The number of cocaine-related hospital emergencies declined 4 percent the first three months of 1990, providing further evidence that the dramatic surge in cocaine abuse during the late 1980s may have ebbed, federal health officials said yesterday.

However, the number of people who died from cocaine use increased 10 percent last year. In addition, the relatively small reduction in cocaine-related hospital emergency visits suggests that inner-city cocaine abuse may be lingering at historically high levels, one analyst said.

The hospital statistics are considered among the government's most reliable indicators of hard-core drug abuse, monitoring trends in cocaine overdoses and other drug-related medical emergencies. Nevertheless, officials acknowledge that they give an incomplete picture of drug abuse, in part because they are affected by a number of variables, such as purity of available drugs and consistency of reporting by hospitals.

The data are collected by the Drug Abuse Warning Network (DAWN) from more than 700 hospital emergency rooms in 21 cities. Between mid-1985 and mid-1989, DAWN reported an explosive, nearly five-fold increase in cocaine-related hospital emergencies -- from 2,462 visits in the second quarter of 1985 to 11,285 in the same three-month period in 1989.

That trend started to level off last year, and during the last three months of 1989, DAWN recorded a 22 percent drop in emergency room visits, prompting Secretary of Health and Human Services Louis W. Sullivan to hail the decline as a sign of "significant headway in our efforts to establish a drug-free America."

The new figures show a much smaller decline in the first three months of 1990, from 8,507 emergency room patients who had used cocaine to 8,135. Hospitals in the District showed a similarly slight dip, from 941 during the last three months of 1989 to 923 the first three months of this year.

"In some senses, these numbers are less encouraging than Secretary Sullivan had suggested," said Mark Kleiman, a drug researcher at Harvard University's John F. Kennedy School of Government. "Instead of peaking and collapsing, it doesn't look like there's going to be a sudden change" in the number of emergencies.

Bush administration officials are preparing to cite the figures next week when they issue an upbeat report on the "state of the drug war" one year after release of their national anti-drug strategy. Charles R. Schuster, director of the National Institute on Drug Abuse, said yesterday that the new figures "confirm the downward trend" first reported by Sullivan last spring and show "we are finally beginning to see some progress in reaching those who are seriously affected by the cocaine epidemic."

But the downward trend was in part contradicted by the increase in cocaine overdose deaths. Between 1988 and 1989, the number of people who died from cocaine in 27 cities rose from 2,254 to 2,496, according to DAWN figures. In the District, cocaine deaths increased from 160 in 1988 to 212 last year.

The same contradiction was also seen with heroin. Emergency room visits related to heroin dropped from 3,554 in the last three months of 1989 to 3,070 the first quarter of 1990. But heroin-related deaths also rose nationally, from 1,884 to 1,995 over the same period. Kleiman said that given the widespread availability of cheap and highly pure heroin on the streets, the decline in heroin-related hospital emergencies may be because users are switching from injecting to smoking the drug, a form of ingestion that is equally addictive but less likely to lead to an overdose.