Cardiovascular disease is top cause of death in schizophrenia.

MADRID -- The largest single cause of death among patients with schizophrenia is cardiovascular disease, Dr. Stefan Leucht reported at the 15th European Congress of Psychiatry.

Cardiovascular disease has this impact on schizophrenia patients not because it has the largest mortality ratio, compared with the general population, he said.

The explanation is that far more people overall die from cardiovascular disease than from other diseases, said Dr. Leucht, who is with the department of psychiatry at Technische Universitat Munchen.

Dr. Leucht's assessment was based on the results of a detailed literature search on medical comorbidity in patients with schizophrenia.

He identified 44,202 papers in his review but was unable to conduct a formal meta-analysis because of the methodologic heterogeneity of the studies involved, Dr. Leucht said at the symposium, which was sponsored by Pfizer Inc.

The overall rate of mortality in patients with schizophrenia is about twice that found in the general population, Dr. Leucht said.

Part of this increased risk is attributable to the patients' psychopathology. The risk of suicide, for example, is about 20 times higher in people with schizophrenia than in the general population. But suicide and accidents account for 40% of the excess mortality, and the remaining 60% is attributable to physical illness, he said.

Dr. Leucht said that male patients have a higher standardized mortality rate (SMR) than does the general population for cardiovascular disease (SMR of 2.3), diabetes (SMR of 2.7), respiratory disease (SMR of 3.2), and infectious disease (SMR of 3.4).

In addition to these well-known general risk factors, Dr. Leucht also identified some rarer comorbidities that are sometimes seen in patients with schizophrenia.

His literature search identified a "surprisingly large literature of 14 studies that show quite clearly increased rates of polydipsia in schizophrenia," he said. Polydipsia is not considered often enough by psychiatrists, Dr. Leucht said, even though the consequences can be serious, including delirium, water intoxication, and death.

Dr. Leucht found that psychiatric patients in general have a wide spectrum of thyroid function test abnormalities, although most of the alterations tend to be transient and "cases of clinically manifest thyroid disease are rare," he said.

He recommends, however, that a screening test for thyroid function be done at admission, as part of any baseline work on newly admitted patients.

Most of the epidemiologic studies assessed by Dr. Leucht were from North America (45% of 225 studies) or Europe (38%). Only 1% were from Africa, 3% were from Australia, 13% were from Asia, and 0.4% were from Latin America.

"The amount and quality of [epidemiologic] studies found in some areas--especially some hot topics such as obesity--could be better," he concluded.

In a separate presentation at the symposium, Dr. Marc De Hert suggested that evidence is growing that cardiometabolic risk factors such as obesity, hypertension, dyslipidemia, and hyperglycemia are more prevalent in patients who have schizophrenia than in the general population.

Dr. De Hert, a clinical psychiatrist and psychotherapist working at the Katholieke Universiteit Leuven (Belgium), presented data from one of his own studies (Clin. Pract. Epidemiol. Ment. Health 2006;2:14), in which he assessed the prevalence of metabolic disorders in a cohort of 415 patients with schizophrenia living in Belgium.

The difference in the prevalence of diabetes in patients with schizophrenia, compared with healthy controls, increased with increasing age: 2.0% of patients with schizophrenia who were aged 15-25 years had diabetes, compared with 0.4% of the general population; but 25% of patients with schizophrenia who were aged 55-65 years had diabetes, compared with 5.8% of the general population.

BY JAMES BUTCHER

Contributing Writer