First, a study by Yale researchers reported in JAMA in January found that Medicare recipients over 65 with mental illness received less aggressive treatment for acute myocardial infarction (AMI) than those without mental illness.

And now a study modeled on the Yale one has reported similar findings in a more recent cohort of all age groups. Findings from the new study by HCIA-Sachs’ researchers appear in the June 28 JAMA.

This second study’s cohort of 25,237 patients with AMI and mental illness included those who were under 65 and over 65, as well as those with private insurance, public insurance, and no insurance at all. Furthermore, another key difference between the two studies is that the Yale researchers’ database consisted of patients treated in 1994 and 1995, whereas the HCIA-Sachs researchers’ database consisted of those treated for AMI in 1998.

Despite these differences, the HCIA-Sachs’ investigators data confirm that patients with mental illness received less aggressive treatment for AMI than those without mental illness.

"Overall, the same patterns the Yale researchers found in their Medicare 1994-1995 population, we also found in our 1998 population of patients of all ages, of all payer types. Less aggressive treatment for those with mental illness is clearly a problem in all age groups and payer types," said investigator David Foster, Ph.D., M.P.H., chief statistician for HCIA-Sachs, "an international company providing strategic intelligence to members of the health care industry including payers, providers, employers, and pharmaceutical companies."

Specifically, HCIA-Sachs’ investigators found that those over age 65 with mental illness were 23 percent less likely to receive cardiac catheterization than those without mental illness; those under age 65 were 12 percent less likely to undergo catheterization.

Logically, it follows that these cohorts with mental illness (schizophrenia, affective disorder, substance abuse, and other psychiatric disorders) were also less likely to undergo PTCA and CABG procedures. And, in fact, those under 65 were 30 percent and 21 percent less likely to undergo PTCA and CABG, respectively. Those over age 65 were 32 percent and 33 pecent less likely to undergo PTCA and CABG, respectively.

Patients over 65 years diagnosed with schizophrenia fared the worst when it came to receiving cardiac catheterization and PTCA: They were 49 percent less likely to undergo catheterization and 68 percent less likely to undergo PTCA. (Similarly, the Yale investigators also found in their study that of the four mental illness categories, those with schizophrenia were the least likely—about half as likely—to undergo catheterization as those without mental illness.)

Because the HCIA-Sachs researchers controlled for age, gender, severity of AMI, complications, and other risk factors throughout the study, the remaining difference in treatment patterns was presumably due to the fact that patients with mental illness were not treated as aggressively as those without mental illness, explained Foster.

Given that those with mental illness were less likely to undergo cardiac catheterization and revascularization procedures, the investigators wondered if these patients would also have higher mortality during their hospitalization for AMI. The findings were mixed: Those in the study cohort older than 65 years of age were 21 percent less likely to die during the hospitalization than those without mental illness. And cohorts younger than age 65 who had other psychiatric disorders and affective disorders were 54 percent and 38 percent less likely to die, respectively.

On the other hand, those under age 65 hospitalized for AMI who also had schizophrenia or substance abuse disorders were 86 percent and 71 percent, respectively, more likely to die during their hospitalization than those without mental illness, after controlling for risk factors.

The HCIA-Sachs’ investigators’ findings are based on an examination of the 1998 Projected Inpatient Database of over 18 million patients. It contains information from 2,400 hospitals on over 18 million discharges per year—more than 40 percent of all U.S. inpatient discharges. The investigators identified 25,237 patients who had acute myocardial infarction and mental illness.

Those 65 and older with mental illness were compared with a control group of 198,406 of individuals who had AMI but no psychiatric illness. Those 65 and younger were compared with a similar control group of 130,550.