Fewer patients are dying in Pennsylvania hospitals from 12 common conditions, according to a new state report.

The biggest improvement came among those diagnosed with sepsis, a potentially deadly inflammation in response to infection.

In fiscal 2016, 8.8 percent of sepsis patients died in the state's hospitals, down from 15.4 percent five years earlier, according to the Pennsylvania Health Care Cost Containment Council — a trend physicians attribute to earlier diagnosis and fast treatment with antibiotics.

Still, at six hospitals in the Philadelphia area, patients with sepsis died at a higher rate than expected in the fiscal year that ended in September 2016, the state agency found.

They are Einstein Medical Center Philadelphia, Fox Chase Cancer Center, Hahnemann University Hospital, Hospital of the University of Pennsylvania, Jennersville Regional Hospital, and Mercy Philadelphia Hospital. Physicians attributed the higher-than-expected mortality to the complexity of their patients' conditions.

[Read more: Sepsis: A stealthy, sudden killer]

Sepsis can be difficult to diagnose in its early stages, and its cause is often unclear, despite a nationwide effort to improve treatment. Each year, 1.5 million people develop sepsis in the United States and 250,000 die from it, according to the U.S. Centers for Disease Control and Prevention.