Cohort profile: Outcomes & Multi-morbidity In Type 2 diabetes (OMIT) – a national registry-based observational cohort with focus on care and treatment of key high-risk groups in Norway

Abstract

PurposeThe ‘Outcomes & Multi-morbidity in Type 2 Diabetes’ (OMIT) is an observational registry-based cohort of Norwegian patients with type 2 diabetes (T2D) established to study high-risk groups often omitted from randomised clinical trials.ParticipantsThe OMIT cohort includes 57 572 patients with T2D identified via linkage of Norwegian Diabetes Register for Adults and the Rogaland-Oslo-Salten-Akershus-Hordaland study, both offering data on clinical patient characteristics and drug prescriptions. Subsequently these data are further linked to the Norwegian Prescription Database for dispensed medications, the Norwegian Population Register for data on death and migration, Statistics Norway for data on socioeconomic factors and ethnicity and the Norwegian Directorate of Health for data on the general practices and clinical procedures involved in the care of cohort patients. OMIT offers large samples for key high-risk patient groups: (1) young-onset diabetes (T2D at age <40 years) (n=6510), (2) elderly (age >75 years) (n=15 540), (3) non-Western ethnic minorities (n=9000) and (4) low socioeconomic status (n=20 500).Findings to dateOn average, patient age and diabetes duration is 67.4±13.2 and 12.3±8.3 years, respectively, and mean HbA1c for the whole cohort through the study period is 7.6%±1.5% (59.4±16.3 mmol/mol), mean body mass index (BMI) and blood pressure is 30.2±5.9 kg/m2 and 135±16.1/78±9.8 mm Hg, respectively. Prevalence of retinopathy, coronary heart disease and stroke is 10.1%, 21% and 6.7%, respectively.Future plansThe OMIT cohort features 5784 subjects with T2D in 2006, a number that has grown to 57 527 in 2019 and is expected to grow further via repeated linkages performed every third to fifth year. At the next wave of data collection, additional linkages to Norwegian Patient Registry and Norwegian Cause of Death Registry for data on registered diagnoses and causes of death, respectively, will be performed.

How valid is a prescription-based multimorbidity index (Rx-risk) in predicting mortality in the Outcomes and Multimorbidity In Type 2 diabetes (OMIT) study? A nation-wide registry-based cohort study from Norway

“…The optimal solution may be to combine diagnostic codes with dispensed drugs, in line with the Nordic multimorbidity index by Kristensen et al , 32 but such data are not currently available in the OMIT study. As part of an updated linkage, we plan to supplement the OMIT cohort with additional data from the Norwegian Patient Registry, 23 which will allow for this type of analysis.…”

“…OMIT is a cohort study including 57 515 persons with type 2 diabetes registered in the Norwegian Diabetes Register for Adults (NDR-A) during 2006–2019 and/or in the Rogaland-Oslo-Salten-Akershus-Hordaland (ROSA4) study during 2012–2014. 23 …”

“…The Outcomes and Multimorbidity In Type 2 diabetes (OMIT) cohort is a new Norwegian registry-based observational cohort constructed to study high-risk patient groups with type 2 diabetes. 23 High-risk patients are often characterised by more complex disease patterns and by higher burden of MM. 24–26 Therefore, it is pivotal to construct a robust and valid measure of overall MM both to study the prevalence, incidence or the effects of MM in itself, but also to balance treatment groups when comparing the effect of treatment on an outcome.…”

Decreasing incidence of stroke, ischaemic heart disease and dementia in Norway, 1990–2019, a Global Burden of Disease study: an opportunity

“…It would not take long to demonstrate that hypertension, which most people will develop at some stage in their lives, is better detected and treated since a key component to brain health is exercise and a healthy diet, which also are the first steps in preventing hypertension [3]. These are the same first steps in preventing obesity, pre‐diabetes and diabetes [23]. So, the risk of two of the major risk factors for chronic diseases would be addressed in tandem.…”