WASHINGTON, D.C.--Obese patients are more likely to be referred for “costly” SPECT testing; and they are more likely to have positive results and longer stays, according to a poster presentation displayed at the annual conference of Cardiovascular Research Technologies (CRT), Feb. 21-23.

The authors defined obesity—a body mass index (BMI) greater than 30—as a “global pandemic associated with cardiovascular disease (CVD), increased morbidity and mortality, decreased life expectancy and multiple comorbidities.”

In addition to altering cardiac structure and function, causing circulatory changes and leading to endothelial dysfunction, they said that obesity impairs the assessment of CVD by reducing the sensitivity of the physical exam, causes alterations in the electrocardiogram (EKG), reduces exercise tolerance and affects the resolution of imaging studies.

In this study, Fatima Ilyas, MD, from King Edward Medical University in Lahore, Pakistan, and colleagues sought to evaluate the impact of obesity on efficacy and cost effectiveness of cardiac stress testing.

The researchers reviewed the records of all adult patients presenting to the emergency room of a university hospital in a one-year period who underwent stress testing for diagnosis of CVD (509 patients). The mean age was 56.9 years with 225 males and 284 females. The average BMI was 29.7 with 27.5 percent of patients being overweight (BMI 25-29), 17.3 percent had class I obesity (BMI 30-34.9), 8.6 percent has class II obesity (BMI 35-39.9) and 7.1 percent had class III obesity (BMI 40+).

According to the authors, the average BMI for different stress modalities was: exercise treadmill 28.1; stress echo 29.5 and nuclear SPECT 30.4.

Ilyas and colleagues found that the obese had a higher proportion of positive tests (14.3 vs. 8.8 percent) and indeterminate tests (12.5 vs. 8.8 percent for non-obese patients). They reported that 33 indeterminate tests were referred for further testing, and 18 of these were negative (54.5 percent) while 15 were positive (45.5 percent).

Obese patients had a higher cost of stay (mean $14,268) compared with non-obese patients (mean $13,107), the researchers found. The length of stay was higher for obese compared with non-obese patients (43.2 hours vs. 38.9 hours).

Due to the higher rate of indeterminate results, which lead to diagnosis and management delays, the authors concluded that obese patients lead to an increase in costs.