The Washington Post zeroed in on the most expensive users of the US health system after a deep dive into a report by the government’s Agency for Healthcare Research and Quality.

The department’s finding: five percent of patients account for about half—as in 50%—of all healthcare expenditures. Heart failure, diabetes and kidney disease were common to this high-cost patient population, as was a persistent problem with access to medical services that could keep conditions in check.

The Washington Post found that many of these patients ended up in hospital rooms because the healthcare system was so hard to navigate, resulting in what the paper called “extreme uncoordinated care,” as patients bounce from care location to care location. Highlighting the cost/access issue was COO Tim McNeil of Medical Mall in Jackson, MS, who told the WaPo, “We’ve seen situations where for want of a $20 cab ride to get dialysis, a patient ended up with an emergency hospitalization costing $20,000.”

Healthcare reform’s penalties for poor performance is nudging hospitals into more efficient means of treating Medicaid patients, thorough re-admission-linked disincentives meant to prompt more thoughtful and possibly cheaper medical interventions.