A Cohort Study Investigating Compliance with Guidelines for Platelet Count Monitoring During Heparin Thromboprophylaxis

Abstract

Background: Heparin is the most common agent used for prevention of venous thromboembolism. To promote early detection of heparin-induced thrombocytopenia, guidelines recommend episodic platelet count monitoring for specified patient populations. However, physician compliance with these guidelines has never been reported for patients receiving heparin for pharmacologic prophylaxis. Aim: The aim of this study was to evaluate the frequency of and factors associated with physician failure to monitor patient platelet counts. Results: We conducted a retrospective cohort study of 2350 admissions of patients aged ≥ 18 years who received ≥ 4 consecutive days of prophylactic heparin. There was nonadherence to monitoring recommendations in 659 (28%) patients. Monitoring was not more likely among patients for whom monitoring was recommended compared with patients for whom no monitoring was recommended (31% vs 27%; adjusted hazard ratio, 0.9; 95% CI, 0.7–1.1). Compared with patients admitted to the general medicine service, monitoring was significantly less common among patients admitted to orthopedic surgery or obstetric-gynecologic services (adjusted hazard ratio, 1.6; 95% CI, 1.1–2.2 and adjusted hazard ratio, 2.4; 95% CI, 1.8–3.2, respectively). A decrease in platelet count (≥ 50%) was detected in 90 (4%) patients, but in only 12 (11%) patients was heparin stopped, and in only 11 (12%) patients were heparin-induced thrombocytopenia antibody levels obtained. Of the 11 patients for whom heparin-induced thrombocytopenia antibody levels were obtained, 6 (0.26% of the patient population) were positive. Conclusion: We found that compliance by physicians with platelet count monitoring recommendations was poor for patients who had received heparin for venous thromboembolism prophylaxis, and platelet count monitoring appeared to be unrelated to American College of Chest Physicians recommendations for routine monitoring. Compliance was particularly poor in orthopedic surgery and obstetric-gynecologic services.