There are concerns that people with mental disorders may not receive proper somatic care within health care systems, and face the risk of poor physical health outcomes and premature death.

To study whether patients with diabetes and comorbid mental illness are at higher risk of amputation of the lower limbs and mortality than diabetic patients without mental illness.

To pinpoint possible disparities in physical health outcomes and mortality in diabetic patients with or without mental disorders.

National Swedish registers; Prescribed Drug Register, Patient Register and Cause of Death Register. All subjects that were prescribed antidiabetics during 2006, at age 35–79, were included (n = 229,956). Subjects with at least 2 hospital inpatient stays during 1996–2005 for psychotic disorders, i.e. schizophrenia/affective psychosis (n = 2,791), or non-psychotic disorders, i.e. depression/anxiety (n = 2,327) were identified. The study population was followed from 2007–2009. A Poisson regression model estimated the effect of mental illness on the likelihood of amputation or death. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were calculated.

Diabetic patients with comorbid psychotic and non-psychotic illness were more likely to die than patients without mental illness, also when suicides and events of undetermined intent were excluded (IRR = 2.44, CI 2.18–2.72 and IRR = 2.43, CI 2.17–2.71, respectively). The risk of amputation was particularly enhanced in diabetic patients with depression or anxiety (IRR = 4.39, CI 2.58-7.49).

In diabetic patients there exist unsettling disparities in physical health outcomes and mortality that are associated with whether a person is mentally ill or not.