Multiple respiratory symptoms predict quality of life in chronic lung disease: a population-based study of Australian adults

Longitudinal changes in pulmonary function and patient-reported outcomes after lung cancer surgery

Background

Surgery is the mainstay of treatment for non-small cell lung cancer, but the decline in pulmonary function after surgery is noticeable and requires attention. This study aimed to evaluate longitudinal changes in pulmonary function and integrated patient-reported outcomes (PROs) after lung cancer surgery.

Methods

Data were obtained from a prospective cohort study, the Coordinate Approach to Cancer Patients’ Health for Lung Cancer. Changes in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) at 2 weeks, 6 months, and 1 year after surgery, and the corresponding modified Medical Research Council (mMRC) dyspnea scale and chronic obstructive lung disease assessment test (CAT) scores were evaluated. Mixed effects model was used to investigate changes in pulmonary function and PROs.

Results

Among 620 patients, 477 (76.9%) underwent lobectomy, whereas 120 (19.4%) and 23 (3.7%) were treated with wedge resection/segmentectomy and bilobectomy/pneumonectomy, respectively. Both FVC and FEV₁ markedly decreased 2 weeks after surgery and improved thereafter; however, they did not recover to baseline values. The corresponding mMRC dyspnea scale and CAT scores worsened immediately after surgery. The dyspnea scale of the mMRC was still higher, while CAT scores returned to baseline one year after surgery, although breathlessness and lack of energy persisted. Compared to the changes from baseline of FVC and FEV₁ in patients who underwent lobectomy, patients who underwent bilobectomy/pneumonectomy showed a greater decrease in FVC and FEV₁, while wedge resection/segmentectomy patients had smaller decreases in FVC and FEV₁ at 2 weeks, 6 months, and 1 year after surgery. Bilobectomy/pneumonectomy patients had the highest mMRC dyspnea grade among the three groups, but the difference was not statistically significant one year after surgery.

Conclusions

After lung cancer surgery, pulmonary function and PROs noticeably decreased in the immediate post-operative period and improved thereafter, except for dyspnea and lack of energy. Proper information on the timeline of changes in lung function and symptoms following lung cancer surgery could guide patient care approaches after surgery.

Trial registration: ClinicalTrials.gov; No.: NCT03705546; URL: www.clinicaltrials.gov

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02149-9.

Health-related quality of life is inversely correlated with C-reactive protein and age in Mycobacterium avium complex lung disease: a cross-sectional analysis of 235 patients

Background

Mycobacterium avium complex (MAC) lung diseases generally cause chronic disease in immunocompetent hosts. Although a few studies have examined health-related quality of life (HRQL) in patients with MAC lung disease, there have been no large studies. This study aimed to evaluate HRQL and its correlation with clinical outcomes in MAC lung disease.

Methods

A cross-sectional study was conducted at Keio University Hospital to investigate the factors associated with HRQL in pulmonary nontuberculous mycobacterial diseases. MAC lung diseases were diagnosed according to the 2007 ATS/IDSA guidelines for nontuberculous mycobacterial diseases. The 36-item short form health survey (SF-36) was administered to assess clinical outcomes. Clinical variables included treatment status, latest haematological data, and bacterial smear and culture results.

Results

The SF-36 scores for the 235 patients (median age, 69 years; 45 men and 190 women) with MAC lung disease, except for the bodily pain and mental health subscale scores, were significantly lower than the Japanese population norms. In the multivariable analyses, current treatment for MAC and a positive sputum smear or culture within the past year were significantly associated with lower SF-36 scores. C-reactive protein (CRP) and age showed stronger inverse correlations with SF-36 scores.

Conclusions

HRQL, especially the physical component, was impaired in patients with MAC lung diseases; this appears to be related with current treatment status, positive sputum smear or culture within the previous year, and particularly CRP and age. Further studies including qualitative assessments are needed to investigate the efficacy of CRP as a marker for progression or treatment response in MAC lung disease.

Trial registration

Clinical trial registered with UMIN (UMIN000007964).

Occurrence of respiratory symptoms in persons with restrictive ventilatory impairment compared with persons with chronic obstructive pulmonary disease: The PLATINO study

Patients with chronic obstructive pulmonary disease (COPD) usually complain of symptoms such as cough, sputum, wheezing, and dyspnea. Little is known about clinical symptoms in individuals with restrictive ventilatory impairment. The aim of this study was to compare the prevalence and type of respiratory symptoms in patients with COPD to those reported by individuals with restrictive ventilatory impairment in the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar study. Between 2002 and 2004, individuals ≥40 years of age from five cities in Latin America performed pre and post-bronchodilator spirometry and had their respiratory symptoms recorded in a standardized questionnaire. Among the 5315 individuals evaluated, 260 (5.1%) had a restrictive spirometric diagnosis (forced vital capacity (FVC) < lower limit of normal (LLN) with forced expiratory volume in the first second to forced vital capacity ratio (FEV1/FVC) ≥ LLN; American Thoracic Society (ATS)/European Respiratory Society (ERS) 2005) and 610 (11.9%) were diagnosed with an obstructive pattern (FEV1/FVC < LLN; ATS/ERS 2005). Patients with mild restriction wheezed more ((30.8%) vs. (17.8%); p < 0.028). No difference was seen in dyspnea, cough, and sputum between the two groups after adjusting for severity stage. The health status scores for the short form 12 questionnaire were similar in restricted and obstructed patients for both physical (48.4 ± 9.4 vs. 48.3 ± 9.8) and mental (50.8 ± 10.6 vs. 50.0 ± 11.5) domains. Overall, respiratory symptoms are not frequently reported by patients with restricted and obstructed patterns as defined by spirometry. Wheezing was more frequent in patients with restricted pattern compared with those with obstructive ventilatory defect. However, the prevalence of cough, sputum production, and dyspnea are not different between the two groups when adjusted by the same severity stage.

Results from several population studies show that recommended scoring methods of the SF-36 and the SF-12 may lead to incorrect conclusions and subsequent health decisions

PURPOSE

To compare the measurement properties of the physical component summary (PCS) and mental component summary (MCS) scores of the SF-36 and SF-12 based on the traditional orthogonal scoring algorithms with the performance of the PCS and MCS scored based on structural equation model coefficients from a correlated model.

METHODS

This study used three large-scale representative population studies to compare the measurement properties of the PCS and MCS scores of the SF-36 and SF-12 with the performance of the PCS and MCS scores based on structural equation models producing coefficients from a correlated model. We assessed the relationships of these scores with selected important mental health measures and chronic conditions from three representative Australian population studies that address clinical conditions of high prevalence and health service importance.

RESULTS

Structural equation model scoring methods produced summary scores with higher correlations than the recommended orthogonal methods across a range of disease and health conditions. The problem experienced in using the orthogonal methods is that negative scoring coefficients are applied to negative z-scores for sub-scales, inflating the resulting summary scores. Effect sizes over a half of a standard deviation were common.

CONCLUSIONS

If health policy or investment decisions are made based on the results of studies employing the recommended orthogonal scoring methods then the expected outcome of such decisions or investments may not be achieved.

The Australian Baby Boomer Population—Factors Influencing Changes to Health-Related Quality of Life Over Time

Objectives: Identify factors associated with changes to health-related quality of life (HRQoL) in baby boomers. Methods: Panel data were collected on baby boomers at two time points, 2000-2002 and 2004-2006. A fixed-effects model was used to identify associations between changes in the dependent variable (SF-36 summary scales) and changes in independent variables (health indicators/employment status). Results: Mental health problems, being out of labor force, sedentary behavior, and severe lung disease were associated with deterioration in physical and mental HRQoL. Obesity was associated with deterioration in physical HRQoL whereas cardiovascular disease was associated with deterioration in mental HRQoL. Unemployment, full-time employment, and absence of lung disease symptoms were associated with improvements in physical and mental HRQoL. Discussion: If we are to maximize the future labor participation, and HRQoL, of this cohort, it will be necessary to reduce obesity and sedentary behavior and to further investigate the association between health and employment.

Depression and obesity in adults with asthma: multiple comorbidities and management issues

OBJECTIVE

To examine the comparative prevalence and distribution of obesity and psychological disturbance in the asthma and non-asthma populations, and to determine how these comorbidities are associated with physical functioning.

DESIGN, SETTING AND PARTICIPANTS

A South Australian population-representative study of 3175 adults who provided data on asthma, psychological morbidity, physical functioning, and body mass index. Bivariate and multivariate analyses identified how these comorbidities were distributed in asthma and non-asthma subpopulations, and the variance in physical functioning that they explained.

MAIN OUTCOME MEASURES

Rates of obesity and psychological morbidity, and physical functioning scores in asthma and non-asthma populations.

RESULTS

Men and women in the asthma population had similar prevalences of obesity (35.3% v 33.6%) and psychological morbidity (29.5% v 29.4%). When compared with non-asthma controls, both comorbidities were significantly higher only in men with asthma. The prevalence of psychological morbidity within different weight categories in the asthma population compared with non-asthma weight-category controls varied by sex. Physical functioning was lower in the asthma population than the non-asthma population (46.6 [95% CI, 45.9-47.3] v 48.8 [95% CI, 47.8-50.0]; P < 0.001), and psychological morbidity explained 22% of this variance.

CONCLUSIONS

Psychological morbidity and obesity are common in people with asthma. The sex-specific variation in psychological morbidity across weight categories suggests that future studies of psychological morbidity in groups with asthma should adopt designs that consider sex-specific controls rather than comparisons between the sexes.

Global Initiative for Chronic Obstructive Lung Disease stage 0 is associated with excess FEV(1) decline in a representative population sample

BACKGROUND

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) guideline removed stage 0 (chronic cough and sputum without airflow obstruction, GOLD-0) because of poor prognostic value. Preventative intervention may be relevant for those with chronic symptoms; therefore, we assessed the stability, morbidity, and FEV(1) decline associated with GOLD stage 0 in a representative adult population cohort.

METHODS

Baseline (n = 4,060) and follow-up (n = 3,206, mean 3.5 years) clinic assessment of the North West Adelaide Health Study included postbronchodilator spirometry, anthropometry, and measures of doctor-diagnosed asthma, respiratory symptoms, smoking status, quality of life, and depression.

RESULTS

Baseline GOLD-0 prevalence was 17.0% (n = 584). At follow-up (n = 420), 39.8% remained stable, 1.4% progressed to GOLD stages 1 to 2, and 58.8% resolved to no symptoms. Persistent GOLD-0 at follow-up was associated with persistent smoking (men: odds ratio [OR] = 11.9, 95% CI, 6.4-22.1; women: OR = 4.0, 95% CI, 2.1-7.4), and depressive symptoms (men: OR = 3.8, 95% CI, 1.9-7.6; women: OR = 3.2, 95% CI, 1.7-5.9), with highest quartile of FEV(1) decline (mL) per year (OR = 2.1, 95% CI, 1.2-3.7) and the metabolic syndrome (OR = 1.7, 95% CI, 1.01-3.0) in men, and with older age in women. These associations generally held in smokers and never-smokers. Resolving GOLD-0 was associated with smoking cessation (OR = 13.7; 95% CI, 4.6-40.1), FEV(1) decline (mL) per year below the median (OR = 2.0; 95% CI, 1.1-3.5), normal BMI, and younger age groups. Sensitivity analyses based on the presence of sputum did not change the observed associations.

CONCLUSION

Persistent GOLD-0 identified people with physical and psychologic morbidity in both smokers and nonsmokers. Identification of those with persistent respiratory symptoms is therefore important. Excess FEV(1) decline in men suggests GOLD-0 may identify a group at risk to progress to COPD over time.

Associations of physical and mental health problems with chronic cough in a representative population cohort

BACKGROUND

Although chronic cough is a common problem in clinical practice, data on the prevalence and characteristics of cough in the general population are scarce. Our aim was to determine the prevalence of chronic cough that is not associated with diagnosed respiratory conditions and examine the impact on health status and psychological health, in a representative adult population cohort

METHODS

North West Adelaide Health Study (n stage 1 = 4060, stage 2 = 3160) is a representative population adult cohort. Clinical assessment included spirometry, anthropometry and skin tests. Questionnaires assessed demographics, lifestyle risk factors, quality of life, mental health and respiratory symptoms, doctor diagnosed conditions and medication use.

RESULTS

Of the 3355 people without identified lung disease at baseline, 18.2% reported chronic cough. In multiple logistic regression models, at follow-up, dry chronic cough without sputum production was significantly more common in males (OR 1.5, 95% CI 1.1, 1.9), current smokers (OR 4.9, 95% CI 3.4, 7.2), obesity (OR 1.9, 95% CI 1.3, 2.9), use of ACE inhibitors (OR 1.8, 95% CI 1.1, 2.9), severe mental health disturbance (OR 2.1, 95% CI 1.4, 3.1) and older age (40-59 years OR 1.7 95% CI 1.2, 2.4; > or = 60 years OR 2.1 95% CI 1.3, 3.5). Among non-smokers only, all cough was significantly more common in men, those with severe mental health disturbance and obesity.

CONCLUSIONS

Chronic cough is a major cause of morbidity. Attention to cough is indicated in patients with obesity, psychological symptoms or smokers. Inquiring about cough in those with mental health problems may identify reversible morbidity.

Evaluating quality of life and pulmonary function of long-term survivors of non-small cell lung cancer treated with radical or postoperative radiotherapy

BACKGROUND

Our aim in the present study was to describe the quality of life (QOL), evaluate pulmonary function, and compare demographic and clinical characteristics with QOL in long-term survivors of non-small cell lung cancer treated with radical or postoperative radiotherapy.

METHODS

Twenty-eight patients were recruited in the study. QOL was evaluated using The European Organization for Research and Treatment of Cancer, Quality of Life Core Questionnaire (EORTC QLQ-C30, v.3). Statistical analysis was performed by SPSS 14.

RESULTS

Patients' files were reviewed in October 2006. Median duration of follow-up was 46 months (range: 25-125 months). Seven of 9 scales were found to meet the minimal reliability limit (Cronbach's alpha >0.70). The lowest and highest reliability coefficients were 0.56 and 0.93 for social and role functioning, respectively. All interscale correlations were statistically significant (P < 0.01). The strongest positive correlation was found between physical functioning and, role and cognitive functioning (r = 0.59, r = 0.37 or P = 0.01, P = 0.05, respectively). The highest correlation of EORTC QLQ-C30 and the Karnofsky performance scale (KPS) during the questionnaire was found to be with physical functioning and constipation (r = 0.41, r = 0.44 or P = 0.02, P = 0.01, respectively). When the effect of various demographic and clinical parameters on QOL was evaluated; initial KPS, age, educational level, health insurance status, stage, chemotherapy, comorbid disease, and passive smoking were determined as significant factors influencing QOL. Physical, role, cognitive, and emotional functions were found to be significantly lower in the presence of dyspnea (r = 0.42, r = 0.58, r = 0.50, r = 0.63 or P = 0.02, P < 0.01, P < 0.01, P < 0.05, respectively). Regarding the symptom scales, dyspnea was found to be correlated with increasing of fatigue, pain, insomnia, and appetite loss (r = 0.52, r = 0.40, r = 0.64, r = 0.38 or P < 0.01, P = 0.03, P < 0.05, P = 0.04, respectively). The parameters of pulmonary function tests (FEV1, FVC, and FEV1/FVC) did not show any significant relation with any scale of QOL.

CONCLUSION

Overall, we found that QOL of our patients who survived at least 2 years after radiotherapy, was good. The Turkish version of the EORTC QLQ-C30, v.3 is a valid and reliable instrument for Turkish lung cancer patients and can be used in clinical studies. We believe further studies are needed to have a better understanding of patients' pretreatment and posttreatment QOLs.

Pneumonectomy: Post-operative quality of life and lung function

BACKGROUND

Pneumonectomy is associated with high morbidity and mortality. After pneumonectomy, data on health-related quality of life (HRQoL) or its correlation with dyspnea and lung function are scarce. Our main aim was to evaluate long-term HRQoL after pneumonectomy.

METHODS

In a retrospective one-center cross-sectional study, we investigated 31 of 98 patients who underwent pneumonectomy between January 1997 and October 2003 due to primary lung cancer. Pre- or postoperative chemotherapy or radiotherapy was applied according to hospital protocol. In June 2004, all patients alive received the generic HRQoL instrument (15D), as well as the Baseline Dyspnea Index (BDI). Results of the 15D were compared with those for an age- and gender-standardized general population. In April 2005, 20 patients participated in follow-up spirometric pulmonary function tests.

RESULTS

The 15D total score and its various dimensions were significantly lower after pneumonectomy than in the general population. Females both in 15D score and in the BDI had more dyspnea (p<0.05). No difference appeared between right and left pneumonectomy patients, except for more prominent dyspnea in women with right-sided pneumonectomy.

CONCLUSIONS

Pneumonectomy had a negative impact on patients' HRQoL. The use of a broad HRQoL instrument like the 15D, which covers multiple dimensions of HRQoL, yields a more accurate evaluation than did a single-dimension HRQoL instrument. Possibilities for sleeve-resection should be considered thoroughly before any pneumonectomy.

SUMMARY

Quality of life (QoL) after pneumonectomy, as measured with a generic QoL instrument, the 15D, was compared in an age- and gender-standardized population. QoL after pneumonectomy was significantly lower, especially in women after right-sided pneumonectomy.

Impact of chronic obstructive pulmonary disease on respiratory status and quality of life in newly diagnosed patients with lung cancer

OBJECTIVE AND BACKGROUND

A significant proportion of patients with lung cancer have associated COPD, which is considered an independent risk factor and cause of morbidity and mortality. However, the effect of COPD on respiratory status and quality of life in lung cancer has not been evaluated.

METHODS

Newly diagnosed patients with lung cancer were assessed at diagnosis before starting treatment, for detailed respiratory status, spirometry and World Health Organization-Bref Quality of Life questionnaire in Hindi (WHOQOL-Bref Hindi).

RESULTS

One hundred and sixty patients were studied. Spirometry was abnormal in 92.7% patients, 42% had COPD, and the majority (88.6%) had advanced disease (stage III and IV). Patients scored poorly in all QOL domains, with social domain faring worst. Karnofsky Performance status (KPS) correlated significantly with all QOL domains. No significant differences were found in clinical profile, KPS, or QOL scores between patients with and without COPD. Chest pain and dyspnoea severity (assessed by Medical Research Council) grading and visual analogue scale correlated with physical QOL domain.

CONCLUSION

Patients with lung cancer have a poor QOL that is affected by the severity of respiratory profile and KPS. The presence of COPD does not significantly affect QOL in lung cancer patients.

Examining the Role of Gender in Health-Related Quality of Life: Perceptions of Older Adults With Chronic Obstructive Pulmonary Disease

The purpose of this cross-sectional study was to explore the impact of gender on health-related quality of life perceptions among 67 older adults with chronic obstructive pulmonary disease who were living with a spouse. Physical and psychosocial health-related quality of life perceptions as well as demographic and illness-related variables were compared by gender. A correlation and regression analysis revealed women experienced significantly greater psychosocial impairment, while preliminary support was found for symptom-related impairment among men. Initial recommendations for nursing interventions include incorporating anticipatory guidance from older adults with late stages of chronic obstructive pulmonary disease as well as exploring the impact of symptoms.

Quality of life in newly diagnosed patients with lung cancer in a developing country: is it important?

There are no data regarding quality of life (QoL) assessments in lung cancer in developing countries like India. Quality of life was evaluated in 76 newly diagnosed lung cancer patients by using the World Health Organization Quality of Life questionnaire in Hindi (WHOQoL-Bref) (men 87%). The mean age was 55 years (SD = 10). Cough, dyspnoea, chest pain and haemoptysis were present in 83%, 72%, 66% and 43% of patients respectively. The median duration of symptoms was 5.9 months (range 1-13). Eighty-nine per cent had non-small cell lung cancer. The median pack-years smoked was 23 (range 0.5-88). Most patients (53%) had a Karnofsky's Performance Status (KPS) of 70 and 83% had stage III or IV disease. Quality of life did not correlate with age, gender, presence or duration of symptoms, histological type, stage of disease or degree of smoking. The physical and psychological domains of QoL correlated significantly with the KPS (P = 0.001 and P = 0.01 respectively). Patients with a KPS of 80 had better physical (P < 0.001), psychological (P < 0.01) and social (P < 0.05) QoL than those with a KPS of 70. In conclusion, patients with lung cancer in a developing country like India have an unsatisfactory QoL. The Karnofsky's Performance Scale is a simple and reliable surrogate marker for assessing QoL in these patients. Larger multi-centric studies may help in providing a more comprehensive evaluation of the effect of various demographic and clinical variables on QoL in this setting.

Spirometric criteria for asthma: adding further evidence to the debate

BACKGROUND

Objective assessments of pulmonary function are considered essential for the diagnosis of asthma. The degree of reversibility of FEV(1) considered supportive of asthma varies between international asthma guidelines.

OBJECTIVE

We sought to compare the relative performance of international guideline reversibility criteria for identifying impairment in persons with a significant bronchodilator response (SBR) without an asthma diagnosis.

METHODS

The North West Adelaide Health (Cohort) Study, a population biomedical study of 4060 subjects, conducted spirometry according to American Thoracic Society criteria. SBR was defined as postbronchodilator FEV(1) responses of at least 12% or 15% of baseline values, 9% of predicted values, or 400 mL. A self-completed questionnaire assessed current asthma (CA), respiratory symptoms, and participant demographics.

RESULTS

The prevalence of CA was 9.4% (n = 380), whereas 1.3% (>/=400 mL) to 4.5% (>/=9% of predicted value) of participants demonstrated an SBR in the absence of CA. With the exception of the 9% predicted criterion, prebronchodilator mean FEV(1) (percent predicted) in those demonstrating an SBR but no CA was significantly worse than that in the CA group. Significantly more respiratory symptoms were experienced by the SBR groups than the group without asthma. Logistic regression analyses identified different characteristics of those classified by the following criteria: 12% and 15%, age of 40 years or greater and household income of less than $40,000; 9% predicted, household income of less than $40,000; 400 mL, male sex (odds ratio, 4.5; 95% CI, 2.1-9.3).

CONCLUSIONS

Different criteria identify different persons, but SBR by any criteria was associated with significant respiratory impairment, some of which might be attributable to asthma. Postbronchodilator change as a percentage of predicted value was the least biased of the criteria.

Impact of respiratory symptoms and pulmonary function on quality of life of long-term survivors of non-small cell lung cancer

PURPOSE

To describe respiratory symptoms and pulmonary function among long-term survivors of non-small cell lung cancer (NSCLC), and their relationship to quality of life (QOL).

METHODS

Cross-sectional survey of disease-free, 5-year minimum survivors of NSCLC (n = 142; 54% women; average age, 71 years); the majority (74%) had received a lobectomy. Analysis included frequency of self-reported respiratory symptoms (cough, phlegm, wheezing, breathlessness) as measured by the American Thoracic Society questionnaire, pulmonary function findings from hand-held spirometry, and QOL (Short Form-36).

RESULTS

Two thirds of survivors reported at least one respiratory symptom (mean, 1.3; SD, 1.2): 25% cough, 28% phlegm, 31% wheezing, and 39% dyspnea. Twenty-one percent reported that they spent most of the day in bed in the past 12 months because of respiratory symptoms. Average FEV(1) percentage predicted was 68% (SD, 23); 21% had < 50% predicted FEV(1). Based on spirometry results, 36% had a moderate/severe obstructive and/or restrictive ventilatory disorder. Survivors exposed to second-hand smoke (28%) were more than three times as likely to report respiratory symptoms. Respiratory symptom burden contributed to diminished QOL in several domains.

CONCLUSIONS

The majority of these survivors experienced respiratory symptoms, and more than one third reported dyspnea, including one of five patients with seriously diminished pulmonary function. Symptom burden, rather than ventilatory impairment, contributed to diminished QOL. Further study is needed to determine the patterns and effective management of posttreatment respiratory symptoms on survivors of lung cancer.

Underdiagnosed asthma in South Australia

BACKGROUND

The prevalence of undiagnosed asthma in the general population and the clinical and demographic characteristics of these patients compared with those with diagnosed asthma are unclear.

METHODS

The North West Adelaide Health Survey (NWAHS) is a population household interview survey of adults (age>18 years) in the north western suburbs of Adelaide, South Australia (regional population 0.6 million). Data obtained were weighted to the closest census data to provide population representative estimates. Positive answers to: "Have you ever had asthma?"; "Has it been confirmed by a doctor?"; "Do you still have asthma?" determined current physician diagnosed asthma. A positive bronchodilator response on spirometric testing according to ATS criteria without a physician's diagnosis determined undiagnosed asthma. Other measures included the SF-12 health survey questionnaire, the Selim index of severity of chronic lung disease, skin allergy tests, and demographic data.

RESULTS

Of the 3422 individuals interviewed, 2523 (74%) agreed to participate in the clinical assessment. Of these, 292 (11.6%) had asthma, 236 (9.3%) with a doctor's diagnosis of asthma and 56 (2.3%) with undiagnosed asthma defined on spirometric criteria; thus, 19.2% of the total asthma group were undiagnosed. Those undiagnosed were more likely (p<0.05) to be >40 years old, on government benefits, with an income <AUD$40,000. Symptom frequency was similar in the two asthma groups, but mean spirometric values were lower in the undiagnosed group (p<0.05) while positive skin allergy tests were more common in the diagnosed group (p<0.05). SF-12 component summary scores were significantly lower in both asthma groups than in the non-asthma population. Undiagnosed asthma was frequent in men and in those aged >65 years. Health service use over the previous year was similar for both asthma groups.

CONCLUSION

Undiagnosed asthma is common among the Australian population, with a similar clinical spectrum to those with diagnosed asthma.