Literature review > Issue 7 > Review on Liu et al. 

In the late 1950s China was able to greatly reduce and in most places eradicate STDs [1]. The success in this campaign was inextricably related to local and national support from the nascent People's Republic of China, and concomitant development of a strong and novel public health system [2]. Simple methods were used to detect and treat STDs [2,3]. Unfortunately, this public health success was not permanent. STDs arose as a novel major problem in the 1980s, with inexorable growth of the epidemic every year [4].

In this article Liu and coworkers [5] compared clinical acumen and laboratory tests available in local STD clinics with nucleic acid amplification testing applied to urine of male subjects with urethral discharge and swabs from subjects with ulcers. As would be predicted, some of the results did not agree very well. Physicians also often ignored the results of the local lab tests in their decisions, perhaps because they realized the limits of the assays employed. The only surprise in the results was that the clinic labs "overdiagnosed" chlamydia, using tests that are considerably less sensitive than the "gold-standard" PCR [6]. Overdiagnosis of syphilis in clinics was also observed, but this may reflect small differences in laboratory reagents. It should be noted that overdiagnosis of STDs has also been observed with syndromic management in China [7].

In reporting their results, the authors used a non-traditional approach for consideration of test performance. Typically, the common test parameters - sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) - are calculated for a single test. Indeed, these measures have their greatest relevance when considered in the context of a single test, or combination of tests, applied to each person in a population. In contrast, the reported measures in this article are not applicable to any specific test. Rather, the authors combined any test that was used into a single "clinic laboratory result" and reported test characteristics for that measure. For example, N. gonorrhoeae results represent gram stain in some persons, culture in others, or both. Note that this differs from reporting sensitivity and specificity for gram stain and culture when both tests are obtained in all patients. Thus, the reported results for the combination of tests are not directly interpretable, and must be considered cautiously. Given the multiple clinics and multiple tests, it is highly likely that considerable heterogeneity would be observed if the results for specific tests, and possibly specific clinics, were reported. The findings would also have been supported more strongly if the procedures for shipping and testing at the central laboratory were reported. One explanation of the low specificity of the local laboratory tests would be reduced sensitivity of the PCR at the central laboratory because of inadequate shipping procedures, but we do not have reported evidence for or against this possibility.

The authors recommend better education for physicians and oversight of laboratories, goals that will be difficult to accomplish in the face of a growing crisis in the Chinese public health and medical care [8,9]. Equipment in basic health care facilities and prevention stations, especially those in poor rural areas, are outdated [9] and patient satisfaction is low in both urban and rural areas [10].

This article and other recent studies in China lead us to several conclusions: i) lab testing for individual subjects in some Chinese clinics lacks accuracy; ii) financial remuneration for lab testing in China is a strong and perverse incentive that stimulates excess use of testing; furthermore, the cheaper the test used, the greater the profit; iii) health care providers would likely be well-advised to use syndromic management guided by more credible lab testing employed at the population level to develop "best practice" algorithms.

References:

1. Hu CK, Ye GY, and Chen ST. Control and eradication of syphilis in China. Thesis collection of Beijing Science Conference. 126:167-177, 1964.

2. Horn, J. Away with all pests: An English surgeon in People's China 1954-1969. Monthly Review Press, 1971. 192 pages.

3. Cohen MS, Henderson GE, Hamilton H, Aiello P, Zheng H, Brandt A. Eradication of syphilis in China--Lessons for the 20th century? J Infect Dis. 174(Suppl.2) S223-230, 1996.

4. Chen XS, Gong, XD, Liang, GJ, Zhang, CC. Epidemiological trends of exually transmitted diseases in CHINA. Sex Transm Dis.2000; 27:138-142.

5. Liu, H, Detels, R, Yin, Y, Li, X and Visscher, B. Do STD clinics correctly diagnose STDs? An assessment of STD management in Hefei, China. Int. J STDs and AIDS 2003; 14: 665-671.

6. World Health Organization Regional Office for the Western Pacific. Laboratory tests for the detection of reproductive tract infections. World Health Organization. 1999.

7. Wang Q, Yang P, Zhong M, Wang G. Validation of diagnostic algorithms for syndromic management of sexually transmitted diseases. Chin Med J. 2003;116(2):181-6.

8. Bloom G., Gu X. Health sector reform: lessons from China. Social Science & Medicine. 1997; 45(3): 351-360.

9. Smith, CJ. Modernization and health care in contemporary China. Health & Place. 1998; 4(2): 125-9

10. He S. Reforms and development of rural preventive care network in Hubei Province. China Rural 1ealth Care Administration. 2001; 21(4): 5-8. (In Chinese).

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