Cheng et al. BMC Public Health 2011, 11:380 http://www.biomedcentral.com/1471-2458/11/380 Page 5 of 9 Figure 2 Spatial clusters of cardiovascular drugs in Taiwan. A high-high association of the LISA statistics indicates the location is higher than the average of the entire study area and so are its neighbors, or a hot spot; a low-low association indicates both the location and its neighbors are lower than the average, or a cold spot. Table 2 The spatial analysis of five category cardiovascular medications by urbanicity, data presented as N (%) Group Ad Group B Group C Group D Group O Ha Lb H L H L H L H L Taipei-Keelung metropolitan area (N = 44) Hsinchu secondary metropolitan Area (N = 10) Tainan metropolitan area (N = 14) Kaohsiung metropolitan area (N = 28) Rural townships area (N = 167) Aboriginal townships area (N = 55) 1 (2.3) 0 (0.0) 0 (0.0) 2 (7.1) 3 (1.7) 0 (0.0) 4 (9.1) 0 (0.0) 0 (0.0) 1 (3.6) 7 (4.0) 5 (9.1) 0 (0.0) 0 (0.0) 0 (0.0) 3 (10.7) 3 (1.7) 1 (1.8) 2 (4.5) 0 (0.0) 2 (14.3) 2 (7.1) 7 (4.0) 4 (7.3) 0 (0.0) 0 (0.0) 0 (0.0) 4(14.3) 4 (2.3) 1 (1.8) 4 (9.1) 1 (10.0) 0 (0.0) 3 (10.7) 6 (3.5) 4 (7.3) 1 (2.3) 0 (0.0) 0 (0.0) 4 (14.3) 2 (1.2) 2 (3.6) 3 (6.8) 3 (30.0) 2 (14.3) 1 (3.6) 6 (3.5) 2 (3.6) 0 (0.0) 0 (0.0) 0 (0.0) 2(7.1) 1 (0.6) 1 (1.8) 5 (11.4) 0 (0.0) 0 (0.0) 1 (3.6) 6 (3.5) 4 (7.3) Total (N = 352)c 6 (1.7) 17 (4.8) 7 (2.0) 17 (4.8) 9 (2.6) 18 (5.1) 9 (2.6) 17 (4.8) 4 (1.1) 16 (4.5) a. High-high association (hot spot), meanings utilization was higher than average b. Low-low association (cold spot), meanings utilization was lower than average c. Three areas did not presented any hot spot or cold spot including Taichung-Changhwa metropolitan, Chungli-Taoyuan metropolitan, and Chiayi secondary metropolitan areas. d. Group A, agents acting on the rennin-angiotensin system; Group B, beta blocking agents; Group C, calcium channel blockers; Group D, diuretics; Group O, antihypertensives