Analysis 3: thrombocytopenia outcome. Comparison: UFH versus LMWH; outcome: thrombocytopenia (HIT and non-HIT). Total events for LMWH = 152; total events for UFH = 238. Test for heterogeneity: χ² = 46.11; df = 9 (P < .001); I² = 80.5%. Test for overall effect: Z = 1.90 (P = .06). Symbols are as in Figure 2.