Chronic Respiratory Disease

We tested associations between risk factors and bone mineral density in airways disease subjects, and developed a clinical screening tool to identify people who could benefit from bone mineral density testing. Subjects were recruited through hospital outpatients and pharmacies (Newcastle, n = 172). With survey refinement, we then tested a revised tool in a second sample (Adelaide, n = 317). Study factors included oral/inhaled corticosteroid use, asthma severity, respiratory admissions, physical activity, percent predicted forced expiratory volume in one second (FEVI), body mass index, and smoking history. Outcomes were bone mineral density of lumbar vertebra (L2–4) and total (or neck of) femur. Analysis was logistic regression with generation of a simple screening algorithm based upon coefficients. Scoring algorithm risk factors for T–score of – 2.0: age 68 = 10 points, bone mineral density <20 = 25, weight <60 kg = 20, 60–69 kg = 10, > 80 cigarette pack years = 15, low–level leisure activity = 5, area under receiver operator curve 0.83. For a cut–off score of 10, sensitivity was 91.2%, specificity 53.9%, positive and negative predictive values 52.3 and 91.7%, and 67.2% were correctly classified. In conclusions, our model has acceptable sensitivity, although limited specificity. Use of this tool may reduce unnecessary referrals for bone mineral density measurement.

This study examined potential modifying effects of income and education on the relationship between chronic obstructive pulmonary disease (COPD) and depression. The analysis was based on 44 963 Canadians aged 35 years or more who participated in the Canadian National Population Health Survey in 1996–1997. Logistic regression analysis was used to examine the association between prevalence of depression and COPD according to sex, income adequacy or educational level. We used a bootstrap procedure to take sampling weights and design effects into account. People with COPD had twice the prevalence of depression compared to those without COPD. The association tended to be stronger in well–educated men [adjusted odds ratio (OR) = 3.02, 95% confidence interval (CI) = 1.04, 8.75] and women (OR = 2.60, 95% CI = 1.55, 4.38) than those less educated (men: OR = 1.19, 95% CI = 0.47, 3.05; women: OR = 1.93, 95% CI = 0.96, 3.87). An increased prevalence of depression associated with COPD was also found in women with higher household income (adjusted odds ratio = 4.57, 95% CI = 2.27, 9.19) than those with lower income. However, this pattern was not found in men. In conclusion, COPD patients with higher education are more likely to be depressed. The modifying effect of income may vary by gender. Possible reasons for these findings are explored.

The short version of the Breathing Problems Questionnaire (BPQ) is used as an outcome tool in pulmonary assessment. The aim of the study was to establish the validity of scoring BPQ with two subscales, reflecting emotional and physical components of health–related quality of life (HRQoL). Two subscales were suggested by exploratory factor analysis conducted on a data set of 97 patients with chronic obstructive pulmonary disease (COPD). Both subscales were significantly associated with the 6 minute walk test, total quality of life, and emotional stability. Only the physical subscale was significantly associated with FEVI, and only the emotional subscale was significantly associated with happiness. Overall, the sizes of the different correlations are consistent with the conceptual differentiation of the two subscales. We suggest that evaluation of rehabilitation can be made with the two subscales as well as an overall score of the BPQ.

Therapy and rehabilitation of common causes of respiratory–induced disability are directed towards a reduction of exacerbations, minimization of symptom severity, and improvement, or at least maintenance, of the patient's health. Unfortunately, these diseases are frequently complicated by chronic respiratory failure (CRF), which determines a rapid increase in the impact of the disease on the patient's daily life and well–being. Under such circumstances, the effect of therapy on a patient's health status and well–being represents the most important subjective outcome of treatment. An adequate assessment of patient's quality of life can only be obtained from the patients themselves; that is, it requires direct measurement through the use of valid and reliable questionnaires, whether generic or disease–specific. The St George's Respiratory Questionnaire and the Maugeri Foundation Respiratory Failure Questionnaire have been shown to be applicable and reliable in patients on long– term ventilation.

The main indications for nebulized antibiotic use are as maintenance therapy for patients with chronic Pseudomonas aeruginosa infection and in treatment protocols aimed at eradicating early P. aeruginosa infection. Daily nebulized antibiotic therapy has been used extensively in Europe for the last 25 years and recently in North America following the introduction of tobramycin solution for inhalation (TSI). The antibiotic is delivered directly to the site of infection, maximizing its efficacy and reducing its potential for toxicity. The efficacy of nebulized antibiotic therapy has been confirmed by meta–analyses of early studies which usually involved only small numbers of patients, and recently by large scale randomized control trials. These studies have shown that regular aerosolized antibiotic treatment results in improved respiratory function, less hospital admissions and respiratory exacerbations, and a significant reduction in the load of P. aeruginosa respiratory tract infection. Concerns about increasing bacterial resistance do not yet seem to have had any clinical impact. Successful eradication of early P. aeruginosa infection has been reported with nebulized colistin (in combination with oral ciprofloxacin), tobramycin and TSI. No advantage has been shown in studies comparing nebulized and intravenous antibiotics versus intravenous antibiotics alone in the treatment of acute respiratory exacerbations. Inhalation of antibiotics may provoke bronchospasm and patients should be assessed before and after treatment prior to continuing long–term therapy at home.

Among the nonpharmacological therapies, pulmonary rehabilitation (PR) is particularly appropriate for patients with chronic respiratory impairment who, despite any optimal drug management, are still symptomatic and experience restriction in every day activities. Pulmonary rehabilitation performed in inpatient, outpatient, or home settings demonstrates short–and long–term clinical efficacy. Although disease severity does not inherently dictate candidacy for exercise training, the degree of physiological and functional impairment may influence setting in which the training should occur. Therefore, inpatient rehabilitation is generally best–suited for the most sick and most disabled patients. The overall results from the literature confirm that the inpatient setting for a PR program is a feasible option and does not necessarily result in higher direct costs when balanced against duration and effectiveness in terms of improved outcomes.

Arterialized earlobe capillary blood samples (ELCS) have been used as a measurement of blood gas status for over 20 years. There is general acceptance that there is a strong correlation and limits of agreement between arterial and arterialized blood samples with respect to pH and PaCO₂. Although the correlation between the arterial and arterialized PaO₂ is good, the limits of agreement poor. Our aim was to improve the accuracy of this technique in the measurement of PaO₂ by simultaneously monitoring the oxygen saturation by pulse oximetry whilst taking an ELCS. We hypothesize that significant discrepancies between the SaO₂ and SpO₂ highlight either a poorly arterialized sample or an over aerated sample from air bubbles. We compared the SpO₂ with the SaO₂ of an arterial sample from 27 inpatients. We used the limits of agreement between these samples to define the degree of discordance we would accept between SaO₂ and SpO₂ before repeat ELCS. Subsequently, 252 consecutive patients attending our respiratory physiology unit over a six-month period had an ELCS and simultaneous SpO₂.If there was a discrepancy between SaO₂ and SPO2 of > 2% the ELCS was repeated. There was a good correlation and limits of agreement between the SPO2 and arterial SaO₂ (r = 0.97, mean difference + 95% limits of agreement: 0.34 + 2.68). A difference of more than 2% between arterialized SaO₂ and SpO₂ was identified in 21 patients out of 252 (8.3%) with SaO₂ higher in two and lower in 19 (r = 0.96, mean difference +95% limits of agreement: 0.66 + 3.1). Repeat ELCS of these 21 samples reduced this discrepancy improving the concordance of the measurements (r = 0.98, mean difference + 95% limits of agreement: 0.47 + 1.0). In one case a difference of 3% remained between the saturations. We conclude that the addition of simultaneous pulse oximetry with ELCS will identify rogue measurements in about 8% of cases highlighting the need for repeat samples and thus increasing the accuracy of the measurement of PaO₂ by ELCS.