Elsevier

Thrombosis Research

Volume 126, Issue 5, November 2010, Pages 367-372
Thrombosis Research

Regular Article
Venous thromboembolism in medical patients treated in the setting of primary care: A nationwide case-control study in Italy

https://doi.org/10.1016/j.thromres.2010.07.005Get rights and content

Abstract

Objectives

The risk of venous thrombotic events (VTE) among medical outpatients is still not clear and it remains to be clarified whether medical diseases involve the same risk if managed at home or in hospital. The aim of this study was to evaluate in the setting of outpatient family medicine the relationship between VTE and medical conditions known to be at risk during a hospital stay.

Design and setting

The study involved a nationwide retrospective observation according to a nested case-control method; 400 general practitioners throughout Italy constituted the network for data collection. Between 2001 and 2004, all cases recorded as having VTE were entered; ten control patients without VTE, matched by sex, physician, and age, were selected from the database for each case.

Results

The eligible population comprised 372,000 patients and 1,624 incident VTE were recorded. Univariate analysis indicated hospitalization (OR 5.02; 95% CI 4.01-6.29), cancer (OR 3.06; 95% CI 2.47-3.79), acute infectious disease (OR 2.93; 95% CI 1.94-4.43), neurological disease (OR 2.60; 95% CI 1.56-4.33), congestive heart failure (CHF) (OR 2.48; 95% CI 1.68-3.69), paralysis (OR 1.87; 95% CI 1.51-2.32), COPD (OR 1.58; 95% CI 1.29-1.95), stroke (OR 1.62; 95% CI 1.24-2.12), superficial venous thrombosis (OR 1.51; 95% CI 1.11-2.04, and rheumatic diseases (OR 1.49; 95% CI 1.28-1.74) as significantly associated with an increased risk for VTE. After adjustment, only transient or definitive paralysis, cancer, acute infectious disease, congestive heart failure, neurological diseases, and previous hospitalization remained associated.

Conclusions

This large study indicates that VTE outpatients seen by general practitioners in Italy have a high prevalence of the same medical diseases associated with VTE among patients treated in hospital.

Introduction

Several clinical conditions in internal medicine involve an increased risk of venous thromboembolism (VTE). Not only common diseases like heart failure, chronic obstructive pulmonary disease (COPD) and acute infections, but also acute myocardial infarction, stroke, inflammatory bowel and rheumatic diseases all raise the risk [1]. These patients are often elderly, with reduced mobility – particularly hospital inpatients – making for an even higher VTE risk profile. It is generally held that pharmacological prophylaxis for VTE should be considered for any person more than 40 years old, with one of these conditions and with recent limited mobility for less than three days, and expected bed rest [1], [2].

The risk of VTE in medical patients in hospital is documented and the methods for prevention are well-defined, but less is known about the risk for patients over 40 years old when the same diseases are treated at home, in the primary care setting. Some reports indicate that non-surgical patients treated at home have the same increased risk of VTE as inpatients [3]. The scenario is complicated by the fact that there is an increasing tendency to treat these medical patients, even in case of acute illness, entirely at home, or to discharge them after only a brief hospital stay.

Current VTE guidelines recommend prophylaxis only for acutely ill medical patients admitted to hospital[4], but there are doubts about whether it is always appropriate to make this distinction between in- and out-patients, as long as they have the same clinical conditions.

The aim of the present study was to assess whether the medical conditions that are considered risk factors for VTE in acutely ill patients while in hospital had the same impact in the primary care setting. We therefore conducted a nation-wide case-control study in Italy, using a national database established by general practitioners (GPs), members of the Italian College of General Practitioners (SIMG).

Section snippets

Data source

We obtained information from the Health Search Database (HSD), an Italian general practice research database that comprises the complete computerized medical records of all patients registered with participating physicians. The HSD contains demographic details, medical records (diagnoses, tests and results, etc.), drug history, and prevention records. A unique identification number links all data for each individual patient anonymously, and no identifying details are available. All general

Incidence

A total of 1624 incident DVT/PE patients were diagnosed during the period 2001-2004. Fig. 1 describes the age-specific and age-adjusted incidence among males (panel A) and females (panel B) for each calendar year. Age-adjusted incidence showed a stable trend from 8.5 cases/10,000 person-years in 2001 to 9.6 cases/10,000 in 2004 for males, and from 11.1 cases/10,000 in 2001 to 11.7 cases/10,000 person-years in 2004 for females. The incidence was age-related, but peaked in the 60-79 years age

Discussion

Huerta et al. [8] reported the incidence of VTE in the general population using data on a large prospective cohort from the General Practice Research Database (GPRD) in the United Kingdom. In this population, which included patients with surgical risk factors, the incidence rate of VTE was 74.5 per 100 000 person-years. The present study too was conducted in the primary care setting, but our incidence figures for these outpatients are hardly comparable to the figures reported by Huerta. In

Conflict of interest statement

Details of nature of conflict of interest: none.

Funding

This work was supported by a sanofi-aventis unrestricted grant.

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