January 2010, Vol. 39 No. 1 9 Thrombocytopenia—Shih-Wei Lai et al Original Article Abstract Introduction: The objective of this study was to explore the association between thrombo- cytopenia and its related factors. Materials and Methods: This was a hospital-based, cross- sectional study. We retrospectively analysed the medical records of all patients who received periodic health examinations at a medical centre located at Taichung in Taiwan between 2000 and 2004. In all, 5585 subjects were included for further analysis. A complete physical exami- nation, laboratory survey and abdominal ultrasonography were performed on each subject. The t-test, chi-square test and multivariate logistic regression analysis were used. Results: The subjects consisted of 3123 men (55.9%) and 2462 women (44.1%). The mean age was 49.4 ± 12.3 years (range, 20 to 87). The overall prevalence of thrombocytopenia was found to be 0.5%, higher in men than in women (0.6% vs 0.4%, P = 0.504). After controlling for the other covari- ates, multivariate logistic regression analysis exhibited that the factors significantly related to thrombocytopenia were increasing age (OR, 1.04; 95% CI, 1.004-1.08), anti-HCV positive (OR, 5.24; 95% CI, 2.08-13.20), liver cirrhosis (OR, 7.93; 95% CI, 2.28-27.62), and splenomegaly (OR, 18.86; 95% CI, 6.86-51.87). Conclusion: It is advisable to further check the hepatic status, if thrombocytopenia is noted. Ann Acad Med Singapore 2010;39:9-12 Key words: Hepatitis C, Liver cirrhosis, Splenomegaly, Thrombocytopenia 1 Department of Family Medicine, China Medical University Hospital, Taichung City, Taiwan 2 Department of Family Medicine, Jen-Ai Clinic, Taichung County, Taiwan 3 Department of Internal Medicine, China Medical University Hospital, Taichung City, Taiwan 4 Department of Internal Medicine, Puli Christian Hospital, Nantou County, Taiwan 5 Department of Family Medicine, Private Clinic, Taichung City, Taiwan Address for Correspondence: Dr Kuan-Fu Liao, Department of Internal Medicine, Puli Christian Hospital, No. 1, Tieshan Road, Puli, Nantou County, 545 Taiwan Email: kuanfuliao@yahoo.com.tw Thrombocytopenia and its Related Factors: A Hospital-based, Cross-sectional Study Shih-Wei Lai, 1 MD, Ching-Yi Huang, 2 MD, Hsueh-Chou Lai, 3 MD, Kuan-Fu Liao, 4 MD, Yen-Miao Lai, 5 MD, Chiu-Shong Liu, 1 MD, Tsann Lin, 1 MD, PhD Introduction Thrombocytopenia is a common clinical problem found in laboratory results during health examinations. Blood platelets play an essential role in haemostasis, thrombosis and coagulation of blood. 1 Platelets are the smallest units of blood cells. They are formed in the bone marrow by the fragmentation of megakaryocyte cytoplasm. 2 The normal platelet concentration in adult ranges from 150,000 to 450,000//μL. 3 They circulate in the blood for 8 to 12 days. 1,2 Bleeding time is generally not prolonged until the platelet count is below 100,000/μL. 4 However, as long as platelet counts are more than 20,000/μL, clinical manifestations may be mild, often limited to easy bruising. 4 If less than 10,000/ μL, the risk of spontaneous mucocutaneous bleeding, intracranial haemorrhage or gastrointestinal bleeding increases markedly. 2,4 A previous study revealed that thrombopoietin, a ligand for the receptor encoded by protooncogene c-mpl, may play an important role in the regulation of megakaryocyte development and platelet production. 5 The production of thrombopoietin is mainly from the liver. 6 In Streiff et al’s study, patients with hepatitis C infection are more likely to have low platelet counts. 7 The hepatitis virus principally replicates in the liver and its cardinal manifestation is progression to chronic liver disease. A decreased production of thrombopoietin in patients with chronic liver disease can result in deficient platelet production by the bone marrow. 8,9 In Taiwan, hepatitis B and hepatitis C infections are hyperendemic, which may lead to liver cirrhosis, and even hepatocellular carcinoma, after many years. We hypothesise a link between the 2 conditions, that patients infected with viral hepatitis may have a higher frequency of thrombocytopenia. To date, there is little evidence of a relationship between thrombocytopenia and its related factors in Taiwan. This study analysed data collected from a medical centre in Taiwan to explore the following questions: (i) what is the prevalence of thrombocytopenia? (ii) what are the related factors of thrombocytopenia?