Size Estimation of Most-at-Risk Groups of HIV/AIDS Using Network Scale-up in Tabriz, Iran

Abstract

Purpose: To begin to manage a serious health problem like AIDS, it is crucial that we know the size of the subpopulation related to the problem. In this study we used Network scale-up method (NSUM), an indirect method of size estimation of hard-to-reach subpopulation, to estimate most at risk population (MARPs) of Tabriz. Methods: Having adapted a purposive sampling, we interviewed 500 people of target population. To estimate the size of social network (C), we used known population method through collecting data of 29 known sub-groups. To estimate most at-risk populations, we applied frequency approach of NSUM. Adjustments were done to correct common errors of this method. Results: Among groups at risk due to sexual contact, the greatest frequency was related to clients of female sex workers (CFSWs) with 831 out of 100000 of men’s population (95% CI: 649, 1055), then female sex workers (FSWs) with 709 out of 100000 of women’s population (95% CI: 512, 930). Among groups at risk due to drug use, the biggest frequency belonged to alcoholic substance users with 1136 out of 100000 of total population (95% CI: 955, 1332). After that, it included opium users, crystal users and injecting drug users (IDUs), respectively. Conclusion: Although the estimated number of MARPs in Tabriz is less than other areas, it is necessary to perform preventive programs like harm reduction programs to reduce transmission of AIDS.