Components of the COPD Assessment Test (CAT) associated with a diagnosis of COPD in a random population sample

Abstract

The aim of this study was to determine if components of the COPD Assessment Test (CAT), a validated health status impairment instrument, had additional utility in identifying patients at risk for COPD in whom spirometry testing is appropriate. This study was part of the Canadian Obstructive Lung Disease prevalence study. Consenting participants ≥ 40 years of age were identified by random digit dialing. Smoking history, 8-item CAT scores, and post-bronchodilator spirometry were recorded for each. Stepwise logistic regression analysis was used to identify variables related to the presence of airway obstruction and a final logistic model was developed which best predicted COPD in this sample. Of the 801 individuals approached, 532 were included: 51 (9.6%) had COPD, the majority (92%) of whom fit GOLD I or II severity criteria. Items that correlated significantly with a COPD diagnosis included the CAT total score (p = 0.01) and its breathlessness (p < 0.0001) and phlegm (p = 0.001) components. The final logistic model included: age (<55 or ≥55 years), smoking status (current, former, never) and the CAT breathlessness score (ordinal scale 0–5). The area under the receiver-operating characteristic curve for this model was 0.77, sensitivity was 77.6%, specificity was 64.9% and the positive likelihood ratio was 2.21. In summary, the triad of smoking history, age at least 55 years and the presence of exertional breathlessness were key elements of a simple model which had reliable measurement properties when tested in a random population. This may help identify patients at risk for COPD for whom spirometry testing is recommended.     

Comparison of the COPD Assessment Test (CAT) and the Clinical COPD Questionnaire (CCQ) in a Clinical Population

Introduction: The COPD Assessment Test (CAT) and the Clinical COPD Questionnaire (CCQ) are both clinically useful health status instruments. The main objective was to compare CAT and CCQ measurement instruments. Methods: CAT and CCQ forms were completed by 432 randomly selected primary and secondary care patients with a COPD diagnosis. Correlation and linear regression analyses of CAT and CCQ were performed. Standardised scores were created for the CAT and CCQ scores, and separate multiple linear regression analyses for CAT and CCQ examined associations with sex, age (≤ 60, 61–70 and >70 years), exacerbations (≥1 vs 0 in the previous year), body mass index (BMI), heart disease, anxiety/depression and lung function (subgroup with n = 246). Results: CAT and CCQ correlated well (r = 0.88, p < 0.0001), as did CAT ≥ 10 and CCQ ≥ 1 (r = 0.78, p < 0.0001). CCQ 1.0 corresponded to CAT 9.93 and CAT 10 to CCQ 1.29. Both instruments were associated with BMI < 20 (standardised adjusted regression coefficient (95%CI) for CAT 0.56 (0.18 to 0.93) and CCQ 0.56 (0.20 to 0.92)), exacerbations (CAT 0.77 (0.58 to 0.95) and CCQ 0.94 (0.76 to 1.12)), heart disease (CAT 0.38 (0.17 to 0.59) and CCQ 0.23 (0.03 to 0.43)), anxiety/depression (CAT 0.35 (0.15 to 0.56) and CCQ 0.41 (0.21 to 0.60)) and COPD stage (CAT 0.19 (0.05 to 0.34) and CCQ 0.22 (0.07 to 0.36)). Conclusions: CAT and CCQ correlate well with each other. Heart disease, anxiety/depression, underweight, exacerbations, and low lung function are associated with worse health status assessed by both instruments.     

Assessing the Effectiveness of the COPD Assessment Test (CAT) to Evaluate COPD Severity and Exacerbation Rates

Aims: The CAT is a short, simple eight-item questionnaire for assessing and monitoring COPD. It is not known how reliable the CAT scores are for COPD patients who are frequently exacerbated. The effectiveness of the CAT for assessing COPD severity and exacerbation rates was evaluated. Methods: This study enrolled 165 stable COPD patients who completed the CAT between April 2011 and February 2012. Results: Patients had a mean forced expiratory volume in one second (FEV₁) equal to 43.7% of the predicted value and a mean CAT score of 21.2 (± 7.56) units. There was a good association between the FEV₁ (percentage of predicted value) and CAT scores (p < 0.0001). Frequent exacerbators had significantly higher CAT scores than infrequent exacerbators (24.8 ± 6.7 versus 17.5 ± 6.5, p < 0.0001). Also, as the frequency of the COPD exacerbations increased, CAT scores (p < 0.0001) significantly increased. There was a significant association between the frequency of hospitalization and the CAT scores (p = 0.001). Conclusions: We observed a good relation between the CAT, FEV 1, and disease severity in patients with COPD. We found that the baseline CAT scores are elevated in frequent exacerbators.     

The COPD Assessment Test (CAT): Short- and Medium-term Response to Pulmonary Rehabilitation

Abstract

Background: The COPD Assessment Test (CAT) is a recently introduced instrument to assess health-related quality of life in COPD. We aimed to evaluate the longitudinal change in CAT following Pulmonary Rehabilitation (PR), and test the relationship between CAT and CRQ-Self Report (SR) over time. We hypothesised that the CAT would show similar responsiveness to PR as the CRQ-SR both in the short and medium-term. Methods: 118 COPD patients completed an eight-week outpatient multidisciplinary PR programme. CAT, CRQ-SR and the incremental shuttle walk (ISW) were measured prior to starting PR (T1), completion of PR (T2) and 6 months after completion of PR (T3). Results: There was a significant improvement in CAT, CRQ-SR and ISW immediately following PR (p?<?0.001). Although there was decline between T2 and T3, CAT, CRQ-SR and ISW remained significantly better at T3 compared with T1 (ANOVA p?<?0.001). Both between T1-T2 and between T2-T3, change in CAT correlated significantly with change in CRQ (both r = -0.44 and p?<?0.001). The slope of the relationship between CAT change and CRQ-SR change at T1-T2 and T2-T3 was not significantly different (ANCOVA: intercept p = 0.79, interaction effect p = 0.95). Conclusions: In COPD, the CAT score is immediately responsive to PR and remains improved at 6 months. There is no significant difference in the short and medium term changes in the CAT and CRQ-SR following PR. We propose that for most clinical indications for assessing health-related quality of life in COPD, the CAT is a robust and practical alternative to longer-established instruments such as the CRQ-SR.     

COPD prevalence in a random population survey: a matter of definition.

A recent American Thoracic Society and European Respiratory Society joint Task Force report recommends using a lower limit of normal (LLN) of forced expiratory volume in one second/forced vital capacity as opposed to a fixed ratio of <0.7 to diagnose airflow obstruction, in order to reduce false positive diagnoses of chronic obstructive pulmonary disease (COPD) as defined by the Global Initiative for Obstructive Lung Disease (GOLD). To date, there is no reliable spirometry-based prevalence data for COPD in New Zealand and the effect of different definitions of airflow obstruction based on post-bronchodilator spirometry is not known. Detailed written questionnaires, full pulmonary function tests (including pre- and post-bronchodilator flow-volume loops) and atopy testing were completed in 749 subjects recruited from a random population sample. The GOLD-defined, age-adjusted prevalence (95% confidence interval) for adults aged >or=40 yrs was 14.2 (11.0-17.0)% compared with an LLN-defined, age-adjusted, post-bronchodilator prevalence in the same group of 9.0 (6.7-11.3)%. The prevalence of chronic obstructive pulmonary disease varied markedly depending on the definition used. Further research using longitudinal rather than cross-sectional data will help decide the preferred approach in chronic obstructive pulmonary disease prevalence surveys.     

Blood pressure associated with sleep-disordered breathing in a population sample of children

The current criteria for sleep-disordered breathing (SDB) in children are not based on a clinically relevant outcome. The purpose of this study was to assess the association of blood pressure with SDB in a random sample of the local elementary school children (kindergarten through grade 5) using a 2-phased strategy. During phase 1, a brief questionnaire was completed for all of the children (N=5740) with a response rate of 78.5%. During phase 2, 700 randomly selected children from phase 1 with a response rate of 70.0% were assessed with a full polysomnograph and a history/physical, including an ECG; ear, nose, and throat; and pulmonary evaluation. We observed a significantly elevated systolic blood pressure associated with the apnea hypopnea index (AHI): AHI >or=1 (2.9 mm Hg); AHI >or=3 (7.1 mm Hg); and AHI >or=5 (12.9 mm Hg). The SDB and blood pressure association remained significant after adjusting for age, sex, race, body mass index percentile or waist circumference, sleep efficiency, percentage of rapid eye movement sleep, and snoring. In addition, older age, body mass index percentile, waist circumference, and snoring were significantly associated with blood pressure, independent of SDB. Based on these findings, our study suggests that SDB is significantly associated with higher levels of systolic blood pressure in children aged 5 to 12 years even after adjusting for the various confounding factors. Clinically, the data support the threshold of AHI >or=5 for the initiation of treatment for SDB. Additional research is indicated to assess the efficacy of SDB treatment on reducing blood pressure.     

Exhaled nitric oxide and influencing factors in a random population sample

The aim of the current study was to determine the impact and interaction of important influencing factors on the fraction of exhaled nitric oxide (FeNO). FeNO was measured in a population-based sample of 1250 middle-aged subjects from the KORA F4 cohort (Augsburg, Germany). Analysis of covariance models was performed including the factors age, height, FVC, FEV(1), sex, current smoking status, recent respiratory tract infection, and respiratory allergy. Geometric mean (SD as factor; 95% confidence interval as factor) FeNO was 13.9 (1.9; 1.033) ppb. FeNO significantly depended on age, height, smoking, infection and allergy. Smoking reduced FeNO by 21%, while infection and allergy led to increases by 9 and 11%, respectively. Increases in age by 10 years and in height by 10 cm were associated with increases of FeNO by 15 and 10%, respectively. Non-smokers demonstrated independent multiplicative superposition of factors affecting FeNO while the effect of allergy was virtually eliminated in smokers without infection. We conclude that in middle-aged non-smokers the effects of infection, age and height can be easily taken into account and do not significantly disturb the effect of respiratory tract allergies on FeNO. In current smokers, however, effects were heterogeneous and information on smoking intensity seems to be useful for better adjustment.     

Risk factors for benign oesophageal disease in a random population sample

The association of sex, age, relative weight, smoking and drinking habits, chronic obstructive pulmonary disease (COPD) and economic and marital status, with benign oesophageal disease (BOD) was investigated by means of a point-prevalence study of BOD in a Danish population. A total of 346 individuals, representing subjects who gave positive responses to the discriminating questions pertaining to BOD and risk factors in a previously described questionnaire, as well as control subjects, were invited to participate in a clinical examination. Invasive investigation was accepted by 175 subjects, 114 of whom were diagnosed as having BOD. A statistically significant relationship between BOD and COPD was demonstrated by univariate analysis, and later confirmed by multivariate analysis (P less than 0.01). Odds ratios suggested a non-significant association between BOD and smoking at least 20 g tobacco a day and consuming greater than or equal to 50 alcoholic drinks per week. Obesity, sex, age, marital and economic status were not risk factors for BOD.     

Using ankle-brachial index to detect peripheral arterial disease: prevalence and associated risk factors in a random population sample

Background and aimThe ankle-brachial index (ABI) is being used increasingly to diagnose peripheral arterial disease (PAD) that predicts cardiovascular morbidity and mortality. The aim of this study is to determine the prevalence of PAD and associated risk factors in a Spanish random population sample of age ≥40.Methods and resultsPAD is defined as an ABI < 0.9 in either leg. 784 participants of age ≥40 were randomly selected in a Spanish province. 55.4% of them were female. The prevalence of PAD in this sample was 10.5% (95% confidence interval (CI) 8.4–12.8); 9.7% in females and 11.4% in males. In logistic regression analyses, adjusted for age and gender, smoking per 10 pack-years (odds ratio (OR) 1.40, 95% CI 1.23–1.58), hypertension (OR 1.85, 95% CI 1.05–3.28), hypercholesterolemia (OR 1.76, 95% CI 1.04–2.98), and diabetes (OR 1.80, 95% CI 1.04–3.11) were positively associated with prevalent PAD. More than 91% of persons with PAD had one or more cardiovascular disease risk factors.ConclusionsWe conclude that in our study hypertension, hypercholesterolemia, diabetes mellitus and smoking are associated with PAD. The majority of individuals with PAD had at least one important cardiovascular risk factor advanced enough to be considered eligible for an aggressive treatment.     

Seven-year cumulative incidence of COPD in an age-stratified general population sample

AIM: To estimate the cumulative incidence of COPD and risk factors related to the development of COPD, including evaluation of the relationship between Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 0 (ie, respiratory symptoms and normal lung function) and the development of COPD, in an age-stratified general population sample of middle-aged and elderly individuals. METHOD: The third survey of the Obstructive Lung Disease in Northern Sweden studies cohort I (three age strata born in 1919 to 1920, 1934 to 1935, and 1949 to 1950) was performed in 1996, and 5,189 subjects (88%) responded to the postal questionnaire. Of the responders, a random sample (1,500 subjects) was invited to an examination in 1996 and in 2003. A total of 963 subjects performed spirometry on both occasions. COPD was defined according to the spirometric criteria of the GOLD. Two levels of disease severity, grade I and higher (GOLD criteria, FEV(1)/FVC ratio of < 0.70) and also grade II and higher (GOLD II criteria, FEV(1)/FVC ratio of < 0.70 and FEV(1) <80% predicted). RESULTS: The 7-year cumulative incidence of COPD was 11.0% and 4.9%, respectively, according to GOLD and GOLD II, and was significantly related to smoking (smokers, 18.8% and 10.6%, respectively; ex-smokers, 10.5% and 5.2%, respectively; non-smokers, 7.6% and 1.6%, respectively). Incident COPD according to GOLD, but not according to GOLD II, was significantly associated with increasing age. Most respiratory symptoms at study entry were markers of increased risk for incident COPD when analyzed in a multivariate model adjusting for confounders. CONCLUSION: The GOLD criteria yielded a higher cumulative incidence (11.0%) compared to the GOLD II (4.9%). Smoking, but not gender, was associated with incident COPD. Most respiratory symptoms at the beginning of the observation period marked an increased risk for developing COPD, thus the classification GOLD stage 0 seems relevant among middle-aged and elderly persons.     

Development of the Japanese version of the COPD Assessment Test

BackgroundWe aimed to develop the Japanese version of the COPD Assessment Test^TM (CAT), which was recently developed in overseas countries, to measure the health status of patients with chronic obstructive pulmonary disease (COPD) and to validate its psychometric properties.MethodsThe original CAT was translated to Japanese through linguistic validation. Then, an Internet-based survey was conducted by including 301 Japanese patients with COPD who were over 40 years of age and had a history of smoking, to assess the reliability and validity of the translated CAT.ResultsThe Japanese CAT was shown to have high internal consistency (Cronbach's α coefficient: 0.891). The assessment using the Japanese CAT was highly correlated with assessment using the COPD-specific St. George's Respiratory Questionnaire (r=0.820). The assessment also showed correlation between the Japanese CAT and a generic health-related quality of life (QOL) questionnaire (SF-12v2).ConclusionThe Japanese version of the CAT has high reliability and validity, and can be expected to serve as a short and simple questionnaire for precise assessment of the health status of Japanese patients with COPD.