To provide information on poorly described Canadian hepatocellular cancer epidemiology, we analyzed incident cases abstracted from the Canadian Cancer Registration Database (1969-1997) and Canadian annual death data (1969-1998). Age, sex, geographic distribution, and secular trends were described. Projection models were developed for the next decade.
Results indicated much higher incidence and mortality rates in males than females, with substantial increases for both with age. Age-standardized incidence rates increased an average of 3.4% per year in males, 1.2% per year in females (1969-1997). Age-standardized mortality rates increased an average of 1.48% in males, but decreased an average of 0.46% per year in females (1969-1998). Join-point analysis of the linear trends in the age-standardized incidence and mortality rates suggested that a new trend started to emerge about 1991. The fitted non-linear multiplicative model predicted the occurrence of 1,565 new cases and 802 deaths in the year 2010. HCC incidence was the highest in British Colombia, followed by Quebec, and the lowest in the Atlantic region.
Incidence rates of hepatocellular carcinoma have increased substantially, consistent with the reported increase in the prevalence of Hepatitis C Virus (HCV) and Hepatitis B Virus (HBV) infections in recent decades.
To assess the potential uses of computer-assisted record linkage in the surveillance of infectious diseases, using the Nova Scotia blood recipient notification program as the example.
We developed a computer-assisted, multiple-pass, probabilistic record linkage to link records for blood recipients identified by the Nova Scotia notification program (Nova Scotia Phase I Blood Bank File information) with corresponding Nova Scotia Health Card Registration File records to obtain current mailing addresses to contact potentially living recipients. We used variables available from both files (e.g., name, date of birth, gender, and health care registration number) to link records, after eliminating duplicates/deceased cases.
Among 23,925 eligible records in the Nova Scotia Phase I Blood Bank File (1984-1990), there were 1,818 (7.8%) duplications and 8,675 deceased cases, leaving 13,432 cases for linkage. 8,713 (65%) cases were successfully linked to the 1998 Health Card Registration Data File for current mailing addresses.
Multiple-pass linkage seems acceptable for maximizing detection of correctly matched records for look-back projects. To overcome quality/lack of information obstacles, future look-back linkages should explore the use of supplementary data files (tax files, voter lists, license files, other provincial databases) to obtain most current addresses.
Current practice in transfusion medicine promotes clear documentation of transfusion-related events including the fact that the patient has been informed of the related risks and benefits.
A retrospective review of 1005 patient charts was carried out to determine documentation.
Most patients were from general surgery (10.8%) and cardiac surgery (14.1%). In 75 percent of cases the physician had not documented that any discussion had occurred regarding the risks and/or benefits or alternatives. Only 12 percent of charts included information that the patient was subsequently told what blood components were given to them. The discharge summary recorded transfusion information in 32.1 percent of cases whereas the consult note had this information in 26.3 percent. Chart records matched the transfusion medicine records in 60.6 percent of cases. The most common error was in the blood unit identification number.
While accepted in theory, the practice of documenting patient information on transfusion is not well done.
A descriptive epidemiological analysis to update trends of Creutzfeldt-Jakob disease (CJD) deaths, from 1979-2001, was undertaken.
Cases with CJD as underlying cause were extracted. Age-adjusted death rates by age, sex, and province were calculated. Information on birthplace, autopsy indications and type of work were examined for death certificates from 1979 to 1997.
462 cases were identified between 1979 and 1997. The average annual age-standardized mortality rate was 0.93 deaths per million persons during this period and 1.03 for 1998-2001. Persons 60 years or older demonstrated the highest average annual mortality rate. Rates were slightly higher among males and increased with age. Persons born in Canada accounted for 72% of deaths. Cause of death was verified by autopsy for 9.1% of patients while 21% of deaths indicated that additional information relating to underlying cause was expected. The service industry occupation represented the largest mortality (Quebec does not capture these data).
Canadian rates are consistent with those of the United States and slightly higher than those of certain European countries. Approximately 44% of CJD cases had an autopsy record, though many were incomplete. We are unable to determine a relation with occupation. We recommend annual analysis of CJD death registrations for updated surveillance of trends, as mortality data are an efficient tool for monitoring incidence.
A descriptive analysis of hepatocellular carcinoma (HCC) deaths in Canada for 1995 was undertaken. Cases (ICD-9 155.0) were identified from the Statistics Canada annual mortality file; age-adjusted death rates by age, sex and province were calculated. Antecedent causes and conditions leading to death listed on the death certificate, including viral hepatitis infection and cirrhosis, were examined, in addition to birthplace information. The 403 cases identified resulted in an annual age-standardized mortality rate of 2.11 deaths per 100,000 persons among men and 0.64 deaths per 100,000 persons among women. Mean age at death was 65.5 years with male-to-female ratio approximately 3:1. Compared to the age-standardized rate for birthplace of Canada of 0.96 per 100,000 (95 percent CI: 0.84, 1.10), the age-standardized mortality rates were significantly elevated for birthplace of Europe 1.72 (95 percent CI: 1.37, 2.28), Asia 5.17 (95 percent CI: 4.11, 6.44), and non-significantly elevated for all other countries 1.54 (95 percent CI: 0.94, 2.39). In total, 60 patients (15 percent) were reported to have had viral hepatitis; sufficient information was not provided for the remainder. Of the total population, 8.7 percent were reported to have had viral hepatitis B and 5.2 percent had viral hepatitis C. Information on cirrhosis was provided in 103 (26 percent) of cases. Of these, the largest proportion (45 percent) was of unknown type while 23 patients (22 percent) had alcohol-related cirrhosis. Prevalence of antecedent causes was slightly lower than reported previously and may be considered minimum estimates since inadequate information was provided in over 50 percent of deaths.
There is a high level of uncertainty surrounding the potential for iatrogenic prion transmission through transplantation, medical instrument reuse, blood transfusion, and blood product use due to a lack of evidence-based research on this important risk issue. A group of specialists was enlisted to evaluate some of the knowledge gaps in this area using the "Classical Model," a structured elicitation procedure for weighting and pooling expert judgment. The elicitation exercise was undertaken in March 2009 with 11 transmissible spongiform encephalopathy (TSE) experts who were first calibrated using a series of seed questions for which the answers are known; they were then asked to answer a number of target questions that are important for risk assessment purposes, but for which there remains high uncertainty at this time. The target questions focused on variant Creutzfeldt-Jakob disease (vCJD) prevalence, incubation times for vCJD, genetic susceptibility to prion disease, blood infectivity, prion reduction of blood and blood products, surgical instrument risks, and interspecies transmission of TSEs. The experts were also asked to perform pairwise risk rankings for 12 different potential routes of infection. Dura mater transplantation was seen as having the highest risk, while dental tissue grafts were viewed as presenting the lowest risk of iatrogenic transmission. The structured elicitation procedure provides a rational, auditable, and repeatable basis for obtaining useful information on prion disease risk issues, for which data are sparse.
Statistics and Risk Assessment Section, Health Care Acquired Infections Division, Population and Public Health Branch, Health Canada, A.L. 0601E2, Building No. 6, Tunney's Pasture, Ottawa, ON K1A 0L2. Susie_ElSaadany@hc-sc.gc.ca
To estimate the incidence of and to describe the risk factors that were associated with the acquisition of hepatitis A, B, and C in well-defined Canadian populations from the Sentinel Health Unit Surveillance System (SHUSS).
We used the 1993 to 1995 data on hepatitis A, B, and C infection in Canada, collected by SHUSS, a national surveillance system established by the Laboratory Centre for Disease Control in Health Canada in 1993, through consultation and collaboration with provincial partners. We calculated the rates of, and described and discussed the risk factors that were associated with, hepatitis A, B, and C infection, based on the SHUSS surveillance data.
From 1993 to 1995, SHUSS reported 92 cases of hepatitis A, 89 hepatitis B, and 720 hepatitis C, yielding a rate of 3.9, 3.8, and 30.3 per 100,000, respectively. The reported rates varied substantially among participating health units, ranging from 0.8 to 8.1 per 100,000 for hepatitis A, 0.0 to 9.0 for hepatitis B, and 5.4 to 73.3 for hepatitis C. The most frequently reported risk factor for hepatitis A was a history of street drug use, followed by recent international travel and household contact with a hepatitis A case, household crowding, and a history of raw or undercooked shellfish consumption. The most frequently reported risk factors for the acquisition of hepatitis B included history of street drug use and occupational exposure. The most frequently reported risk factor for the acquisition of hepatitis C was a history of street drug use, followed by health care exposure and occupational exposure. Only 5% of persons with hepatitis B infection had a history of hepatitis B immunization.
Despite the limitations of possible bias due to selective participation of SHUSS and the lack of information on risk factors among controls, the high exposure to known risk factors and the low rate of vaccination among hepatitis patients can provide useful information for the development of public health policies to control hepatitis A, B, and C infection in Canada.
Department of Anesthesia, Toronto General Hospital, University Health Network, Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada. firstname.lastname@example.org
When comparing transfused versus nontransfused patients, erythrocyte transfusion is consistently associated with increased mortality. Nonetheless, unmeasured confounding may unduly influence this comparison. This unmeasured risk may have less influence on comparisons of patients undergoing surgery at hospitals with differing transfusion rates.
Administrative databases were used to conduct a population-based cohort study of patients who underwent elective hip- or knee-replacement surgery from 1999 to 2008 in Ontario, Canada. The authors used Cox proportional-hazards models to determine the adjusted association of hospital-specific erythrocyte transfusion rates (i.e., comparing hospitals with differing transfusion rates) with postoperative mortality. For comparison, they also determined the adjusted association of patient receipt of transfusion (i.e., comparing transfused vs. nontransfused patients) with mortality.
Of 162,190 patients, 23% (n=37,015) were transfused. Hospital-specific transfusion rates at the 66 included hospitals ranged from 10.3 to 57.9%. Compared with nontransfused patients, transfused patients experienced increased adjusted 30-day (hazard ratio 2.32; 95% CI, 1.91-2.83) and 1-yr mortality (hazard ratio 1.75; 95% CI, 1.60-1.91). However, when hospitals were categorized into quartiles based on hospital-specific transfusion rates, mortality rates were similar (highest transfusion quartile vs. lowest transfusion quartile: 30-day mortality, hazard ratio 1.11, 95% CI 0.82-1.50; 1-yr mortality, hazard ratio 1.02, 95% CI 0.82-1.26).
The association of transfusion with postoperative mortality differed significantly when comparing transfused versus nontransfused patients, as opposed to comparing hospitals with differing transfusion rates. This discrepancy raises questions about the true relationship between transfusion and mortality.