Comorbid conditions increase fall risk

To study the risk of falls in patients undergoing orthopedic procedures, researchers at the Hospital for Special Surgery (HSS) turned to the Nationwide Inpatient Sample, sponsored by the Agency for Healthcare Research and Quality (AHRQ).

The sample is the largest inpatient database available in the United States that includes information on patients of all ages. It collects data from about 20% of all hospitalizations in the United States. This large cohort of patient information is unparalleled and allows for the appropriate study of relatively rare events surrounding surgery, notes Stavros Memtsoudis, MD, PhD, an anesthesiologist at HHS, who led the study.

The investigators analyzed data between 1998 and 2007 to identify patients who had undergone a total hip or knee replacement. Using statistical modeling, they then compared characteristics of patients who had suffered in-hospital falls to those who had not suffered a fall. During the study period, the rate of patients that fell during their in-hospital recovery was 0.85%, representing 2.1 falls per 1,000 inpatient days. The incidence of falls increased from 0.4% to 1.3% during the study period.

Patients were more likely to fall if they were male, older, belonged to a minority race, or were undergoing a revision joint replacement surgery. Patients also were at heightened risk if they had certain comorbid conditions, including congestive heart failure, a clotting or bleeding disorder, liver disease, neurologic disease, electrolyte/fluid abnormalities, and recent weight loss.

Pulmonary circulatory disease posed the greatest risk. Obesity, hypothyroidism, uncomplicated diabetes, and cancer were not associated with an increased risk of falling. Postoperative complications including deep vein thrombosis, adult respiratory distress syndrome, and pulmonary embolism also were associated with higher fall rates, although Memtsoudis says it remains unclear if they were the reason or the consequence for this event.

In line with other studies, patients who experienced falls had longer hospital stays and were more frequently discharged to other healthcare facilities, instead of their primary residence.