The pill and thrombosis: epidemiological considerations

Evidence-based risk factors for postoperative deep vein thrombosis

BACKGROUND

Deep vein thrombosis (DVT) is a common postoperative complication that is associated with significant morbidity and mortality. Thromboprophylaxis has been shown to be underused. In the absence of prophylaxis, rates as high as 50% have been reported following orthopaedic surgery, and 25% following general surgery. Many risk factors have been suggested but there is often little evidence to support these claims.

METHODS

A systematic review was performed to determine the evidence base behind each suggested risk factor, and, where sufficient data were available, a random-effects meta-analysis was performed.

RESULTS

There is evidence to support a significant association between increased age, obesity, a past history of thromboembolism, varicose veins, the oral contraceptive pill, malignancy, Factor V Leiden gene mutation, general anaesthesia and orthopaedic surgery, with higher rates of postoperative DVT, although there remain some variables within the study designs that may lead to overestimation of effect. There is no evidence to support the suggested risk factors of hormone replacement therapy, gender, ethnicity or race, chemotherapy, other thrombophilias, cardiovascular factors, smoking and blood type.

CONCLUSIONS

An accurate knowledge of evidence-based risk factors is important in predicting and preventing postoperative DVT, and can be incorporated into a decision support system for appropriate thromboprophylaxis use.

Over-the-counter use of oral contraceptives in Kuwait

Oral contraceptive pills (OCPs) are available over-the-counter (OTC) in Kuwait, and constitute a leading method for spacing and limiting children. Data from a nationally representative survey of Kuwaiti women are used to examine OTC use of OCPs. One-fourth of the women initiated use without consulting a doctor, and 50% bought OCPs from the pharmacy. No socioeconomic or demographic differences were found between those who consulted a physician, implying that women of different background have similar accessibility to the physician. Using multivariate analysis, the odds of consulting a physician were found to be significantly lower for women who first bought OCPs directly from the commercial pharmacy. The duration of first time OCP use did not differ according to physician consultation. It is concluded that OTC availability of OCPs has many advantages and prevents unwanted pregnancy. However, there is a need for better packaging and instructions that would enable high-risk women to identify themselves and to use OCPs under physician supervision.

Pulmonary embolism: sifting the risk factors

A 20-year-old female college cross-country runner developed chest pain and dyspnea that increased with running. A chest radiograph revealed a right-side pleural effusion, and a ventilation-perfusion scan indicated a probable pulmonary embolism. The diagnosis was left-side pulmonary emboli. Testing for genetic risk factors was negative, leaving oral contraceptive use as the likely cause of the condition. The patient was treated with anticoagulant drugs and discontinuation of oral contraceptives, and was allowed to resume running gradually. Discussion covers genetic and other risk factors, anticoagulation therapy, and return to play.