For the second year in a row, Cambridge Health Alliance earned the top grade in patient safety from a national employer-sponsored group that rates hospitals, although even hospital officials acknowledged that the grade isn’t unusual in Massachusetts.

The Leapfrog Group, established to reduce health costs by pushing hospitals to improve quality of care and steer patients and insurers to top-rated hospitals, gave the Alliance an “A” based on performance in 26 areas that measure health outcomes including infections and hospital processes such as use of electronic drug orders.

In Massachusetts, 43 hospitals earned an A;  13 hospitals scored a B and three had a C. Of 25 hospitals within Route 495, only three got a B, including the prestigious Massachusetts General Hospital, according to the Leapfrog website. The statewide figures work out to 71 percent getting an A grade; 23 percent getting a B grade; and 6 percent getting a C grade.

Nationally, the breakdown was different: 31 percent of 2,514 rated hospitals scored an A grade, 25 percent got a B grade; 37 percent got a C grade; almost 6 percent got a D grade; and about half of 1 percent got an F grade.

Dr. Gerald Steinberg, chief medical officer of the Alliance, told its board of trustees Tuesday that the “A” score this year “is fairly common [in Massachusetts] but not in the rest of the country.”

The grade “is important to our public profile,” he said. In addition, the individual measures used in the grading “are increasingly being used by various [private and public health insurers] to calculate pay for performance,” increased reimbursement for meeting performance goals.

Hospitals are graded by a number of public and private groups, and the results can vary depending on the details. For example, Medicare is penalizing the Alliance this year for not meeting standards in areas such as patient satisfaction, quality of care and the number of Medicare patients who return to the hospital within 30 days of being discharged.

The Alliance was formed in 1996 when the city helped Cambridge City Hospital acquire Somerville Hospital. Five years later the system added Whidden Memorial Hospital in Everett.