HSR&D Home » Research » IIR 07-124 – HSR&D Study
Determinants of Diabetes Control in Veterans with Serious Mental Illness
Judith A. Long, MD
Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
Funding Period: June 2009 - June 2012
Among people with serious mental illness (SMI), the prevalence of diabetes is 2-3 times higher than in the general population. Because of their SMI these patients are likely to require unique approaches to their diabetes specific care. Given the magnitude of the problem in the SMI population determining how best to deliver this disease specific care to patients with SMI is a vital area for further study. Collocated mental health and primary care, where patients receive primary care in mental health clinics, is one approach advocated for improving chronic disease outcomes in patients with SMI. Collocated care is not ubiquitous throughout the VA and a multi-site evaluation of VA collocated and usual primary care provides a real opportunity to understand the strengths and weaknesses of collocated care for non-mental health disease specific management and outcomes in patients with SMI.
The primary objective of this study was to understand if and how care influences diabetes glucose control and medication adherence. We hypothesized that compared to veterans with SMI and diabetes receiving usual primary care, veterans with SMI and diabetes receiving collocated primary care would have better glucose control and diabetes medication adherence. Our secondary objective was to identify potential patient level mediators that help explain why veterans with SMI and diabetes receiving collocated primary care have better glucose control and diabetes medication adherence than veterans with SMI and diabetes receiving usual primary care.
We performed a cross sectional study of patients with Type 2 diabetes and SMI seeking care from three VA medical facilities. We mailed potential participants a letter describing the study. At two sites this was followed by a phone call and at a third site patients were approached by clinic staff at scheduled appointments. Interested patients met individually with a research assistant who obtained informed consent and administered the research questionnaire. Following completion of the questionnaires participants had a glycosylslated hemoglobin (HbA1c) drawn.
Our outcomes of interest were glucose control as measured by the HbA1c and hypoglycemic medication adherence as measured by the medication possession ratio (MPR) over the prior year for diabetes medications and the self-reported diabetes specific Morisky Medication Adherence scale. We evaluated HbA1c and MPR as continuous variables. We dichotomized self-reported adherence as perfect versus non-perfect adherence.
Our main independent variable of interest was receipt of collocated care (yes/no). The three study sites were chosen because each provides a different model of primary care for patients with SMI. Site 1, Philadelphia integrates primary care providers into the mental health clinics. At this site the primary care providers deliver care in the exact same space as the mental health providers and participate in mental health clinic conferences. We call this model integrated collocated care. Site 2, Pittsburgh collocates primary care providers in a specialized site where a majority of the mental health care is delivered such that the primary care providers at this site predominantly care for veterans with mental illness. At this site, the primary care providers only see patients who are seen in the mental health clinics but they do not formally co-manage care. We call this model specialized collocated care. At Bedford there is no special arrangement between primary care and the mental health services. We call this model usual care. While Site 1 and 2 both strive to accommodate most of their SMI patients in the collocated primary care clinics described, some SMI patients receive care from routine primary care clinics and these patients were also designated as receiving usual care.
We evaluated the unadjusted association between collocation and all covariates as well as the outcomes of interest. Linear regressions were used for the analysis of HbA1c and MPR while logistic regression was used for the analysis of self-reported adherence. Covariates were retained in the final models if the association with the outcome of interest was p < 0.05. Since participation varied by demographic characteristics, we created weights to make responses representative of the eligible populations at each site and report weighted results. Finally, because the models of collocation in site 1 and 2 were different from each other we also looked the associations between the type of collocation (integrated or specialized) and the outcomes of interest.
We enrolled 363 individuals out of 681 eligible participants for an overall response rate of 53%. Compared to non-participants, participants were more likely to be black (43% vs 38% p < 0.001), have bipolar disorder (41% vs 25% p < 0.001) and be younger (mean age 58 vs 62 p < 0.001). There was no difference by sex or medical record documented last HbA1c.
On average participants were 59 years old and had diabetes for 10 years. The mean number of psychotic symptoms was 0.99, the mean number of depressive symptoms was 1.36, and 88% of the sample was on a psychiatric medication. Patients seen in collocated care were more likely to be black (48% vs 35% p = 0.044), less likely to have seen an endocrinologist in the last year (31% vs 46% p = 0.017), and more likely to have a low Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) score (70 vs 76 p = 0.001).
In unadjusted analyses there were no differences by collocation and the three outcomes of interest. The mean HbA1c was 7.4, the mean MPR was 80%, and 51% of the sample self-reported perfect adherence to their diabetes medications. In adjusted analyses patients seen in collocated care tended towards having better HbA1c levels and MPR values but this was not statistically significant at a p < 0.05 level. This trend was driven primarily by integrated collocated care over specialized collocated care.
We found that in a population of veterans with co-morbid SMI and diabetes patients on average had good medication adherence and glucose control regardless of where they received primary care. While there was a trend toward better outcomes in those receiving integrated collocated care it was not statistically significant, mostly because there was not much to be achieved over what was already being achieved in usual care. From the results of this study, the VA seems to be meeting standard diabetic recommendations for their patients with both SMI and diabetes.
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DRA: Mental, Cognitive and Behavioral Disorders, Diabetes and Other Endocrine Disorders
DRE: Treatment - Observational
MeSH Terms: none