we used the arizona and california state inpatient databases ( sid ) from the us agency for healthcare research and quality ( ahrq ) to describe clinical and demographic characteristics of persons hospitalized for disseminated coccidioidomycosis who did not have known primary immune conditions , hiv infection , or aids . the sid contains state - level data , including information from 90% of community hospital in - patient stays , and is maintained as part of the healthcare utilization project at ahrq . we extracted records from the available annual datasets for arizona ( 20002009 ) and california ( 20032008 ) that listed any diagnosis of disseminated coccidioidomycosis ( code 114.3 from the international classification of diseases , 9th revision , clinical modification [ icd-9-cm ] ) . we excluded records that listed any diagnosis of hiv infection or aids ( icd-9-cm code 042 ) or primary immune deficiency ( icd-9-cm code 279.xx ) . this study was not considered human subject research by the national institutes of health office of human subjects protection . we calculated the average annual incidence of hospitalizations as the average annual number of disseminated coccidioidomycosis hospitalizations divided by the midyear population , as determined by us census estimates ( 9 ) . by using the revisit files available from ahrq , we assessed differences in readmissions by race by comparing the proportion of persons with only 1 disseminated coccidioidomycosis infection among race groups . we also calculated all - cause hospitalization rates for blacks and whites in our dataset by using total hospitalizations from hcupnet ( http://hcupnet.ahrq.gov ) . in years for which patient state of residency was available , we assessed the potential bias from hospitalizations of persons with out - of - state residency by determining the percentage of total admissions from out - of - state patients . we used the mann - whitney test for nonparametric comparisons ; the significance level used for all statistical tests was   =  0.05 . all analyses were completed in sas version 9.2 software ( sas institute , cary , nc , usa ) . the average annual incidence of hospitalizations/100,000 persons / year was 4.8 ( 95% ci 4.25.3 ) for arizona and 0.89 ( 95% ci 0.790.99 ) for california . overall , the rate of hospitalization for blacks in arizona was 12.0-fold higher than the rate of hospitalization for whites and 20.8-fold higher than for hispanics ( figure 1 ) . the rate of hospitalization in california was 8.8-fold higher for blacks than for whites and 5.6-fold higher for blacks than for hispanics ( figure 2 ) . average annual incidence ( per 100,000 population ) of disseminated coccidioidomycosis  associated hospitalizations , by race / ethnicity , arizona , usa . average annual incidence ( per 100,000 population ) of disseminated coccidioidomycosis hospitalizations , by race / ethnicity , california , usa . ( note : average annual incidence not reported for native americans because of low numbers . ) the median age of patients with disseminated coccidioidomycosis  associated hospitalizations was lower than the median age of all hospitalizations for both blacks and whites in arizona and california ( p<0.001 for all comparisons ) . the median age at hospitalization for hispanics was higher than the median age for all hospitalizations in arizona ( p<0.001 ) and california ( p = 0.01 ) ( table ) . * boldface indicates a significant difference ( p<0.05 ) compared with all - cause hospitalizations . nr , information not reported because cell size is < 10 or to prevent calculation of a cell size < 10 . the proportion of persons with > 1 hospital admission for disseminated coccidioidomycosis among blacks was higher than for whites in california in 2008 ( 29.8% vs. 17.3% ) and in arizona in 2007 ( 19.3% vs. 17.0% ) . among all disseminated coccidioidomycosis associated hospitalizations , 98% of hospitalizations in arizona and 99% of hospitalizations in california were from in - state residents , indicating minimal bias from nonresidents . all - cause hospitalization rates did not differ greatly between whites and blacks : 121 hospitalizations/1,000 persons for whites and 104 hospitalizations/1,000 persons for blacks in arizona ; 125 hospitalizations/1,000 persons for whites and 143 hospitalizations/1,000 persons for blacks in california . we identified a higher incidence and lower patient age at hospitalization for disseminated coccidioidomycosis  associated hospitalizations among blacks in california and arizona . we were unable to determine if the higher incidence of hospitalization was a result of environmental , host , or behavioral factors . however , this study suggests that hiv infection , aids , and primary immune conditions are not the main reason for the racial / ethnic disparity for hospitalizations associated with disseminated coccidioidomycosis . because most coccidioidomycosis cases in california occur in the san joaquin valley region ( 6 ) and 90% of the population of california lives outside this region ( 10 ) , the california - specific incidence rate is likely to be an underrepresentation of the extent of the disease in the san joaquin valley region . in addition , because of this disparity , we are unable to make comparisons between rates for california and arizona . the state - specific incidence is a better description of the extent of disease in arizona because the 3 counties with 93% of the coccidioidomycosis cases in arizona represent 79% of the state s population ( 11 ) . the classification of race / ethnicity in this dataset may not completely describe the true distribution of disease among the diverse groups comprising these populations . these categories include a wide range of racial / ethnic backgrounds , representing multiple potential environmental , social , cultural , behavioral , or genetic susceptibilities . however , the higher incidence among blacks suggests that unknown factors uniquely affect a high proportion of this population . our analysis is likely to be specific for accurately detecting the number of cases of disseminated coccidioidomycosis because most cases require hospitalization of the patient . furthermore , in arizona and southern california , where the infection is common , awareness of coccidioidomycosis and disseminated coccidioidomycosis is high , and disseminated coccidioidomycosis cases are likely to be recognized . this analysis method is also likely to be specific because results of cultures , biopsies , histologic testing , and serologic testing provide strong evidence of infection . however , our use of administrative data , such as the sid , is limited by the use of icd-9-cm codes , and the sensitivity and specificity of those codes for disseminated coccidioidomycosis has not been evaluated . an additional limitation of our study was that we could not determine if a single person was hospitalized multiple times during the study years . although we identified higher rates of readmission among blacks , consistent with previous studies for coccidioidomycosis ( 12 ) , this does not completely explain the large relative rates that we identified . this finding could indicate different disease pathology with more serious or long - term infection . potential bias from out - of - state residents was minimal because most disseminated coccidioidomycosis hospitalizations occurred within the state of residence . differences in all - cause hospitalization rates were not likely to account for the differences in rates observed for our study condition . a better understanding of the progression of disease , including the number of previous hospitalizations , information on all coexisting conditions , and the severity of disease , could help explain the differences in incidence of hospitalization . overall , we found a higher incidence of disseminated coccidioidomycosis  associated hospitalizations for blacks compared with whites and other racial / ethnic groups living in these coccidioidomycosis - endemic areas , a finding that is consistent with previous studies ( 6,7 ) . however , our study identifies this difference specifically in the absence of hiv / aids and primary immune conditions among a large cohort , which suggests other , unknown reasons for this disparity among races / ethnicities .
we analyzed hospitalization databases from arizona and california for disseminated coccidioidomycosis  associated hospitalizations among immunocompetent persons . 
 racial / ethnic disease ratios were characterized by a higher incidence of hospitalization among blacks compared with other groups . 
 this finding suggests that hiv infection , aids , and primary immune conditions are not a major factor in this disparity .