[Case control studies of the risk factors for deep-vein thrombosis in an adult population hospitalized in internal medicine].

BACKGROUND

The ain of this study was to demonstrate risk factors for deep-vein thrombosis in adults in a hospital setting.

MATERIALS AND

METHODS

From May 1993 to Februrary 1995, 233 patients hospitalized in the internal medicine unit at the Montpellier University Hospital for deep-vein thrombosis were included. Each case was matched to a control case for age, hospitalization unit, and use or not of anti-thrombosis prophylaxy. Venous thrombosis was diagnosed in patients and confirmed to be absent in controls using duplex Doppler when phlebography findings were unconvincing. To eliminate possible false negatives (poor sensitivity of duplex Doppler in asymptomatic patients), all controls were contacted by telephone 3 to 6 months after discharge to ascertain whether or not they had been rehospitalized and if so for what reason. The patients and controls responded to questions designed to identify risk factors for deep-vein thrombosis described in the literature (patient characteristics, personal and family history, surgical history, associated diseases, abnormal blood tests, medical treatment, life style).

RESULTS

The three main risk factors for deep-vein thrombosis for all ages and both sexes identified by multivariate analysis were: personal history of venous thrombosis (OR = 4.7, 95% CI = [2.4; 8.9]), family history of venous thrombosis (OR = 3.3, 95% CI [1.8; 5.9]) and surgical during the preceding 45 days (OR = 3.7, 95% CI = [1.2; 10.9]). In non-menopaused women, the main risk factor was minidose oral contraception (OR = 6.9, 95% CI = [1.9; 25.4]).

CONCLUSION

In our population of hospitalized patients in an internal medicine unit, the main risk factor for thrombosis appeared to be, in general, a past history of venous thrombosis and in non-menopaused women, minidose oral contraception.