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Mark Loeb

Publications and source records attributed to Mark Loeb.

53 records · Page 3Linked to original sources
PubMed2004

Pneumonia in the elderly.

PURPOSE OF REVIEW: This review provides an update on new data about the etiology, clinical characteristics, outcomes, and prevention of community-acquired pneumonia. The impact of severe acute respiratory syndrome in older persons is also addressed. RECENT FINDINGS: Streptococcus pneumoniae remains the most important cause of community-acquired pneumonia in the very elderly (80 years and over). Pneumococcus is also an important etiologic agent of pneumonia in residents of long-term care facilities. Clinical signs and symptoms of community-acquired pneumonia are less distinct in this group compared with younger patients. New data about influenza immunization reveal better mucosal immunity with the intranasal vaccine compared with the intramuscular vaccine. A review of clinical trial evidence differs from observational studies that demonstrate a clear benefit of the polysaccharide pneumococcal vaccine in the elderly. The prospect of severe acute respiratory syndrome in older adults is the most important new issue to emerge, as older adults are at increased risk from complications and death. SUMMARY: There are many challenges in preventing and managing community-acquired pneumonia in the elderly. S. pneumoniae remains the most important cause. The clinical presentation of pneumonia in the very elderly can be nonspecific. Given the safety profile of the vaccine and supportive observational evidence, public health policymakers should continue to support use of the polysaccharide pneumococcal vaccine. However, research into new vaccine strategies, including use of conjugate or common antigen vaccines, is a priority.

Aged↗
PubMed2004

Performance and Cost evaluation of one commercial and six in-house conventional and real-time reverse transcription-pcr assays for detection of severe acute respiratory syndrome coronavirus.

We evaluated seven reverse transcription-PCR (RT-PCR) assays, including six in-house assays and one commercial assay for the detection of severe acute respiratory syndrome coronavirus (SARS-CoV) RNA in clinical specimens. RT-PCR assays targeted different genomic regions and included three conventional assays (one nested and two non-nested) run on a conventional heat block and four real-time assays performed in a LightCycler (LC; Roche Diagnostics). All in-house assays were optimized for assay parameters, including MgCl2, primer, and probe concentrations. The commercial assay was the RealArt HPA CoV RT-PCR assay (Artus), which was run in the LC. Testing serial dilutions of cultured SARS-CoV showed that the analytical sensitivity of the assays ranged from 10(-8) to 10(-6), corresponding to 1 and 100 copies of viral RNA, respectively. Significant differences in analytical sensitivities were observed between assays (P < 0.01, probit regression analysis for 50% sensitivity levels for the top two assays versus the others). Testing 68 clinical specimens (including 17 respiratory tract specimens, 29 urine samples, and 22 stools or rectal swabs) demonstrated that six of the seven assays detected at least 17 of 18 positives (defined as positive in at least two assays), and two of the assays had a sensitivity of 100%. There were no significant differences in sensitivity between the assays (P = 0.5 [Cochrance Q test, least sensitive 15 of 18 versus 18 of 18]). The specificities of the assays ranged from 94.0 to 100% without significant differences (P = 0.25 to 0.5 [McNemar test]). The reagent and technologist cost of performing the in-house PCR assays ranged from $5.46 to $9.81 Canadian dollars (CDN) per test. The commercial assay cost was considerably higher at $40.37 per test. The results demonstrated good performance for all assays, providing laboratories that need to do SARS RNA testing with a choice of assay formats.

Costs and Cost Analysis↗
PubMed2004

SARS among critical care nurses, Toronto.

To determine factors that predispose or protect healthcare workers from severe acute respiratory syndrome (SARS), we conducted a retrospective cohort study among 43 nurses who worked in two Toronto critical care units with SARS patients. Eight of 32 nurses who entered a SARS patient's room were infected. The probability of SARS infection was 6% per shift worked. Assisting during intubation, suctioning before intubation, and manipulating the oxygen mask were high-risk activities. Consistently wearing a mask (either surgical or particulate respirator type N95) while caring for a SARS patient was protective for the nurses, and consistent use of the N95 mask was more protective than not wearing a mask. Risk was reduced by consistent use of a surgical mask, but not significantly. Risk was lower with consistent use of a N95 mask than with consistent use of a surgical mask. We conclude that activities related to intubation increase SARS risk and use of a mask (particularly a N95 mask) is protective.

Cohort Studies↗
PubMed2003

Pneumonia in older persons.

Community-acquired pneumonia (CAP) is an important threat to the health of older adults. Streptococcus pneumonia remains the most important cause of CAP. Risk factors for CAP include alcoholism, asthma, immunosuppression, chronic respiratory or cardiac disease, institutionalization, and increasing age. Residents of long-term care facilities--a distinct subpopulation of elderly people--are at particularly high risk for developing pneumonia. In this setting, swallowing difficulties, witnessed aspiration, and receipt of sedatives are potentially modifiable risk factors. The clinical presentation in elderly patients is characterized by a reduced prevalence of nonrespiratory symptoms. Few randomized, controlled trials of therapy exist for elderly persons living in the community or in a long-term care setting. Good evidence exists to support the annual administration of influenza vaccine to older adults. Although evidence in clinical trials differs from evidence in observational studies that demonstrate clear benefits associated with the polysaccharide pneumococcal vaccine in this population, the vaccine is recommended for adults aged

Aged↗
PubMed2003

Clinical and epidemiologic features of group a streptococcal pneumonia in Ontario, Canada.

BACKGROUND: Since the 1960s, group A streptococcus (GAS) has accounted for less than 1% of cases of community-acquired pneumonia. During the past 2 decades there has been a resurgence of invasive GAS infection, but no large study of GAS pneumonia has been performed. METHODS: To determine the clinical and epidemiologic features of GAS pneumonia, we conducted prospective, population-based surveillance of all invasive GAS infection in residents of Ontario from January 1, 1992, through December 31, 1999. RESULTS: Of 2079 cases of invasive GAS infection, 222 (11%) represented GAS pneumonia. The incidence of GAS pneumonia ranged from 0.16 per 100 000 in 1992 to 0.35 per 100 000 in 1999. Most cases were community acquired (81%). Forty-four percent of nursing home-acquired cases occurred during outbreaks. The case fatality rate was 38% for GAS pneumonia, compared with 12% for the entire cohort with invasive GAS infection and 26% for patients with necrotizing fasciitis. The presence of streptococcal toxic shock syndrome (odds ratio, 19; 95% confidence interval, 8.4-42; P =.001) and increasing age (odds ratio per decade, 1.45; 95% confidence interval, 1.2-1.7; P<.001) were associated with fatal outcome. Time to death was rapid, with a median of 2 days despite antimicrobial therapy and supportive measures. CONCLUSIONS: Group A streptococcal pneumonia is a common form of invasive GAS disease but remains an uncommon cause of community-acquired pneumonia. Progression is rapid despite appropriate therapy. The incidence is similar to, and the case fatality rate higher than, that of necrotizing fasciitis.

Chi-Square Distribution↗
PubMed2003

Implementation of the Canadian contingency plan for a case of suspected viral hemorrhagic fever.

OBJECTIVE: To describe the implementation of the Canadian contingency plan for viral hemorrhagic fever (VHF) in response to a suspected case. SETTING: A 300-bed, tertiary-care, university-affiliated hospital. PARTICIPANTS: A 32-year-old Congolese woman admitted to the hospital with suspected VHF in February 2001. Contact evaluation included hospital healthcare workers and laboratory staff. INTERVENTION: Enhanced isolation precautions were implemented in the patient care setting to prevent nosocomial transmission. Contact tracing and evaluation of close and high-risk contacts with symptoms was conducted. Laboratory precautions included barrier precautions and diversion of specimens. Communication occurred media. to both hospital employees and the media. RESULTS: Three high-risk contacts, 13 close contacts, and 60 casual contacts were identified. Two close contacts became symptomatic and required evaluation. Challenging process issues included tracing of laboratory specimens, decontamination of laboratory equipment, and internal and external communication. After 5 days, a transmissible VHF of public health consequence was ruled out in the index case. CONCLUSION: Contingency plans for VHF can be implemented in an efficient and feasible manner. Contact tracing, laboratory issues, internal communication, and media interest can be anticipated to be the key challenges.

Canada↗
PubMed2002

Optimizing antibiotics in residents of nursing homes: protocol of a randomized trial.

BACKGROUND: Antibiotics are frequently prescribed for older adults who reside in long-term care facilities. A substantial proportion of antibiotic use in this setting is inappropriate. Antibiotics are often prescribed for asymptomatic bacteriuria, a condition for which randomized trials of antibiotic therapy indicate no benefit and in fact harm. This proposal describes a randomized trial of diagnostic and therapeutic algorithms to reduce the use of antibiotics in residents of long-term care facilities. METHODS: In this on-going study, 22 nursing homes have been randomized to either use of algorithms (11 nursing homes) or to usual practise (11 nursing homes). The algorithms describe signs and symptoms for which it would be appropriate to send urine cultures or to prescribe antibiotics. The algorithms are introduced by inservicing nursing staff and by conducting one-on-one sessions for physicians using case-scenarios. The primary outcome of the study is courses of antibiotics per 1000 resident days. Secondary outcomes include urine cultures sent and antibiotic courses for urinary indications. Focus groups and semi-structured interviews with key informants will be used to assess the process of implementation and to identify key factors for sustainability.

Aged↗
PubMed2002

Adverse events associated with pyrazinamide and levofloxacin in the treatment of latent multidrug-resistant tuberculosis.

BACKGROUND: The current Canadian and US guidelines for the treatment of multidrug-resistant latent tuberculosis infection advocate the use of pyrazinamide and a fluoroquinolone as a first-line treatment option. However, there is very little information in the literature that describes the use of these agents together. This case series describes the probable association between multiple adverse events and the use of pyrazinamide and levofloxacin in the treatment of individuals with suspected latent multidrug-resistant tuberculosis infection. METHODS: We studied a case series of 17 individuals with suspected latent multidrug-resistant tuberculosis infection in Hamilton, Ont., who were being treated with pyrazinamide and levofloxacin. The Naranjo scale was used to assess patients for musculoskeletal, central nervous system, gastrointestinal and dermatological adverse events. Hepatocellular events were assessed and defined using criteria established by the Council for International Organizations of Medical Sciences. Laboratory abnormalities and adverse events that were documented during combination drug therapy were evaluated to determine the likelihood of an association. RESULTS: Fourteen individuals developed musculoskeletal adverse effects (11 were deemed to be probably related to combination therapy). There were 8 reports of central nervous system effects (5 of which were assessed as being probably associated with therapy). Hyperuricemia and gastrointestinal and dermatological effects were also common; the use of pyrazinamide and levofloxacin was believed to be probably responsible for the emergence of these adverse effects. There were 5 cases of hepatocellular injury. Therapy was discontinued in all individuals. INTERPRETATION: The combination of pyrazinamide and levofloxacin appears to be a poorly tolerated regimen. The mechanism of a possible interaction is not yet understood. Given the severity of some of the adverse events, a better understanding of dosing and clearer guidelines for monitoring therapy are imperative if these drugs are to be prescribed together.

Adolescent↗
PubMed2002

Use of oseltamivir during influenza outbreaks in Ontario nursing homes, 1999-2000.

OBJECTIVES: To describe the experience of Ontario long-term care facilities that used oseltamivir during influenza outbreaks in 1999/2000. DESIGN: Case series. SETTING: Ten Ontario long-term care facilities for older people and their residents. PARTICIPANTS: Older residents of long-term care facilities. INTERVENTION: Oseltamivir for treatment or prophylaxis during 11 influenza outbreaks in 1999/2000. MEASUREMENTS: Control of outbreaks; pneumonia, hospitalization, and death complicating acute influenza. RESULTS: All outbreaks were due to influenza A//H3N2/Sydney/05/97. One facility elected to use oseltamivir for treatment and amantadine for prophylaxis. The remaining nine facilities (10 outbreaks) recommended oseltamivir for treatment and prophylaxis (after amantadine failure in five and as primary prophylaxis in five). Use of oseltamivir was associated with termination of the outbreak in all eight evaluable outbreaks. Overall, 178/185 (96%) case-residents met the case definition of influenza and had complete data for evaluation. Of these, 63 (35%) were treated with antibiotics, 37 (21%) were diagnosed with pneumonia, 19 (11%) were hospitalized, and 16 (9%) died. Compared with residents receiving no therapy or who became ill while taking amantadine, residents who received oseltamivir within 48 hours of the onset of symptoms were less likely to be prescribed antibiotics, to be hospitalized, or to die (P <.05 for each outcome). These differences persisted and remained statistically significant when corrected for influenza immunization status. A total of 730 residents received oseltamivir prophylaxis for a median of 9 days (range 5-12). Of these, side effects were identified in 30 (4.1%), the most common being diarrhea (12 residents, 1.6%), cough (5, 0.7%), confusion (4, 0.5%) and nausea (4, 0.5%). CONCLUSIONS: Oseltamivir is safe and appears to be effective when used as treatment or prophylaxis to control outbreaks of influenza in older nursing home residents.

Acetamides↗
PubMedDate not supplied

Oseltamivir for treatment of influenza in healthy adults: pooled trial evidence and cost-effectiveness model for Canada.

BACKGROUND: Influenza is a common viral respiratory infection that is associated with significant morbidity. Oseltamivir (Tamiflu) is a neuraminidase inhibitor-a new class of antiviral treatment for influenza where efficacy and safety has been established but cost-effectiveness is unknown. METHODS: A decision analytic model was used to estimate the costs and effectiveness of two treatment scenarios for empiric management of otherwise healthy nonelderly patients, presenting with influenza-like illness (ILI) to primary care physicians in Canada: 1) where oseltamivir is reimbursed and on formulary for prescription; and 2) where oseltamivir is not on formulary. Outcomes are influenza-days averted and quality-adjusted life-years (QALYs) gained. Effectiveness, utility, and pneumonia complication risk estimates are by pooled analysis of patient-level data from four clinical trials. Unit cost information (Canadian dollars) was obtained from published sources in Ontario. Probabilistic sensitivity analysis was conducted using Monte Carlo simulation. RESULTS: Of 2288 patients randomized, influenza was confirmed in 1575 (69%) and oseltamivir treatment reduced the mean time to symptom alleviation by 1.08 days (95% confidence interval CI] 0.58-1.59). Infected patients treated with oseltamivir had higher utility scores (quality of life) than placebo patients over the 7 days of follow-up (P <.05). Cost per influenza-day averted with oseltamivir on formulary is 49 US dollars (95% CI 31-107) and the cost per QALY is 57,863 US dollars (95% CI 48,919- 70,149 US dollars). Results are sensitive to the percentage of patients presenting to their physician beyond 48 hours from symptom onset who get oseltamivir and the prevalence of influenza among patients presenting with ILI. CONCLUSIONS: Oseltamivir for treatment of patients with ILI is potentially cost-effective if clinical diagnostic specificity for influenza observed in clinical trials is applicable to routine practice. More population-based information on the prevalence of influenza among early (<48 hours) presenters with ILI would be valuable.

Acetamides↗