The hospital saw significant improvement in the areas of physician staffing levels in the intensive care unit and the numbers of wounds to split open after surgery, according to Leapfrog's data.
Monthly meetings of directors and managers from multiple disciplines allowed the hospital to identify and solve problems, said Sonja Draganic, the hospital's director for quality improvement.
For Glendale Memorial, the C was a downgrade from the B it received last year, when it was the highest-scoring hospital in the area.
Glendale Memorial's evaluation declined in the areas of teamwork training and skill building, identification and mitigation of risks and hazards, and hand hygiene.
Glendale Memorial spokesman Jae Chung said in a statement that the hospital supports public reporting of hospital performance and is working every day to improve patient care. He also cited Glendale Memorial's status as one of 262 hospitals nationwide to receive a HealthGrades Patient Safety Excellence Award in 2012.
Huntington Memorial and Glendale Adventist were dinged for the staffing levels in their intensive care units, with each receiving five out of 100 points.
Huntington also scored below average for timely catheter removal after surgery, and Glendale Adventist came in below average in falls and traumas while in the hospital, according to Leapfrog.
Alicia Gonzalez, spokeswoman at Glendale Adventist, said via email that the hospital wants patients to look at a variety of information sources, and said the nonprofit Joint Commission's ORYX hospital quality report recently gave Glendale Adventist a 99.4% score.
"Hospital report cards and quality-ranking websites like Leapfrog do provide valuable information," she said. "We recommend consumers use them as one tool when evaluating a hospital — just not the only tool."
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