PubMed · 15301444
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Allison Samuels. 2004-07-05. Smooth operations.. https://pubmed.ncbi.nlm.nih.gov/15301444/
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BACKGROUND: Glomerular filtration rate (GFR) is a heritable trait, and hyperfiltration (GFR increment in remnant nephrons) may accelerate renal functional decline in chronic kidney disease (CKD). Mesangial and vascular smooth myocytes control GFR by contraction, dependent on voltage-gated Ca(2+) influx, which is controlled by the regulatory β₁-subunit (KCNMB1) of large-conductance heteromeric K+ ('BK') channels. KCNMB1 gain-of-function variant Glu65Lys results in generalized vasorelaxation and thus protection against systemic hypertension. Here we asked whether the Glu65Lys variant influences GFR, in the basal state or during progressive renal decline. METHODS: We explored Glu65Lys effects on GFR in three populations spanning two ethnicities and two diseases (hypertension and nephrosclerosis). GFR was either estimated (eGFR from serum creatinine) or directly measured (iothalamate clearance). RESULTS: The 65Lys variant was relatively common, occurring on ∼5-10% of chromosomes in different biogeographic ancestry groups, and 65Lys carriers exhibited higher eGFR in two primary care populations: extreme BP values in Kaiser clinics (p = 0.029, accounting for ∼0.2% of trait variance), or treated hypertensives in VA clinics (p = 0.017, accounting for ∼0.9% of trait variance). In blacks with progressive renal disease (NIDDK AASK), 65Lys carriers displayed a steeper slope in GFR chronic decline (p = 0.030, accounting for ∼0.4% of trait variance), and Glu65Lys genotype also predicted time of onset of renal failure (log rank p = 0.019). CONCLUSIONS: Common KCNMB1 gain-of-function variant Glu65Lys influences GFR, and 65Lys carriers exhibit not only elevated baseline GFR, but also more rapid GFR decline (and consequent development of renal failure) in CKD. The results suggest that profiling patients at Glu65Lys can assist in gauging renal prognosis as well as selection of rational therapy in hypertension with progressive renal disease.
BACKGROUND: There is a lack of data on the access to mammography and its relation to the incidence of early breast cancer. In this study, the authors evaluated access by correlating geographically the number of U.S. Food and Drug Administration (FDA)-certified mammography facilities and the AJCC stage of breast cancer at diagnosis by county. METHODS: Breast cancer incidence rates and stage at diagnosis were compared with the number of FDA-certified mammography facilities by county in the Surveillance, Epidemiology, and End Results reporting areas. The objective was to determine whether the number of certified facilities was associated with the percent of breast cancers diagnosed at the in situ stage. This was a multiple-group ecologic study, and counties were used as the units of analysis. RESULTS: There was a strong correlation between the number of mammography facilities and the population of a county, whereas there was no correlation between the number of mammography facilities and the land area of a county. A correlation existed between the percent of incident breast cancers that were diagnosed as in situ disease and the number of mammography facilities per 10,000 women among both whites and African Americans. CONCLUSIONS: There was an association between the number of mammography facilities and population. In counties with >/= 30,000 black and white females, 1) the percent of in situ breast cancers in black women and white women was correlated with the number of facilities per 10,000 women, indicating that population density is a factor in access for both racial groups; 2) except for 2 counties with >/= 30,000 black women, the percent of incident in situ cases was similar in both black women and white women, indicating equal access in both groups; and 3) there was a correlation between the percent in situ incidence and number of facilities per 1000 square miles in white women, but not in black women. There was a direct correlation of statewide mammography rates with the number of facilities per 1000 square miles, indicating that the rate of screening depends on availability. Maximum rates of statewide screening were achieved when there were > 15 mammography facilities per 1000 square miles.
BACKGROUND: Few studies have examined the association of race and outcomes after coronary artery bypass graft (CABG) surgery while controlling for both patient and hospital effects. METHODS AND RESULTS: We retrospectively analyzed data on a cohort of 566,785 white and 24,354 black Medicare beneficiaries 65 years old and older undergoing CABG in 1091 US hospitals from 1997 to 2000. Mortality and repeat revascularization rates were examined after sequential adjustment for patient and hospital differences by use of generalized estimating equations. Unadjusted mortality was higher (P<0.001) in black than in white patients at 30 (6.4% versus 5.2%), 90 (8.3% versus 6.6%), and 365 days (13.5% versus 9.8%) after surgery. Black patients were more likely (P<0.001) to undergo CABG at hospitals with the highest mortality (56% versus 47%) and at hospitals in the lowest volume quintile (24% versus 20%). Adjusted only for patient characteristics, mortality was 8%, 11%, and 25% higher in black patients at 30, 90, and 365 days. After adjustment for hospital effects, 30 and 90 day mortality was similar but 17% higher in black patients at 365 days. Racial differences in mortality were greater in men than in women. On adjustment for patient and hospital effects, repeat revascularization rates were similar in black and white patients. CONCLUSIONS: Racial disparities in CABG outcomes are sensitive to the effects of sex and duration of postsurgical follow-up. The increasing disparity in outcomes as follow-up increased is consistent with the hypothesis that black patients have less access to secondary prevention and rehabilitation services after surgery.