Analysis 1: HIT outcome (RCTs). Comparison: UFH versus LMWH. There were no LMWH events and 10 UFH events. Test for heterogeneity: χ² = 0.36; df = 1 (P = .55); I² = 0%. Test for overall effect: Z = 2.14 (P = .03). ▪ represents the summary OR; vertical line, 95% CI; and ♦, OR and 95% CI.