Open Journal Systems

CLINICAL AND SURGICAL PRACTICE

Received: June 26^th 2014

Accepted: July 18^th 2014

Quality of life in chronic obstructive lung disease. Experience in a hospital from western Mexico

Luis Alfonso Durán-Montes,^a Francisco Javier Cisneros-Sandoval,^b Elsa Armida Gutiérrez-Román^c

^aCoordinación Auxiliar de Investigación en Salud

^bJefatura de Servicios de Prestaciones Médicas

^cCoordinación de Planeación y Enlace Institucional

Instituto Mexicano del Seguro Social, Delegación Estatal en Jalisco, México

Communication with: Luis Alfonso Durán-Montes

Telephone: 01 (33) 3617 0060, extensions 31030 y 31150

E-mail: laduranm@yahoo.com

Background: The chronic obstructive lung disease (COPD) is a common, expensive and preventable disease, and the evaluation of the quality of life in patients with the condition widens the scope of the results in their attention. The objective was to evaluate the health related quality of life (HRQL) according to the severity of the COPD.

Methods: Descriptive study. Patients with COPD diagnosis according with the severity and related with the HRQL measured using a specific questionnaire. Statistical analyses were made using c2 or ANOVA in ranks according with the variables. A p value ≤ 0.05 was considered significant.

Results: 62 patients were included; 61% women. HRQL questionnaire showed the Activity dimension as the more negatively affected (65 ± 24 points, p < 0.05). In the Impact dimension, severity groups III and IV were more affected compared with groups I and II (p < 0.05). There was a directly correlation between a better FEV1 with better HRQL results (r2-0.544 p < 0.0001).

Conclusions: HRQL is affected and clinically meaningful in patients with a major severity degree of the COPD condition. The parameters that better predicts a worst HRQL was % FEV1 and FVC.

Keywords: COPD; Quality of life; HRQL; Severity

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Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation, usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles and gases; it is mainly related to smoking.¹ COPD imposes considerable burdens on health systems, the economy, and society. Projections of the World Health Organization (WHO) suggest that by 2020 the disease will move from twelfth to fifth as a cause of overall morbidity, and from sixth to third place as a cause of overall mortality.²

The prevalence of COPD in the world, estimated by the World Bank and WHO, is nearly 1% among adults. Its prevalence in big cities in Latin America ranges from 7.8% in Mexico City to 20% in Montevideo, Uruguay.³ In Mexico, the health sector spends 20,000 million pesos a year (0.3% of gross domestic product [GDP]) to address the problems caused by tobacco use. In 2004, the direct costs of care for patients with COPD for the Instituto Mexicano del Seguro Social (IMSS) alone amounted to 1,469 million pesos.⁴

The severity of COPD, as well as post-treatment improvement and the progression of the disease⁵ have traditionally been measured by lung physiology tests, specifically the forced expiratory volume in 1 second (FEV1),¹ which is accepted as an objective parameter of airflow obstruction. As the disease progresses, patients with COPD experience a decline in their quality of life (QOL), a decrease of working capacity, and the gradual loss of autonomy, transforming their relationship with the social environment and increasing their dependence on health syss.⁶ temThis greater reliance is exemplified by exacerbations of the disease, which are the most common reason for medical care, hospitalization and hospital death among patients with COPD.⁷

The concept of quality of life related to health (HRQOL) refers to limitations, derived from a specific disease or its treatment, in daily life and in a sense of wellbeing.⁸ It is evident that when one wants to assess the importance of COPD and the burden of disease, it is necessary to consider the health outcomes reported by the patient, because the data on HRQOL provides valuable information complementary to the results of lung function.⁵ Despite the many studies published on HRQOL and COPD during the last decade, our care of patients with COPD has not incorporated the measurement of HRQOL, thus our monitoring of the disease and the results of treatment is lacking a valuable tool to support treatment decisions, as well as planning and resource allocation. Therefore, the objective of this study was to compare HRQOL according to the severity of COPD.

Methods

Descriptive study including a representative sample of 62 patients selected from the population served in the Hospital General de Zona (HGZ) 14 of the IMSS in Guadalajara, Jalisco, in whom the diagnosis of COPD according to their lung function was confirmed by spirometry according to the criteria established by the American Thoracic Society/European Respiratory Society (ATS/ERS).⁹ The patients were over 40 years old, of either sex and any time of development of COPD. Patients previously diagnosed with asthma, with reduced auditory acuity, mental disabilities, and those with comorbidities that affect the quality of life (chronic renal failure, congestive heart failure III-IV, cancer and chronic liver failure) were excluded. The study was approved by the Local Committee on Health Research for the corresponding Hospital.

To measure the HRQOL, in a first interview a detailed medical history and clinical examination was performed. Subsequently the survey called Saint George Respiratory Questionnaire (SGRQ), specifically utilized for COPD, was used. It was translated and validated in the Spanish language by Ferrer et al. in 1996,¹⁰ and its validation in the Mexican population was carried out by Aguilar et al. in 2000.¹¹ It contains 50 items that address 76 weighted answers divided into three domains (dimensions): 1) Symptoms, 2) Activity and 3) Impact; also it includes a total score. Each item has a theoretical weight assigned to it and the scale is from 0 to 100 points, with 0 representing the best quality of life possible.⁷ The HRQOL measurement was made based on the criteria established to score the questionnaire.⁷ The questionnaire was administered by adequately trained staff after the patient agreed to participate in the study under informed consent.

To measure lung function, each patient underwent spirometry at baseline, with SP-1 Schiller Spirometer (Schiller AG, Baar, Switzerland), according to the ATS/ERS.⁹  FEV1 (L/min), forced vital capacity (FVC, L,%) and the FEV1/FVC ratio were registered, and COPD was diagnosed by a FEV1/FVC ratio of < 70%, ranking the severity into four groups according to the Global Initiative on Obstructive Lung Disease 2007:¹² GOLD I (mild) FEV1 ≥ 80%; GOLD II (Moderate): FEV1 50% < 80%; GOLD III (Severe): FEV1 30% < 50%; FEV1 and GOLD IV (Very Severe): FEV1 < 30%.

Statistical analysis

In the case of quantitative variables, data are shown as mean ± standard deviation (SD) or median (minimum-maximum), depending on whether the distribution was parametric or non-parametric, respectively. Nominal variables are shown as numbers or percentages. Comparisons between groups, in the case of nominal or categorical variables, were assessed by chi-squared, and for quantitative variables between degrees of severity ANOVA was used in ranges. A p-value < 0.05 was considered significant. Data were analyzed with SPSS for Windows, version 17.0.

Results

62 patients were studied with an average age of 64 ± 13 years, of which 61% were women; marital status was most often married (59%) and the most common level of education was equal to or less than primary (81%). 94% of patients live with at least one immediate family member, and 69% live in their own home; 40% are completely dependent on the income of a family member. 57% of the sample had comorbidities (26% one, 24% two, 7% three). Regarding risk factors for COPD, 56% of patients had a history of tobacco consumption, with a median of 18 packets/year. Of the population with a history of smoking, 53% continue to smoke. 42% of the population has a history of exposure to biomass (wood smoke), with an average exposure time of 9 ± 6 years (Table I).

Severity of COPD

According to the definitions in this study, 11 patients had a GS GOLD I (mild), 27 GOLD II (moderate), 11 GOLD III (severe) and 13 patients GOLD IV (very severe). In Table II, demographic, clinical and biochemical characteristics of the patients are presented by degree of GOLD severity. Age was significantly higher in patients with GOLD III and IV as compared with the GOLD I group. The PaO2 was significantly lower in the GOLD IV group as compared to group I; among the other groups no significant differences were observed. The % SatO₂ was significantly lower in the GOLD IV group as compared to groups I and II. The number of women in each group, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), hemoglobin (Hb), hematocrit (Hct) and PaCO₂ were not statistically different between groups.

Lung function tests

As expected by the definitions used, FEV1%, FVC% and FEV1/FVC% were significantly worse in patients in the GOLD IV group as compared to patients with the other three degrees of COPD severity. As the degree of severity increases, the value of these three parameters is significantly reduced (Table III).

HRQOL by degree of COPD severity

Regarding the overall results of the sample in each domain that integrates HRQOL and considering a scale of 0 to 100, where 0 represents the best possible quality of life, symptoms showed a mean ± standard deviation of 58 ± 20, activity of 65 ± 24, and the impact of COPD on quality of life was 44 ± 21. The total value was 54 ± 18 points.

When these results were compared according to GOLD severity (Table IV), a significant degree of effect was observed, even among patients with GOLD I in most domains. Activity and Impact dimensions were significantly worse in the GOLD III and IV groups as compared to the COPD in GOLD severity I. In the Impact domain there was also a significant difference between GOLD IV and II. Values for the Symptoms domain ​​were not significantly different between groups. As for the HRQOL for Total, it can be seen that when the degree of severity is greater, HRQOL is worse, where GOLD II, III and IV groups showed statistically significant difference when compared with GOLD I group; a significant trend (p = 0.06) between the HRQOL of GOLD IV group versus the GOLD II group was also observed.

Predictors of quality of life

In multivariate analysis, only FEV1 % and FVC significantly and independently predicted poorer quality of life in this sample of patients: FEV1 was B -8.63, odds ratio (OR) = -0.414, p = 0.023, 95% CI = -16.1-0.09; FVC was B -0.59, OR = -0.67, p = 0.011 and 95% CI = -1.05-0.14. Other factors that were included and did not predict changes in quality of life were: age, SBP, DBP, BMI, Hb, Htc, PaO2, PaCO₂, SatO₂%.

Discussion

In Mexico, recent studies have shown a significant increase in the prevalence of chronic diseases, including COPD.3 Since it is a non-curable disease in which therapeutic approaches are only palliative, the limited information in our area on health outcomes reported by the patient is striking,^11,13 especially since this is the first study in a second-level care hospital on a national level.

Our results show that in the study population, all domains that evaluate HRQOL in patients with COPD are affected by the disease, and each stage of severity is different: the deleterious effects of COPD on HRQOL increase as the disease’s severity is exacerbated, which matches findings of studies by Miratvilles,¹⁴ Anthonelli,¹⁵ and Jones et al.,¹⁶ among others.

This level of correlation is important, even among patients with mild degrees of COPD (GOLD I) in most domains; within each group there was considerable heterogeneity, as can be seen by the amplitude of the SD. In all groups, greater effects were evident in the Activity domain, while the lowest score was obtained in the Impact dimension — results that are consistent with previous reports,^16,18 including the original description included in the study of Jones et al.¹⁶ One possible explanation may be the natural history of the disease; since the progression of COPD can be considered gradual, patients often change their physical and social activities, and thus perceive less COPD impact on their HRQOL.¹⁹

Consistent with the results reported by Jones et al.,16 comorbidities in our group of patients with COPD were found in a high percentage (57%), coinciding with the conditions most frequently associated with the disease, such as hypertension and type 2 diabetes mellitus.

As shown by Sin et al.,¹⁷ the association between COPD and cardiovascular disease can be explained at least in part by the common findings of lung inflammation and the presence of markers of systemic inflammation such as C-reactive protein (CRP), fibrinogen, circulating leukocytes, and tumor necrosis factor (TNFα).

In this paper we characterize a population consisting predominantly of older adults with a mean age of 64 years; a high prevalence of early COPD (stages I and II) was found (71% of cases) and advanced COPD was found in 29% of patients. However, differing from most of the results reported in Caucasian patients, 61% of patients were female. These results are consistent with reports of studies in Latin America^3,11, although they differ from what has been published from most studies from Europe^16,20 and the United States¹⁸ in Saxon populations, in that the male gender is predominantly affected. This could be related to the use of wood fuel in Latin America for domestic activities,3 so the importance and significance of these cases lies in the exposure to this risk factor.^21,22 It is also noteworthy that the proportion of patients with a low level of education is similar to the reported average in the general population in Mexico and in Jalisco. This could reflect a negative impact of poverty and other disadvantageous conditions associated with the development of COPD. Because they were not objectives in this study, family history of smoking and other risk factors (such as exposure to wood smoke) were not revised to try to clear the role of social and family factors involved in the development of COPD. BMI shows a downward gradient to greater COPD severity; an argument that explains this association is found in recent reports showing COPD as a systemic disease with an important inflammatory component and high levels of TNF and IL-6.^20,23.

Health outcomes reported by the patient, and among them specifically HRQOL, have become unquestionably useful tools for the care of COPD from different perspectives. The study by Sin et al. defines composite indicators (such as HRQOL) as the best predictors of mortality, even more so than the FEV1 alone;¹⁷ while Hurst et al. shows increased susceptibility to both the occurrence and frequency of exacerbations of COPD in patients with poorer HRQOL measured by SGRQ.²⁴

Previous reports in our country are scarce and the objectives various. Unlike our research, the study by López-Vargas et al. retrospectively evaluated the relationship between the shuttle walk and chronic pulmonary disease in 95 patients in pulmonary rehabilitation, 37 carriers of COPD.²⁵ Aguilar et al. studied 51 patients with obstructive pulmonary disease during their hospital stay, of which 26 were patients with COPD and 25 with asthma, all from the Instituto  Nacional  de  Enfermedades Respiratorias, a hospital exclusively for lung diseases and conditions.13 In Chile, Lisbon et al. reported findings in HRQOL in 55 patients that were assessed with a different instrument, the chronic respiratory disease questionnaire (CRQ), and they compared a subset of 30 patients post-workout (pulmonary rehabilitation).²⁶

Moreover, assessing the economic impact of the treatment of diseases has become as important as the clinical understanding of them. Because of the high prevalence of COPD and the disabling effects as the disease’s severity progresses, the direct and indirect costs may represent a significant burden on health systems, societies, and individuals. The costs of COPD in productivity (labor absenteeism, disability, and premature death) may be significantly higher for developing countries. According to the study by Ramsey et al., the economic evaluation of COPD care should incorporate both the quality of life as well as the factor of time, both significant to the patient, the clinician, and health systems.²⁷

In conclusion, the greater the degree of severity of COPD, the more effected HRQOL, especially in the domains of Activity and Impact.

The need for early detection of COPD’s negative effect on HRQOL should be emphasized in order to establish multidisciplinary interventions to reduce the global burden of disease on patients, society, and health systems. Future studies are needed with larger numbers of patients or controlled clinical trials to ensure the effectiveness of the intervention of a multidisciplinary health team in improving HRQOL in patients with COPD.

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