Publications

The alpha9beta1 integrin accelerates cell migration through binding of spermidine/spermine acetyltransferase (SSAT) to the alpha9 cytoplasmic domain. We now show that SSAT enhances alpha9-mediated migration specifically through catabolism of spermidine and/or spermine. Because spermine and spermidine are effective blockers of K(+) ion efflux through inward-rectifier K(+) (Kir) channels, we examined the involvement of Kir channels in this pathway. The Kir channel inhibitor, barium, or knockdown of a single subunit, Kir4.2, specifically inhibited alpha9-dependent cell migration. alpha9beta1 and Kir4.2 colocalized in focal adhesions at the leading edge of migrating cells and inhibition or knockdown of Kir4.2 caused reduced persistence and an increased number of lamellipodial extensions in cells migrating on an alpha9beta1 ligand. These results identify a pathway through which the alpha9 integrin subunit stimulates cell migration by localized polyamine catabolism and modulation of Kir channel function.

CONTEXT

Safety-net hospitals (ie, those that predominantly treat poor and underserved patients) often have lower quality of care than non-safety-net hospitals. While public reporting and pay for performance have the potential to improve quality of care at poorly performing hospitals, safety-net hospitals may be unable to invest in quality improvement. As such, some have expressed concern that these incentives have the potential to worsen existing disparities among hospitals.

OBJECTIVE

To examine trends in disparities of quality of care between hospitals with high and low percentages of Medicaid patients.

DESIGN AND SETTING

Longitudinal study of the relationship between hospital performance and percentage Medicaid coverage from 2004 to 2006, using publicly available data on hospital performance. A simulation model was used to estimate payments at hospitals with high and low percentages of Medicaid patients.

MAIN OUTCOME MEASURES

Changes in hospital performance between 2004 and 2006, estimating whether disparities in hospital quality between hospitals with high and low percentages of Medicaid patients have changed.

RESULTS

Of the 4464 participating hospitals, 3665 (82%) were included in the final analysis. Hospitals with high percentages of Medicaid patients had worse performance in 2004 and had significantly smaller improvement over time than those with low percentages of Medicaid patients. Hospitals with low percentages of Medicaid patients improved composite acute myocardial infarction performance by 3.8 percentage points vs 2.3 percentage points for those with high percentages, an absolute difference of 1.5 (P = .03). This resulted in a relative difference in performance gains of 39%. Larger performance gains at hospitals with low percentages of Medicaid patients were also seen for heart failure (difference of 1.4 percentage points, P = 0.04) and pneumonia (difference of 1.3 percentage points, P <.001). Over time, hospitals with high percentages of Medicaid patients had a lower probability of achieving high-performance status. In a simulation model, these hospitals were more likely to incur financial penalties due to low performance and were less likely to receive bonuses.

CONCLUSIONS

Safety-net hospitals tended to have smaller gains in quality performance measures over 3 years and were less likely to be high-performing over time than non-safety-net hospitals. An incentive system based on these measures has the potential to increase disparities among hospitals.

BACKGROUND

Veterans Affairs medical centers (VAMCs) provide better preventive and chronic disease care when compared with other health care organizations, although recent health care quality improvement initiatives outside the VAMC sector may have narrowed quality differences.

METHODS

Using the nationally representative 2000 and 2004 surveys of the Behavior Risk Factor Surveillance System, which included 152,310 community-dwelling insured adults in 2000 and 251,570 in 2004, we compared self-reported use of 17 recommended ambulatory care services for cancer prevention, cardiovascular risk reduction, diabetes mellitus management, and infectious disease prevention among insured adults receiving and not receiving care at VAMCs.

RESULTS

A total of 2852 insured adults (1.9%) received care at VAMCs in 2000 and 7155 (2.4%) received care at VAMCs in 2004. Use of 9 of the 17 services was greater in 2004 when compared with 2000 (P < or = .05). In 2000, receiving VAMC care was associated with greater use of 6 of the 17 services; in 2004, receiving VAMC care was associated with greater use of 12 of the 17 services (P < or = .05). In 2004, greater use among these 12 services ranged from 10% greater use of cholesterol screening to 40% greater use of colorectal cancer screening. For 13 of the 17 services, the likelihood of service use among adults receiving VAMC care when compared with adults not receiving VAMC care was not significantly different in 2004 than in 2000. However, this likelihood was significantly greater (for VAMC vs non-VAMC use) in 2004 than in 2000 for breast cancer screening (relative risk [RR], 1.21 [95% confidence interval {CI}, 1.15-1.25] vs 0.80 [95% CI, 0.58-0.98]; P < .001), dilated eye examination among adults with diabetes (RR, 1.12 [95% CI, 1.07-1.15] vs 1.01 [95% CI, 0.88-1.09]; P = .04), and influenza (RR, 1.30 [95% CI, 1.24-1.36] vs 1.06 [95% CI, 0.89-1.21]; P = .006) and pneumococcal (RR, 1.27 [95% CI, 1.23-1.31] vs 1.04 [95% CI, 0.86-1.21]; P = .005) vaccinations.

CONCLUSION

Despite increasing emphasis on quality of care and improved performance throughout the US health care system, adults receiving VAMC care remain more likely to receive recommended ambulatory care.