Chronic rhinosinusitis with nasal polyposis and biological agents: the ARIA-ITALY Survey

Summary

Background. Chronic rhinosinusitis (CRS) is an inflammatory disease that affects the nasal mucosa and the paranasal sinuses. CRS can be associated by nasal polyposis (CRSwNP phenotype) in up to 30% of patients and it is frequently associated with bronchial asthma. CRSwNP shows predominantly an underlying activation of type 2 inflammatory pathways with the involvement of eosinophils, IgE, interleukin (IL)-4, IL-5 and IL-13. Biological drugs that target these inflammatory cytokines are currently a therapeutic option recognized by guidelines for the treatment of uncontrolled form of the disease. Methods. As part of the activity of the "ARIA-Italy" working group, a panel of 255 Italian Ear, Nose and Throat (ENT) specialists, pneumologists and immuno-allergologists actively participated in this national survey and answered a series of questions geared toward understanding the main criteria for patient characterization and therapeutic decision, highlighting multidisciplinarity, and the implementation of the management of CRSwNP patients, as a part of the precision medicine concept and the appropriate use of the biologicals. Results. Two hundred and fifty-five experts and specialists participated in the survey. Conclusions. The results of this survey obtained from an extensive number of active specialists throughout Italy allow some important concluding remarks to be drawn. The main points of agreement were that multidisciplinary care teams provide many benefits but that, once the team is established, meetings and communication between members must be coordinated. Finally, the dissemination of national disease registries and the continuous updating of guidelines and position papers related to CRSwNP and comorbidities should be encouraged.

Severe asthma: follow-up after one year from the Italian Registry on Severe Asthma (IRSA)

Summary

Background. Asthma affects millions of people worldwide, with a subgroup suffering from severe asthma (SA). Biologics have revolutionized SA treatment, but challenges remain in managing different patient traits. This study analyzed data from the Italian Registry on Severe Asthma (IRSA) to investigate changes in SA characteristics and effectiveness of treatments after one year of follow-up, and to identify factors associated with response to treatments in a real-world setting. Methods. Data on SA patients with one year of follow-up were extracted from IRSA. Asthma control, exacerbations, lung function, and treatments, were assessed at follow-up and analyzed against baseline characteristics. Results. After one year of follow-up, notable improvements were observed in all the outcomes of SA of the included patients (n = 570). The effectiveness of biologic therapies was particularly evident, as they contributed significantly to these positive outcomes. Additionally, certain factors were found to be associated with improvement, namely T2 phenotype, baseline eosinophil count (BEC), and area of residence. On the other hand, comorbidities (obesity, gastro-esophageal reflux disease) and poor lung function were risk factors. Notably, poor-responders to biologics exhibited lower level of education, BEC, and exacerbations, and higher frequency of atopy and ACT score ≥ 20. Conclusions. The findings demonstrate the effectiveness of biologics in asthma management, when implemented as part of a planned follow-up strategy aimed at optimizing and fine-tuning the therapy. Moreover, the study highlights the importance of considering key traits such as the T2 phenotype, BEC, education, and comorbidities when tailoring SA treatment. Overall, this study contributes to enhancing our understanding of SA management and guiding the development of personalized treatment approaches for patients with SA.

Severe asthma management in the era of biologics: insights of the Italian Registry on Severe Asthma (IRSA)

Summary

Background. The Italian Registry on Severe Asthma (IRSA) is the most recent and largestregistry in Italy. Objective. To improve the knowledge on the clinical and biological features of severe asthma (SA), and to monitor its treatments. Methods. To analyze clinical,functional, inflammatory, and treatment characteristics of severe asthmatics from the IRSA registry. Results. 851 subjects were enrolled. 31.8% and 64.5% of patients were submitted to oral corticosteroids (OCS), and monoclonal antibodies (MABs), respectively. At least tw ocomorbidities affected 77.4% patients. Asthma was uncontrolled in 62.2% patients. Uncontrolled patients had a higher frequency of exacerbations, and hospitalization, showing a highere osinophilic phenotype, a greater use of OCS, and being treated with MAB less frequently. However, uncontrolled patients treated with MAB had a lower use of OCS and a lower rateof hospitalization. Comparing SA patients with atopy and without atopy, the latter showeda greater use of OCS, and more frequent nasal polyposis and osteoporosis. Among SA patients with atopy treated with MAB, 36% were on a treatment targeting the IL-5 pathway. Conclusions and clinical relevance. This study shows the features of the greatest Italian registryof SA patients, revealing at the time of enrollment a poor disease control, and the use of OCSand MABs in about one third and two thirds of patients, respectively. SA is a complex diseasethat requires a more precise phenotyping and a greater disease control.

Doubly robust nonparametric inference on the average treatment effect

Doubly robust estimators are widely used to draw inference about the average effect of a treatment. Such estimators are consistent for the effect of interest if either one of two nuisance parameters is consistently estimated. However, if flexible, data-adaptive estimators of these nuisance parameters are used, double robustness does not readily extend to inference. We present a general theoretical study of the behaviour of doubly robust estimators of an average treatment effect when one of the nuisance parameters is inconsistently estimated. We contrast different methods for constructing such estimators and investigate the extent to which they may be modified to also allow doubly robust inference. We find that while targeted minimum loss-based estimation can be used to solve this problem very naturally, common alternative frameworks appear to be inappropriate for this purpose. We provide a theoretical study and a numerical evaluation of the alternatives considered. Our simulations highlight the need for and usefulness of these approaches in practice, while our theoretical developments have broad implications for the construction of estimators that permit doubly robust inference in other problems.

Propensity score estimators for the average treatment effect and the average treatment effect on the treated may yield very different estimates

Objective

Propensity score matching is typically used to estimate the average treatment effect for the treated while inverse probability of treatment weighting aims at estimating the population average treatment effect. We illustrate how different estimands can result in very different conclusions.

Study design

We applied the two propensity score methods to assess the effect of continuous positive airway pressure on mortality in patients hospitalized for acute heart failure. We used Monte Carlo simulations to investigate the important differences in the two estimates.

Results

Continuous positive airway pressure application increased hospital mortality overall, but no continuous positive airway pressure effect was found on the treated. Potential reasons were (1) violation of the positivity assumption; (2) treatment effect was not uniform across the distribution of the propensity score. From simulations, we concluded that positivity bias was of limited magnitude and did not explain the large differences in the point estimates. However, when treatment effect varies according to the propensity score (E[Y(1)–Y(0)|g(X)] is not constant, Y being the outcome and g(X) the propensity score), propensity score matching ATT estimate could strongly differ from the inverse probability of treatment weighting-average treatment effect estimate. We show that this empirical result is supported by theory.

Conclusion

Although both approaches are recommended as valid methods for causal inference, propensity score-matching for ATT and inverse probability of treatment weighting for average treatment effect yield substantially different estimates of treatment effect. The choice of the estimand should drive the choice of the method.

Comparing Preliminary and Final Neuroradiology Reports: What Factors Determine the Differences?

BACKGROUND AND PURPOSE

Trainees' interpretations of neuroradiologic studies are finalized by faculty neuroradiologists. We aimed to identify the factors that determine the degree to which the preliminary reports are modified.

MATERIALS AND METHODS

The character length of the preliminary and final reports and the percentage character change between the 2 reports were determined for neuroradiology reports composed during November 2012 to October 2013. Examination time, critical finding flag, missed critical finding flag, trainee level, faculty experience, imaging technique, and native-versus-non-native speaker status of the reader were collected. Multivariable linear regression models were used to evaluate the association between mean percentage character change and the various factors.

RESULTS

Of 34,661 reports, 2322 (6.7%) were read by radiology residents year 1; 4429 (12.8%), by radiology residents year 2; 3663 (10.6%), by radiology residents year 3; 2249 (6.5%), by radiology residents year 4; and 21,998 (63.5%), by fellows. The overall mean percentage character change was 14.8% (range, 0%-701.8%; median, 6.6%). Mean percentage character change increased for a missed critical finding (+41.6%, P < .0001), critical finding flag (+1.8%, P < .001), MR imaging studies (+3.6%, P < .001), and non-native trainees (+4.2%, P = .018). Compared with radiology residents year 1, radiology residents year 2 (-5.4%, P = .002), radiology residents year 3 (-5.9%, P = .002), radiology residents year 4 (-8.2%, P < .001), and fellows (-8.7%; P < .001) had a decreased mean percentage character change. Senior faculty had a lower mean percentage character change (-6.88%, P < .001). Examination time and non-native faculty did not affect mean percentage character change.

CONCLUSIONS

A missed critical finding, critical finding flag, MR imaging technique, trainee level, faculty experience level, and non-native-trainee status are associated with a higher degree of modification of a preliminary report. Understanding the factors that influence the extent of report revisions could improve the quality of report generation and trainee education.

Study of mitochondrial DNA alteration in the exhaled breath condensate of patients affected by obstructive lung diseases

Mitochondrial DNA (MtDNA) has been studied as an expression of oxidative stress in asthma, COPD, lung cancer and obstructive sleep apnea, but it has been mainly investigated systemically, although the pathogenetic mechanisms begin in the airways and only later progress to systemic circulation. The aim of this study was to investigate the MtDNA alterations in the exhaled breath condensate (EBC) of patients with asthma, COPD and asthma-COPD overlap syndrome (ACOS). In order to analyze better what happens to mitochondria, both locally and systemically, we compared MtDNA/nDNA in blood and EBC of paired patients. Thirteen (13) COPD patients, 14 asthmatics, 23 ACOS (10 according to Spanish guidelines, 13 in line with GINA guidelines) and 12 healthy subjects were enrolled. Patients underwent clinical and functional diagnostic tests as foreseen by the guidelines. They underwent blood and EBC collection. Content of MtDNA and nuclear DNA (nDNA) was measured in the blood cells and EBC of patients by Real Time PCR. The ratio between MtDNA/nDNA was calculated. For the first time we were able to detect MtDNA/nDNA in the EBC. We found higher exhaled MtDNA/nDNA in COPD, asthmatic and ACOS patients respectively compared to healthy subjects (21.9  ±  4.9 versus 6.51  ±  0.21, p  <  0.05; 7.9  ±  2.5 versus 6.51  ±  0.21, p  =  0.06; 18.3  ±  3.4 versus 6.51  ±  0.21, p  <  0.05). The level of exhaled MtDNA/nDNA was positively correlated with the plasmatic one. The levels of MtDNA/nDNA in the EBC, as expression of oxidative stress, are increased in COPD, asthmatic and ACOS patients compared to healthy subjects. These are preliminary results in a small number of well characterized patients that requires confirmation on a larger population. We support new studies directed toward the analysis of exhaled MtDNA/nDNA as a new exhaled non-invasive marker in other inflammatory/oxidative airways diseases.

Analysis of mitochondrial DNA alteration in new phenotype ACOS

BACKGROUND

Mitochondria contain their own DNA (MtDNA) that is very sensitive to oxidative stress and as a consequence could be damaged in quantity. Oxidative stress is largely recognized to play a key role in the pathogenesis of asthma and COPD and might have a role in the new intermediate phenotype ACOS (asthma-COPD overlap syndrome). The aim of this study was to investigate MtDNA alterations, as an expression of mitochondrial dysfunction, in ACOS and to verify whether they might help in the identification of this new phenotype and in its differentiation from asthma and COPD.

METHODS

Ten (10) ACOS according to Spanish guidelines, 13 ACOS according to GINA guidelines, 13 COPD, 14 asthmatic patients and ten normal subjects were enrolled. They further underwent a blood, induced sputum and exhaled nitric oxide collection. Content of MtDNA and nuclear DNA (nDNA) were measured in the blood cells of patients by Real Time PCR.

RESULTS

ACOS patients showed an increase of MtDNA/nDNA ratio. Dividing ACOS according to guidelines, those from the Spanish showed a higher value of MtDNA/nDNA compared to those from GINA/GOLD (92.69 ± 7.31 vs 80.68 ± 4.16). Spanish ACOS presented MtDNA/nDNA ratio closer to COPD than asthma. MtDNA was higher in asthmatic, COPD, GINA and Spanish ACOS patients compared to healthy subjects (73.30 ± 4.47-137.0 ± 19.45-80.68 ± 4.16-92.69 ± 7.31 vs 65.97 ± 20.56).

CONCLUSION

We found an increase of MtDNA/nDNA ratio in ACOS subjects that led us to conclude that there is presence of mitochondrial dysfunction in this disease, that makes it closer to COPD than to asthma. Although the MtDNA/nDNA ratio results are a useful marker for differential diagnosis from asthma, COPD and ACOS, further studies are needed to confirm the potentiality of MtDNA/nDNA ratio and to a better characterization of ACOS.

Mesial Temporal Sclerosis: Accuracy of NeuroQuant versus Neuroradiologist

BACKGROUND AND PURPOSE

We sought to compare the accuracy of a volumetric fully automated computer assessment of hippocampal volume asymmetry versus neuroradiologists' interpretations of the temporal lobes for mesial temporal sclerosis. Detecting mesial temporal sclerosis (MTS) is important for the evaluation of patients with temporal lobe epilepsy as it often guides surgical intervention. One feature of MTS is hippocampal volume loss.

MATERIALS AND METHODS

Electronic medical record and researcher reports of scans of patients with proved mesial temporal sclerosis were compared with volumetric assessment with an FDA-approved software package, NeuroQuant, for detection of mesial temporal sclerosis in 63 patients. The degree of volumetric asymmetry was analyzed to determine the neuroradiologists' threshold for detecting right-left asymmetry in temporal lobe volumes.

RESULTS

Thirty-six patients had left-lateralized MTS, 25 had right-lateralized MTS, and 2 had bilateral MTS. The estimated accuracy of the neuroradiologist was 72.6% with a κ statistic of 0.512 (95% CI, 0.315-0.710) [moderate agreement, P < 3 × 10(-6)]), whereas the estimated accuracy of NeuroQuant was 79.4% with a κ statistic of 0.588 (95% CI, 0.388-0.787) [moderate agreement, P < 2 × 10(-6)]). This discrepancy in accuracy was not statistically significant. When at least a 5%-10% volume discrepancy between temporal lobes was present, the neuroradiologists detected it 75%-80% of the time.

CONCLUSIONS

As a stand-alone fully automated software program that can process temporal lobe volume in 5-10 minutes, NeuroQuant compares favorably with trained neuroradiologists in predicting the side of mesial temporal sclerosis. Neuroradiologists can often detect even small temporal lobe volumetric changes visually.

Imaging characteristics of oligodendrogliomas that predict grade

BACKGROUND AND PURPOSE

Oligodendrogliomas are tumors that have variable WHO grades depending on anaplasia and astrocytic components and their treatment may differ accordingly. Our aim was to retrospectively evaluate imaging features of oligodendrogliomas that predict tumor grade.

MATERIALS AND METHODS

The imaging studies of 75 patients with oligodendrogliomas were retrospectively reviewed and compared with the histologic grade. The presence and degree of enhancement and calcification were evaluated subjectively. rCBV and ADC maps were measured. Logistic linear regression models were used to determine the relationship between imaging factors and tumor grade.

RESULTS

Thirty of 75 (40%) tumors enhanced, including 9 of 46 (19.6%) grade II and 21 of 29 (72.4%) grade III tumors (P < .001). Grade III tumors showed lower ADC values compared with grade II tumors (odds ratio of a tumor being grade III rather than grade II = 0.07; 95% CI, 0.02-0.25; P = .001). An optimal ADC cutoff of 925 10(-6) mm(2)/s was established, which yielded a specificity of 89.1%, sensitivity of 62.1%, and accuracy of 78.7%. There was no statistically significant association between tumor grade and the presence of calcification and perfusion values. Multivariable prediction rules were applied for ADC < 925 10(-6) mm(2)/s, the presence of enhancement, and the presence of calcification. If either ADC < 925 10(-6) mm(2)/s or enhancement was present, it yielded 93.1% sensitivity, 73.9% specificity, and 81.3% accuracy. The most accurate (82.2%) predictive rule was seen when either ADC < 925 10(-6) mm(2)/s or enhancement and calcification were present.

CONCLUSIONS

Models based on contrast enhancement, calcification, and ADC values can assist in predicting the grade of oligodendrogliomas and help direct biopsy sites, raise suspicion of sampling error, and predict prognosis.

A population-based case-control study of 1250 stroke deaths in rural Bangladesh

BACKGROUND AND PURPOSE

There are limited population-based studies to determine the risk factors for stroke in Bangladesh.

METHODS

A health and demographic surveillance system has been maintained in Matlab, Bangladesh (population 223 886, 142 villages in 2008). All adult stroke and injury deaths (2005-2008) were monitored by verbal autopsy. Risk factors for stroke deaths were calculated using a multivariable logistic regression model with adult injury deaths as controls.

RESULTS

A total of 1250 stroke deaths (51% women; mean age 72.3 years, range 20-101) occurred out of 4955 total deaths and were compared with 246 adult injury deaths (47% women, mean age 55.8 years, range 20-100). The population-attributable mortality of stroke was 25.2% based on the verbal autopsy instrument and 17.8% when accounting for the reported sensitivity and specificity of a similar verbal autopsy instrument that has been validated for stroke death. Risk of stroke death was significantly increased with hypertension (OR 7.94, 95% CI 4.44-15.54, P < 0.001), diabetes mellitus (OR 2.54, 1.21-6.21, P = 0.02), and betel consumption (OR 2.36, 1.45-3.80, P < 0.001) when adjusted for age and sex. An increased risk was not observed with heart disease (OR 1.37, 0.45-5.95, P = 0.62), cigarette smoking (OR 1.41, 0.82-2.45, P = 0.22), tobacco powder (OR 1.15, 0.30-7.64, P = 0.86), or cigar/hookah pipe smoking 0.94 (0.45-2.18, P = 0.88) when adjusted for age and sex. There were more strokes in winter (December-March) than summer (June-September) (P < 0.001).

CONCLUSIONS

There is a high modifiable burden of risk factors for adult stroke deaths in rural Bangladesh, most notably including hypertension. Betel consumption may be an under-recognized risk factor for stroke death.

Quality control in neuroradiology: impact of trainees on discrepancy rates

BACKGROUND AND PURPOSE

Prior studies have found a 2%-8% clinically significant error rate in radiology practice. We compared discrepancy rates of studies interpreted by subspecialty-trained neuroradiologists working with and without trainees.

MATERIALS AND METHODS

Subspecialty-trained neuroradiologists reviewed 2162 studies during 41 months. Discrepancies between the original and "second opinion" reports were scored: 1, no change; 2, clinically insignificant detection discrepancy; 3, clinically insignificant interpretation discrepancy; 4, clinically significant detection discrepancy; and 5, clinically significant interpretation discrepancy. Faculty alone versus faculty and trainee discrepancy rates were calculated.

RESULTS

In 87.6% (1894/2162), there were no discrepancies with the original report. The neuroradiology division had a 1.8% (39/2162; 95% CI, 1.3%-2.5%) rate of clinically significant discrepancies. In cases reviewed solely by faculty neuroradiologists (16.2% = 350/2162 of the total), the rate of discrepancy was 1.7% (6/350). With fellows (1232/2162, 57.0% of total) and residents (580/2162, 26.8% of total), the rates of discrepancy were 1.6% (20/1232) and 2.2% (13/580), respectively. The odds of a discrepant result were 26% greater (OR = 1.26; 95% CI, 0.38-4.20) when reading with a resident and 8% less (OR = 0.92; 95% CI, 0.35-2.44) when reading with a fellow than when reading alone.

CONCLUSIONS

There was a 1.8% rate of clinically significant detection or interpretation discrepancy among academic neuroradiologists. The difference in the discrepancy rates between faculty only (1.7%), fellows and faculty (1.6%), and residents and faculty (2.2%) was not statistically significant but showed a trend indicating that reading with a resident increased the odds of a discrepant result.

[Questionnaires for occupational disability evaluation in patients with chronic respiratory diseases]

Chronic Obstructive Pulmonary Disease (COPD) represents a model of respiratory degenerative chronic disabling disorder. In Pulmonary Rehabilitation (PR), occupational approach is aimed at restoring patient's abilities at best in the social, familiar and working scenarios, and it is an essential part of a good PR Programme. To evaluate first occupational disability and then the occupational outcome of a PR programme, we need appropriate tools. London Chest Activity of Daily Living (LCADL) ed il Manchester Respiratory Activities of Daily Living (MRADL) are two questionnaires with such characteristics available in the literature. Our aim was to translate into Italian and adapt to the Italian social reality these two questionnaires. This may be a preliminary albeit necessary step to obtain reliable data on the occupational outcome of PR programmes in Italy.

Maugeri Respiratory Failure questionnaire reduced form: A method for improving the questionnaire using the Rasch model

PURPOSE

The Maugeri Respiratory Failure questionnaire (MRF-28) is the first instrument specifically developed for use with chronic respiratory failure (CRF) patients. The 28 items were selected using classical test theory. The purpose of the current analysis was to further refine the questionnaire using item response theory, specifically, the Rasch model analysis.

METHODS

Three hundred and seventeen CRF patients (mean aged 66.7 yrs; Male 219, Female 98) completed the MRF-28 health status measure. Data were collected through the self-report questionnaire and analyzed using 1-parameter logistic models by means of RUMM software.

RESULTS

The 28-item questionnaire has good psychometric properties in terms of discriminant power because the Person Separation Index is 0.896. However, the item-trait interaction was not good as shown by the total-item Chi-square (chi(2)(112), p<0.001). Removing two items that did not fit the Rasch model well, produced a minor improvement in Person Separation Index to 0.899 and the item-trait interaction improved (chi(2)(104), p = NS). In the preliminary analysis we identified 21 patients who were outliers; when they were excluded the distribution of the residuals, according to the Kolmogorov-Smirnov statistics, was normal and factor analysis of the item residuals showed that the components had similar eigenvalues and no strong correlation with items. These results suggest that the MRF-26 is a unidimensional measure of health-related quality of life impairment for chronic respiratory failure patients.

CONCLUSIONS

A combination of classical psychometric tests and Rasch analysis produced an instrument of moderate size that covers a wide range of effects of CRF and has interval scaling properties.

Efficacy of pulmonary rehabilitation in chronic respiratory failure (CRF) due to chronic obstructive pulmonary disease (COPD): The Maugeri Study

While the effectiveness of pulmonary rehabilitation (PR) in chronic obstructive pulmonary disease (COPD) is well established, its effectiveness in the most severe category of COPD, i.e. patients with chronic respiratory failure (CRF), is less well known.

OBJECTIVE

To verify the effects of PR in patients with CRF, and compare the level of improvement with PR in these patients to that of COPDs not affected by CRF.

METHODS

A multi-centre study was carried out on COPD patients with versus without CRF. The PR program included educational support, exercise training, and nutritional and psychological counselling. Lung function, arterial gases, walk test (6MWT), dyspnoea (MRC; BDI/TDI), and quality of life (MRF(28); SGRQ) were evaluated.

RESULTS

Thousand forty seven consecutive COPD inpatients (327 with CRF) were evaluated. In patients with CRF all parameters improved after PR (0.001). Mean changes: FEV(1), 112 ml; PaO(2), 3.0 mmHg; PaCO(2), 3.3 mmHg; 6MWT, 48 m; MRC, 0.85 units; MRF(28) total score, 11.5 units. These changes were similar to those observed in patients without CRF.

CONCLUSIONS

This study, featuring the largest cohort so far reported in the literature, shows that PR is equally effective in the more severe COPD patients, i.e. those with CRF, and supports the prescription of PR also in these patients.

Degree of control of physician-diagnosed asthma and COPD in Italy

BACKGROUND

It is important for the Italian National Health Service to obtain data on the degree of control of asthma and chronic obstructive pulmonary disease (COPD) in the general population in Italy in order for balanced planning of future investments in these diseases to be made. Currently, precise estimates of these parameters are not available in literature.

OBJECTIVES

In collaboration with the Italian Academy of General Practitioners (SIMG; www.simg.it) we have investigated the degree of control of physician-diagnosed asthma and COPD in Italy.

METHODS

A standardised questionnaire on asthma and COPD has been self-administered to a sample of 1937 Italian family physicians (representing around 5% of all the Italian doctors involved in general practice) chosen to cover all the Italian counties.

RESULTS

We have collected questionnaire data from 19,917 patients with asthma and COPD followed in their practice and 12,438 (62.4%) were correctly filled in enabling evaluation. We selected the number of emergency room visits, hospitalisations and intensive care unit admissions for asthma and COPD in the last 12 months as objective measures of the degree of asthma and COPD morbidity in these patients. The figures were respectively 12.4% (emergency room visits), 17.3% (hospitalisations) and 1.2% (intensive care unit admissions) of all patients with physician-diagnosed asthma and COPD.

CONCLUSIONS

This data suggests that in Italy the morbidity of asthma and COPD remains high; representing a significant burden for the Italian National Health Service. There is a clear necessity for further studies to investigate the causes of this incomplete control.

A new questionnaire specifically designed for patients affected by chronic obstructive pulmonary disease

The aim of this study was to develop a specific and valid questionnaire for Italian COPD patients, living on the north or the south of Italy-which are two culturally distinct areas. The project consisted in three steps: (1) initial item set generation to identify items relevant to both genders, all ages and both regions; (2) item reduction including tests of regional specificity; (3) tests of internal validity using item-response theory using Rasch one-parameter modelling. Ninty-six COPD patients (mean aged 69 yr; 78 Male) completed the original set of 124 items of the Italian Health Status Questionnaire (IHSQ). Item reduction was carried out using an established standardised approach employing classical psychometric test theory. The internal construct validity of the 47 items that survived this process were tested to determine whether they constituted a unidimensional construct "impaired health due to COPD" using Rasch analysis. This showed that the questionnaire had very good psychometric properties, with an excellent Person Separation Index of 0.95 and no evidence of bias due to item-trait interaction (chi104(2)=127.1, P=n.s.). The combination of classical test theory and modern item-response methodology has produced a questionnaire with excellent measurement properties suitable for COPD patients whether from the north or south of Italy.

Impact of long-term ventilation on patients' health status

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.

EDU-CARE, a randomised, multicentre, parallel group study on education and quality of life in COPD

Chronic obstructive pulmonary disease (COPD) represents one of the main causes of morbidity and mortality in the western world. Unfortunately, its therapy is largely palliative, the key aims of treatment being to reduce exacerbations, minimise symptoms, and improve patients' ability to perform their usual daily activities. In the absence of true disease-modifying treatments, the concept of rehabilitation has become important. In addition, it has been shown that educational and self-management programmes may play a role in the general treatment of COPD patients. This study was promoted by the Italian Association of Hospital Pulmonologists (AIPO) with the aim to verify changes and improvements induced by an educational programme validated by AIPO in patients with COPD. Edu-Care is a 6-month, multicentre, randomised, controlled, parallel-group study. In addition to treatment within the usual therapeutic schemes for COPD, patients were randomised to either the 'Educational' group, i.e. to receive a formal and structured educational programme, or the 'Normal General Advice' group, i.e. to receive the usual general advice given by general practitioners on life-style and on the disease's risk factors and treatment. A number of evaluations were performed: pulmonary function test, walking distance, quality of life, locus of control, register of number of exacerbations and hospital admissions. To date, of the 1,230 patients enrolled interim data are available from 1,003 patients. Males represent 85% of the study population. Smoking habit is quite a common status (21%). In the year prior to enrolment 34% of patients had one exacerbation, 49% 2-3 exacerbations, and 17% more than 3 exacerbations. Seventy-two percent of patients were not hospitalised over the year prior to enroLlment, while 22% were hospitalised once and 6% had more than 2 hospitalisations. Edu-Care is the first large study aimed to evaluate the efficacy of an educational programme for patients with COPD. AIPO wishes to make a contribution to this important field. This is the reason why Edu-Care includes a very large number of patients in numerous Italian centres throughout northern and southern Italy.

[Sickness Impact Profile: the Italian version]

The Sickness Impact Profile (SIP) is one of the questionnaires most widely used for the generic evaluation of functional health status. Besides measuring functional status or quality of life, it is also a precious font of information for the psychologist in the inpatient-rehabilitative context when planning an intervention focused on the most dysfunctional areas indicated by the subject. In producing the Italian version of the SIP, attention was duly paid in the translation to maintain equivalence in terms of idioms, grammar and syntax, so as to render it free of erroneous translations or possible. misunderstandings. Since the SIP employs "weighted" items, in order to obtain the weights corresponding to each individual statement a 3-phase procedure was followed: A) each subject "judge" was asked to express on a scale his/her own dysfunctionality judgement for each item; B) statements with the highest and lowest mean weight for each category were identified; C) the same "judges" were then asked to reclassify the statements which had obtained the highest and lowest weights, respectively, on a scale of 15 equidistant intervals; subsequently the same subjects completed the SIP a second time (retest). Results show that the judges were coherent in their estimation of the specific weights for each item. In the judges' second completion of the SIP it was found that the majority of the test-retest correlations fell almost always within the r = 0.70-0.90 range. Moreover, given the marginal difference between Italian and United States weights, both methods may be used for the calculation of the scores. One thus concludes that the SIP questionnaire can be applied in the Italian context.

Reliability of a questionnaire for evaluating the understanding of asthma

The present study was designed to evaluate the repeatability of a questionnaire developed to assess the understanding that asthma patients have of their disease and, on the basis of its variability, estimate the sample size necessary for determining the efficacy of a future structured program on asthma knowledge. The repeatability of the Asthma Questionnaire (AQ) was evaluated by asking 89 patients to complete it twice within a period of 7-10 days without the subject being exposed to any programme on asthma knowledge between the two administrations. The AQ was demonstrated to have good content and face validity. Results showed that neither age nor sex had a significant influence on total scores, and that the degree of reliability was adequate (R = 0.769). The mean percentage of correct answers was observed to be approximately 70% in both sessions, suggesting a consistent area for possible improvement which could be targeted by means of an appropriately structured programme on asthma knowledge. For comparative purposes before and after the programme, or for measuring its efficacy, the AQ should be recommended. In conclusion the Asthma Questionnaire could provide a useful tool for the general practitioner, chest physician and other health professionals, to assess what the patient really does understand or does not, concerning asthma management, and hence be the starting point for a well-tailored educational intervention.

Quality of Life Evaluation and Survival Study: a 3-yr prospective multinational study on patients with chronic respiratory failure

Therapy of patients with chronic respiratory failure is mainly directed at minimizing symptoms in order to improve, or at least to prevent a deterioration of, patients' well-being. Under such circumstances, the perceived effect of therapies on patients' well-being and daily life represents the most important subjective outcome of treatment. Therefore, there is a need to provide a global estimate of health in patients on long term oxygen therapy or overnight home mechanical ventilation. The Maugeri Foundation Respiratory Failure Questionnaire (MRF28) is the first health status ("quality of life") questionnaire specifically developed for use in CRF and its items were selected to be applicable to patients with both obstructive and restrictive diseases. The Quality of Life Evaluation and Survival Study (QuESS) is a multinational study with the aim of re-evaluating the natural history of chronic respiratory failure in about 300 patients. To the authors knowledge, the Quality of Life Evaluation and Survival Study is the first study to evaluate the natural history of chronic respiratory failure in such a large number of subjects and with a complete set of data. In fact, both pathophysiologic and health status assessments will be made. Moreover, by collecting data on mortality, disease exacerbations and hospitalization, it will also be possible to verify the predictive ability of health status versus pathophysiology in terms of mortality and healthcare utilization.

Impaired glucose oxidation and glucose-induced thermogenesis in renal transplant recipients

BACKGROUND

Renal transplant recipients often show various metabolic abnormalities including reduced glucose tolerance, impaired insulin sensitivity and altered lipid metabolism. However, the acute effects of carbohydrate ingestion on substrate utilization and energy expenditure have not been fully elucidated.

METHODS

We evaluated: (i) basal energy expenditure (EE) and substrate utilization, (ii) metabolic fate of an oral glucose load, and (iii) substrate-induced thermogenesis in: (a) 15 non-diabetic renal transplant recipients (Tx) (BMI 25+/-1) on triple immunosuppressive therapy, (b) 11 patients with primary glomerulonephritis (BMI 25+/-1) (Cort) receiving prednisone treatment, and (c) 12 healthy subjects (BMI 26+/-1) (N). Continuous indirect calorimetry was performed in the basal post-absorptive state for 60 min and continued for an additional 180 min following an oral glucose load (75 g).

RESULTS

In the basal state, EE was similar in the three study groups. It averaged 14.6+/-0.7, 15.7+/-1.3, and 14.1+/-0.8 cal/kg/min in Tx, Cort, and N respectively. Glucose oxidation was higher in N (1.3+/- 0.2 mg/kg/min) than in Tx (0.7+/-0.2) and Cort (1.0+/-0.2) (P<0.05 in N vs. Tx and vs. Cort), whereas lipid oxidation was lower in N (0.6+/-0.1 mg/kg/min) than in Tx (0.9+/-0.1) and Cort (0.9+/-0.05) (P<0.03 in N vs. Tx and vs. Cort). After glucose ingestion, total carbohydrate oxidation averaged 21.2+/-2, 31.0+/-3, and 29.6+/-3 g, which represented 28+/-3, 41+/-3 and 39+/-2% of the total glucose load in Tx, Cort and N respectively (P<0.01 Tx vs Cort and N). The cumulative increase of EE (180 min) was 9.7+/-2, 13.2+/-3 and 13+/-3 kcal in Tx, Cort, and N respectively.

CONCLUSIONS

The present data show that in non-diabetic renal transplant recipients basal EE is normal. However, basal lipid oxidation is higher and glucose oxidation is lower than in healthy subjects. In addition, the oxidative disposal of a glucose load and substrate-induced thermogenesis are impaired.

Physiological and symptom determinants of exercise performance in patients with chronic airway obstruction

To evaluate the physiological and symptom determinants of exercise performance (EP) as measured by a 6-min walking test (6MWD), Watt(max), and peak oxygen consumption (VO2 ml/min/kg), 105 patients with chronic airway obstruction (CAO) [50 chronic obstructive pulmonary disease (COPD): 44 men, aged 63+/-7 years, forced expiratory volume in 1 sec (FEV1) forced vital capacity (FVC)(-1)% 54+/-13; and 55 asthmatic: 23 men, aged 55+/-10 years, FEV1 FVC(-1) % 65+/-10] underwent evaluation of 6MWD, symptom limited cyclo-ergometer exercise test, spirometry, respiratory muscle function, arterial blood gases and sensation of dyspnoea [using the Borg scale, Visual Analogue Scale (VAS) and Baseline Dyspnoea Index (BDI)]. A hierarchical method of analysis identified the residual volume (RV), total lung capacity (TLC)(-1) ratio, BDI and the patient's age as the strongest and most consistent correlates of EP (r2 = 0.14-0.21). The correlation between EP and its various determinants was not influenced by diagnosis. The relationship between breathlessness and EP was different between men and women: at any given level of exercise, women were more breathless than men. In multivariate analyses that contained both RV TLC(-1) and BDI, the RV TLC(-1) ratio was the strongest correlate of EP, although the BDI remained a significant covariate. Overall, age was the major determinant of EP but inclusion of the RV TLC(-1) ratio and the BDI into the model explained a further 9-15% of the variance in EP. These three covariates together explained 26-34% of the variance between patients. We conclude that in stable CAO patients, the prediction of exercise capacity by anthropometric, demographic, clinical and physiological variables is likely to be low. Age, pulmonary hyperinflation and dyspnoea are the strongest and most consistent correlates of impaired exercise performance. Airways obstruction, measured during expiration using FEV1, does not appear to be a predictor of physiological impairment. These results underline the importance of performing exercise evaluation in CAO patients.

Analysis of factors that characterize health impairment in patients with chronic respiratory failure. Quality of Life in Chronic Respiratory Failure Group

This study was designed to identify a core set of items that may characterize impaired health in chronic respiratory failure (CRF) since none of the questionnaires commonly used to measure impaired health in patients with CRF were developed for use in such patients. Questionnaire items, identified from several sources, were administered to 92 patients with stable severe chronic hypoxia or hypercapnia, together with physiological measures of disease severity, the Sickness Impact Profile (SIP) and the St George's Respiratory Questionnaire (SGRQ). Of the 152 items identified, only 28 correlated with patients' perceptions of overall health and were also independent of age, sex, disease or type of treatment and did not show floor or ceiling effects. Principal components analysis identified three specific factors: "daily activities", "cognitive function", and "invalidity". The total score for the whole 28-item set correlated with other measures of disease activity, including SGRQ (r = 0.86) and SIP (r = 0.70), but not spirometry. The interquartile range of the 28-item set was wider than that of the SGRQ or the SIP. This study characterized two areas of health impairment in chronic respiratory failure that had not previously been identified: effects of impaired cognitive function on daily life, and a sense of invalidity. The measurements properties of this 28-item set suggest that it may be a more discriminative instrument for patients with chronic respiratory failure than existing questionnaires.

Comparison of invasive and noninvasive saturation monitoring in prescribing oxygen during exercise in COPD patients

The aim of this study was to determine whether it is possible using ear-oximetry to prescribe the correct oxygen flow rates during exercise in chronic obstructive pulmonary disease (COPD) patients on long-term oxygen therapy (LTOT). Twenty COPD patients on LTOT, with exercise desaturation breathing oxygen at resting flow rates, performed a series of 6-min treadmill walking tests, with a progressive increase in oxygen flows until oxygen saturation measured by ear- or pulse-oximetry (Sp,O2) was above 90%. The exercise studies were repeated the next day, saturation being measured both noninvasively by ear-oximetry (Sp,O2) and invasively by CO-oximeter (Sa,O2). The exercise studies continued until both Sa,O2 and Sp,O2 were above 90%. Reproducibility and agreement of the results were analysed according to Bland and Altman. Sp,O2 was significantly lower than Sa,O2 by, on average, 0.7% (p < 0.004). Sp,O2 reproducibility between the two days was good. The invasive and noninvasive oxygen flow prescriptions agreed in only 10 subjects; in six subjects ear-oximetry over-estimated the oxygen supply (p < 0.0005), whilst in four subjects it underestimated (p < 0.01). Contingency table analysis with coded raw data for the values of the sixth minute (that of the deepest desaturation) showed poor agreement between CO- and pulse-oximetry (Chi-squared p < 0.003). However, theoretically, if the Sp,O2 target had been raised to 93%, there would have been hardly any underestimations of Sa,O2 p = NS). We concluded that noninvasive measurement of oxygen saturation is not adequate for estimating arterial saturation in chronic obstructive pulmonary disease. We suggest, as a working solution, that a new cut-off limit of 93% oxygen saturation measured by pulse oximetry should be used as the value below which exercise-induced desaturation should be corrected in order to allow oxygen to be properly prescribed during activities of daily life.

Correlation between glomerular morphology and renal haemodynamic response to amino-acid administration in patients with IgA nephropathy

RATIONALE

To establish relationship, if any, between renal morphology and renal haemodynamic response to amino acids.

DESIGN AND METHODS

We investigated the correlation between renal haemodynamic regulation and morphology in a group of 15 patients with primary IgA nephropathy (IgAN) (age 26 +/- 2 years, BMI 24.4 +/- 1, GFR 64 +/- 5 ml/min, RPF 377 +/- 34 ml/min, FF 0.17 +/- 0.02). Twelve normal subjects (age 30 +/- 3 years, BMI 24 +/- 1, GFR 82 +/- 6 ml/min, RPF 421 +/- 42 ml/min, FF 0.19 +/- 0.02) were studied as controls. IgA patients were divided into two groups according to the histological staging of glomerular lesions: group I (n = 7) stage II, and group II (n = 8) stage III-IV.

RESULTS

In the basal state GFR was similar in the two groups and averaged 64 +/- 9 and 64 +/- 6 ml/min respectively. In contrast, FF was significantly lower in group II (0.14 +/- 0.01) (P < 0.05) in comparison to group I (0.21 +/- 0.03) and controls (0.19 +/- 0.02). In order to evaluate the renal functional reserve, all study groups underwent to an intravenous amino-acid infusion designed to increase plasma amino acid levels twofold (total from 2096 +/- 145 to 4301 +/- 221 mumol/l in IgA nephropathy patients and from 2272 +/- 83 to 3844 +/- 238 mumol/l in controls). In response to amino-acid infusion, GFR rose significantly in group I (GFR 20 +/- 2% and RPF 37 +/- 4% versus basal) and controls (GFR 20 +/- 2% and RPF 20 +/- 3% versus basal) (both P < 0.01 vs basal). In contrast, in patients with more severe glomerular lesions (group II) neither GFR nor RPF rose significantly (GFR -1 +/- 4% and RPF -8 +/- 6% versus basal) (P NS versus basal, P < 0.01 versus group I and controls).

CONCLUSIONS

The data show that in IgA nephropathy: severe forms of glomerular lesions are associated with a complex alteration of glomerular haemodynamic regulation, characterized by lower basal FF and loss of haemodynamic response to hyperaminoacidaemia.

Partitioning of inspiratory muscle workload and pressure assistance in ventilator-dependent COPD patients

To investigate the mechanisms underlying ventilator-dependence in patients with chronic obstructive pulmonary disease (COPD), and to assess the effects of the combination of positive end-expiratory pressure (PEEP) and pressure-support ventilation (PSV) on inspiratory muscle effort, we investigated respiratory mechanics in eight ventilator-dependent COPD patients. The patients' breathing pattern, lung mechanics, diaphragmatic effort (PTPdi), diaphragmatic tension-time index (TTdi), and arterial blood gases were measured during both spontaneous breathing (SB) and ventilatory assistance consisting of PSV alone (15, 20, and 25 cm H2O) and PSV combined with a PEEP of 5 cm H2O (reducing PSV to 10, 15, and 20 cm H2O, respectively, to maintain equivalent inspiratory pressure). The different levels of ventilatory support were delivered in a randomized sequence. Maximal inspiratory (MIP), esophageal (PpImax) and transdiaphragmatic (Pdi(max)) pressures and respiratory drive (P(0.1)) were measured at the beginning of the procedure during SB. We found a high P(0.1) (6.1 +/- 1.7 cm H2O), which seemed to rule out an impairment of respiratory-center output. Apparently, inspiratory muscle strength was compatible with successful weaning (38.5 +/- 8.8, 50.9 +/- 9.7, and 51.8 +/- 9.5 cm H2O for MIP, PPImax and Pdi(max), respectively). However, abnormal respiratory mechanics (particularly an intrinsic positive end-expiratory pressure (PEEPi) of 8.3 +/- 1.9 cm H2O and pulmonary resistance 24.7 +/- 9.5 cm H2O/L/s imposed an excessive load on the inspiratory muscles, as indicated by a high PTPdi (499 +/- 122 cm H2O x s). Increasing levels of PSV progressively and significantly unloaded the patients' inspiratory muscles, although at pressures above 20 cm H2O uncoupling occurred between patient and ventilator respiratory frequency. Application of PEEP during PSV improved ventilatory assistance by further reducing the inspiratory effort (by 17% on average) and by ameliorating patient-ventilator interaction. We conclude that the excessive mechanical load, and in particular the high PEEPi, is the major determinant of ventilator-dependence in COPD patients. Application of PEEP improves the efficiency of PSV in unloading these patients' inspiratory muscles, and can sometimes improve patient-ventilator interaction.

Renal hemodynamics in renal transplant recipients. The role of reduced kidney mass and cyclosporine administration

It has been hypothesized that both the cyclosporine (CsA) treatment and the reduction of renal mass may affect the renal hemodynamic regulation in kidney transplant recipients. To address this question, we evaluated the renal hemodynamic response to hyperaminoacidemia (i.v. mixed amino acid infusion 3.3 mg/kg/minute for 150 minutes) in four study groups: (1) 16 renal transplant recipients (Tx), (2) 6 uninephrectomized (Nx) subjects, (3) 7 subjects treated with CsA for chronic uveitis (CsA), and (4) 9 normal controls (NC). In response to amino acid administration (AA), glomerular filtration rate (GFR) rose significantly in NC subjects (80 +/- 6 vs. 91 +/- 6 ml/minute; P<0.01) and Nx patients (57 +/- 3 vs. 68 +/- 7 ml/minute; P<0.01) and failed to increase in Tx recipients (39 +/- 3 vs. 37 +/- 3 ml/minute) and CsA-treated patients (58 +/- 3 vs. 53 +/- 4 ml/minute). Renal plasma flow (RPF) did not change in Tx recipients (243 +/- 27 vs. 235 +/- 25 ml/minute) but rose significantly in all other groups (257 +/- 17 vs. 344 +/- 33 in NX, 364 +/- 6l vs. 441 +/- 55 in CsA, 412 +/- 49 vs. 472 +/- 72 ml/min in NC subjects; P<0.05 vs. basal). Basal renal vascular resistances were significantly higher in Tx (0.29 +/- 0.04 mmHg/mlxmin; P<0.01 vs. all other groups) than in Nx (0.21 +/- 0.01 mmHg/mlxmin), CsA (0.23 +/- 0.04 mmHg/mlxmin) (both P<0.01 vs. NC subjects), and NC subjects (0.13 +/- 0.02 mmHg/mlxmin). Renal vascular resistance failed to decline in Tx (0.31 +/- 0.04 mmHg/mlxmin) during AA infusion but declined significantly in all other groups. In Tx, basal GFR was positively correlated to renal allograft volume (r=0.547, P<0.03); however, no relationship was found between the latter and basal RPF or the AA induced changes in GFR. In summary, the present study demonstrates that in kidney transplant recipients and in CsA-treated subjects, the renal functional reserve to hyperaminoacidemia is impaired. This is at variance to what is observed in normal controls and uninephrectomized subjects. In renal transplant recipients, basal but not amino acid stimulated GFR correlates with renal allograft volume. We conclude that basal GFR is related to renal volume in Tx and that the response to hyperaminoacidemia seems to be affected by chronic CsA administration.

From mechanical ventilation to home-care: the psychological approach

The mechanically ventilated individual has to cope with being in a situation of total dependence on a bodily external object for life-support. This condition may give rise to unprecedented psychological complaints, often concerning the patient's fear of death, feeling of abandonment, mutilation, and perceived changes of self-image. It is not only the patients but also their family members who will need help dealing with stressful situations, false beliefs, anxiety, and all the other emotions linked to mechanical ventilation. After discharge from the hospital, the immediate need to master and manage the home ventilator equipment may overshadow the psychological needs of the patients. Therefore, psychological support should be offered well before discharge, and periodically during ambulatory sessions. Another important factor associated with adaptation to mechanical ventilation and the following period at home, appears to be the level of communication within the family, and the degree of commitment between all family members. Helping patients and their family members to cope with technical and psychological aspects of mechanical ventilation will make the transition from the hospital environment to the home easier for both. From an ethical point of view, it is suggested that patients be informed that ventilation will not change the course of their underlying disease or prognosis.

Physiologic effects of positive end-expiratory pressure and mask pressure support during exacerbations of chronic obstructive pulmonary disease

To assess physiologic effects of continuous positive airway pressure (CPAP) and positive end-expiratory pressure (PEEP) during noninvasive pressure support ventilation (PSV) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD), we measured in seven patients the breathing pattern, lung mechanics, diaphragmatic effort (PTPdi), and arterial blood gases under four conditions: (1) spontaneous breathing (SB); (2) CPAP; (3) PSV of 10 cm H2O; and (4) PSV plus PEEP (PEEP + PSV). CPAP and PEEP were set between 80 and 90% of dynamic intrinsic PEEP (PEEPidyn) measured during SB and PSV, respectively. PEEPidyn was obtained (1) from the decrease in pleural pressure (delta Ppl) preceding inspiration, and (2) subtracting the fall in gastric pressure (delta Pga) caused by relaxation of the abdominal muscles from the delta Ppl decrease. Abdominal muscle activity made PEEPidyn overestimated in almost all instances (p < 0.0001). PSV increased minute ventilation, improved gas exchange, and decreased PTPdi. PEEP added to PSV, likewise CPAP compared with SB, further significantly decreased the diaphragmatic effort (PTPdi went from 322 +/- 111 to 203 +/- 63 cm H2O.s) by counterbalancing PEEPidyn, which went from 5.4 +/- 4.0 to 3.1 +/- 2.3 cm H2O. These data support the use of low levels of PEEP (80 to 90% of PEEPidyn) to treat acute exacerbation of COPD by means of mask PSV.

Respiratory Illness Opinion Survey: a short form for COPD patients

Psychological assessment of respiratory patients often necessitates an understanding of their attitudes towards respiratory disease and hospitalization. The Respiratory Illness Opinion Survey (RIOS) is a 78 item questionnaire, which explores six attitude dimensions regarding respiratory illness and hospitalization, namely: 1) Optimism; 2) Specific Internal Awareness; 3) External Control; 4) Negative Staff Regard; 5) Psychological Stigma; and 6) Authoritarian Attitudes. However, as the current form of RIOS presents some limitations with regard to its length and complexity, we decided to review and shorten it with the aim of facilitating administration. Eighty eight hospitalized patients with chronic obstructive pulmonary disease (COPD) (mean age 59 yrs) completed the RIOS. Factor analyses were carried out to identify the principal components, and to verify psychometric validity. Results indicate that the RIOS can be used after being reduced to 31 items, without substantially altering its original factorial structure.

Comparison of gas exchange, lactate, and lactic acidosis thresholds in patients with chronic obstructive pulmonary disease

During an incremental exercise test, three consequences of the onset of anaerobic metabolism can be observed: rise in blood lactate (lactate threshold, LT); fall in standard bicarbonate (lactic acidosis threshold, LAT); nonlinear increase in CO2 output (V-slope gas exchange threshold, GET). We compared these thresholds in 31 patients with COPD. We found that the GET and LAT overestimated the LT. A better relationship was found between LAT and GET, even though GET was significantly higher than LAT (by 124 ml/min; p < 0.0001). However, since the bias is appreciably greater at lower LAT values (likely because VCO2 kinetics are slower than VO2 kinetics), we separated the studies into two groups: (A) tests where LAT occurred within the first 2 min of the increasing work rate period, and (B) tests where LAT occurred after 2 min. For Group A, there was a substantial bias between LAT and GET (323 ml/min, p < 0.0001), whereas the bias was much smaller (only 5.4%, though statistically significant) for Group B (57 ml/min, p < 0.01). We conclude that when lactic acidosis occurs after the first 2 min of incremental exercise, the GET closely approximates the point at which blood bicarbonate begins to fall.

Ventilatory and metabolic changes as a result of exercise training in COPD patients

Patients with COPD feel better and are able to sustain a given level of activity longer after a program of exercise training, but the underlying physiologic mechanisms have not been completely elucidated. Since the physical performance of patients with COPD is limited mainly by pathophysiologic derangements of the ventilatory system, the exercise performance can be ameliorated by increasing the level of ventilation that they can sustain or by reducing the ventilatory requirement for a given level of activity. Almost all studies have yielded negative results in patients with COPD in terms of exercise training having the ability to improve VEmax. The only way to reduce the ventilatory requirement is to reduce CO2 output. Lower levels of lactate result in less nonmetabolic CO2 produced by bicarbonate buffering and this is the likely mechanism responsible for a lower ventilatory requirement for work rates above the pretraining anaerobic threshold. We specifically wished to determine whether a program of intensity, frequency, and duration known capable of producing a physiologic training effect in healthy subjects would do so in patients with COPD. Further, we sought to determine whether exercise training at a work rate associated with lactic acidosis is more effective in inducing a training effect in patients with COPD than a work rate not associated with lactic acidosis. Nineteen patients with COPD were selected and performed an incremental test as well as 2 square wave tests at a low and a high work rate. Identical tests were performed after an 8-week program of cycle ergometer training either for 45 min/day at a high work rate or for a proportionally longer time at a low work rate. For the high work rate training group, identical work rates engendered less lactate (4.5 vs 7.2 mEq/L) and less VE (48 vs 55 L/min) after training; the low work rate training group had significantly less lactate and VE decrease (p less than 0.01). Further, in the first group, there was an increase in exercise tolerance averaging 71% in the high constant work rate test. There was a good correlation (r = 0.73, p less than 0.005) between the decrease in blood lactate and the decrease in ventilation. The major findings of this study are that patients with COPD who experience lactic acidosis during exercise can achieve physiologic training responses from a program of endurance training and that training work rates engendering high levels of blood lactate are more effective than work rates eliciting low lactate levels.