The index date for these patients was defined as 1 January 1995 or the date of HIV diagnosis, whichever was more recent. We included all HIV-infected patients in the DHCS, who were (1) registered in the DCRS, (2) living in Denmark on 1 January 1995 or on the date of HIV diagnosis and (3) not diagnosed with VTE prior to the index date. HAART was defined as a treatment regimen of at least three antiretroviral drugs including a nonnucleoside

reverse transcriptase inhibitor, a protease inhibitor and/or abacavir, or a treatment regimen with a combination of a nonnucleoside reverse transcriptase inhibitor and a boosted protease inhibitor. For each HIV-infected patient, we identified 10 HIV-negative individuals from the general population in the DCRS, who were alive on the patient’s index date and not diagnosed with VTE prior

to study inclusion. The population cohort U0126 clinical trial was matched with HIV-infected patients by age and gender. The index date for the population comparison cohort was defined as the index date of the matched HIV-infected patient. The study outcome was time to VTE, defined as the first date an individual was registered with a diagnosis of deep venous thrombosis Selleckchem Tofacitinib (DVT) and/or pulmonary embolism (PE) in DNHR (ICD-8 or ICD-10 diagnosis codes: 451.00, 450.99, I80.1–I80.3 and I26.0–I26.9). Provoked VTE was defined according to the following criteria: presence of a malignancy diagnosed prior to or within 90 days after the thrombotic event or a discharge diagnosis of fracture, surgery, trauma, or pregnancy Non-specific serine/threonine protein kinase (including delivery and the postpartum period) during or within 90 days before the hospitalization for VTE [34,35]. The remaining VTE cases were classified as unprovoked [34,35]. The date of the first diagnosis of malignancy was extracted from the DNHR

using the ICD-8 diagnosis codes 140.00–209.09 and ICD-10 diagnosis codes C0.00–C97.9. Dates of pregnancy and delivery were identified using ICD-8 diagnosis codes 630–680 and ICD-10 diagnosis codes O00–O99. ICD-8 diagnosis codes 800–999 and ICD-10 diagnosis codes S00–T14 were used to extract dates of fracture or trauma. Date of surgery was defined as the date of any surgical operation as recorded in the DNHR. Date of HIV infection was extracted from the DHCS. IDUs were defined as those registered in the DHCS with IDU as the route of HIV infection. For HIV-infected patients, several additional time-updated binary variables were introduced into the model: time before vs. after initiating HAART, and time at or above a CD4 count of 200 cells/μL or below a CD4 count of 200 cells/μL. A patient who had initiated HAART was considered on HAART for the rest of the observation period independent of cessation or changes in antiretroviral therapy. The CD4 cell count was carried forward until the next measurement or last observation.