Highlight
- Individuals with mental disorders are 19% less likely to receive the full spectrum of recommended diabetes monitoring compared to those without psychiatric diagnoses.
- The most severe disparity exists in the prescription of GLP-1 receptor agonists, with patients with mental disorders being 74% less likely to receive these cardio-protective medications.
- Paradoxically, patients with mental disorders are 52% more likely to be treated with insulin, potentially reflecting delayed diagnosis or more advanced disease progression at the time of treatment.
- Significant deficits were identified across all major NICE indicators, including HbA1c testing, retinal screening, and foot examinations.
Background: The Dual Burden of Metabolic and Mental Health
The intersection of mental health and metabolic disease represents one of the most challenging frontiers in contemporary clinical medicine. It is well-established that individuals with severe mental illnesses, such as schizophrenia and bipolar disorder, as well as common mental disorders like major depressive disorder, face a significantly higher risk of developing type 2 diabetes. This increased risk is multifactorial, stemming from genetic predispositions, sedentary lifestyles, and the metabolic side effects of second-generation antipsychotics. However, the more pressing clinical question is not just whether these patients develop diabetes, but whether they receive equitable care once diagnosed.
Despite the high mortality rates associated with this population—often driven by cardiovascular disease rather than their primary psychiatric condition—evidence regarding the quality of their diabetes care has been conflicting. Some studies have suggested that frequent contact with the healthcare system for mental health reasons might lead to better monitoring, while others point toward “diagnostic overshadowing,” where physical health needs are neglected in favor of psychiatric management. To clarify these discrepancies, a team of researchers led by Wagner et al. conducted a comprehensive systematic review and meta-analysis, published in The Lancet Psychiatry, to quantify the disparities in diabetes monitoring and treatment.
Study Design: A Global Evidence Synthesis
This systematic review and random-effects meta-analysis was meticulously designed to compare diabetes quality of care between individuals with and without comorbid mental disorders. The researchers searched major databases including Scopus, Embase, MEDLINE, and PsycINFO for cohort and case-control studies published up to February 2025. The inclusion criteria were rigorous, focusing on studies that allowed for the generation of pooled summary odds ratios (ORs).
The primary outcome was a binary composite measure of diabetes quality of care, defined by the percentage of patients receiving any of the nine NICE-recommended monitoring indicators. These include HbA1c testing, blood pressure measurement, foot surveillance, serum creatinine, serum cholesterol, BMI recording, smoking status documentation, and retinal monitoring. Secondary outcomes included specific individual indicators and the types of anti-diabetes medications prescribed, specifically looking at insulin and GLP-1 receptor agonists (GLP-1 RAs).
The final analysis included 49 studies (42 cohort and 7 case-control) encompassing a massive sample size of 5,503,712 individuals with diabetes. Within this cohort, 838,366 (15.2%) had a diagnosed mental disorder, including mood disorders, schizophrenia, anxiety, and substance use disorders. The mean age of the population was 61.4 years, providing a clear window into the care provided to middle-aged and older adults who are at the highest risk for diabetic complications.
Key Findings: Quantifying the Care Disparity
The Monitoring Gap
The meta-analysis revealed a stark and statistically significant negative association between having any mental disorder and the likelihood of receiving recommended diabetes monitoring. Individuals with mental disorders had an OR of 0.81 (95% CI 0.70–0.94, p=0.0049) for receiving the composite quality of care measure. When broken down into individual indicators, the disparities remained consistent and troubling:
- HbA1c Measurement: OR 0.81 (p=0.024)
- Retinal Screening: OR 0.77 (p=0.013)
- Lipid/Cholesterol Measurement: OR 0.83 (p=0.043)
- Foot Examination: OR 0.85 (p=0.0044)
- Renal Investigation: OR 0.78 (p=0.022)
These findings suggest that nearly every major preventative screening tool for diabetes complications is underutilized in the psychiatric population. The only outlier was the recording of smoking status, which showed a slight positive association (OR 1.09), perhaps reflecting the high prevalence of smoking in psychiatric settings and the routine nature of this inquiry during intake assessments.
The Treatment Paradox: Insulin versus GLP-1 RAs
Perhaps the most striking findings of the study related to pharmacological interventions. The meta-analysis found that any mental disorder was significantly associated with higher odds of receiving insulin (OR 1.52, 95% CI 1.16–1.99, p=0.0022). While at first glance this might appear to be more intensive care, clinicians often interpret high insulin use in this context as a marker of poorly controlled disease or a failure of early-stage management with oral agents. Insulin therapy is also more complex to manage, requiring higher levels of health literacy and self-monitoring, which can be challenging for patients with cognitive or emotional impairments.
Conversely, there was a profound negative association with the use of GLP-1 receptor agonists. Patients with mental disorders were 74% less likely to be treated with these medications (OR 0.26, 95% CI 0.13–0.49, p<0.0001). This is particularly concerning given that GLP-1 RAs are not only highly effective at lowering glucose but also offer significant benefits for weight loss and cardiovascular protection—benefits that are desperately needed in a population often struggling with antipsychotic-induced weight gain and high cardiovascular mortality.
Expert Commentary: Mechanistic Insights and Clinical Barriers
The results of this meta-analysis underscore a systemic failure in the integration of mental and physical healthcare. Several factors likely contribute to these disparities. First, “diagnostic overshadowing” remains a pervasive issue; clinicians may focus so intently on stabilizing a patient’s psychiatric symptoms that metabolic monitoring falls by the wayside. Second, the fragmentation of care—where psychiatrists manage the mind and primary care physicians or endocrinologists manage the body—often leads to patients falling through the cracks, especially those with impaired executive function who may struggle to navigate multiple appointments.
The under-prescription of GLP-1 RAs is a critical missed opportunity. There may be a perceived concern among clinicians regarding the side effects or the ability of patients with mental disorders to adhere to injectable therapies, despite evidence that many of these patients can manage such regimens with proper support. Furthermore, the higher rate of insulin use suggests that when these patients are finally treated aggressively, it is often too late to utilize simpler, more protective first-line or second-line therapies.
From a biological perspective, the lack of monitoring is catastrophic. Patients with schizophrenia and major depression often have altered pain perception or may not report early symptoms of peripheral neuropathy or retinopathy, making routine objective screening even more vital than in the general population.
Conclusion: Toward Integrated Cardio-Metabolic-Mental Health Care
The study by Wagner and colleagues provides definitive evidence that people with mental disorders receive lower-quality diabetes care across almost all clinical benchmarks. These disparities are not merely administrative failures; they are direct contributors to the 10- to 20-year gap in life expectancy faced by this population. Addressing this requires a fundamental shift in how we deliver care.
Potential solutions include the implementation of integrated medical-psychiatric clinics, the use of electronic health record prompts to ensure monitoring compliance, and a more proactive approach to prescribing modern metabolic therapies like GLP-1 RAs in psychiatric patients. By bridging the gap between the psychiatrist’s office and the diabetes clinic, the medical community can begin to dismantle the inequities that currently compromise the health and longevity of patients with mental disorders.
References
Wagner E, Højlund M, Fiedorowicz JG, et al. Disparities in diabetes treatment and monitoring for people with and without mental disorders: a systematic review and meta-analysis. Lancet Psychiatry. 2026;13(2):112-124. doi:10.1016/S2215-0366(25)00332-3.
