In patients with diabetes and foot ulcers or lower extremity amputations, geographic variations in Medicare spending and mortality rates were associated with regional differences in the use of inpatient services and the prevalence of macrovascular complications, according to study results published in the Journal of Diabetes and Its Complications.

“Diabetic patients with foot ulcers and lower extremity amputations are particularly expensive to treat,” Michael Sargen, MD candidate at the University of Pennsylvania Perelman School of Medicine, told O&P Business News. “The purpose of this study was to determine if there exists regional variation in Medicare spending for these patients and if areas with higher spending are associated with reduced 1-year mortality.”

Variations in spending

More than 8,400,000 Medicare beneficiaries with diabetic foot ulcers and lower extremity amputations who were enrolled in Medicare Parts A and B during 2007 were included in the study. Overall, study results showed that health care spending and mortality rates varied considerably across the nation for patients with foot ulcers and lower extremity amputations, but that higher spending was not associated with a statistically significant reduction in 1-year patient mortality.

Researchers found that macrovascular complications for amputees were more common in parts of the country with higher mortality rates. Although this association was not observed for the foot ulcer cohort, macrovascular complications were associated with increased per capita spending for beneficiaries with foot ulcers, according to study results. Higher per capita spending and increased mortality rates for individuals with foot ulcers and lower extremity amputations were also associated with rates of hospital admissions.

“We expected rates of microvascular complications — eg, renal failure — to be associated with higher spending,” Sargen said. “For example, renal insufficiency requiring dialysis or transplant, which occurs frequently in patients with foot ulcers and amputations, would dramatically increase patient annual health care costs.

“Medicare spending varies considerably between hospital referral regions. However, increased Medicare spending within a hospital referral region is not associated with improved outcomes as measured by 1-year mortality rates,” Sargen said. “Hospital admission rates were strongly associated with higher spending and mortality for both groups, suggesting that the health status of patients may explain much of the geographic variation observed.”

Limitations, future studies

The researchers reported one possible limitation of the study. Patients with higher treatment costs and more advanced disease disproportionately, who used health services within referral regions that contain medical centers specializing in diabetes care, could distort hospital admission and mortality rates. In the current study, the researchers assumed that patients generally received treatment within the hospital referral region in which they lived.

The researchers said future studies should investigate whether hospital admissions and macrovascular complications are likely to be associated with Medicare spending and mortality rates for diabetic patients without foot ulcers and amputations. Sargen also said that smaller units are always preferred, because hospital referral regions are very large and have a diverse racial and socioeconomic composition. Practice management styles may also vary considerably between zip codes.

“Further studies should evaluate and confirm the associations identified in this study at the zip code level or smaller where populations are more homogenous,” Sargen said. “Confirmation of these associations at the local level would require further investigation as to the reasons why increased Medicare spending does not result in improved patient outcome for our two patient cohorts.” — by Casey Murphy

Disclosure: Sargen has no relevant financial disclosures.