Wang et al. BMC Public Health 2011, 11:955 http://www.biomedcentral.com/1471-2458/11/955 Table 1 STD/HIV infection by Provinces Syphilis N.gonorrhoea C. trachomatis HIV Overall 10.7 (315/2951) 4.3 (88/2041) 6.9 (140/2041) 0.7 (21/2951) Jiangsu 19.4 (202/1041) 8 (58/725) 5.9 (43/725) 0.6(6/1041) Guangxi 6 (47/788) 2.1(11/533) 6.9 (37/533) 1.8(14/788) Guangdong 8.9 (35/394) 4.1 (15/364) 8.2 (30/364) 0(0/394) Page 4 of 8 Hainan 4.3 (31/729) 1 (4/419) 7.2(30/419) 0.1 (1/729) The feasibility of providers-initiated HIV testing A total of 3243 eligible attendees were screened in clinics. With informed consent, 2951(91.0%) patients agreed to provide blood for HIV and syphilis testing and were included in the final analysis. Twenty-one (0.7%) were confirmed to be HIV positive and were managed either in the investigating clinics with help from the local CDC or were referred to specialized hospitals for HIV management. HIV/STD associated risk factors An extremely low proportion (6.2%, 182/2933) of the participants had ever received HIV testing and counsel- ing. Of the 21 HIV positive patients, 66.7% (14) reported no STD-related symptoms in the last year. Most of the HIV positive patients were from the Guangxi and Table 2 Demographic Characteristics of Population Tested (N = 2951) % (No.) or Mean With Range Characteristics Median age (range), in years Ethnicity Han Others Education Level Primary school equivalent or less Middle school High school junior college Marital status Single Married Divorced/Widowed Living Arrangement Status Residency Living alone Living with spouse Cohabited with other female Living with male Living with family/others Local city Local province(not local city) Other province 34.8 (18-88) 96.5 (2828/2932) 3.5 (104/2932) 11.5 (338/2944) 44.5(1309/2944) 28.6(843/2944) 15.4(454/2944) 28.4 (835/2937) 68.7 (2014/2937) 3.0 (88/2937) 15.1 (445/2939) 60.9 (1789/2939) 3.2 (93/2939) 5.5 (163/2939) 15.2 (449/2939) 77.5 (2247/2899) 9.0 (260/2899) 13.5 (392/2899) Jiangsu Provinces. Fourteen (66.7%) of the HIV positive patients were married and 12 lived with their spouses, none used condoms consistently. Six patients had visited FSWs in the past 3 months and none had used condoms in their last sex encounters. One HIV positive patient had casual sex with a woman other than a FSW in the past 3 months. In univariate logistic regression analyses, the following participant characteristics were significantly associated with HIV infection: being from the Guangxi province, age ≥ 40 years, lower education level (elementary school or illiterate), being homosexual/bisexual, and IDU. Multi- variate logistic regression analyses showed that factors strongly associated with HIV infection were: investigation site (patients from Guangxi Province, AOR, 12.3, 95% CI, 1.5-97.4), being homosexual/bisexual (AOR, 16.9, 95% CI, 3.2-90.6) and IDU (AOR, 19.1, 95% CI, 2.1-176.1) (Table 4). For the combination of the 3 STDs (syphilis, C. tracho- matis and N. gonorrhoeae), our multivariable logistic regression suggested that investigation site, older age, lower education level, unsafe sex with a FSW (defined as visiting a FSW in the past 3 months and no condom use in their last sexual encounter), and unsafe sex with a non- FSW casual sex partner (defined as having a non-FSW casual sex partner in the past 3 months and no condom use in their last sexual encounter) were independent risks factors (Table 4). Discussion This large-scale cross-sectional study using identical laboratory methods among different areas in China demonstrates a high prevalence of STDs in patients attending STD clinics. Overall prevalence rates of syphi- lis, N. gonorrhoeae, C. trachomatis and HIV were 10.7%, 4.3%, 6.9% and 0.7% respectively. After decades of exceedingly low STD rates in China, STDs had become widely-spread through commercial sex work and bridging populations. Syphilis prevalence is much higher than N. gonorrhoeae prevalence. This result is consistent with national surveillance data on STD infection. During the past decades, the incidence rate of gonorrhea had declined while the syphilis incidence rate increased dra- matically [2,21,22]. This might be attributed to the rela- tive ease of detection and treatment of gonorrhea. Meanwhile, under-reporting of gonorrhea cases by health