Clinical use of the erythrocyte sedimentation rate in the evaluation of febrile intravenous drug users.

STUDY OBJECTIVE

To investigate the use of the erythrocyte sedimentation rate in the evaluation of febrile IV drug users.

DESIGN

Prospective observational cohort study.

SETTING

Municipal hospital emergency department.

TYPE OF PARTICIPANTS

One hundred six IV drug users aged 18 years or older, with rectal temperatures of 37.8 C or more.

INTERVENTIONS

Clinical and laboratory variables were obtained by trained research assistants, using a standardized data collection instrument.

RESULTS

The erythrocyte sedimentation rate was the only variable consistently associated with illness severity in both the univariate and multivariable analyses (P < .0001). At an erythrocyte sedimentation rate of 100 mm/hr or more, the test had a specificity of 96% (95% confidence interval, 81% to 100%). In contrast, the erythrocyte sedimentation rate displayed a relatively poor sensitivity at low values (88% [95% confidence interval, 77% to 95%] at an erythrocyte sedimentation rate less than 20).

CONCLUSION

An erythrocyte sedimentation rate of 100 or more should be regarded as a marker for serious illness in IV drug users with fever, but a "normal" erythrocyte sedimentation rate of less than 20 does not reliably exclude the presence of serious disease in this patient population.