Parkinsonism a Major Mortality Risk Factor in Schizophrenia

Daniel M. Keller, PhD

March 05, 2014

MUNICH — Compared with control individuals, patients with schizophrenia have significantly more physical comorbidity, including the novel finding that Parkinsonism is a major risk factor for inhospital mortality in this population, new research shows.

A case-control study of general hospital admissions showed that the most common comorbidity among patients with schizophrenia was type 2 diabetes mellitus (T2DM). Twenty more physical diseases were also more prevalent, many of them associated with diabetic complications. Interestingly, Parkinsonism was a major risk factor for inhospital mortality in schizophrenia.

The research was a collaboration between investigators in Germany and the United Kingdom. Speaking here at the 22nd European Congress of Psychiatry (EPA), Dieter Schoepf, MD, of the Department of Psychiatry at the University Hospital of Bonn, Germany, said that the study population comprised all admissions to 3 general hospitals in Manchester, United Kingdom (N = 369,488) between January 1, 2000, and June 30, 2012.

It included 1418 patients who met diagnostic criteria for schizophrenia at initial admission according to the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10). Control patients were 14,180 age- and gender-matched hospital patients at initial admission.

Five Major Findings

The study produced 5 major findings related to comorbidities affecting hospitalized patients with schizophrenia. First, they had a nearly 2-fold increased hospital-based mortality rate (18.0%) compared with control patients (9.7%) during the observation period. And the schizophrenic patients died at a younger mean age (64.4 ± 1.0 vs 66.2 ± 0.4 years, respectively).

Second, "schizophrenics as compared to controls had a more severe course of illness and a shorter survival after their initial hospitalization," Dr. Schoepf reported. For the entire group of schizophrenic patients, survival averaged 1895 ± 35.1 days vs 2161 ± 11.6 days for all control patients. For deceased patients in each group, survival averaged 951.4 ± 62.9 vs 1030 ± 28.0 days, respectively.

Third, patients with schizophrenia had substantially more physical diseases. Among 21 diseases with increased prevalence among the study population compared with control patients, odds ratios (ORs) ranged from 5.3 for fracture of the femur neck to 1.3 for asthma.

"T2DM was the most common disproportionally increased physical comorbidity," Dr. Schoepf said. Its prevalence among schizophrenic patients was double that of the control patients (17.4% vs 8.5%; OR = 2.3; 95% confidence interval [CI], 2.0 - 2.6).

The fourth major finding was that among schizophrenic patients who died, T2DM was the most common physical comorbidity, contributing to about one third (31.4%) of those deaths, compared with 16.9% of deceased control patients.

Parkinsonism affected 1.6% of the study group vs 0.4% of control patients (OR = 4.7; 95% CI, 2.8 - 7.7). It was present in 5.5% of deceased study group patients but in only 1.5% of control patients who died.

Excluding Parkinsonism, a major risk factor for death among the schizophrenic group, the researchers developed a model that identified 9 other mortality risk factors that "had an equal impact on inhospital death in schizophrenics as compared to controls," Dr. Schoepf reported.

Although the prevalence of these risk factors differed between the 2 groups, their impact on inhospital mortality did not differ when these comorbidities were present in patients in either group. The comorbidities were as follows: T2DM, chronic obstructive pulmonary disease, pneumonia, bronchitis, iron-deficiency anemia, type 1 diabetes, ischemic stroke, nonspecific renal failure, and alcoholic liver disease.

Novel Result

Speaking with Medscape Medical News, session chair Guillermo Lahera Forteza, MD, PhD, professor of psychiatry at the University of Alcalá, Spain, who was not involved in the study, praised it as "impressive...especially the relationship between Parkinsonism and mortality in patients with schizophrenia. I was really shocked about this figure." He added that the relationship between T2DM and mortality has been well known, but the finding about Parkinsonism is something new.

Dr. Lahera Forteza said he has questions about the causes of death in cases in which comorbidities exist. There may be differences between different antipsychotic medications and their possible contribution.

"Specific treatments with clozapine or olanzapine could be related to more comorbidity and mortality," he said, but Dr. Schoepf noted that there are not enough data from this study on this point.

Dr. Lahera Forteza advises physicians "to restudy every treatment when the patient has this kind of comorbidity ― to re-evaluate and reassess the pharmacological treatment in every patient." In addition, physicians should recognize the impact of lifestyle on these patients, who often smoke, drink alcohol, and do not get enough exercise. Negative symptoms, cognitive impairment, and social stigma can all affect lifestyle and contribute to or exacerbate physical comorbidities.

Dr. Schoepf and Dr. Lahera Forteza report no relevant financial relationships. The study had no commercial funding.

22nd European Congress of Psychiatry (EPA). Session FC07. Presented March 3, 2014.

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