Racial differences in the use of lumbar spine radiographs: results from the Veterans Health Study.

Abstract

We analyzed data from the Veterans Health Study, a longitudinal study of male patients receiving VA ambulatory care. To determine whether clinical differences and/or race account for disparities between white and nonwhite patients in the use of lumbar spine radiographs. Four hundred one patients with low back pain (LBP) receiving ambulatory care services in four VA outpatient clinics in the greater Boston area were followed for 12 months. Participants were mailed the Medical Outcome Study Short Form Health Survey (SF-36) and had scheduled interviews that included the completion of a low back questionnaire, a comorbidity index, and a straight leg raising (SLR) test. Using self-reported racial data, patients were grouped as whites (315 patients) and nonwhites (among whom 22 were black, 4 nonwhite Hispanics, and 1 other race). Nonwhite patients had lumbar spine films more often (13 of 27, 48%) than white patients (87 of 315, 27%)(P = 0.02). Nonwhite patients had higher pain intensity scores than white patients (63 +/- 21 vs. 48 +/- 21, P < 0.01) and were more likely to have radiating leg pain (20 of 27, 76%; compared with 171 of 315, 55%; P = 0.01) than white patients. Nonwhite patients had worse physical functioning (P = 0.01), general health perception (P = 0.05), social functioning (P = 0.02), and role limitations because of emotional problems (P < 0.01). At higher LBP intensity level, nonwhite patients received more lumbar spine films (20 of 27, 74%) than did white patients (155 of 315, 50%)(P < 0.01). Among patients with positive SLR test, nonwhite patients also had lumbar spine films more often (5 of 22, 23%) than white patients (29 of 315, 11%) (P < 0.01). However, after adjusting for multiple clinical characteristics, race was no longer found to be an independent predictor of lumbar spine radiograph use. A positive SLR test remained to be associated with higher radiograph use, whereas better mental health status was associated with lower radiograph use. There was greater use of lumbar spine radiographs by nonwhite patients compared with white patients. This remained true when patients were subcategorized by severity of LBP or SLR test. However, race had no influence when multiple clinical characteristics of the patients were controlled for simultaneously. This study demonstrates the importance of careful and comprehensive case-mix adjustment when assessing apparent differences in the use of medical services.