1. Shared Positive Affect Shared Negative Affect
Observational Evidence of Much Better Cancer Care Among Extremely Poor Canadians Than Americans, 1996 to Kevin M. Gorey,a Isaac N. Luginaah,b Madhan K. Balagurusamy,a Frances C. Wright,c Caroline Hammd & Sindu M. Kanjeekald aUniversity of Windsor, bUniversity of Western Ontario, cSunnybrook Health Sciences Center, dWindsor Regional Cancer Center
Abstract
Method
Results
Samples
Canadian cancer care has been observed to be advantaged in Canadian-US studies of near poor to poor places. None have studied extremely poor places. This study observed the differential effects of extreme poverty on breast & colon cancer care in Ontario (N = 585) and California (N = 2,925). Registry-based random samples diagnosed between 1996 & 2000 were followed until High poverty neighborhoods (30+% poor) were compared between-country. Extremely poor cancer patients in Ontario were largely advantaged as compared with their California counterparts. The relative risks of long waits or not receiving indicated radiation or chemotherapy and of not surviving were much greater among extremely poor patients in California. Such much greater risks of substandard American cancer care among extremely poor people as compared with significant, but smaller effects observed among the near poor/poor suggests a dose-response relationship.
Sampling Frames: Ontario (previously enhanced samples) & California Cancer Registries, 1996 to 2000
Cancer Cases: All selected in very low-income Ontario census tracts (50+% LI); cases in high poverty (30 to 40+% poor) California CTs randomly selected at a 5:1 ratio (Jargowsky, 1997; Stats Canada, 2002; US Census Bureau, 2001; Wilson, 1987)
Ecologically adjusted for CAD-USD differences, purchasing power and median household income
Stratified by Place & Disease Stage at Diagnosis :
Places: Large megalopolises, smaller metropolitan areas and rural to remote areas
Sentinel diseases (treatable & good prognoses with timely best treatment) sampled in Ontario & California:
Node negative breast cancer: 65 & 325 cases
AJCC stage II or III colon cancer: 520 & 2,600 cases
Synchrony (IS)
Shared Positive Affect
Shared Negative Affect
Cooperation
.440*
-.065
Assertion
.458*
.540**
-.560**
Responsibility
.368
.488*
-.233
Self Control
.451*
.469*
-.220
TOTAL
.535**
.586**
-.325
HYPOTHESIS SUPPORTED
HYPOTHESIS REJECTED
* Significant at p < .05 ** Significant at p < .01
Analyses
Introduction
Effect of country estimated on Surveillance Epidemiology & End Results (SEER) program-based cancer directed treatments and 8-year survival; to 2009
Primary Research: Effect of country estimated with maximum likelihood logistic regression model
Rate ratios internally standardized for age & gender
95% CIs based on the Mantel-Haenszel c2 test
Research Syntheses: Age & gender-adjusted rate ratios pooled with fixed effects meta-models; updated to 2011
RRs weighted by their inverse variances
Discussion
Political & scientific debates on the relative access & effectiveness of US & Canadian health care systems are longstanding & unresolved.
Breast & colon cancer care may be conceived as sentinel health care performance indicators.
3. Systematic & meta-analytic reviews identified 3 methodological problems and 3 research needs
(Gorey, 2009; Guyatt et al., 2007)
Methodological problems: (1) Between-country case-mix differences on disease stage at diagnosis and (2) Diverse urban and rural places not accounted for & (3) Power problems
Research needs: (1) Advance understandings beyond survival to care processes (timely access to best initial and adjuvant treatments); (2) Care processes & outcomes among extremely poor people & (3) Longer term follow-up beyond 5 years
6. Research question: Are extremely poor Americans (vs. Canadians) with breast or colon cancer disadvantaged on treatment access and survival?
Summary: We observed very large Canadian cancer care advantages in extremely poor places. Modest to large advantages had been observed in near poor to poor places. And studies have consistently observed no such Canada-US differences in middle or high-income places. This study’s observations of much greater risks of substandard American cancer care among the extremely poor suggests a dose-response relationship, that is, that very low-income is a causal barrier to effective cancer care in the US.
Rates of uninsured or underinsured were 9-fold greater in extremely poor US places than elsewhere.
Treatment refusal rates for these generally very treatable cancers were less than 5% in both countries.
Conclusion: More inclusive health care insurance coverage in Canada seems the most plausible explanation. It underscores the need to enact recent health care reforms across all 50 states in ways that are consistent with their federal legislative intent.
Hypotheses
Primary Research: Extremely poor breast and colon cancer patients in Ontario will be much more likely to gain timely access to initial cancer care and to survive for 8 years than will their counterparts in California.
Research Syntheses: Canadian cancer care advantages among extremely poor people will be larger than those previously observed among the near poor or the poor.
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