Unlinked anonymous HIV study of hospital patients and general practice attenders in Glasgow, 1991-1997

To determine whether HIV is spreading from injecting drug users and homosexual/bisexual males into lower risk heterosexual populations in Glasgow, Scotland, and to pilot a method of monitoring HIV prevalence which involves testing routine biochemistry specimens.

An unlinked anonymous HIV testing study of hospital patients and general practice attenders was conducted during January 1992 to December 1997. Testing was performed on routine biochemistry specimens from patients aged 16-49 years attending two hospitals with catchment areas covering the north and the east of the city.

78,260 specimens were tested in the study period and no patient objected to their samples being tested anonymously. HIV prevalence rates among male and female subjects were 0.63% and 0.01%, respectively; the large difference in prevalence resulted, in part, from the inclusion of HIV infected haemophiliac patients who attended one of the hospitals. Prevalence among male general practice patients ranged between 0.1% and 0.2%, while that for male patients attending surgical or surgically related specialties was 0.1%.

The prevalence data indicate that HIV has not seeded from the high risk groups into the wider heterosexual population, and that the risk of a surgeon acquiring HIV occupationally is extremely low in a city which has an HIV prevalence similar to or greater than that seen in most other parts of the United Kingdom. Large numbers of residual specimens from busy biochemistry laboratories can be processed for unlinked anonymous testing without interfering with the laboratories' routine functions. This survey approach might be best suited to monitoring HIV trends in developing countries with relatively high prevalence rates and where transmission is principally heterosexual.