BACKGROUND: Knowledge of co-occurring mental disorders (termed 'dual diagnosis') among patients receiving opioid agonist treatment (OAT) is scarce. This study aimed (1) to estimate the prevalence and structure of dual diagnoses in two national cohorts of OAT patients and (2) to compare mental disorders between OAT patients and the general populations stratified on sex and standardized by age. METHODS: A registry-linkage study of OAT patients from Czechia (N = 4,280) and Norway (N = 11,389) during 2010-2019 was conducted. Data on mental disorders (F00-F99; ICD-10) recorded in nationwide health registers were linked to the individuals registered in OAT. Dual diagnoses were defined as any mental disorder excluding substance use disorders (SUDs, F10-F19; ICD-10). Sex-specific age-standardized morbidity ratios (SMR) were calculated for 2019 to compare OAT patients and the general populations. RESULTS: The prevalence of dual diagnosis was 57.3% for Czechia and 78.3% for Norway. In Czechia, anxiety (31.1%) and personality disorders (25.7%) were the most prevalent, whereas anxiety (33.8%) and depression (20.8%) were the most prevalent in Norway. Large country-specific variations were observed, e.g., in ADHD (0.5% in Czechia, 15.8% in Norway), implying differences in screening and diagnostic practices. The SMR estimates for any mental disorders were 3.1 (females) and 5.1 (males) in Czechia and 5.6 (females) and 8.2 (males) in Norway. OAT females had a significantly higher prevalence of co-occurring mental disorders, whereas SMRs were higher in OAT males. In addition to opioid use disorder (OUD), other substance use disorders (SUDs) were frequently recorded in both countries. CONCLUSIONS: Results indicate an excess of mental health problems in OAT patients compared to the general population of the same sex and age in both countries, requiring appropriate clinical attention. Country-specific differences may stem from variations in diagnostics and care, reporting to registers, OAT provision, or substance use patterns.

• Klíčová slova
• Dual diagnosis, Opioid agonist treatment, Opioid use disorder, Psychiatric comorbidity, Registry-based study,
• MeSH
• diagnóza dvojí (psychiatrie) MeSH
• dospělí MeSH
• duševní poruchy * epidemiologie   farmakoterapie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• opiátová substituční terapie * statistika a číselné údaje   MeSH
• opioidní analgetika terapeutické užití   MeSH
• poruchy osobnosti epidemiologie   MeSH
• poruchy spojené s užíváním opiátů * epidemiologie   farmakoterapie   MeSH
• prevalence MeSH
• registrace * MeSH
• senioři MeSH
• sexuální faktory MeSH
• úzkostné poruchy epidemiologie   farmakoterapie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Norsko epidemiologie   MeSH
• Názvy látek
• opioidní analgetika MeSH

BACKGROUND: Physical diseases represent a significant burden for opioid agonist treatment (OAT) patients. This study described physical morbidity in two national cohorts of OAT patients focusing on gender differences. METHODS: This population-based cohort study linking multiple health registers investigated physical diseases (ICD-10) in patients receiving OAT in the Czech Republic (N = 4,280) and Norway (N = 11,389) during 2010-2019. Gender-stratified analysis was performed. RESULTS: Overall, we found a large burden of physical morbidity across gender groups in OAT patients. In the Czech Republic and Norway, women in OAT had a significantly higher prevalence of physical diseases across most diagnostic chapters, notably genitourinary diseases and neoplasms. Injuries/external causes and infectious/parasitic diseases were among the most common diseases in both women and men. Viral hepatitis accounted for over half of infectious morbidity in women and men in both cohorts. CONCLUSIONS: Our findings support the need for early screening, detection, and treatment of diseases and conditions across organ systems and the integration of health promotion activities to reduce physical morbidity in OAT patients. The gender differences underline the need for a tailored approach to address specific medical conditions.

• Klíčová slova
• Health registers, ICD-10, Opioid use disorder, Physical disease, Record-linkage study, Somatic disease, Substance use,
• MeSH
• kohortové studie MeSH
• lidé MeSH
• opiátová substituční terapie MeSH
• opioidní analgetika * terapeutické užití   MeSH
• poruchy spojené s užíváním opiátů * farmakoterapie   epidemiologie   MeSH
• prevalence MeSH
• sexuální faktory MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Norsko MeSH
• Názvy látek
• opioidní analgetika * MeSH