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BACKGROUND/RATIONALE:
Veterans with schizophrenia consume a disproportionate amount of VA health services, yet many still have poor psychiatric and medical outcomes. The mean lifespan of patients with schizophrenia is 10 years less than that of the general population. The literature is mixed as to the quantity and quality of care schizophrenia patients receive, relative to non-schizophrenic patients with the same medical illnesses. Cross-sectional study design or rigorous (but poorly generalizable) inclusion criteria (such as studying only patients well-engaged in care) may explain mixed findings.
Patients with schizophrenia experience elevated rates of several medical conditions, including cardiovascular disease, respiratory problems, and diabetes (DM). We propose comparing the care and outcomes of VA patients with schizophrenia, diabetes, or both diagnoses. Diabetes is common among VA patients (~20% of patients), incurs significant morbidity and mortality, is treated with an array of medications, and has several indicators of care recorded in VA databases (clinic visits, blood glucose and HbA1c, blood pressure control). It is a compelling disease to examine in schizophrenia patients because (a) schizophrenia patients have limited insight into medical or psychiatric conditions and are frequently non-compliant; (b) schizophrenia itself appears to be an independent risk factor for DM; (c) the medications used to treat schizophrenia increase the risk of blood glucose abnormalities/DM; (d) additional side effects of antipsychotics are the same illnesses monitored among DM patients: hypertension and hypercholesterolemia; and (e) both DM and schizophrenia require high levels of involvement with the health care system. Overall, we hypothesize that lack of persistent engagement in care is an independent predictor of premature mortality among veterans with schizophrenia.
OBJECTIVE(S):
Objective 1: Compare patterns of care among patients aged 50+ with schizophrenia, diabetes, or both schizophrenia and diabetes. Hypothesis for Objective 1: Patients with schizophrenia are more likely to reduce their use of VA care than diabetes patients, variably over time. Objective 2: Compare prescription profiles (e.g., use of antipsychotic or antidiabetic agents) and clinical indicators (e.g., blood glucose, A1c testing, lipids). Hypotheses for Objective 2: Patients with schizophrenia are less likely to fill prescriptions for appropriate medications than DM-only patients. Schizophrenia patients have fewer assays and greater fluctuations in glucose, HbA1c, and lipid levels over time than DM-only patients. Objective 3: Assess the impact of patterns of care and intermediate processes and outcomes on mortality among the three groups of patients. Hypothesis for Objective 3: Patients with both schizophrenia and diabetes experience higher mortality than age-matched patients with diabetes or schizophrenia alone.
METHODS:
Study design: retrospective cohort study. Major characteristics: veterans with schizophrenia, diabetes, or both conditions age 50 or older receiving VA care nationwide; no non-VA sites. Major variables/sources of data: inpatient medical care, psychiatric care, & nursing home days of stay; outpatient primary, specialty, & psychiatric care (alcohol/drug-related, other psychiatric), and laboratory and medication histories derived from VA administrative databases including VA-Medicare data for fiscal years FY02 through FY05. Main types of analysis: generalized linear models appropriate to the distribution of the outcome measures (e.g., Poisson regression), controlling for demographic and clinical correlates as well as facility-level clustering of patients.
FINDINGS/RESULTS:
Summary [6/17/2008]:
Pre-diabetes and Diabetes Assessment and Follow-up in Veterans with Schizophrenia
This study assessed the prevalence of pre-diabetes and undiagnosed diabetes using archival lab data in a sample of 39,825 VA patients with schizophrenia. Patients were aged 50 or older with diagnosed schizophrenia and no recorded diagnosis of diabetes and no use of hypoglycemic medications (non-diabetic at baseline). Because of premature mortality in this vulnerable patient population, age 50 and older was considered "late-life". Risk factors common among these patients include sedentary lifestyle, poor nutrition, comorbid cardiovascular disease, and the use of atypical antipsychotics which are associated with increased blood sugar abnormalities. Available blood glucose and hemoglobin A1c tests for one year were examined (fiscal year 2002, Oct. 2001-Sep. 2002). To approximate fasting glucose, we used blood glucose results where there was a same-day low-density lipoprotein test result, because lipid panels require fasting. We then assessed rates of testing for fasting blood glucose and glycosylated hemoglobin A1c. Among tested patients, we determined rates of subsequent diagnosis of diabetes, prescription of hypoglycemic medications, and death over the next three years.
Using cut-points from the literature and the American Diabetes Association, 32% of older patients with schizophrenia had either a fasting blood glucose or A1c test during the year, in spite of multiple risk factors for developing diabetes.
Combining the tests, 5,353 patients had pre-diabetes (13%) and 1,291 patients had likely diabetes (3%).
Only 12% of pre-diabetic patients were diagnosed with or treated for diabetes during the next three years (deaths and lost-to-follow-up excluded), although 25% of dysglycemic patients might be expected to progress to diabetes over 3-5 years per the literature.
Mortality was higher among patients meeting criteria for diabetes if their condition remained undiagnosed/untreated over the next three years (13% vs 8%).
IMPACT:
This study will provide important data on medical care provided to late-life veterans with schizophrenia, diabetes, or both conditions, including relative levels and quality of care, and outcomes. Results will be disseminated to the Mental Health and Diabetes QUERIs through our QUERI advisors and will inform the development of future interventions to provide effective chronic illness management for these complex patients. [8/2/2006]
The summary of findings was submitted to QUERI-DM and QUERI-MH. [6/17/2008]
PUBLICATIONS:
None at this time.
DRA:
Chronic Diseases, Mental Illness
DRE:
Treatment, Quality of Care
Keywords:
Chronic disease (other & unspecified), Diabetes, Schizophrenia
MeSH Terms:
none
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