Gender and Utilization of Ancillary Services

Men and women often receive different medical care. However, these differences are not always based on clinical characteristics.1, 2 Studies comparing care for women and men have yielded varying results depending in part on the care setting and variables studied.3–12 Among outpatients, women generally have had more visits to physicians and receive more care per visit, including more laboratory tests.3 Hibbard et al. found that the largest differences between women and men in utilization rates occurred among patients who had symptoms associated with the mildest morbidities. They concluded that gender differences in utilization were due to differences in ways that physicians perceive and evaluate symptoms.2 Cleary et al. suggested that women's higher outpatient utilization might be largely due to reported health differences.4 Among inpatients, many studies on gender and resource utilization have examined specific disease entities such as coronary disease and the use of interventional procedures. Tobin et al. found that men were 10 times more likely to be referred for cardiac catheterization after an abnormal radionuclide test, and that women were more likely to have true cardiac symptoms dismissed as having a noncardiac etiology.6 Ayanian and Epstein studied coronary angiography and revascularization in coronary heart disease and found 15% to 45% higher rates for men.7 The SAVE trial found that although women reported worse anginal symptoms, they received fewer catheterizations and coronary artery bypass grafts.8 Differences in care have been demonstrated in noncardiac areas as well. For instance, among those who fit the criteria for chronic dialysis, men are more likely than women to receive dialysis,9 while women on chronic dialysis are approximately 30% less likely to receive a cadaveric renal transplant than their male counterparts.10 Gender also has been shown to be an independent predictor for non-gender-specific preventive care, such as screening for lung cancer; after controlling for known risk factors, one study found that men had increased rates of screening sputum samples.11 Some research has failed to demonstrate any effect of gender on resource use. For instance, McGann et al. studied men and women admitted for suspected transient ischemic attacks and found no difference between men and women in the use of computed tomography of the head, carotid and cardiac Doppler ultrasonography, or carotid angiography.13 This finding may reflect the relative standardization of care and a correspondingly lower level of discretion available to physicians in this clinical context. Subtle differences in the ways physicians treat men and women may be most apparent in discretionary areas of care. Ancillary services represent such an area, given that studies have suggested that up to 50% of ancillary services performed on hospitalized patients may be unnecessary.14––17 In one study addressing whether women are treated differently from men, Bernard analyzed resource utilization of patients hospitalized on the medicine service and found that women had longer lengths of stay yet used fewer ancillary “relative value units.”18 Because ancillary testing of inpatients is an area in which discretion plays a large role, and because earlier studies suggest differences in utilization by gender of several important inpatient services, we undertook a study with the following goals: First, to compare crude differences between men and women in clinical laboratory and radiology tests performed for inpatients in the hospital, and then to determine the effect of gender on utilization after adjusting for a number of potential confounders.