Finally, multivariate linear regression analysis indicated that the following variables were independently associated with the total expenditure in the first ARV treatment year: CD4 cell count (100-199 cells/μL versus <100 cells/μL: P = 0.02; and ≥200 cells/μL versus <100 cells/μL: P < 0.004), residence in Mangshi (P < 0.0001), ADE incidence (P = 0.04) and OI incidence (P = 0.02; Table 5). This evidence concerns the gene CD4 and osteogenesis imperfecta.