BETHESDA, Md--As expected, the number of reported AIDS cases increased substantially in 1993 due to the expansion of the surveillance case definition in January of that year, but an adjusted analysis shows only a slight overall increase.

This analysis showed a 1993 incidence increase of 3% (62,000 cases in 1993 versus 60,000 in 1992). However, a slight decrease (1%) was seen in homosexual/bisexual men, while the AIDS incidence for intravenous drug users increased by 8%, and for heterosexuals by 23% (MMWR 43:826-831, 1994).

Still, the number of persons infected through heterosexual contact remains small (7,500 in 1993), compared with the number infected through homosexual sex (30,300) or IV drug use (17,800).

The report also showed significant geographic differences in AIDS incidence trends. Although the number of cases contracted through heterosexual sex rose in all four regions of the country, the increases varied widely, from 11% in the South to 39% in the Northeast.

The incidence among IV drug users increased in the Northeast, where most lived when diagnosed, but remained stable in the South and West. The number of homosexual cases decreased in the West while remaining stable in the Northeast, South, and Midwest.