A relatively small proportion of patients account for a disproportionate share of healthcare utilization and cost with, on average, 1% of patients responsible for 20-25% of cost, 5% of patients for 40% and 10% for two thirds. These “high-utilizers” frequently suffer from co-morbid medical and psychiatric illnesses, but they are not well characterized in terms of diagnoses, current treatment patterns, or long-term outcomes. We sought to characterize further such patients at a large inner city acute care hospital.

We applied a validated tool, Patients At Risk for Re-hospitalization, to the entire hospital population and then performed a mixed methods (quantitative/qualitative) study of 100 patients judged to be at high risk (>67%) of re-hospitalization during the ensuing year.

Of over 130,000 patients, 6,000 were identified. These individuals were overwhelmingly non-elderly adults (96% ages 18-64). Most common medical diagnoses were hypertension (49%), asthma (41%), diabetes (33%), and HIV/AIDS (32%). Schizophrenia, bipolar illness, or other psychosis was found in 48%. Over two-thirds had substance abuse diagnoses. Although 56% had made at least one emergency department visit in the past two years, only 37% had seen a primary care provider. Patient interviews revealed high rates of unstable housing, social isolation, and failure to appreciate the severity of health problems.

High utilizers of general health care have very high rates of serious mental illness and substance abuse. Interviews suggest need for improved medical/psychiatric coordination with community outreach. Although such interventions are resource intense, the economic and health benefits may be large.