An increasing number of U.S. hospitals have adopted policies that explicitly ban discrimination against lesbian, gay and bisexual patients, according to a report to be released Tuesday.

An annual survey by the Human Rights Campaign, an advocacy group, found that over 95 percent of more than 400 hospitals and clinics included sexual orientation in their nondiscrimination policies and nearly 80 percent included gender identity in those policies. Additionally, more than 65 percent of inpatient hospitals had explicit policies granting equal visitation rights to same-sex couples and same-sex parents.

The results of the voluntary survey, taken last year, reflect the increased prominence of nondiscriminatory care, the advocacy group said. In 2010, President Obama mandated that nearly all hospitals extend visitation rights to the partners of gay men and lesbians, and new rules were subsequently issued by the U.S. Department of Health and Human Services. Last year, the Joint Commission, the largest accrediting organization for U.S. hospitals, also issued new standards specifically prohibiting discrimination based on sexual orientation and gender identity.

“I commend the LGBT and healthcare communities for the progress made and I am proud to be part of an administration that has a historic record of accomplishment for the LGBT community,” Health and Human Services Secretary Kathleen Sebelius said in a statement. “We will continue to take action to ensure that LGBT Americans get equal treatment in healthcare settings and that all patients are treated with the dignity they deserve.”

The report is scheduled to be presented at Howard University Hospital in Washington.

The advocacy group said there was a 40 percent increase in the number of health-care facilities participating in the voluntary survey, from 87 respondents in 2010 to 122 respondents, representing 407 hospitals and clinics, in 2011. Although that represents a fraction of the more than 4,000 hospitals in the United States, the issue is gaining prominence, the group said.

“Just a few short years ago, the healthcare industry wasn’t having conversations about LGBT healthcare equality,” Chad Griffin, president of the organization, said in a statement.

Among the facilities participating for the first time were a Veterans Administration hospital in Madison, Wis., and the Bon Secours Health System, which operates 14 hospitals in Maryland, Virginia and three other states.

Locally, Washington Adventist and Shady Grove Adventist hospitals also took part for the first time. This year, Washington Adventist apologized after a Takoma Park woman filed complaints with federal health authorities and the main hospital accreditation commission after staff at the hospital denied her permission to visit her same-sex partner, who was taken there after suffering a seizure.

The two Maryland hospitals and Howard University Hospital were among 234 facilities that received perfect ratings for protecting patients and employees from discrimination, ensuring equal visitation access for same-sex couples and same-sex parents, and providing specific staff training for lesbian, gay, bisexual and transgender care.

The report revealed other gaps. For example, 34 percent of facilities that ask about marital status at admitting or registration do not offer a “partner” or “significant other” option. The facilities that took part in the survey are located in 32 states and the District. In 18 states, mostly in the Midwest, no health-care facilities participated.

Not all hospitals within a network chose to participate. In the Washington region, MedStar Georgetown Hospital earned a perfect rating, but MedStar Washington Hospital Center did not participate. Johns Hopkins Hospital in Baltimore also earned a perfect score, as did Sibley Memorial Hospital, part of the Hopkins health system. But Suburban Hospital, in Bethesda, which is also part of that system, did not participate.