AbstractBackground and aimsIn the Western world, it has become clear that we are facing a crisis of overuse, abuse and improperly prescribed use of opioids. As part of the ongoing discussion on opioid use, the use and prescription of tramadol have been addressed in recent years. A significant portion of this discussion should adequately address the risk factors for the use of weak opioid products such as tramadol. The risk factors which characterise the long-term tramadol use are still incompletely understood. Thus, we aimed to describe the characteristics of Danish patients using tramadol in more detail, under different scenarios and determinants of subsequent usage patterns.MethodsWe conducted a nationwide cohort study to identify individuals purchasing tramadol from 01/01/2004 to 31/12/2015 who are age 16 + years old by using data from The Danish National Databases; these databases consist of unique information for all citizens in Denmark. Logistic regression analyses were used to assess the potential risk factors for repeated tramadol use.ResultsThe final cancer-free cohort consisted of N = 941,839 tramadol users: 54.4% women, with a mean age of 53.2 years. The number of chronic noncancer pain (CNCP) was 430,641 individuals, and 56% of the total third who repeated the use of tramadol with two + purchased prescriptions were CNCP patients. The increased risk of repeated use for CNCP was, among others, associated with: male sex (HR 1.21), age 69–110 (HR 1.72), back/spine pain men (HR 1.47), women (HR 1.46), spondylopathies (HR 1.24), male osteoporosis (HR 1.22), multimorbid ulcer/skin (HR 1.28), region of municipality Northern Jutland (HR 1.74), Central Jutland (HR 1.75), number of co-medication 4–9 (HR 1.33), dementia (HR 1.27). Factors associated with decreased risk: co-medication ischemic heart disease (HR 0.85), diagnosis headache (HR 0.70), household income highest tertile (HR 0.81), unknown (HR 0.70), single women (HR 0.96).ConclusionsThis study proved a widespread prescribed use of tramadol in Denmark, and, as know from the literature, weak opioid use may lead to long-term use of high potent opioids, this usage is inappropriate, in general, but especially for the treatment of CNCP.ImplicationsWhen striving to reduce the overuse of opioids, focus on the extensive use of tramadol may be essential. The current study indicates an excessive and not appropriately prescribed use of tramadol among Danish CNCP patients. In addition to being inappropriate, such use may also have an impact on the growing problem of an illicit Internet market for this drug. Thus, the situation must be taken seriously. The current study confirms the recent clinical guideline and the National Recommendations in Denmark, which emphasises the risks of problematic use of tramadol. The research may also be relevant in other comparable countries. Caution must especially be taken with CNCP patients with comorbidities like diabetes, lung disease, dementia, and osteoporosis.