Objective
To update the 1984 recommendations of the Canadian Task Force on the
Periodic Health Examination on the routine screening of asymptomatic patients
for infection with Chlamydia trachomatis.
Burden of Suffering
Infection with C. trachomatis is the most common sexually transmitted
disease (STD) in North America, causing infection in two to three times
more people than Neisseria gonorrhoeae. In Canada, the incidence rate of
C. trachomatis infection is estimated to be 216 per 100 000 people per
year. Although there are no Canadian estimates of the associated cost of
infection, in the United States there are more than 4 million infections
each year, with an estimated cost in 1990 of $2.2 billion (US). Most
infections (60% to 80%) among women are asymptomatic, but the spectrum
of symptoms includes mucopurulent cervicitis, endometritis, salpingitis,
postabortal pelvic sepsis and perihepatitis. Among men, the spectrum
of symptoms caused by C. trachomatis includes urethritis, epididymitis
and conjunctivitis.
Options
Screening, with the use of culture or nonculture tests, of the general
population, of certain high-risk groups or of all pregnant women; or no
routine screening.
Outcomes
Rates of asymptomatic and symptomatic chlamydial infection, perinatal
complications, long-term complications of infection (i.e., pelvic inflammatory
disease, infertility and ectopic pregnancy), coinfection with other sexually
transmitted diseases, disease spread, hospital care, complications of therapy
and costs of infection and of screening.
Evidence
A MEDLINE search of articles published from Jan. 1, 1983, to Dec. 31,
1995, was conducted by exploding the major MeSH heading chlamydial infections
with the subheadings complications, diagnosis, drug therapy, economics,
cost, epidemiology, etiology, history, microbiology, mortality, mass screening,
prevention and control, therapy and transmission.
Values
The 13-member Task Force of experts in family
medicine, geriatric medicine, pediatrics, psychiatry and epidemiology used
an evidence-based method for evaluating the effectiveness of preventive
health care interventions. Recommendations were not based on cost-effectiveness
of options. Patient preferences were not discussed.
Background papers providing critical appraisal of the evidence and tentative recommendations prepared by the chapter author were pre-circulated to the members. Evidence for this topic was presented and deliberated upon in 1- to 2-day meetings. Consensus was reached on final recommendations.
Advice from reviewers and experts and recommendations
of other organizations were taken into consideration. Prevention
of symptomatic disease and decreased overall costs were given high values.
Benefits, Harms, and Costs
The greatest potential benefits of screening asymptomatic patients
for chlamydial infections are the prevention of complications, especially
infertility and perinatal complications, and the prevention of disease
spread. There is no evidence that screening of the general population for
chlamydial infections leads to a reduction in complications, and screening
may increase costs. However, there is evidence that annual screening of
selected high-risk groups and of pregnant women during the first trimester
is beneficial in preventing symptoms and reducing the overall cost resulting
from infection.
Recommendations
Recommendation grade [A, B, C, D, E] and level of evidence
[I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations
in support of individual recommendations are identified in the guideline
text.