(HealthDay)—Change in physician call systems may increase hospital readmission rates, according to a study published recently in The American Journal of Medicine.

Christopher J. Yarnell, M.D., from the University of Toronto, and colleagues compared readmission rates before and after a change in physician call system at the Sunnybrook Health Sciences Centre in Toronto; the change was implemented on Jan. 1, 2009. Data were included for 89,697 patients who were discharged from 2004 through 2013, 11 percent of whom were subsequently readmitted.

The researchers observed a 26 percent increase in the risk of readmission following change in the physician call system, from 9.7 to 12.2 percent (P < 0.001). This increase was confirmed in time-series analysis (P < 0.001). The increase in readmission rate persisted across patients with varying ages, estimated readmission risks, and diagnoses. The net effect was equivalent to 7,240 additional patient days in the . At a nearby acute care hospital, which did not change physician call system there was a modest increase in readmission rates. An increase in hospital readmissions was not associated with an increase in the risk of death.

"We suggest that changes in physician call systems sometimes increase subsequent hospital ," the authors write. "Further reductions in readmissions may instead require additional resources or ingenuity."