GEOGRAPHIC-VARIATION IN RATES OF SELECTED SURGICAL-PROCEDURES WITHIN LOS-ANGELES-COUNTY

Objective. We explore the contribution of income and ethnicity to geog raphic variation in utilization of surgical procedures. Data Sources/S tudy Setting. We assessed the use of eight procedures from 1986 throug h 1988 among residents of Los Angeles County using data from the Calif ornia Discharge Dataset, the 1980 census, and other secondary sources. Procedures chosen for evaluation were coronary artery bypass grafting (CABG), coronary artery angioplasty, permanent pacemaker insertion, m astectomy, simple hysterectomy, transurethral prostate resection (TURF ), carotid endarterectomy, and appendectomy. Study Design. The amount of inter-zip code variation for each procedure was first measured usin g various estimates including the analysis of variance coefficient of variation (CVA). Population-weighted multivariate regression analysis was used to model variation in age- and gender-adjusted rates of proce dure use among 236 residential zip codes. Principal Findings. Highest- variation procedures were coronary artery angioplasty (CVA = .392) and carotid endarterectomy (CVA = .374). The procedures with the lowest d egree of variation were cardiac pacemaker implantation (CVA = .194) an d hysterectomy (CVA = .195). Variation was significantly related to in come (carotid endarterectomy) and either African American or Latino zi p code ethnicity for all procedures except pacemaker implantation. For all procedures except appendectomy, the direction of the effect was t oward fewer procedures with lower income. However, the effect of Afric an American or Latino population ethnicity varied. Conclusions. In thi s large urban area both population ethnicity and socioeconomic status are significantly associated with the geographic utilization of select ed surgical procedures.