[Effect of data missing on population based viral load survey in HIV infected men who have sex with men sampled in 16 large cities, China].

Objective: To analyze the effect of missing data in population based viral load (PVL) survey in HIV infected men who have sex with men (MSM) sampled in 16 cities in China. Methods: The database of 3 virus load sampling survey conducted consecutively in HIV infected MSM population in 16 large cities (Beijing, Shanghai, Nanjing, Hangzhou, Wuhan, Chongqing, Kunming, Xi'an, Guangzhou, Shenzhen, Nanning, Urumuqi, Harbin, Changchun, Chengdu and Tianjin) during 2013-2015 was used. SPSS 17.0 software was used to describe distribution of the missing data and analyze associated factors. Results: A total of 12 150 HIV infected MSM were randomly selected for the surveys, in whom, 9 141 (75.2%) received virus load tests, while 3 009 (24.8%) received no virus load tests, whose virus load data missed. The virus load data missing rates in MSM with or without access to antiretroviral therapy (ART) were 11.5% (765/6 675) and 39.4% (2 060/5 223) respectively, and the virus load data missing rates were 21.9% (1 866/8 523) and 28.4% (959/3 374), respectively, in local residents and non-local residents (migrants). Conclusions: The analysis indicated that the data missing occurred in the virus load survey in HIV infected MSM population. ART status and census registering status were the main influencing factors. Data missing could influence the accurate evaluation of community viral load (CVL) and population viral load(PVL) levels in HIV infected MSM in China.