The association between phylogenetic lineage and the subclinical phenotype of pulmonary tuberculosis: A retrospective 2-cohort study.

BACKGROUND: Subclinical pulmonary tuberculosis (PTB) is an asymptomatic disease state between established TB infection and symptomatic (clinical) TB disease. It is present in 20-25% of PTB patients in high-income countries. Mycobacterium tuberculosis complex (MTBC) genetic heterogeneity, and differential host immunological responses, have been implicated in its pathogenesis. METHODS: To determine the association between MTBC lineage and PTB disease phenotype, we used two retrospective cohorts of PTB patients in Canada and two independent lineage attribution methods (DNA fingerprinting and genome sequencing). The first cohort, Cohort 1, consisted of consecutively diagnosed PTB patients between 2014 and 2020. The second, Cohort 2, consisted of newly-arrived foreign-born PTB patients who either were or were not referred for post-landing medical surveillance between 2004 and 2017. Univariable and multivariable logistic regression models were sequentially fitted to both cohorts, adjusting for age, sex, disease type, drug resistance and HIV. Evolution of radiographic features was correlated to lineage in Cohort 2. FINDINGS: Cohort 1 and 2 included 874 (209 subclinical) and 111 (44 subclinical) patients, respectively. In both cohorts, subclinical patients were more likely than clinical patients to have relapse/retreatment disease, be smear-negative, have longer times-to-culture positivity and to harbor an ancestral MTBC lineage (Indo-Oceanic or Mycobacterium africanum). Relapse/retreatment disease and ancestral MTBC lineage were independent predictors of subclinical disease (ORs and 95% CIs in Cohort 1, 1.85 [1.07,3.28], p < 0.029 and 2.30 [1.66,3.18], p < 0.001, respectively, and Cohort 2, 5.74 [1.37-24.06], p < 0.017 and 3.21 (1.29,7.97], p < 0.012, respectively). The geographic distribution of Indo-Oceanic strains causing subclinical disease was uneven. Non-progressive lung disease was more common in patients infected with ancestral than modern lineages in Cohort 2, 56.0% vs 25.4%, p < 0.005. INTERPRETATION: MTBC lineage is a strong predictor of PTB disease phenotype. The genetic drivers of this association, and the relative contribution of other explanatory variables, are unknown.

A comparison of the chest radiographic and computed tomographic features of subclinical pulmonary tuberculosis.

Subclinical pulmonary tuberculosis (PTB) is a recently described intermediate state of great interest, but about which little is known. This study sought to describe and compare the frequency of key radiologic features of subclinical PTB on chest radiograph (CXR) versus computed tomographic scan (CT), and to interpret the clinical and public health relevance of the differences. Diagnostic CXRs and CT scans of the thorax and neck in a 16-year cohort of subclinical PTB patients in Canada were re-acquired and read by two independent readers and arbitrated by a third reader. Logistic regression models were fit to determine how likely CXR features can be detected by CT scan versus CXR after adjustment for age and sex. Among 296 subclinical patients, CXRs were available in 286 (96.6%) and CT scans in 94 (32.9%). CXR features in patients with and without CT scans were comparable. Lung cavitation was 4.77 times (95% CI 1.95-11.66), endobronchial spread 19.36 times (95% CI 8.05-46.52), and moderate/far-advanced parenchymal disease 3.23 times (95% CI 1.66-6.30), more common on CT scan than CXR. We conclude that the extent to which CXRs under-detect key radiologic features in subclinical PTB is substantial. This may have public health and treatment implications.

The Radiographic and Mycobacteriologic Correlates of Subclinical Pulmonary TB in Canada: A Retrospective Cohort Study.

BACKGROUND: Very little is known about subclinical pulmonary TB (PTB), a recently described intermediate state, in high-income countries. RESEARCH QUESTION: What is the prevalence of subclinical PTB in Canada? What are its diagnostic chest radiography features? What is the relationship between those features and time to culture positivity, and what is the association between DNA fingerprint clustering, a measure of local transmission, and radiographic or other features in the foreign-born? STUDY DESIGN AND METHODS: We used primary source data to identify a 16-year retrospective cohort of patients with PTB. Demographic and mycobacteriologic features in patients with subclinical and clinical disease were compared, and the reason for assessment of patients with subclinical disease was described. Diagnostic chest radiographs in patients with subclinical disease were read by two independent readers and were arbitrated by a third reader. Linear regression was used to compute time to culture positivity (in days) in relationship to the change in chest radiograph findings from normal or minimally abnormal to moderately or far advanced, adjusted for age and sex and stratified by reason for assessment. Multivariate logistic regression was used in foreign-born patients with subclinical disease to determine associations between DNA fingerprint clustering of Mycobacterium TB isolates and age, sex, chest radiograph features, and time since arrival. RESULTS: We identified 1,656 patients with PTB, 347 of whom (21%) were subclinical. Compared with patients with clinical disease, patients with subclinical disease were more likely to be foreign-born (90.2% vs 79.6%) and to demonstrate negative smear results (88.2% vs 43.5%). The median time to culture-positivity was 18 days (interquartile range [IQR], 14-25 days) vs 12 days (IQR, 7-17 days). Most patients with PTB (75.2%) were identified during active case finding. Parenchymal disease was absent or minimal on chest radiography in 86.4% of patients. More advanced disease on chest radiography was associated with shorter times to culture positivity in nonstratified (by 3.3 days) and stratified (by 4.5-5.8 days) analysis (active case-finding groups). DNA fingerprint clustering was associated with male sex and a longer time between arrival and diagnosis. INTERPRETATION: Subclinical patients with PTB constitute a substantial and heterogeneous minority of patients with PTB in high-income countries. DNA fingerprint clustering is consistent with some, albeit limited, local transmission.

High-dose rifamycins in the treatment of TB: a systematic review and meta-analysis.

BACKGROUND: There is growing interest in using high-dose rifamycin (HDR) regimens in TB treatment, but the safety and efficacy of HDR regimens remain uncertain. We performed a systematic review and meta-analysis comparing HDR to standard-dose rifamycin (SDR) regimens. METHODS: We searched MEDLINE, Embase, CENTRAL, Cochrane Database of Systematic Reviews and clinicaltrials.gov for prospective studies comparing daily therapy with HDRs to SDRs. Rifamycins included rifampicin, rifapentine and rifabutin. Our primary outcome was the rate of severe adverse events (SAEs), with secondary outcomes of death, all adverse events, SAE by organ and efficacy outcomes of 2-month culture conversion and relapse. This study was prospectively registered in the International Prospective Register of Systematic Reviews (CRD42020142519). RESULTS: We identified 9057 articles and included 13 studies with 6168 participants contributing 7930 person-years (PY) of follow-up (HDR: 3535 participants, 4387 PY; SDR: 2633 participants, 3543 PY). We found no significant difference in the pooled incidence rate ratio (IRR) of SAE between HDR and SDR (IRR 1.00, 95% CI 0.82 to 1.23, I 2=41%). There was no significant difference when analysis was limited to SAE possibly, probably or likely medication-related (IRR 1.07, 95% CI 0.82 to 1.41, I 2=0%); studies with low risk of bias (IRR 0.98, 95% CI 0.79 to 1.20, I 2=44%); or studies using rifampicin (IRR 1.00, 95% CI 0. 0.75-1.32, I 2=38%). No significant differences were noted in pooled outcomes of death, 2-month culture conversion and relapse. CONCLUSIONS: HDRs were not associated with a significant difference in SAEs, 2-month culture conversion or death. Further studies are required to identify specific groups who may benefit from HDR.

How much do smear-negative patients really contribute to tuberculosis transmissions? Re-examining an old question with new tools.

BACKGROUND: Sputum smear microscopy is a common surrogate for tuberculosis infectiousness. Previous estimates that smear-negative patients contribute 13-20% of transmissions and are, on average, 20 to 25% as infectious as smear-positive cases are understood to be high. Herein, we use an ideal real-world setting, a comprehensive dataset, and new high-resolution techniques to more accurately estimate the true transmission risk of smear-negative cases. METHODS: We treated all adult culture-positive pulmonary TB patients diagnosed in the province of Alberta, Canada from 2003 to 2016 as potential transmitters. The primary data sources were the Alberta TB Registry and the Provincial Laboratory for Public Health. We measured, as primary outcomes, the proportion of transmissions attributable to smear-negative sources and the relative transmission rate. First, we replicated previous studies by using molecular (DNA) fingerprint clustering. Then, using a prospectively collected registry of TB contacts, we defined transmission events as active TB amongst identified contacts who either had a 100% DNA fingerprint match to the source case or a clinical diagnosis. We supplemented our analysis with genome sequencing on temporally and geographically linked DNA fingerprint clusters of cases not identified as contacts. FINDINGS: There were 1176 cases, 563 smear-negative and 613 smear-positive, and 23,131 contacts. Replicating previous studies, the proportion of transmissions attributable to smear-negative source cases was 16% (95% CI, 12-19%) and the relative transmission rate was 0.19 (95% CI, 0.14-0.26). With our combined approach, the proportion of transmission was 8% (95% CI, 3-14%) and the relative transmission rate became 0.10 (95% CI, 0.05-0.19). INTERPRETATION: When we examined the same outcomes as in previous studies but refined transmission ascertainment with the addition of conventional epidemiology and genomics, we found that smear-negative cases were ∼50% less infectious than previously thought. FUNDING: Alberta Innovates Health Solutions.

Decline of Influenza and Respiratory Viruses With COVID-19 Public Health Measures: Alberta, Canada.

OBJECTIVE: To determine the incidence of influenza and noninfluenza respiratory viruses (NIRVs) pre-/post-implementation of public health measures aimed to decrease coronavirus disease 2019 (COVID-19) transmission using population-based surveillance data. We hypothesized that such measures could reduce the burden of respiratory viruses (RVs) transmitting via the same routes. PATIENTS AND METHODS: An interrupted time-series analysis of RV surveillance data in Alberta, Canada, from May 2017 to July 2020 was conducted. The burden of influenza and NIRVs before and after intervention initiation at week 11 was compared. The analysis was adjusted for seasonality, overdispersion, and autocorrelation. RESULTS: During the study period, an average of 708 and 4056 weekly respiratory multiplex molecular panels were conducted pre-/post-intervention, respectively. We found significant reductions in test positivity rates in the postintervention period for influenza (-94.3%; 95% CI, -93.8 to 97.4%; P<.001) and all NIRVs (-76.5%; 95% CI, -77.3 to -75.8%; P<.001) in the crude model, and -86.2% (95% CI, -91.5 to -77.4%: P<.001) and -75% (95% CI, -79.7 to -69.3%; P<.001), respectively, in the adjusted models. Subanalyses for individual viruses showed significant decreases in respiratory syncytial virus, human metapneumovirus, enterovirus/rhinovirus, and parainfluenza. For non-severe acute respiratory coronavirus 2 human coronaviruses, the decline was not statistically significant after adjustment (-22.3%; 95% CI, -49.3 to +19%, P=.246). CONCLUSION: The implementation of COVID-19 public health measures likely resulted in reduced transmission of common RVs. Although drastic lockdowns are unlikely to be required given widespread COVID-19 vaccination, targeted implementation of such measures can lower RV disease burden. Studies to evaluate relative contributions of individual interventions are warranted.

Individual and public health consequences associated with a missed diagnosis of pulmonary tuberculosis in the emergency department: A retrospective cohort study.

OBJECTIVES: To determine: i) the emergency department (ED) utilization history of pulmonary tuberculosis (PTB) patients, and ii) the potential individual and public health consequences of a missed diagnosis of PTB in this setting. DESIGN: Retrospective observational cohort study. PARTICIPANTS: Patients with PTB aged >16 years diagnosed between April 1, 2010 and December 31, 2016 in the Province of Alberta, Canada. METHODS: We identified valid new cases of PTB from a provincial registry and linked them to ED attendees in administrative databases. Visits are considered 'PTB', pulmonary 'other', and non-pulmonary based on the most responsible discharge diagnosis. Individual consequences of a missed diagnosis included health system delay and PTB-related death; public health consequences included nosocomial ED exposure time and secondary cases. RESULTS: Of 711 PTB patients, 378 (53%) made 845 ED visits in the six months immediately preceding the date of diagnosis. The most responsible ED discharge diagnosis was PTB in 92 (10.9%), pulmonary 'other' in 273 (32%) and non-pulmonary in 480 (56.8%). ED attendees had a median (IQR) health system delay of 27 (7,180) days and, compared to non-ED attendees were more likely to die a TB-related death 5.9% vs 1.2%, p = 0.001. Emergency attendees generated 3812 hours of ED nosocomial exposure time, and 31 secondary cases (60.8% of all secondary cases reported). Mycobacterium tuberculosis isolates from ED-attendees were more likely than non-attendees to be clustered-i.e., have an identical DNA fingerprint with another isolate (27% vs. 21%, p = 0.037). CONCLUSIONS: ED utilization by PTB patients, and related consequences, are substantial. EDs are a potential resource for earlier PTB diagnosis.

The effects of trained observers (dofficers) and audits during a facility-wide COVID-19 outbreak: A mixed-methods quality improvement analysis.

BACKGROUND: In response to a facility-wide COVID-19 outbreak, our tertiary acute care hospital implemented an evidence-based bundle of infection control practices including the use of audits and trained observers "dofficers" to provide real-time constructive feedback. METHODS: We trained furloughed staff to perform the role of dofficer. They offered support and corrective feedback on proper PPE use and completed 21-point audits during a 4-week intervention period. Audits tracked appropriate signage, placement and availability of supplies (equipment), correct PPE use, enhanced environmental cleaning, along with cohorting and social distancing rates. Audit data was used to provide weekly quality improvement reports to units. RESULTS: Nine hundred and sixty two separate audits recorded 36,948 observations, over 7,696 observer-hours. The most common errors were with environmental cleaning and PPE use; the least common were with regards to equipment availability and cohorting and social distancing. Mean error rates decreased from 9.81% to 2.88% (P < .001). The largest reduction, 22.57%, occurred in the category of PPE doffing errors. CONCLUSIONS: Dofficer led audits effectively identified areas for improvement. Feedback through weekly reports and real-time correction of PPE errors by dofficers led to statistically significant improvements; however, error rates remained high. Further research is needed establish if these relationships are causal.

Is there a fundamental flaw in Canada's post-arrival immigrant surveillance system for tuberculosis?

BACKGROUND: New immigrants to Canada with a history of tuberculosis or evidence of old healed tuberculosis on chest radiograph are referred to public health authorities for medical surveillance. This ostensible public health protection measure identifies a subgroup of patients (referrals) who are at very low risk (compared to non-referrals) of transmission. METHODS: To assess whether earlier diagnosis or a different phenotypic expression of disease explains this difference, we systematically reconstructed the immigration and transmission histories from a well-defined cohort of recently-arrived referral and non-referral pulmonary tuberculosis cases in Canada. Incident case chest radiographs in all cases and sequential past radiographs in referrals were re-read by three experts. Change in disease severity from pre-immigration radiograph to incident radiograph was the primary, and transmission of tuberculosis, the secondary, outcome. RESULTS: There were 174 cohort cases; 61 (35.1%) referrals and 113 (64.9%) non-referrals. Compared to non-referrals, referrals were less likely to be symptomatic (26% vs. 80%), smear-positive (15% vs. 50%), or to have cavitation (0% vs. 35%) or extensive disease (15% vs. 59%) on chest radiograph. After adjustment for referral status, time between films, country-of-birth, age and co-morbidities, referrals were less likely to have substantial changes on chest radiograph; OR 0.058 (95% CI 0.018-0.199). All secondary cases and 82% of tuberculin skin test conversions occurred in contacts of non-referrals. CONCLUSIONS: Phenotypically different disease, and not earlier diagnosis, explains the difference in transmission risk between referrals and non-referrals. Screening, and treating high-risk non-referrals for latent tuberculosis is necessary to eliminate tuberculosis in Canada.

Effectiveness of Canada's tuberculosis surveillance strategy in identifying immigrants at risk of developing and transmitting tuberculosis: a population-based retrospective cohort study.

BACKGROUND: In Canada, tuberculosis disproportionately affects the foreign-born population. The national tuberculosis medical surveillance programme aims to prevent these cases. Individuals referred for further in-country surveillance (referrals) have a history of active tuberculosis or have features of old, healed tuberculosis on chest radiograph; those not referred (non-referrals) do not undergo surveillance. We aimed to examine the risk of transmission arising from referrals versus non-referrals. METHODS: We did this population-based retrospective cohort study of foreign-born migrants (aged 15-64 years) to Alberta, Canada, between Jan 1, 2002, and Dec 31, 2013. We obtained information about year of arrival and country of citizenship from Immigration, Refugees and Citizenship Canada, and data for tuberculosis cases and their contacts from the Alberta Tuberculosis Registry. The outcome of interest was culture-positive pulmonary tuberculosis. We compared the incidence of pulmonary tuberculosis and the odds of transmission among referrals versus non-referrals. By use of conventional and molecular epidemiological techniques, we defined transmission as either a secondary case or a tuberculin skin-test (TST) conversion among close contacts. We used multivariate logistic regression to determine the independent association between referral for tuberculosis surveillance and transmission. FINDINGS: Between 2002 and 2013, there were 223 225 foreign-born migrants to Alberta, of whom 5500 (2%) were referrals and 217 657 (98%) were non-referrals. 3805 (69%) referrals and 115 226 (53%) non-referrals were from countries with a tuberculosis incidence of more than 150 per 100 000 populations, or sub-Saharan Africa. 234 foreign-born individuals were diagnosed with culture-positive pulmonary tuberculosis between Jan 1, 2004, and Dec 31, 2013. The incidence of culture-positive pulmonary disease was nine times higher in referrals (n=50) than all non-referrals (n=184; incidence rate ratio 9·1, 95% CI 6·7-12·5) and five times higher in referrals than non-referrals from high-risk countries (n=167; 5·0, 3·6-6·8). 71 total transmission events arose from the individuals with culture-positive pulmonary tuberculosis-three (4%) from referrals and 68 (96%) from non-referrals. No secondary cases were attributable to a referral source case, whereas 18 secondary cases were attributable to 11 different non-referral source cases. Three TST conversions were attributable to three different referral source cases compared with 50 conversions from 31 different non-referral source cases. That is, three (6%) referrals transmitted tuberculosis compared with 42 (22%) non-referrals (adjusted odds ratio of 0·19, 95% CI 0·054-0·66; p=0·009). INTERPRETATION: Despite a much higher incidence of pulmonary tuberculosis in referrals than non-referrals, referrals were 80% less likely to transmit tuberculosis. Rather than a focus on referrals, Canada could consider screening and treatment of latent tuberculosis in all migrants from high-risk countries-a group that accounted for 100% of secondary cases. FUNDING: Canadian Institutes of Health Research.

Clinical Outcomes Associated with Home Mechanical Ventilation: A Systematic Review.

Background. The prevalence of patients supported with home mechanical ventilation (HMV) for chronic respiratory failure has increased. However, the clinical outcomes associated with HMV are largely unknown. Methods. We performed a systematic review of studies evaluating patients receiving HMV for indications other than obstructive lung disease, reporting at least one clinically relevant outcome including health-related quality of life (HRQL) measured by validated tools; hospitalization requirements; caregiver burden; and health service utilization. We searched MEDLINE, EMBASE, CINAHL, the Cochrane library, clinical trial registries, proceedings from selected scientific meetings, and bibliographies of retrieved citations. Results. We included 1 randomized control trial (RCT) and 25 observational studies of mixed methodological quality involving 4425 patients; neuromuscular disorders (NMD) (n = 1687); restrictive thoracic diseases (RTD) (n = 481); obesity hypoventilation syndrome (OHS) (n = 293); and others (n = 748). HRQL was generally described as good for HMV users. Mental rather than physical HRQL domains were rated higher, particularly where physical assessment was limited. Hospitalization rates and days in hospital appear to decrease with implementation of HMV. Caregiver burden associated with HMV was generally high; however, it is poorly described. Conclusion. HRQL and need for hospitalization may improve after establishment of HMV. These inferences are based on relatively few studies of marked heterogeneity and variable quality.

Delayed Hemolysis After Parenteral Artesunate Therapy for Severe Malaria in Two Returning Canadian Travelers.

Delayed hemolysis after parenteral artesunate has been described in Europe and Asia, but until recently had not been reported in patients receiving the artesunate product used in the United States and Canada. We report two cases of severe delayed hemolysis after the treatment with intravenous artesunate in Canada.

Macrolides and mortality in critically ill patients with community-acquired pneumonia: a systematic review and meta-analysis.

OBJECTIVE: Some studies suggest better outcomes with macrolide therapy for critically ill patients with community-acquired pneumonia. To further explore this, we performed a systematic review of studies with mortality endpoints that compared macrolide therapy with other regimens in critically ill patients with community-acquired pneumonia. DATA SOURCES: Studies were identified via electronic databases, grey literature, and conference proceedings through May 2013. STUDY SELECTION: Using prespecified criteria, two reviewers selected studies; studies of outpatients and hospitalized noncritically ill patients were excluded. DATA EXTRACTION: Two reviewers extracted data and evaluated bias using the Newcastle-Ottawa Scale. Random effects models were used to generate pooled risk ratios and evaluate heterogeneity (I). DATA SYNTHESIS: Twenty-eight observational studies (no randomized control trials) were included. Average age ranged from 58 to 78 years and 14-49% were women. In our primary analysis of 9,850 patients, macrolide use was associated with statistically significant lower mortality compared with nonmacrolides (21% [846 of 4,036 patients] vs 24% [1,369 of 5,814]; risk ratio, 0.82; 95% CI, 0.70-0.97; p = 0.02; I = 63%). When macrolide monotherapy was excluded, the macrolide mortality benefit was maintained (21% [737 of 3,447 patients] vs 23% [1,245 of 5,425]; risk ratio, 0.84; 95% CI, 0.71-1.00; p = 0.05; I = 60%). When broadly guideline-concordant regimens were compared, there was a trend to improved mortality and heterogeneity was reduced (20% [511 of 2,561 patients] mortality with beta-lactam/macrolide therapy vs 23% [386 of 1,680] with beta-lactam/fluoroquinolone; risk ratio, 0.83; 95% CI, 0.67-1.03; p = 0.09; I = 25%). When adjusted risk estimates were pooled from eight studies, macrolide therapy was still associated with a significant reduction in mortality (risk ratio, 0.75; 95% CI, 0.58-0.96; p = 0.02; I = 57%). CONCLUSIONS: In observational studies of almost 10,000 critically ill patients with community-acquired pneumonia, macrolide use was associated with a significant 18% relative (3% absolute) reduction in mortality compared with nonmacrolide therapies. After pooling data from studies that provided adjusted risk estimates, an even larger mortality reduction was observed. These results suggest that macrolides be considered first-line combination treatment in critically ill patients with community-acquired pneumonia and support current guidelines.

Macrolide-based regimens and mortality in hospitalized patients with community-acquired pneumonia: a systematic review and meta-analysis.

BACKGROUND: Macrolides are used to treat pneumonia despite increasing antimicrobial resistance. However, the immunomodulatory properties of macrolides may have a favorable effect on pneumonia outcomes. Therefore, we systematically reviewed all studies of macrolide use and mortality among patients hospitalized with community-acquired pneumonia (CAP). METHODS: All randomized control trials (RCTs) and observational studies comparing macrolides to other treatment regimens in adults hospitalized with CAP were identified through electronic databases and gray literature searches. Primary analysis examined any macrolide use and mortality; secondary analysis compared Infectious Diseases Society of America/American Thoracic Society guideline-concordant macrolide/beta-lactam combinations vs respiratory fluoroquinolones. Random effects models were used to generate pooled risk ratios (RRs) and evaluate heterogeneity (I(2)). RESULTS: We included 23 studies and 137,574 patients. Overall, macrolide use was associated with a statistically significant mortality reduction compared with nonmacrolide use (3.7% [1738 of 47,071] vs 6.5% [5861 of 90,503]; RR, 0.78; 95% confidence interval [CI], .64-.95; P = .01; I(2)= 85%). There was no survival advantage and heterogeneity was reduced when analyses were restricted to RCTs (4.6% [22 of 479] vs 4.1% [25 of 613]; RR, 1.13; 95% CI, .65-1.98; P = .66; I(2)= 0%) or to patients treated with guideline-concordant antibiotics (macrolide/beta-lactam, 5.3% [297 of 5574] vs respiratory fluoroquinolones, 5.8% [408 of 7050]; RR, 1.17; 95% CI, .91-1.50; P = .22; I(2)= 43%). CONCLUSIONS: In hospitalized patients with CAP, macrolide-based regimens were associated with a significant 22% reduction in mortality compared with nonmacrolides; however, this benefit did not extend to patients studied in RCTs or patients that received guideline-concordant antibiotics. Our findings suggest guideline concordance is more important than choice of antibiotic when treating CAP.

Guideline adherence and macrolides reduced mortality in outpatients with pneumonia.

BACKGROUND: For outpatients with pneumonia, guidelines recommend empiric antibiotics and some suggest macrolides are preferred agents. We hypothesized that both guideline-concordant antibiotics and macrolides would be associated with reduced mortality. METHODS: All outpatients with pneumonia assessed at 7 Emergency Departments in Edmonton, Alberta, Canada were enrolled in a population-based registry that included clinical-radiographic data, Pneumonia Severity Index (PSI) and treatments. Guideline-concordant regimens included macrolides and respiratory fluoroquinolones; other regimens were "discordant". Main outcome was 30-day all-cause mortality. RESULTS: The study included 2973 outpatients; mean age 51 years, 47% female, most had mild pneumonia (73% PSI Class I-II). Over 30-days, 38 (1%) patients died, 228 (8%) were hospitalized, and 253 (9%) reached the endpoint of death or hospitalization. Most (2845 [96%]) patients received guideline-concordant antibiotics. Compared to patients receiving discordant antibiotics, those receiving guideline-concordant antibiotics were less likely to die within 30-days (8 [6%] versus 30 [1%], adjusted OR 0.23, 95% CI 0.09-0.59, p = 0.002). Within the guideline-concordant subgroup, compared to the 947 (33%) patients treated with fluoroquinolones, those receiving macrolides [1847 (64%)] were less likely to die (25 [3%] versus 4 [0.2%], adjusted OR 0.28, 95% CI 0.09-0.86, p = 0.03). CONCLUSIONS: In outpatients with pneumonia, treatment with guideline-concordant antibiotics and macrolides were both associated with mortality reduction.

Natural health product-drug interactions: evolving responsibilities to take complementary and alternative medicine into account.

Natural health products (NHPs) (known as dietary supplements in the United States) are a popular form of self-care, yet many patients do not disclose their use to clinicians. NHP-drug interactions are known to occur and can harm patients and affect the efficacy of conventional treatment. Using the example of an HIV-positive adolescent who had been responding well to antiretroviral therapy but then experienced a sudden unexplained deterioration in her condition, we review (1) clinicians' obligation to inquire about complementary and alternative medicine (CAM) use when assessing, treating, and monitoring patients, (2) how clinicians' duty to warn about risks associated with treatment has evolved and expanded, and (3) patients' and parents' responsibility to disclose CAM use. It also addresses the responsibility of hospitals and health facilities to ensure that the reality of widespread CAM/NHP use is taken into account in patient care to effectively protect patients from harm.