RESUMEN
Objective: To explore the causes of secondary drug resistance among HIV infected persons who were receiving antiretroviral therapy in Shandong province, and provide evidence for the improvement of antiretroviral therapy strategy. Methods: A case-control study was designed with 1∶2 matching on case and control groups. Household and face-to-face interview were conducted in October, 2015. All the study subjects were screened from both the drug resistant database of antiretroviral therapy of Shandong provincial laboratory and national comprehensive HIV/AIDS database in Shandong. The sample size was estimated as 330 cases including 110 drug resistant and 220 non-drug resistant cases. Subjects were people living with HIV/AIDS (PLWHA) aged 15 or older and received antiretroviral therapy for more than 6 months with records of virus load (VL). Subjects who presented VL above 1 000 copies/ml would receive drug resistance testing. Subjects who were confirmed resistant to with secondary drug, were selected as case group, the rest subjects with non-secondary drug resistance would form the control group. EpiData 3.1 software and SPSS 22.0 software were used to establish a database. Related influencing factors were analyzed with non- conditional stepwise logistic regression model. Results: A total of 288 cases were enrolled, including 103 in the case and 185 cases in the control groups, with average age as (37.62±1.06) years and (37.90±0.74) years old, respectively. Most of them were male, married/cohabitant, with education level of junior/senior high school or below and under Han nationality. Results from the multivariate logistic regression model showed that ORs (95%CI) of receiving antiretroviral therapy for 1-3 years, or more than 3 years were equal to 8.80 (3.69-21.00), 3.00 (1.20-7.53), compared with receiving antiretroviral therapy less than one year, respectively. OR (95%CI) of Among the PLWHA that with missing rate above 25.0% on medication, the OR appeared as 15.41(4.59-51.71), compared with not missing medication. OR (95%CI) among those who took the medicine themselves was 0.22 (0.07-0.74). Conclusions: Factors as duration of treatment, missing rate on medication and taking medicine by oneself were of influence on secondary drug resistance. Other factors as duration on antiretroviral therapy longer than 1 year, missing rate above 25.0% on medication, were related to the risk on secondary drug resistance. However, if the medicine was taken by oneself, it served as a protective factor for secondary drug resistance. It is necessary to strengthen the intervention and health education programs related to antiretroviral therapy.