Trends in physician‐diagnosed osteoarthritis incidence in an administrative database in British Columbia,Canada, 1996–1997 through 2003–2004

Objective

Prevalence of osteoarthritis (OA) is expected to increase due to population aging. However, there is little information on the trends in the incidence of OA over time. The purpose of this study was to describe changes in physician‐diagnosed OA incidence rates between 1996–1997 and 2003–2004 in British Columbia (BC), Canada.

Methods

We used data on all visits to health professionals and hospital admissions covered by the Medical Services Plan of BC (population ～4 million) for the fiscal years 1991–1992 through 2003–2004. Rates were standardized to the BC population in 2000. We used 2 definitions of OA: 1) at least 1 visit or hospitalization with a diagnostic code for OA, and 2) at least 2 visits or 1 hospitalization with a code for OA. Incidence rates were calculated with a 5‐year run‐in period to exclude prevalent cases.

Results

Between 1996–1997 and 2003–2004, crude incidence rates of OA based on definition 1 increased from 10.5 to 12.2 per 1,000 in men and from 13.9 to 17.4 per 1,000 in women. The age‐standardized rates did not change in men and increased from 14.7 to 16.7 per 1,000 in women. Incidence rates based on definition 2 were almost 50% lower, but the trends were similar.

Conclusion

We observed an increase in the incidence of OA in both men and women due to population aging and an additional increase in women beyond the effect of aging. These trends have important implications for public health and provision of health services to this very large group of patients.     

Descriptive epidemiology of osteoarthritis in British Columbia, Canada

OBJECTIVE: Osteoarthritis (OA) is a highly prevalent and often disabling disease. Data on the incidence of OA in the general population are limited. Our objectives were (1) to estimate OA prevalence and incidence rates by age and sex in a geographically defined population of 4 million people [British Columbia (BC), Canada] using an administrative database; and (2) to determine the effects of different administrative definitions of OA and observation (run-in) time on such estimates. METHODS: We used data on all visits to health professionals and hospital admissions covered by the Medical Services Plan (MSP) of BC for the fiscal years 1991-92 through 2000-01. OA was defined based on International Classification of Diseases, 9th Revision, diagnostic codes required for administrative purposes. RESULTS: The overall prevalence of OA in 2001 was 10.8%: 8.9% in men and 12.6% in women. Prevalence was higher in women in all age groups. By age 70-74 years, about one-third of men and 40% of women had OA. Incidence rates in 2000-01 were 11.7 per 1000 person-years in the total population, 10.0 in men and 13.4 in women. Rates increased linearly with age between 50 and 80 years. Both prevalence and incidence depended strongly on the definition of OA and the run-in period. CONCLUSION: Prevalence of physician-diagnosed OA in BC was slightly lower than self-reported prevalence of arthritis in population surveys. Routinely collected administrative data could be a valuable source of information for OA surveillance, but more research is needed on the validity of OA diagnosis in administrative databases.     

Evaluating the predictive value of osteoarthritis diagnoses in an administrative database

OBJECTIVE: To assess the positive and negative predictive values of osteoarthritis (OA) diagnoses contained in an administrative database. METHODS: We identified all members (> or =18 years of age) of a Massachusetts health maintenance organization with documentation of at least one health care encounter associated with an OA diagnosis during the period 1994-1996. From this population, we randomly selected 350 subjects. In addition, we randomly selected 250 enrollees (proportionally by the age and sex of the 350 subjects) who did not have a health care encounter associated with an OA diagnosis. Trained nurse reviewers abstracted OA-related clinical, laboratory, and radiologic data from the medical records of both study groups (all but 1 chart was available for review). Pairs of physician reviewers evaluated the abstracted information for both groups of subjects and rated the evidence for the presence of OA according to 3 levels: definite, possible, and unlikely. RESULTS: Among the group of patients with an administrative diagnosis of OA, 215 (62%) were rated as having definite OA, 36 (10%) possible OA, and 98 (28%) unlikely OA, according to information contained in the medical record. The positive predictive value of an OA diagnosis was 62%. In those without an administrative OA diagnosis, 44 (18%) were assigned a rating of definite OA. The negative predictive value of the absence of an administrative OA diagnosis was 78%. CONCLUSION: Use of administrative data in epidemiologic and health services research on OA may lead to both case misclassification and under ascertainment.     

Tuberculosis in recent Asian immigrants to British Columbia, Canada: 1982-1985.

The prevalence and incidence of active tuberculosis among 21,959 recently arrived (1982-1985) immigrants from 7 selected Asian countries into British Columbia (BC), Canada, were reviewed. Among these newly arrived immigrants, 1173 (5.3%) were judged to have inactive tuberculosis at the immigration examination in their country of origin. In this subgroup, 14 of 932 (1.5%) were found to have active tuberculosis at the initial examination after arrival in Canada. Subsequently, 7 further cases arose in this group of inactive cases giving an average annual incidence rate of 0.33% over the 4-year period of study. Only 3 of these 21 cases had had previous antituberculosis chemotherapy. The remaining 20,786 recent immigrants with normal X-rays at the immigration examination contributed 30 cases during the next 4 years--an average annual incidence rate of 0.08% or 8 times the comparable rate for BC (0.01%). The limitations of the immigration screening process are illustrated and the value of early surveillance of immigrants designated as having inactive tuberculosis is underlined. The apparent failure to exclude active disease prior to the arrival of these immigrants is one factor elevating the incidence of active tuberculosis in the first few years after arrival in the host country. Other factors include the relatively high prevalence of inactive tuberculosis among the immigrants from certain countries and their high rate of early relapse after entry, especially in those not previously treated. Such immigrants should be considered for chemoprophylaxis immediately after entry.     

Tuberculosis incidence, hospitalisation prevalence and mortality in Lazio, Italy, 1997-2003.

SETTING: Lazio region (5.15 million, including Rome, 2.8 million), Italy. OBJECTIVE: To monitor pulmonary tuberculosis (TB) epidemiology from 1997 to 2003. DESIGN: We used data from the mandatory National Infectious Diseases Surveillance system, the regional Hospital Information System and the regional Mortality Register. The number of prevalent pulmonary TB cases hospitalised was determined by linking notifications and hospitalisations. To estimate incidence, we excluded all cases with previous TB hospitalisations since 1995, and those reported as a secondary diagnosis in the Hospital Information System. Mortality rates were ascertained from mortality records reporting TB as the principal cause of death. RESULTS: The record linkage identified 4885 incident cases, 9010 hospital prevalent cases and 217 deaths. Incidence decreased from 15/100000 in 1997 to 11 in 2003, and consistent decreases were also observed in hospitalisation prevalence and mortality (P for trend <0.0005, <0.0005 and =0.063, respectively). The number of AIDS-related TB cases dropped from 85 to 49 (P < 0.0005). The number of incident cases in non-Italians increased significantly, from 171 to 267 (P < 0.0005). Notification underreporting was estimated at 39%. CONCLUSIONS: Despite a decreasing trend, TB incidence is still over 10/100000 in Lazio region. Targeted interventions for immigrant populations are essential for controlling TB.     

Trends in pediatric bacterial meningitis in Japan (2003-2004)

We surveyed the epidemiology of pediatric bacterial meningitis between January 2003 and December 2004 in Japan, with the following results: Bacterial meningitis cases numbered 233 (132 boys, 98 girls, and 3 unidentified), equivalent to 1.13-1.6 children of 1000 hospitalized in pediatrics per year. The age distribution for the infections was the highest under 1 year of age, decreasing with increasing age. Haemophilus influenzae was the most common pathogen, followed by Streptococcus pneumoniae, group B streptococcus, and Escherichia coli. The relationship between causactive pathogens and age distribution was as follows: group B. streptococcus and E. coli were major pathogens below 4 months of age and H. influenzae and S. pneumoniae were major pathogens above 4 months of age. Susceptibility tests at each facility demonstrated that 65.0% of H. influenzae isolates and 83.0% of S. pneumoniae isolates in 2004 were drug-resistant. Ampicillin and cephem antibiotics are currently effective against GBS, E. coli and Listeria so a combination of ampicillin and cephem antibiotics is used first line at many facilities for patients below 4 months of age. A combination of carbapenem which showed effective against PRSP and cephem which showed effective against H. influenzae is the first choice in childhood bacterial meningitis for patients above 4 months of age.     

Epidemiology of Pseudomonas aeruginosa in cystic fibrosis in British Columbia,Canada

Pseudomonas aeruginosa is the most common respiratory pathogen in patients with cystic fibrosis (CF), but the predominant mechanism by which it is acquired is controversial. To determine the frequency of patient-to-patient spread, we evaluated P. aeruginosa isolates from 174 patients treated at the CF clinics in Vancouver, BC, Canada, since 1981. Multiple isolates were obtained from each patient and genetically typed by random amplified polymorphic DNA and pulsed field gel electrophoresis analyses. A total of 157 genetic types of P. aeruginosa was identified, 123 of which were unique to individual patients. A total of 34 types was shared by more than one patient; epidemiologic evidence linked these individuals only in the cases of 10 sibships and 1 pair of unrelated patients. We conclude that there is an extremely low risk in Vancouver for patients with CF to acquire P. aeruginosa from other patients. It appears that prolonged close contact, such as occurs between siblings, is necessary for patient-to-patient spread. The major source of acquisition of P. aeruginosa in CF appears to be from the environment. Considering these observations, we do not recommend segregation of patients with CF on the basis of their colonization status with P. aeruginosa.     

A population-based study of childhood myelodysplastic syndrome in British Columbia, Canada

Myelodysplastic syndrome (MDS) is considered to be very rare in children. However, the only two published population-based studies reported widely divergent incidence figures. To further explore the epidemiology of childhood MDS and to evaluate the accuracy of cancer registry and treatment trial data, we conducted a population-based study of children aged 0-14 years in British Columbia (BC), Canada, between 1982 and 1996. MDS was diagnosed in 31 cases corresponding to an annual incidence of 3.2 per million children or 6% of all leukaemias, compared with an incidence of 6.0/million for acute myeloid leukaemia (AML), and of 0.5/million for chronic myeloid leukaemia. There was a non-significant (P = 0.19) trend toward an increase in MDS incidence with time, the increase was partly explained by an increasing number of patients with Down syndrome. Associated abnormalities were found in 48% of the MDS cases with Down syndrome as the most common (seven cases). Only one third of the MDS cases were correctly registered in the Cancer Registry and less than half of the eligible MDS patients were enrolled on a cooperative group study. Data on MDS from treatment-based studies and cancer registries were inaccurate and seemed to significantly underestimate the incidence of MDS in children.     

Exploring Aging-in-Place Among Chinese and Korean Seniors in British Columbia,Canada

British Columbia, Canada, has emerged as a popular settlement area for Chinese and Korean immigrants. Responding to the demographic trend, the goal of this study was to examine current characteristics of housing and neighborhoods and utilization of local amenities of Chinese and Korean seniors in BC in exploring the possibility of aging-in-place in their home and community. The data were collected using face-to-face interviews for 99 participants (50 for Chinese and 49 for Koreans). To compare group differences between Chinese and Koreans, chi-square and t tests were conducted. Results indicated that Chinese and Korean seniors stayed at current housing about 10 years and did not plan to move out in the next 3 years. However, Chinese seniors were more likely to live with their adult children and church was an important resource for Korean seniors. Local amenities created more resources and social support for both Chinese and Korean seniors, but Chinese seniors tended to actually use various local amenities more than Korean seniors. To Korean seniors, ethnic Korean church was an important source of community links. The role of housing should be discussed from a bigger context to enable the participants to remain in their familiar environment.

Molecular epidemiology of cryptosporidiosis outbreaks and transmission in British Columbia, Canada.

Isolates from 25 (13 sporadic and 12 outbreak) cryptosporidiosis cases, 24 of which were from British Columbia, Canada, were characterized using nested polymerase chain reaction amplification of the polymorphic internal transcribed spacer 1 locus. Two predominant Cryptosporidium parvum genotypes were found. Twelve (8 sporadic and 4 outbreak) isolates amplified with the cry7/cry21 primer pair and 12 (5 sporadic and 7 outbreak) isolates amplified with the cry7/cryITS1 primer pair. Multi-locus gene analysis using sequence polymorphisms on 3 other loci, i.e., the thrombospondin-related adhesion protein gene, the dihydrofolate reductase gene, and the 18S rRNA gene on 8 (4 outbreak and 4 sporadic) isolates showed non-random association among the human and animal alleles of the 4 different C. parvum gene loci. Associations between these 2 parasite genotypes and different routes of cryptosporidiosis transmission such as zoonotic, anthroponotic, and waterborne transmission were studied using municipal population and agricultural information, as well as detection of C. parvum oocysts in municipal drinking water specimens of the residential communities of sporadic and outbreak cases.     

Asthma Hospitalization Trends in California, 1983-1996

Annual asthma hospitalization rates were calculated for California's ethnically diverse population from 1983 through 1996. Trends were examined for four race/ethnicity groups: Hispanics, African-Americans, non-Hispanic Caucasians, and Asians/Pacific Islanders. The overall rate decreased by 30% during the time period. African-Americans had the highest rate, more that three times greater than the rate for Caucasians. Among children, the rates for Caucasians decreased by one-third, while rates increased for Hispanics and Asians. The rate for African-American children remained generally constant and was four times higher than the rate for Caucasians. Data from 1996 were assessed for repeat admissions, age and sex differences in rates, costs, and progress toward national goals.