To Örebro University

BACKGROUND: People with mental disorders have an increased risk of diabetes, yet conflicting evidence exists regarding the quality of diabetes care they receive. To address this evidence gap, we conducted a systematic review and meta-analysis to assess and compare diabetes quality of care in people with diabetes with mental disorders versus people with diabetes without mental disorders.

METHODS: In this systematic review and random-effects meta-analysis, we searched Scopus, Embase, MEDLINE, and PsycINFO for cohort and case-control studies published between database inception and Feb 8, 2025. We estimated summary odds ratios (ORs) for diabetes quality of care indicators in individuals with any mental disorder versus without mental disorders to investigate the association between the presence of a mental disorder and diabetes quality of care indicators, including overall diabetes monitoring and treatment. Studies were excluded if it was not possible to generate pooled quantitative data. The primary outcome was a binary composite measure of diabetes quality of care, meaning the percentage of people receiving any diabetes monitoring and treatment (ie, urine albumin-creatinine ratio test, HbA1c test, blood pressure measured, foot surveillance, serum creatinine test, serum cholesterol test, BMI recorded, smoking status recorded, retinal monitoring). Secondary outcomes were study-specific diabetes quality of care individual indicators matched to the nine NICE diabetes monitoring indicators and specific diabetes interventions and anti-diabetes medications. We analysed primary and secondary outcomes according to any mental disorder and to specific diagnostic subgroups. Study quality was evaluated using the Newcastle-Ottawa Scale (NOS).

FINDINGS: Data from 49 studies (42 cohort and seven case-control) were included, comprising 5 503 712 individuals with diabetes, of whom 838 366 (15·2%) had a diagnosed mental disorder (defined using ICD-9 or ICD-10 criteria in 40 studies). Sex was reported in 35 of 49 studies, comprising 4 250 666 individuals, 1 956 506 (46·0%) of whom were female and 2 294 160 (54·0%) were male. The mean age was 61·4 years (SD 8·7; range 47-82 years). 38 studies reported on various mental disorders, 21 on mood disorders spectrum, 21 on major depressive disorder, 20 on schizophrenia, 11 on bipolar disorder, 11 on substance use disorder spectrum, including alcohol use disorder, six on dementia, five on anxiety disorder spectrum, and one on personality disorder spectrum. Most studies were high quality and spanned Asia, North America, Europe, and Australasia. Significant negative associations were observed between having any mental disorder and the likelihood of receiving any recommended diabetes monitoring (29 studies, OR=0·81 [95% CI 0·70-0·94], p=0·0049). Negative associations were also observed for HbA1c measurement (24 studies, 0·81 [0·68-0·97], p=0·024), retinal screening (21 studies, 0·77 [0·63-0·95], p=0·013), lipid and cholesterol measurement (20 studies, 0·83 [0·69-0·99], p=0·043), foot examination (11 studies, 0·85 [0·76-0·95], p=0·0044), and renal investigation (16 studies, 0·78 [0·63-0·96], p=0·022). A significant positive association was found between any mental disorder and recorded smoking status (two studies, 1·09 [1·02-1·17]; p=0·0076). Any mental disorder was significantly associated with higher odds of receiving insulin (ten studies, 1·52 [95% CI 1·16-1·99]; p=0·0022), but negatively associated with treatment with a GLP-1 receptor agonist (two studies, 0·26 [0·13-0·49]; p<0·0001). There was no evidence of publication bias.

INTERPRETATION: Mental disorders are negatively associated with receiving adequate diabetes monitoring and GLP-1 agonist therapy. Addressing these disparities has the potential to address the increased mortality associated with mental disorders. FUNDING: None.