District of Columbia hospitals spent $135 million last year to provide free medical care for patients who could not or did not pay their bills, according to a survey released yesterday by the D.C. Hospital Association.

The average amount of free care provided by District hospitals is double the average amount provided by hospitals in the Maryland and Virginia suburbs and double the national average, the survey indicated.

Because hospitals traditionally pass on the cost of uncompensated care in the fees that are charged to paying patients, those that perform substantial free care become less attractive for patients shopping for hospitals with low rates, the report noted. It concluded that District hospitals, if their fees increase too quickly, could lose large numbers of the 90,000 suburban patients who now seek care here annually.

The report concludes that a decline in patients at District hospitals might lead to inadequate medical care for some District residents and force some hospitals to reduce services or close.

"In human terms, the most serious risk posed by the uncompensated care problem is that uninsured D.C. residents may not receive appropriate medical care," the report stated.

"While the existence of D.C. General Hospital supported by tax dollars with its strictly open door policy should lessen this possibility," the report added, "if a substantial portion of the uncompensated care that is provided by the other hospitals eventually has to be cut back to fend off untenable financial losses, no guarantee can be made that all of the uninsured will find their way to a hospital which can meet all of their needs."

Stephen H. Lipson, president of the D.C. Hospital Association, said the association does not have any evidence that people are being turned away from District hospitals because they cannot afford to pay. He added, however, that he is convinced that in some cases the indigent are not seeking care.

Of the hospitals surveyed by the medical association, D.C. General, with $41 million in uncompensated care, and Howard University Hospital, with $42.3 million in uncompensated care, provided the largest amounts of free care in 1984. For the same period, Children's Hospital National Medical Center provided $11.2 million in free care and the Washington Hospital Center provided $8.9 million.

Earlier this month, the General Accounting Office launched a study at the request of Rep. Ronald V. Dellums (D-Calif.), chairman of the House District Committee, to determine whether patients are being "dumped" on D.C. General.

In 1984, 904 patients were transferred to D.C. General from other hospitals for financial reasons.

Association officials noted yesterday that a hospital's mission and its proximity to poor neighborhoods become factors influencing the number of indigent patients it recieves.

According to the hospital association report, the combined total of uncompensated care provided by 13 District hospitals included in the survey represented 13.7 percent of the total charges for those hospitals in 1984, and is projected to increase to 13.9 percent, or $136.2 million, this year. Bad debts represented $45.6 million of the uncompensated care for 1984 and a projected $43.1 million for this year.

The hospital association report also revealed that based on 1983 data from community hospitals in the 20 largest U.S. cities, the District ranked second only to Houston in the percentage of total hospital charges spent on free health care.

Of the 20 cities, the District ranked 12th in the percentage of population living below the poverty income level and had the fifth highest unemployment rate. The hospital association has formed a task force to develop ways to solve the problmes problems of providing free medical care to the poor.