factors associated with lower BMI in males with COPD were aging, current smoking, and global initiative for chronic obstructive lung disease (GOLD) stages III-IV, whereas wheeze and residing in Santiago and Montevideo were associated with higher BMI. In females with COPD, current smoking, lower education, and GOLD stages II-IV were associated with lower BMI, while dyspnea and wheeze were associated with higher BMI.

CONCLUSIONS

BMI alterations are common in COPD with no significant differences among countries. Current smoking, age, GOLD stages, education level, residing in Santiago and Montevideo, dyspnea and wheeze were independently associated with BMI in COPD.

Tuberculosis and airflow obstruction: evidence from the PLATINO study in Latin America

The aim of the present study was to evaluate the association between history of tuberculosis and airflow obstruction. A population-based, multicentre study was carried out and included 5,571 subjects aged > or =40 yrs living in one of five Latin American metropolitan areas: Sao Paulo (Brazil); Montevideo (Uruguay); Mexico City (Mexico); Santiago (Chile); and Caracas (Venezuela). Subjects performed pre- and post-bronchodilator spirometry and were asked whether they had ever been diagnosed with tuberculosis by a physician. The overall prevalence of airflow obstruction (forced expiratory volume in one second/forced vital capacity post-bronchodilator <0.7) was 30.7% among those with a history of tuberculosis, compared with 13.9% among those without a history. Males with a medical history of tuberculosis were 4.1 times more likely to present airflow obstruction than those without such a diagnosis. This remained unchanged after adjustment for confounding by age, sex, schooling, ethnicity, smoking, exposure to dust and smoke, respiratory morbidity in childhood and current morbidity. Among females, the unadjusted and adjusted odds ratios were 2.3 and 1.7, respectively. In conclusion, history of tuberculosis is associated with airflow obstruction in Latin American middle-aged and older adults.

Impact of bronchodilator use on the prevalence of COPD in population-based samples

The aim of this study was to describe the impact of using bronchodilators on the prevalence of Chronic Obstructive Pulmonary Disease in a population-based survey (Platino study). A cluster sampling of subjects 40 years of age or older, representative of the metropolitan areas of 5 Latin American cities (Sao Paulo, Mexico, Montevideo, Santiago and Caracas) was chosen. Spirometry according to ATS standards was done before and after inhalation of 200 micrograms of salbutamol in 5183 subjects. Prevalences of airflow obstruction were estimated using different criteria, in tests done before and after bronchodilator use, and with reference values for pre- or post-bronchodilator use. Bronchodilator testing reduced the overall prevalence of FEV(1)/FVC% < 0.70 from 21.7% to 14% (35%). In the group with FEV(1)/FVC < 0.70 after bronchodilator use, 21% were asymptomatic from the respiratory point of view, and lacked significant adverse exposures. Subjects below the 5th percentile for FEV(1)/FVC and FEV(1)/FEV(6) were fewer than those with FEV(1)/FVC < 0.70, especially among the elderly. More subjects are below the 5th percentile of FEV(1)/FVC and FEV(1)/FEV(6) using reference values for tests after bronchodilator use than using the reference values determined without bronchodilator testing. Testing after bronchodilator use reduces the prevalence of airflow obstruction from 32 to 39% depending on the definition used. In addition, the subjects who were still obstructed after bronchodilator use were the ones who showed more respiratory symptoms and exposure to tobacco and other smokes and dusts, than subjects with reversible obstruction, suggesting an increased specificity for COPD.

Risk factors for wheezing in early adolescence: a prospective birth cohort study in Brazil

BACKGROUND

Many asthma studies are available in the literature, but few investigated whether risk factors for asthma differ by sex.

OBJECTIVE

To evaluate risk factors for wheezing in early adolescence, with emphasis on sex differences.

METHODS

A prospective birth cohort study was initiated in 1993; 87.5% of the original cohort was traced at 11 years, totaling 4,452 adolescents. Current wheezing was defined as at least 1 crisis in the previous 12 months. The following independent variables were analyzed: maternal smoking during pregnancy, wheezing at 4 years, maternal wheezing, and adolescent body mass index.

RESULTS

Current wheezing affected 13.5% (95% confidence interval [CI], 12.4%-14.5%) of the cohort. The prevalence of current wheezing was 15.3% (95% CI, 13.7%-16.8%) in boys and 11.7% (95% CI, 10.4%-13.1%) in girls (P < .001). Maternal smoking was related to an increased risk of wheezing for boys but not for girls. There was a significant tracking of wheezing from 4 to 11 years in both sexes, although the magnitude was stronger for boys. A dose-response association between maternal wheezing and adolescent wheezing was observed in boys but not in girls. Finally, obesity was associated with an increased risk of wheezing in boys but not in girls.

CONCLUSIONS

The variables explored in this investigation had a stronger effect on adolescent wheezing in boys than in girls. Public health strategies aimed at minimizing the burden of wheezing should take these sex differences into account.

[Spirometric reference values in 5 large Latin American cities for subjects aged 40 years or over]

OBJECTIVE

In clinical practice, spirometry is a extremely useful test that requires strict quality control, an appropriate strategy for interpretation, and reliable reference values. The aim of this study was to report spirometric reference values for 5 cities in Latin America.

PATIENTS AND METHODS

From data for 5315 subjects who had undergone spirometry in the PLATINO study in Caracas, Mexico City, Santiago, São Paulo, and Montevideo, we selected information for 906 (17%) individuals aged between 40 years and 90 years to provide reference values. The chosen subjects had never smoked, were asymptomatic, had not been diagnosed with lung disease, and were not obese. Multiple regression models were constructed with the following spirometric parameters: forced expiratory volume in 1 second (FEV1) and in 6 seconds (FEV6), peak expiratory flow, forced vital capacity (FVC), FEV1/FEV6, FEV1/FVC, and forced midexpiratory flow rate. Height, sex, and age were also included in the model.

RESULTS

Average values for the subjects studied were similar to those for the white North American population and the Mexican-American population of the third National Health and Nutrition Examination Survey, but exceeded those of the black population of the same survey by 20%.

CONCLUSIONS

The proposed reference values are an improvement on those currently available for Latin America because the participants were chosen by population sampling methods and standardized up-to-date methodology was used.

Diagnostic Labeling of COPD in Five Latin American Cities

BACKGROUND

COPD is a major worldwide problem with a rising prevalence. Despite its importance, there is a lack of information regarding underdiagnosis and misdiagnosis of COPD in different countries. As part of the Proyecto Latinoamericano de Investigación en Obstrucción Pulmonar study, we examined the relationship between prior diagnostic label and airway obstruction in the metropolitan areas of five Latin American cities (São Paulo, Santiago, Mexico City, Montevideo, and Caracas).

METHODS

A two-stage sampling strategy was used in each of the five areas to obtain probability samples of adults aged >or= 40 years. Participants completed a questionnaire that included questions on prior diagnoses, and prebronchodilator and postbronchodilator spirometry. A study diagnosis of COPD was based on airway obstruction, defined as a postbronchodilator FEV(1)/FVC < 0.70.

RESULTS

Valid spirometry and prior diagnosis information was obtained for 5,303 participants; 758 subjects had a study diagnosis of COPD, of which 672 cases (88.7%) had not been previously diagnosed. The prevalence of undiagnosed COPD was 12.7%, ranging from 6.9% in Mexico City to 18.2% in Montevideo. Among 237 subjects with a prior COPD diagnosis, only 86 subjects (36.3%) had postbronchodilator FEV(1)/FVC < 0.7, while 151 subjects (63.7%) had normal spirometric values. In the same group of 237 subjects, only 34% reported ever undergoing spirometry prior to our study.

CONCLUSIONS

Inaccurate diagnostic labeling of COPD represents an important health problem in Latin America. One possible explanation is the low rate of spirometry for COPD diagnosis.

Prevalence of oxygen desaturation and use of oxygen at home in adults at sea level and at moderate altitude

The aim of this study was to determine the prevalence of oxygen desaturation in adults aged>or=40 yrs as altitude above sea level increases. A population-based, cross-sectional study with a multistage cluster sampling of 1,063 subjects from metropolitan Mexico City (Mexico; 2,240 m above sea level), 1,357 from Caracas (Venezuela; 950 m) and 943 from Montevideo (Uruguay; 35 m). The mean of six measurements of arterial oxygen saturation (SP,O2) was estimated using a pulse oximeter. Mean SP,O2 decreased with altitude. No subject from Montevideo had a mean SP,O2<or=88%. Prevalence of subjects with SP,O2<or=88%, a common criterion used for oxygen prescription, was 1.0% in Caracas and 6.0% in Mexico City. Additional predicting factors for hypoxaemia in multiple regression models were age, body mass index and a low forced expiratory volume in one second as a percentage of the predicted value. In Mexico City and Caracas, <10% of the hypoxaemic subjects reported use of domiciliary oxygen, whereas at least half of the subjects reporting use of oxygen at home had a resting SP,O2>88%. In conclusion, the prevalence of hypoxaemia was closely related to altitude. Priorities for oxygen prescription must be defined in moderate altitudes because it is unfeasible to provide it to all subjects fulfilling the criteria commonly used.

The long-term stability of portable spirometers used in a multinational study of the prevalence of chronic obstructive pulmonary disease

BACKGROUND

We report the performance of an ultrasound-based portable spirometer (EasyOne) used in a population-based survey of the prevalence of chronic obstructive pulmonary disease, conducted in 5 Latin American cities: São Paulo, Brazil; México City, México; Montevideo, Uruguay; Santiago, Chile; and Caracas, Venezuela (the Latin American COPD Prevalence Study [PLATINO]).

METHODS

During the survey period (which ranged from 3 months to 6 months in the various locations) we collected daily calibration data from the 70 EasyOne spirometers used in the 5 survey cities. The calibrations were conducted with a 3-L syringe, and the calibration data were stored in the spirometer's database.

RESULTS

Ninety-seven percent of the calibration volumes were within +/- 64 mL (2.1%) of the 3-L calibration signal. Excluding data from the first city studied (São Paulo), where one calibration syringe had to be replaced, 98% of the calibration checks were within +/- 50 mL (1.7%). The measured volume was affected only minimally by the syringe's peak flow or emptying time.

CONCLUSION

In these 70 EasyOne spirometers neither calibration nor linearity changed during the study. Such calibration stability is a valuable feature in spirometry surveys and in the clinical setting.

Chronic obstructive pulmonary disease in five Latin American cities (the PLATINO study): a prevalence study

BACKGROUND

Both the prevalence and mortality attributable to chronic obstructive pulmonary disease (COPD) seem to be increasing in low-income and middle-income countries, but few data are available. The aim of the PLATINO study, launched in 2002, was to describe the epidemiology of COPD in five major Latin American cities: São Paulo (Brazil), Santiago (Chile), Mexico City (Mexico), Montevideo (Uruguay), and Caracas (Venezuela).

METHODS

A two-stage sampling strategy was used in the five areas to obtain probability samples of adults aged 40 years or older. These individuals were invited to answer a questionnaire and undergo anthropometry, followed by prebronchodilator and postbronchodilator spirometry. We defined COPD as a ratio less than 0.7 of postbronchodilator forced expiratory volume in the first second over forced vital capacity.

FINDINGS

Complete information, including spirometry, was obtained from 963 people in São Paulo, 1173 in Santiago, 1000 in Mexico City, 885 in Montevideo, and 1294 in Caracas. Crude rates of COPD ranged from 7.8% (78 of 1000; 95% CI 5.9-9.7) in Mexico City to 19.7% (174 of 885; 17.2-22.2) in Montevideo. After adjustment for key risk factors, the prevalence of COPD in Mexico City remained significantly lower than that in other cities.

INTERPRETATION

These results suggest that COPD is a greater health problem in Latin America than previously realised. Altitude may explain part of the difference in prevalence. Given the high rates of tobacco use in the region, increasing public awareness of the burden of COPD is important.