Dynamic hyperinflation is a risk factor for mortality and severe exacerbations in COPD patients

OBJECTIVE

To assess if dynamic hyperinflation is an independent risk factor for mortality and severe exacerbations in COPD patients.

METHODS

A cohort of 141 patients with stable COPD and moderate to very severe airflow limitation, treated according to conventional guidelines, was followed for a median of 9 years. Clinical characteristics were recorded and arterial blood gases, pulmonary function tests, 6-min walk and incremental exercise test with measurement of respiratory pattern and operative lung volumes were performed. Endpoints were all-cause mortality and hospitalization for COPD exacerbation.

RESULTS

58 patients died during the follow-up period (1228 patients x year). The mortality rate was higher in patients with dynamic hyperinflation (n = 106) than in those without it (n = 35) (14.6; 95% CI, 14.5-14.8 vs. 7.2; 95% CI, 7.1-7.4 per 1000 patients-year). After adjusting for sex, age, body mass index, pack-years and treatment with inhaled corticosteroids, dynamic hyperinflation was associated with a higher mortality risk (adjusted hazard ratio [aHR], 2.725; 95% CI, 1.010-8.161), and in a multivariate model, comorbidity, peak oxygen uptake and dynamic hyperinflation were retained as independent predictors of mortality. The time until first severe exacerbation was shorter for patients with dynamic hyperinflation (aHR, 3.961; 95% CI, 1.385-11.328), and dynamic hyperinflation, FEV1 and diffusing capacity were retained as independent risk factors for severe exacerbation. Moreover, patients with dynamic hyperinflation had a higher hospitalization risk than those without it (adjusted incidence rate ratio, 1.574; 95% CI, 1.087-2.581).

CONCLUSION

In stable COPD patients, dynamic hyperinflation is an independent prognostic factor for mortality and severe exacerbations.

Syntheses and crystal structures of the anhydride 4-oxa-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione and the related imide 4-(4-bromo-phen-yl)-4-aza-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione

The Diels–Alder cyclo­addition of cyclo­hepta­triene and maleic anhydride produces the title carb­oxy­lic anhydride; reaction of this anhydride with 4-bromo­phenyl­aniline forms the corresponding tetra­cyclic imide. The anhydride features C—H⋯O hydrogen bonds in the solid state, while the imide also features C—H⋯O hydrogen bonds as well as C—H⋯π and lone pair–π inter­actions.

The syntheses and crystal structures of the two title compounds, C₁₁H₁₀O₃ (I) and C₁₇H₁₄BrNO₂ (II), both containing the bi­cyclo­[2.2.2]octene ring system, are reported here [the structure of I has been reported previously: White & Goh (2014 ▸). Private Communication (refcode HOKRIK). CCDC, Cambridge, England]. The bond lengths and angles of the bi­cyclo­[2.2.2]octene ring system are similar for both structures. The imide functional group of II features carbonyl C=O bond lengths of 1.209 (2) and 1.210 (2) Å, with C—N bond lengths of 1.393 (2) and 1.397 (2) Å. The five-membered imide ring is nearly planar, and it is positioned exo relative to the alkene bridgehead carbon atoms of the bi­cyclo­[2.2.2]octene ring system. Non-covalent inter­actions present in the crystal structure of II include a number of C—H⋯O inter­actions. The extended structure of II also features C—H⋯O hydrogen bonds as well as C—H⋯π and lone pair–π inter­actions, which combine together to create supra­molecular sheets.

Respiratory infection and iatrogenic diarrhea in Honduras and El Salvador during the 1991-1992 season

The etiology of acute respiratory tract infection and its association with diarrhea was analyzed in 135 hospitalized children less than three years of age with mainly respiratory symptoms in two pediatric hospitals in Honduras and El Salvador. Etiologic diagnoses were performed on nasopharyngeal samples by tissue culture and immunofluorescence, including a search for the presence of respiratory virus-specific immunoglobulin A antibodies. Fecal samples were subjected to electron microscopy and tissue culture. The majority (83%) of the children (65% boys and 35% girls) were less than 12 months old and 45% were less than four months old. In 63 (47%) patients, at least one viral infection of the respiratory tract was identified. Respiratory syncytial virus (RSV) or the respective IgA antibodies were found in 43 (32%) patients., influenza A and B viruses in 29 (21%) patients, adenovirus in four patients, and enterovirus in two patients. Twenty (15%) patients had two or more viral agents. An association between RSV cases and environmental temperature was established. In 124 fecal samples, we identified four cases with astrovirus, seven with nonpolio enterovirus, and eight with adenovirus, but only three cases with rotavirus. Diarrhea was present in 55 (45%) of the patients. There was a statistically significant association between diarrhea and cases with RSV. This was shown to be associated with antibiotic treatment.

Epstein-Barr virus and childhood Hodgkin's disease in Honduras and the United States

In industrialized populations, Hodgkin's disease (HD) has an initial peak in young adulthood, whereas in economically developing populations the initial peak occurs in childhood. This pattern resembles that of infection with poliovirus and suggests an infectious cofactor in the etiology. Serologic studies have linked Epstein-Barr virus (EBV) to young adult and adult HD, and viral nucleic acids and antigens have been detected in a subset of Hodgkin's tumor specimens. To investigate the association of childhood HD with EBV we studied tumor specimens from 11 children treated in Honduras and 25 children treated in the United States using in situ hybridization and antigen detection techniques. Among the patients from Honduras, tumor specimens from all cases were EBV positive. Among the patients from the United States, tumor specimens from six of seven patients with mixed cellularity histology, 2 of 15 with nodular sclerosis histology, and neither of two patients with lymphocyte-predominant histologies were EBV positive. These findings support the hypothesis that EBV contributes to the pathogenesis of HD in children, particularly in mixed cellularity HD, and raises the possibility that there are important geographic, racial, or ethnic factors in the EBV association with HD.

Human immunodeficiency virus infection and syphilis in Hondurian female prostitutes

The seroprevalence of human immunodeficiency virus (HIV) infection and syphilis was investigated in 181 female prostitutes in Tegucigalpa, Honduras. One particle agglutination test and two enzyme immunoassays, as well as one immunofluorescence test were used for the screening of HIV antibodies. Confirmation of positive results by the screening tests was carried out by Western blot. The prevalence of HIV seropositivity was 4% (8 women). Specific treponemal antibodies were found in 50% (90/181) of the prostitutes as judged by Treponema pallidum haemagglutination assay (TPHA) and/or fluorescent treponemal antibody-absorption (FTA-ABSIgG) test. As estimated by the positivity of any or both non-treponemal tests (VDRL and RPR), a total of 31 (17%) out of the 181 women had active syphilis. A good correlation was found between the results obtained by TPHA and FTA-ABSIgG. IgM antibodies were found in 72% of sera positive by TPHA and/or FTA-ABSIgG. Four out of the 181 women were found to have antibodies to both HIV and Treponema pallidum.