Accuracy of condom studies affected by key measurements.
This systematic review assesses the importance of four key design
and measurement factors in studying condom effectiveness: distinguishing
consistent from inconsistent use; measured correct use and condom use
problems; distinguished new infection from pre-existing infection; and
selected a study population with documented exposure to gonorrhea or
chlamydia during the time condom use was being assessed. The authors
find that 80% of studies using two or more of these measurement factors
found statistically significant protective effects of condom use
compared to only 43% of those studies including one or none of them.
Most studies showed that condom use was associated with some reduced
risk for gonorrhea and chlamydia, but magnitude of risk reduction was
unclear due to limitations and variations in methods and study designs.
The authors write that in comparison to studies on condom use and HIV prevention these studies suffered from methodological weaknesses. Key
areas to develop are methods for accurate measurement of condom
use--given the problems with self-reporting--and how best to identify
study populations with documented exposure to infection to ensure that
measurement of reductions in risk are possible during the actual period
of observation. (1)
(1.) Macaluso M, Warner L, Stone KM. Condom use and risk of
gonorrhea and chlamydia: a systematic review of design and measurement
factors assessed in epidemiologic studies. Sexually Transmitted Diseases 2006;33(1)36-51.