Cheng et al. BMC Public Health 2011, 11:380 http://www.biomedcentral.com/1471-2458/11/380 Competing interests The authors declare that they have no competing interests. Received: 24 November 2010 Accepted: 24 May 2011 Published: 24 May 2011 References 1. Allen NB, Holford TR, Bracken MB, Goldstein LB, Howard G, Wang Y, Lichtman JH: Geographic variation in one-year recurrent ischemic stroke rates for elderly Medicare beneficiaries in the USA. Neuroepidemiology 2010, 34(2):123-129. 2. Ashton CM, Petersen NJ, Souchek J, Menke TJ, Yu HJ, Pietz K, Eigenbrodt ML, Barbour G, Kizer KW, Wray NP: Geographic variations in utilization rates in Veterans Affairs hospitals and clinics. N Engl J Med 1999, 340(1):32-39. 3. Domanski M, Antman EM, McKinlay S, Varshavsky S, Platonov P, Assmann SF, Norman J: Geographic variability in patient characteristics, treatment and outcome in an International Trial of Magnesium in acute myocardial infarction. Control Clin Trials 2004, 25(6):553-562. 4. Gatrell AC, Bailey TC: Interactive spatial data analysis in medical geography. Social Science & Medicine 1996, 42(6):843-855. 5. Parson RL, Frost JD: Interactive analysis of spatial subsurface data using GIS-based tool. Journal of Computing in Civil Engineering 2000, 14(4):215-222. 6. Gilberg K, Laouri M, Wade S, Isonaka S: Analysis of medication use patterns:apparent overuse of antibiotics and underuse of prescription drugs for asthma, depression, and CHF. J Manag Care Pharm 2003, 9(3):232-237. 7. Jia H, Ried LD, Wang X, Damush TM, Young LJ, Cameon RH, Williams LS: Geographic variation in poststroke depression among veterans with acute stroke. J Rehabil Res Dev 2008, 45(7):1027-1035. 8. Mathur AK, Ashby VB, Sands RL, Wolfe RA: Geographic variation in end- stage renal disease incidence and access to deceased donor kidney transplantation. Am J Transplant 2010, 10(4 Pt 2):1069-1080. 9. Rezaeian M, Dunn G, St Leger S, Appleby L: Geographical epidemiology, spatial analysis and geographical information systems: a multidisciplinary glossary. J Epidemiol Community Health 2007, 61(2):98-102. 10. Gesler W: The uses of spatial analysis in medical geography: a review. Soc Sci Med 1986, 23(10):963-973. 11. Anselin L: Local Indicators of Spatial Association - Lisa. Geographical Analysis 1995, 27(2):93-115. 12. Emch M, Ali M, Root ED, Yunus M: Spatial and environmental connectivity analysis in a cholera vaccine trial. Soc Sci Med 2009, 68(4):631-637. 13. Paulozzi LJ, Ryan GW: Opioid analgesics and rates of fatal drug poisoning in the United States. Am J Prev Med 2006, 31(6):506-511. 14. Latkin C, Glass GE, Duncan T: Using geographic information systems to assess spatial patterns of drug use, selection bias and attrition among a sample of injection drug users. Drug Alcohol Depend 1998, 50(2):167-175. 15. Wysowski DK, Governale LA, Swann J: Trends in outpatient prescription drug use and related costs in the US - 1998-2003. Pharmacoeconomics 2006, 24(3):233-236. 16. Jackevicius CA, Tu K, Filate WA, Brien SE, Tu JV, Canadian Cardiovascular Outcomes R: Trends in cardiovascular drug utilization and drug expenditures in Canada between 1996 and 2001. Canadian Journal of Cardiology 2003, 19(12):1359-1366. 17. Harris KM, Pastorius CA, Duval S, Harwood E, Henry TD, Carabello BA, Hirsch AT: Practice variation among cardiovascular physicians in management of patients with mitral regurgitation. Am J Cardiol 2009, 103(2):255-261. 18. Kumar A, Fonarow GC, Eagle KA, Hirsch AT, Califf RM, Alberts MJ, Boden WE, Steg PG, Shao M, Bhatt DL, et al: Regional and practice variation in adherence to guideline recommendations for secondary and primary prevention among outpatients with atherothrombosis or risk factors in the United States: a report from the REACH Registry. Crit Pathw Cardiol 2009, 8(3):104-111. 19. Laskey W, Spence N, Zhao X, Mayo R, Taylor R, Cannon CP, Hernandez AF, Peterson ED, Fonarow GC: Regional differences in quality of care and outcomes for the treatment of acute coronary syndromes: an analysis Page 8 of 9 from the get with the guidelines coronary artery disease program. Crit Pathw Cardiol 2010, 9(1):1-7. 20. Levin S, Welch VL, Bell RA, Casper ML: Geographic variation in cardiovascular disease risk factors among American Indians and comparisons with the corresponding state populations. Ethn Health 2002, 7(1):57-67. 21. O’Connor GT, Quinton HB, Traven ND, Ramunno LD, Dodds TA, Marciniak TA, Wennberg JE: Geographic variation in the treatment of acute myocardial infarction: the Cooperative Cardiovascular Project. JAMA 1999, 281(7):627-633. 22. Baldwin LM, MacLehose RF, Hart LG, Beaver SK, Every N, Chan L: Quality of care for acute myocardial infarction in rural and urban US hospitals. Journal of Rural Health 2004, 20(2):99-108. 23. Lin TL, Yang YHK, Tang CH, Wu HM, Cheng HW: Impact of introduction of angiotensin II antagonist on the anti hypertensive utilization in Taiwan. Journal of Food and Drug Analysis 2008, 16(4):21-29. 24. Dai CL, Chu HF, Lin HD, Ng YY, Wu SC: Use of angiotensin converting enzyme inhibitors and angiotensin II receptor blockers in patients with type 2 diabetic chronic kidney disease. Taiwan Journal of Public Health 2007, 26:7. 25. National Health Insurance Research Database. [http://w3.nhri.org.tw/ nhird/en/Background.html]. 26. Hsiao FY, Yang CL, Huang YT, Huang WF: Using Taiwan’s national health insurance research databases for pharmacoepidemiology research. Journal of Food and Drug Analysis 2007, 15(2):99-108. 27. Statistical Yearbook of Interior. [http://www.moi.gov.tw/english/index. aspx]. 28. Library information management. [http://gis.ascc.net/NDASupport/index-2. html]. 29. Anselin L, Florax RJGM: New directions in spatial econometrics. Berlin; New York: Springer; 1995. 30. Anselin L, Syabri I, Kho Y: GeoDa: An introduction to spatial data analysis. Geographical Analysis 2006, 38(1):5-22. 31. Chadha SL, Gopinath N, Shekhawat S: Urban-rural differences in the prevalence of coronary heart disease and its risk factors in Delhi. Bull World Health Organ 1997, 75(1):31-38. 32. Liu Z, Albanese E, Li S, Huang Y, Ferri CP, Yan F, Sousa R, Dang W, Prince M: Chronic disease prevalence and care among the elderly in urban and rural Beijing, China - a 10/66 Dementia Research Group cross-sectional survey. BMC Public Health 2009, 9:394. 33. Weeks WB, Wallace AE, Wang S, Lee A, Kazis LE: Rural-urban disparities in health-related quality of life within disease categories of veterans. Journal of Rural Health 2006, 22(3):204-211. 34. Pan WH, Chang HY, Yeh WT, Hsiao SY, Hung YT: Prevalence, awareness, treatment and control of hypertension in Taiwan: results of Nutrition and Health Survey in Taiwan (NAHSIT) 1993-1996. Journal of Human Hypertension 2001, 15(11):793-798. 35. Sheikh K, Bullock C: Urban-rural differences in the quality of care for Medicare patients with acute myocardial infarction. Archives of Internal Medicine 2001, 161(5):737-743. 36. Gornick ME, Eggers PW, Reilly TW, Mentnech RM, Fitterman LK, Kucken LE, Vladeck BC: Effects of race and income on mortality and use of services among Medicare beneficiaries. New England Journal of Medicine 1996, 335(11):791-799. 37. Chan L, Hart LG, Goodman DC: Geographic access to health care for rural medicare beneficiaries. Journal of Rural Health 2006, 22(2):140-146. 38. Chen CL, Chen LW, Yang WC: The influences of Taiwan’s generic grouping price policy on drug prices and expenditures: Evidence from analysing the consumption of the three most-used classes of cardiovascular drugs. BMC Public Health 2008, 8. 39. Chaix B, Boelle PY, Guilbert P, Chauvin P: Area-level determinants of specialty care utilization in France: a multilevel analysis. Public Health 2005, 119(2):97-104. 40. Chin MH, Friedmann PD, Cassel CK, Lang RM: Differences in generalist and specialist physicians’ knowledge and use of angiotensin-converting enzyme inhibitors for congestive heart failure. Journal of General Internal Medicine 1997, 12(9):523-530. 41. Edep ME, Shah NB, Tateo IM, Massie BM: Differences between primary care physicians and cardiologists in management of congestive heart