The Geography of COPD Hospitalization in California

Abstract

Exposure to tobacco smoke is an important risk factor for chronic obstructive pulmonary disease. We investigated the relationship between chronic obstructive pulmonary disease hospitalization counts (and hospitalization-related charges) in California and sociodemographic and smoking measures, employing geospatial techniques that permit more sensitive scrutiny at the zip code level while controlling for spatial confounding. We analyzed 1,707 zip code tabulation areas in California for chronic obstructive pulmonary disease hospitalization rates and related hospitalization charges (using 1999 hospital discharge data). After controlling for spatial auto-correlation, positive relationships were found for age, percentage Hispanics, number of tobacco outlets and level of smoking. Inverse relationships were found for percentage with undergraduate degrees and income level. When examining “hotspot” zip code tabulation areas (those with higher than expected model-based chronic obstructive pulmonary disease hospitalization counts), minority/immigrant status, depressed socioeconomic measures, and elevated tobacco use were clearly associated, suggesting the need for increased intervention among the poor and persons of color. Although limited by the availability of air pollution monitoring data, a preliminary descriptive analysis indicated that the numbers of particulate matter exceedances mirrored both the hotspots of the Los Angeles air basin and coldspots in the San Francisco Bay Area.