For the first time, the share of workers with employer-sponsored coverage who are enrolled in HMOs or point-of-service plans is falling, according to a William M. Mercer Inc. survey. Half of all covered employees in 1997 were enrolled in HMOs or POS plans, but that dropped to 47 percent last year. PPOs' share, meanwhile, grew from 35 to 40 percent.... Another first: Inpatient days per 1,000 HMO enrollees increased in 1997 to 255, up from 246 in 1996, says Maryland-based HCIA Inc.... HMOs will fund patient care in some National Institutes of Health-sponsored clinical trials, under an agreement brokered by NIH and the American Association of Health Plans.... The Health Care Financing Administration will now give Medicare beneficiaries specific reasons for denials of claims. No longer will HCFA use the term "not medically necessary." ... The California Medical Association sued FPA Medical Management, alleging breach of fiduciary duty. CMA says the bankrupt PPM owes physicians millions in unpaid claims.... The New Mexico Medical Society is trying to figure out what to do about physicians deserting the state, attracted to bigger paychecks in Texas. The AMA says New Mexico lost an average of 27 physicians a month in 1998, up from 18 per month in 1997.