Fatal venous thromboembolism associated with different combined oral contraceptives: a study of incidences and potential biases in spontaneous reporting.
ABSTRACT Fatal venous thromboembolism (VTE) is a rare complication of combined oral contraceptive (COC) treatment. This study aims to determine incidences of fatal VTE in relation to the type of COC and the percentage of cases reported to the Swedish Adverse Drug Reactions Advisory Committee (SADRAC). A further aim is to compare the characteristics of reported and not reported cases.
This retrospective study is a separate analysis using data from a larger study that included women aged 15-44 years between 1990 and 1999 with VTE coded as the underlying or contributory cause of death in the Swedish Cause of Death Register. COC use within 2 months of the date of symptom onset or death was identified in 28 cases. Sales data were obtained from the National Corporation of Swedish Pharmacies. Reported cases were identified in the SADRAC database.
After excluding two cases where the type of COC was unknown, the crude incidences of fatal VTE were 5.1 (95% CI 2.3, 9.6), 8.6 (95% CI 4.3, 15.4) and 9.1 (95% CI 3.3, 19.8) cases per million women per year for levonorgestrel-, desogestrel- and norethisterone-containing COCs, respectively. Age-adjusted incidences were approximately twice as high for desogestrel- and norethisterone-containing COCs compared with levonorgestrel-containing COCs, although differences were not statistically significant. Thirty-six percent of cases were reported. Reporting was positively associated with information in medical records relevant to the VTE diagnosis that the patient was a COC user and was significantly higher in northern Sweden.
Results from this study support a higher incidence of fatal VTE with desogestrel-containing COCs than with levonorgestrel-containing COCs.
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ABSTRACT: The objective of this study was to report deaths from amniotic fluid embolism (AFE) and pregnancy-related venous thromboembolism (VTE), to study contributing factors, and to analyse mortality trends. Using the Swedish Cause of Death Register (CDR), we identified all women aged 15-44, who died during 1990-1999, with VTE or AFE coded as the underlying or contributory cause of death. We scrutinised medical records, and women who had died during pregnancy or within 6 weeks of terminated pregnancy were included. We also used data from the Medical Birth Register (MBR) on incident and fatal cases. Mortality data from the 1970s and 1980s were based on previous studies, in which cases were identified through register linkage (CDR and MBR). Five women died of AFE and 10 of VTE - 6 in early pregnancy - during the 1990 s. Five of the cases were not registered as maternal deaths. Only 4 cases were reported as pregnancy-related deaths from pulmonary embolism (PE). Cesarean section/surgery without thromboprophylaxis, overweight, severe intercurrent disease, delays in seeking health care, and verbal miscommunication were contributing factors in the VTE cases. VTE mortality rates (pregnancy >28 weeks and/or a registered birth) were 1.0 (0.5-1.8), 0.8 (0.3-1.6), and 0.4 (0.1-1.0) per 100,000 live births during the 1970s, 1980s and 1990 s, respectively; the corresponding respective figures for AFE were 1.0 (0.5-1.8), 1.1 (0.6-2.1), and 0.5 (0.2-1.1) per 100,000 live births. The case fatality rate for VTE decreased from 4.5% in the 1970s, to 0.6% in the 1990 s, paralleled with quadrupled incidence. The case fatality rate for AFE was unaltered and high, around 45%, during those 3 decades. Mortality from pregnancy-related PE in Sweden is in the lowest range ever reported, and shows a downward trend during the 1990 s, with a shift towards early pregnancy. In order to monitor mortality trends, death certificate quality must improve, and registers must be linked routinely.Acta Obstetricia Et Gynecologica Scandinavica 02/2007; 86(4):435-43. DOI:10.1080/00016340701207500 · 1.99 Impact Factor