Flock worker's lung disease: natural history of cases and exposed workers in Kingston, Ontario.

BACKGROUND: The natural history of flock worker's lung (FWL) and longitudinal lung function changes in nylon flock-exposed workers have not been well characterized. METHODS: Symptoms, pulmonary function testing, and chest radiographs from five index cases, subsequent case referrals, and screened employees of a flocking plant in Kingston, Ontario, Canada, were compared and analyzed for changes over time (variable follow-up intervals between 1991 and 2011). RESULTS: Nine cases and 30 flock-exposed workers without FWL were identified. Four cases had persistent interstitial lung disease despite three having left the workplace. Two developed hypoxemic respiratory failure and secondary pulmonary hypertension and died of complications 18 and 20 years after diagnosis, respectively. Five cases resolved after leaving the workplace. Compared with resolved cases, persistent cases had lower diffusing capacity of the lung for carbon monoxide at presentation (P < .05) and follow-up (P < .05). Among exposed workers employed for 14.5 ± 4.7 years, five had abnormal chest radiographs vs none at baseline (P = .001) over 14.8 ± 4.6 years of follow-up. The prevalence of wheeze increased (P = .001), and FEV1/FVC decreased (P < .001). FEV1% predicted was significantly lower at follow-up (P = .05). Average FEV1 decline was 46 mL/year (range, -27 to 151 mL/y). Seventy-seven percent of exposed workers were current or former smokers. CONCLUSIONS: The natural history of FWL includes the following patterns: complete resolution of symptoms; radiographic and pulmonary function abnormalities; permanent, but stable symptoms and restrictive pulmonary function deficits; and progressive decline in pulmonary function, causing death from respiratory failure and secondary pulmonary hypertension. A low baseline diffusing capacity of the lung for carbon monoxide is associated with the persistence and progression of FWL.

Conventional versus automated measurement of blood pressure in primary care patients with systolic hypertension: randomised parallel design controlled trial.

OBJECTIVE: To compare the quality and accuracy of manual office blood pressure and automated office blood pressure using the awake ambulatory blood pressure as a gold standard. DESIGN: Multi-site cluster randomised controlled trial. SETTING: Primary care practices in five cities in eastern Canada. PARTICIPANTS: 555 patients with systolic hypertension and no serious comorbidities under the care of 88 primary care physicians in 67 practices in the community. INTERVENTIONS: Practices were randomly allocated to either ongoing use of manual office blood pressure (control group) or automated office blood pressure (intervention group) using the BpTRU device. The last routine manual office blood pressure (mm Hg) was obtained from each patient's medical record before enrollment. Office blood pressure readings were compared before and after enrollment in the intervention and control groups; all readings were also compared with the awake ambulatory blood pressure. MAIN OUTCOME MEASURE: Difference in systolic blood pressure between awake ambulatory blood pressure minus automated office blood pressure and awake ambulatory blood pressure minus manual office blood pressure. RESULTS: Cluster randomisation allocated 31 practices (252 patients) to manual office blood pressure and 36 practices (303 patients) to automated office blood pressure measurement. The most recent routine manual office blood pressure (149.5 (SD 10.8)/81.4 (8.3)) was higher than automated office blood pressure (135.6 (17.3)/77.7 (10.9)) (P < 0.001). In the control group, routine manual office blood pressure before enrollment (149.9 (10.7)/81.8 (8.5)) was reduced to 141.4 (14.6)/80.2 (9.5) after enrollment (P < 0.001/P = 0.01), but the reduction in the intervention group from manual office to automated office blood pressure was significantly greater (P < 0.001/P = 0.02). On the first study visit after enrollment, the estimated mean difference for the intervention group between the awake ambulatory systolic/diastolic blood pressure and automated office blood pressure (-2.3 (95% confidence interval -0.31 to -4.3)/-3.3 (-2.7 to -4.4)) was less (P = 0.006/P = 0.26) than the difference in the control group between the awake ambulatory blood pressure and the manual office blood pressure (-6.5 (-4.3 to -8.6)/-4.3 (-2.9 to -5.8)). Systolic/diastolic automated office blood pressure showed a stronger (P < 0.001) within group correlation (r = 0.34/r = 0.56) with awake ambulatory blood pressure after enrollment compared with manual office blood pressure versus awake ambulatory blood pressure before enrollment (r = 0.10/r = 0.40); the mean difference in r was 0.24 (0.12 to 0.36)/0.16 (0.07 to 0.25)). The between group correlation comparing diastolic automated office blood pressure and awake ambulatory blood pressure (r = 0.56) was stronger (P < 0.001) than that for manual office blood pressure versus awake ambulatory blood pressure (r = 0.30); the mean difference in r was 0.26 (0.09 to 0.41). Digit preference with readings ending in zero was substantially reduced by use of automated office blood pressure. CONCLUSION: In compliant, otherwise healthy, primary care patients with systolic hypertension, introduction of automated office blood pressure into routine primary care significantly reduced the white coat response compared with the ongoing use of manual office blood pressure measurement. The quality and accuracy of automated office blood pressure in relation to the awake ambulatory blood pressure was also significantly better when compared with manual office blood pressure. Trial registration Clinical trials NCT 00214053.

Diagnostic cardiac catheterization and revascularization rates for coronary heart disease.

BACKGROUND: Despite evidence of regional variation across North America, there have been no comprehensive studies of cardiac procedure rates for coronary heart disease in Canada. OBJECTIVES: To use available administrative data and a survey of catheterization facilities to examine regional and demographic variations in cardiovascular procedure rates. METHODS: A survey of all cardiac catheterization facilities in Canada was conducted, and the procedure counts from these facilities were used to determine provincial catheterization rates from 1997/1998 to 2001/2002. Procedure counts for 1997/1998 to 1999/2000 for coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) were provided by the Canadian Institute for Health Information and used to calculate revascularization procedure rates. Population projections provided by Statistics Canada were used as denominators for calculating the rates, and direct standardization was used to obtain age- and sex-adjusted rates. RESULTS AND CONCLUSIONS: The crude rate of cardiac catheterization in Canada increased from 359.9 to 471.5 per 100,000 population across the five years studied. There was considerable variation in revascularization procedure rates across health regions and provinces. Between 1997/1998 and 1999/2000, there was little increase in the rate of CABGs performed in Canada but a marked increase in the rate of PCIs. For both CABG and PCI, rates were higher for men than women, and highest in the 65- to 74-year-old age category. This study provides a valuable 'snapshot' of cardiac procedure use rates but indicates a clear need for more comprehensive collection of cardiac care data in Canada.

Effectiveness of implantable defibrillators for preventing arrhythmic events and death: a meta-analysis.

OBJECTIVES: The aim of this study was to compare the effectiveness of the implantable cardioverter defibrillator (ICD) and medical strategies for prevention of arrhythmic events and death. BACKGROUND: The ICD is a potential strategy to reduce mortality in patients at risk of sudden death. METHODS: The MEDLINE, EMBASE, and Cochrane Library electronic databases were searched from January 1966 to April 2002. All published randomized controlled trials comparing ICD implantation with medical therapy were reviewed. Four independent reviewers extracted data on all-cause mortality, nonarrhythmic death, and arrhythmic death using a standardized protocol. RESULTS: Nine studies including over 5,000 patients were synthesized using both fixed-effects and random-effects models. The primary and secondary prevention trials showed a significant benefit of the ICD with respect to arrhythmic death, with relative risks (RR) of 0.34 and 0.50, respectively (both p < 0.001). The mortality benefit of the ICD was entirely attributable to a reduction in arrhythmic death (all trials: p < 0.00001). Whereas the secondary prevention trials exhibited a robust decrease in all-cause ICD mortality (RR 0.75; p < 0.001), the pooled primary prevention trials demonstrated decreased all-cause ICD mortality (RR 0.66; p < 0.05) which was dependent on selected individual trials. The disparity in ICD-related mortality reductions in the primary prevention trials was related to variability in the incidence of arrhythmic death between individual studies. CONCLUSIONS: Although the ICD decreases the risk of arrhythmic death, its impact on all-cause mortality is related to the underlying risk of arrhythmia-related death relative to competing causes. Given the cost of the device strategy, policies of targeted intervention based on the future risk of arrhythmia are warranted.

CCORT/CCS quality indicators for congestive heart failure care.

BACKGROUND: Quality indicators are measurement tools for assessing the structure, processes and outcomes of care. Although quality indicators have been developed in other countries, Canadian cardiovascular disease indicators do not exist. OBJECTIVE: To develop quality indicators for measuring and improving congestive heart failure (CHF) care in Canada. METHODS: An 11-member multidisciplinary national expert panel was selected from nominees from national medical organizations. Potential quality indicators were identified by a detailed search of published guidelines, randomized trials and outcomes studies. A two-step modified Delphi process was employed with an initial screening round of indicator ratings, followed by a national quality indicator panel meeting, where definitions of the indicators were developed using consensus methods. Indicators were designed to be measurable, using retrospective chart review and linking existing administrative databases. RESULTS: The case definition criterion was developed based on a discharge diagnosis of CHF (International Classification of Diseases, 9th revision [ICD-9] code 428.x), with diagnostic confirmation using clinical criteria. In total, 29 indicators and five test indicators were recommended. Process indicators included prescription for angiotensin-converting enzyme inhibitors, beta-blockers or warfarin (for atrial fibrillation) at hospital discharge. Nonpharmacological in hospital process indicators included evaluation of left ventricular function, weight measurement and selected patient education counselling instructions. Process indicators in the ambulatory setting included prescription and adherence to drug therapies and physician follow-up. Outcome indicators included mortality, readmissions and emergency visits. CONCLUSIONS: A set of Canadian quality indicators for CHF care encompassing organizational attributes, pharmacotherapy, investigations, counselling, continuity of care and disease outcomes has been developed. These quality indicators will serve as a foundation for future studies evaluating the quality of CHF care in Canada.

CCORT/CCS quality indicators for acute myocardial infarction care.

BACKGROUND: Although quality indicators for the care of acute myocardial infarction (AMI) patients have been described for other countries, there are none specifically designed for the Canadian health care system. The authors' goal was to develop a set of Canadian quality indicators for AMI care. METHODS: A literature review identified existing quality indicators for AMI care. A list of potential indicators was assessed by a nine-member panel of clinicians from a variety of disciplines using a modified-Delphi panel process. After an initial round of rating the potential indicators, a series of indicators was identified for a second round of discussion at a national meeting. Further refinement of indicators occurred following a teleconference and review by external reviewers. RESULTS: To identify an AMI cohort, case definition criteria were developed, using a hospital discharge diagnosis for AMI of International Classification of Diseases-Ninth revision (ICD-9) code 410.x. Thirty-seven indicators for AMI care were established. Pharmacological process of care indicators included administration of acetylsalicylic acid, beta-blockers, angiotensin-converting enzyme inhibitors, thrombolytics and statins. Mortality and readmissions for AMI, unstable angina and congestive heart failure were recommended as outcome indicators. Nonpharmacological indicators included median length of stay in the emergency department, and median waiting times for cardiac catheterization, percutaneous coronary intervention and/or coronary artery bypass graft surgery. INTERPRETATION: A set of Canadian quality indicators for the care of AMI patients has been established. It is anticipated that these indicators will be useful to clinicians and researchers who want to measure and improve the quality of AMI patient care in Canada.