Spatial access to primary care providers and colorectal cancer-specific survival in Cook County, Illinois.

BACKGROUND: Spatial access to primary care has been associated with late-stage and fatal breast cancer, but less is known about its relation to outcomes of other screening-preventable cancers such as colorectal cancer. This population-based retrospective cohort study examined whether spatial access to primary care providers associates with colorectal cancer-specific survival. METHODS: Approximately 26 600 incident colorectal cancers diagnosed between 2000 and 2008 in adults residing in Cook County, Illinois were identified through the state cancer registry and georeferenced to the census tract of residence at diagnosis. An enhanced two-step floating catchment area method measured tract-level access to primary care physicians (PCPs) in the year of diagnosis using practice locations obtained from the American Medical Association. Vital status and underlying cause of death were determined using the National Death Index. Fine-Gray proportional subdistribution hazard models analyzed the association between tract-level PCP access scores and colorectal cancer-specific survival after accounting for tract-level socioeconomic status, case demographics, tumor characteristics, and other factors. RESULTS: Increased tract-level access to PCPs was associated with a lower risk of death from colorectal cancer (hazard ratio [HR], 95% confidence interval [CI]) = 0.87 [0.79, 0.96], P = .008, highest vs lowest quintile), especially among persons diagnosed with regional-stage tumors (HR, 95% CI = 0.80 [0.69, 0.93], P = .004, highest vs lowest quintile). CONCLUSIONS: Spatial access to primary care providers is a predictor of colorectal cancer-specific survival in Cook County, Illinois. Future research is needed to determine which areas within the cancer care continuum are most affected by spatial accessibility to primary care such as referral for screening, accessibility of screening and diagnostic testing, referral for treatment, and access to appropriate survivorship-related care.

Multilevel Examination of Health Disparity: The Role of Policy Implementation in Neighborhood Context, in Patient Resources, and in Healthcare Facilities on Later Stage of Breast Cancer Diagnosis.

BACKGROUND: There is a substantial racial/ethnic disparity in female breast cancer mortality in Chicago between non-Hispanic black (NHblack) and Hispanic patients compared with their non-Hispanic white (NHwhite) counterparts. This observation prompted a multilevel examination of factors that might account for the disparity, with the goal of identifying potential policy interventions that might meaningfully address it METHODS: In the Breast Cancer Care in Chicago study, 411 NHblack, 397 NHwhite, and 181 Hispanic patients diagnosed between the ages of 30 and 79 were interviewed, and medical records were abstracted for information on screening and diagnostic follow-up. We conducted a multilevel analysis to assess the role of neighborhood context, patient resources, facility characteristics, and mode of detection in determining the disparity in later stage at diagnosis. RESULTS: After adjustment for neighborhood context, mode of detection, and facility accreditation/resources, there was no significant disparity in later stage breast cancer diagnosis between NHblack or Hispanic patients compared with NHwhite patients. CONCLUSIONS: The results suggest that racial/ethnic differences in mode of detection and facility accreditation/resources account for most of the disparity in stage at diagnosis. Understanding the causes of differential screen detection and access to highly accredited facilities could inform interventions to meaningfully address this disparity. IMPACT: Multilevel approaches to studying health disparities are becoming the research standard for understanding and addressing health disparities. Optimal design of multilevel interventions addressing disparities in later stage diagnosis would benefit from enhanced understanding of pathways to detection and diagnosis available to patients in medically underserved communities.

The effect of neighborhood disadvantage on the racial disparity in ovarian cancer-specific survival in a large hospital-based study in cook county, illinois.

This paper examines the effect of neighborhood disadvantage on racial disparities in ovarian cancer-specific survival. Despite treatment advances for ovarian cancer, survival remains shorter for African-American compared to White women. Neighborhood disadvantage is implicated in racial disparities across a variety of health outcomes and may contribute to racial disparities in ovarian cancer-specific survival. Data were obtained from 581 women (100 African-American and 481 White) diagnosed with epithelial ovarian cancer between June 1, 1994, and December 31, 1998 in Cook County, IL, USA, which includes the city of Chicago. Neighborhood disadvantage score at the time of diagnosis was calculated for each woman based on Browning and Cagney's index of concentrated disadvantage. Cox proportional hazard models measured the association of self-identified African-American race with ovarian cancer-specific survival after adjusting for age, tumor characteristics, surgical debulking, and neighborhood disadvantage. There was a statistically significant negative association (-0.645) between ovarian cancer-specific survival and neighborhood disadvantage (p = 0.008). After adjusting for age and tumor characteristics, African-American women were more likely than Whites to die of ovarian cancer (HR = 1.59, p = 0.003). After accounting for neighborhood disadvantage, this risk was attenuated (HR = 1.32, p = 0.10). These findings demonstrate that neighborhood disadvantage is associated with ovarian cancer-specific survival and may contribute to the racial disparity in survival.

The association between neighborhood socioeconomic status and ovarian cancer tumor characteristics.

PURPOSE: Higher pathologic grade, suboptimal debulking surgery, and late-stage are markers of more aggressive and advanced ovarian cancer. Neighborhood socioeconomic status (SES) has been associated with more aggressive and advanced tumors for other cancer sites, and this may also be true for ovarian cancer. METHODS: We examined the association between neighborhood SES and ovarian cancer tumor characteristics using data on 581 women diagnosed with epithelial ovarian cancer in Cook County, Illinois. Two complementary measures (concentrated disadvantage and concentrated affluence) were used to estimate neighborhood SES. Prevalence differences and 95 % confidence intervals were estimated in logistic regression models adjusted for age and race. RESULTS: Greater disadvantage was associated with higher grade tumors (p = 0.03) and suboptimal debulking (p = 0.05) and marginally associated with later tumor stage (p = 0.20). Greater affluence was inversely associated with stage at diagnosis (p = 0.004) and suboptimal debulking (p = 0.03) and (marginally) with tumor grade (p = 0.21). CONCLUSION: Our findings suggest that lower SES, estimated by neighborhood SES, is associated with ovarian cancer tumor characteristics indicative of more advanced and aggressive disease.

Spatial error in geocoding physician location data from the AMA Physician Masterfile: implications for spatial accessibility analysis.

The accuracy of geocoding hinges on the quality of address information that serves as input to the geocoding process; however errors associated with poor address quality are rarely studied. This paper examines spatial errors that arise due to incorrect address information with respect to physician location data in the United States. Studies of spatial accessibility to physicians in the U.S. typically rely on data from the American Medical Association's Physician Masterfile. These data are problematic because a substantial proportion of physicians only report a mailing address, which is often the physician's home (residential) location, rather than the address for the location where health care is provided. The incorrect geocoding of physicians' practice locations based on inappropriate address information results in a form of geocoding error that has not been widely analyzed. Using data for the Chicago metropolitan region, we analyze the extent and implications of geocoding error for measurement of spatial accessibility to primary care physicians. We geocode the locations of primary care physicians based on mailing addresses and office addresses. The spatial mismatch between the two is computed at the county, zip code and point location scales. Although mailing and office address locations are quite close for many physicians, they are far apart (>20 km) for a substantial minority. Kernel density estimation is used to characterize the spatial distribution of physicians based on office and mailing addresses and to identify areas of high spatial mismatch between the two. Errors are socially and geographically uneven, resulting in overestimation of physician supply in some high-income suburban communities, and underestimation in certain central city locations where health facilities are concentrated. The resulting errors affect local measures of spatial accessibility to primary care, biasing statistical analyses of the associations between spatial access to care and health outcomes.

Access to oral health services for urban low-income Latino children: social ecological influences.

OBJECTIVES: Using an ecological conceptual model, this study examined the social context, structural, and behavioral factors within an immigrant community that contribute to increased access and use of oral health services by Latino children. The predictors of health service use at the level of the individual, the family, the provider, and the health service system were studied for their effects on the initiation of care, continuity of care, and frequency of planned visits. METHODS: In-depth face-to-face interviews were conducted with 320 Latino mothers regarding their use of oral health services for 4-8-year-old children [Mexican (n = 221), Puerto Rican (n = 69), and Central and South American (n = 30)]. Outcome measures of dental care utilization were early age at initiation of care, continuity of care, and frequency of planned dental visits. RESULTS: Regular planned dental visits were significantly related to the structural variables of household income and provider availability. The initiation of dental care was related to the mother's beliefs about the value of early preventive dental care. Mothers were more likely to continue care if they believed that the purpose was to keep the child's teeth healthy and had satisfactory communication with the dentist. CONCLUSIONS: Identifying the structural and behavioral factors that increase the likelihood of the use of oral health services can provide the basis for developing effective interventions specific to Latino children at the neighborhood level. The study findings can be also used for designing culturally appropriate oral health promotion programs and provider coordination of care.

Association of census tract-level socioeconomic status with disparities in prostate cancer-specific survival.

BACKGROUND: Social determinants of prostate cancer survival and their relation to racial/ethnic disparities thereof are poorly understood. We analyzed whether census tract-level socioeconomic status (SES) at diagnosis is a prognostic factor in men with prostate cancer and helps explain racial/ethnic disparities in survival. METHODS: We used a retrospective cohort of 833 African American and white, non-Hispanic men diagnosed with prostate cancer at four Chicago area medical centers between 1986 and 1990. Tract-level concentrated disadvantage (CD), a multidimensional area-based measure of SES, was calculated for each case, using the 1990 U.S. census data. Its association with prostate cancer-specific survival was measured by using Cox proportional hazard models adjusted for case and tumor characteristics, treatment, and health care system [private sector vs. Veterans Health Administration (VA)]. RESULTS: Tract-level CD associated with an increased risk of death from prostate cancer (highest vs. lowest quartile, HR = 2.37, P < 0.0001). However, the association was observed in the private sector and not in the VA (per 1 SD increase, HR = 1.33, P < 0.0001 and HR = 0.93, P = 0.46, respectively). The multivariate HR for African Americans before and after accounting for tract-level CD was 1.30 (P = 0.0036) and 0.96 (P = 0.82), respectively. CONCLUSIONS: Census tract-level SES is a social determinant of prostate-specific mortality and helps account for racial/ethnic disparities in survival. An equal-access health care system may moderate this association. IMPACT: This study identifies a potential pathway for minimizing disparities in prostate cancer control. The findings need confirmation in a population-based study.

Neighborhood changes in concentrated immigration and late stage breast cancer diagnosis.

Immigrant women are at greater risk for late stage breast cancer diagnosis. The rapid increase in the US foreign-born population and new immigration patterns lead us to investigate the association between changes in immigrant population and the likelihood of distant metastasis stage at diagnosis of breast cancer among women in Cook County, Illinois. Analyses employed Illinois State Cancer Registry data for 42,714 breast cancer cases diagnosed between 1994 and 2003 in conjunction with 1990 and 2000 Census tract data. We find that concentration of and increases in immigrant populations within neighborhoods contributed to the risk of late stage breast cancer diagnosis. These findings suggest that, although some health indicators for immigrant populations have improved in recent years, important health disparities in breast cancer diagnosis still remain at the neighborhood level. They further suggest that cancer screening and follow-up resources should be directed to areas experiencing rapid increases in immigrant populations.

Economic, racial and ethnic disparities in breast cancer in the US: towards a more comprehensive model.

Using cancer registry data, we focus on racial and ethnic disparities in stage of breast cancer diagnosis in Cook County, IL. The county health system is the "last resort" health-care provider for low-income persons. Socioeconomic status is measured using empirical Bayes estimates of tract-level poverty, specific to non-Hispanic whites, non-Hispanic blacks or Hispanics in one of three age groups. We use ordinal logistic regression with non-proportional odds to model stage. Blacks and Hispanics are at greater risk for regional and distant stage diagnosis, but the disparity declines with age. Women in high-poverty areas are at substantially greater risk for late-stage diagnosis. The effects of poverty do not differ by age or across racial and ethnic groups.

Neighborhood change and distant metastasis at diagnosis of breast cancer.

PURPOSE: To test whether upward socioeconomic neighborhood change has an effect on probability of distant metastasis at diagnosis of breast cancer among women who live there. METHODS: Census tract data (N = 1,137) from Cook County. IL, from 1990 and 2000 and cancer registry data for female breast cancer cases for these census tracts from 1994-2000 (N = 21,516) were used. A multilevel model of 1990 baseline socioeconomic status (SES) of neighborhoods and degree of neighborhood change 1990-2000 (compositional characteristics) and patient's age and race/Hispanic status (individual characteristics) was constructed to predict distant metastasis (vs. local and regional stage) at diagnosis. RESULTS: While residence in a census tract with lower baseline SES in 1990 (higher concentrated disadvantage and immigration and lower concentrated affluence) and being African American were associated with increased odds of distant metastasis at diagnosis, residence in an improving census tract was also associated with increased odds of distant metastasis at diagnosis. CONCLUSIONS: Paradoxically, both measures of initial neighborhood disadvantage and upward neighborhood socioeconomic change were independently associated with greater odds of distant metastasis at diagnosis of breast cancer. Neighborhood social and economic change can affect health.

Detection of paralytic shellfish poisoning (PSP) toxins in shellfish tissue using MIST Alert, a new rapid test, in parallel with the regulatory AOAC mouse bioassay.

In parallel trials with the mouse bioassay, MIST Alert for Paralytic Shellfish Poisoning (PSP), a rapid diagnostic test for PSP, detected 100% of the toxic extracts in over 2100 regulatory samples. Toxic extracts contained at least 80 microg saxitoxin equivalents (STX equiv.) in 100 g of shellfish tissue, or more, as measured by the regulatory AOAC mouse bioassay. Only one potentially toxic sample, which contained 78 and 86 microg STX equiv./100 g shellfish tissue in two different mouse bioassays, was recorded as negative in one replicate of MIST Alert. All other toxic extracts among more than 2100 regulatory shellfish tissue samples were detected by MIST Alert for PSP. The MIST Alert for PSP also detected the majority of extracts containing PSP toxin greater than 32 microg STX equiv./100 g, which is the mouse bioassay detection limit. The MIST Alert for PSP gave a false positive result compared to the mouse bioassay at an average rate of about 14% over all sites, although some differences were seen between sites. Further analysis by high performance liquid chromatography (HPLC) of the (false positive) extracts showed that many contained PSP toxicity in the range of 20-40 microg STX equiv./100 g, below the level detectable by the mouse bioassay. The MIST Alert for PSP gave false positive results from extracts containing less than 20 microg STX equiv./100 g shellfish tissue only about 6% of the time. The PSP family of toxin analogues can occur in any combination in naturally contaminated shellfish tissue and the antibody mixture in the MIST Alert tests detect each of the different PSP toxin analogues with different efficacy. It is therefore impossible to provide an exact detection limit for the MIST Alert that would be applicable for all possible toxin profiles. Through the experience of comparison testing with the regulatory mouse bioassay in many parts of the world, with over 2100 different samples, the MIST Alert for PSP has proven its ability to detect all types of profiles of the PSP toxin analogues. The detection limit for MIST Alert for PSP was about 40 microg STX equiv./100 g for the 'average' profile of PSP toxin analogues. Since the detection limit depends on the toxin profile in the individual extract, it will also vary depending on the profile of analogues most commonly found at each geographic location. This was observed in our study. Over all sites in the trials, approximately 5% of samples below 40 microg STX equiv./100 g were positive, and 5% of samples between 40-80 microg STX equiv./100 g were negative. This is a reflection of the different analogue profiles found in naturally contaminated extracts, even after acid hydrolysis using the AOAC extraction method.