Research Article: Loss to Followup in HIV-Infected Patients from Asia-Pacific Region: Results from TAHOD

Date Published: February 22, 2012

Publisher: Hindawi Publishing Corporation

Author(s): Jialun Zhou, Junko Tanuma, Romanee Chaiwarith, Christopher K. C. Lee, Matthew G. Law, Nagalingeswaran Kumarasamy, Praphan Phanuphak, Yi-Ming A. Chen, Sasisopin Kiertiburanakul, Fujie Zhang, Saphonn Vonthanak, Rossana Ditangco, Sanjay Pujari, Jun Yong Choi, Tuti Parwati Merati, Evy Yunihastuti, Patrick C. K. Li, Adeeba Kamarulzaman, Van Kinh Nguyen, Thi Thanh Thuy Pham, Poh Lian Lim.


This study examined characteristics of HIV-infected patients in the TREAT Asia HIV Observational Database who were lost to follow-up (LTFU) from treatment and care. Time from last clinic visit to 31 March 2009 was analysed to determine the interval that best classified LTFU. Patients defined as LTFU were then categorised into permanently LTFU (never returned) and temporary LTFU (re-entered later), and these groups compared. A total of 3626 patients were included (71% male). No clinic visits for 180 days was the best-performing LTFU definition (sensitivity 90.6%, specificity 92.3%). During 7697 person-years of follow-up, 1648 episodes of LFTU were recorded (21.4 per 100-person-years). Patients LFTU were younger (P = 0.002), had HIV viral load ≥500 copies/mL or missing (P = 0.021), had shorter history of HIV infection (P = 0.048), and received no, single- or double-antiretroviral therapy, or a triple-drug regimen containing a protease inhibitor (P < 0.001). 48% of patients LTFU never returned. These patients were more likely to have low or missing haemoglobin (P < 0.001), missing recent HIV viral load (P < 0.001), negative hepatitis C test (P = 0.025), and previous temporary LTFU episodes (P < 0.001). Our analyses suggest that patients not seen at a clinic for 180 days are at high risk of permanent LTFU, and should be aggressively traced.

Partial Text

Loss to followup (LTFU) in patients receiving antiretroviral therapy can cause serious consequences such as discontinuation of treatment and increased risk of death [1–3]. At a program level, LTFU can make it difficult to evaluate outcomes of treatment and care [4, 5]. In resource-limited settings, where treatment has become rapidly available following the rollout of antiretroviral therapy, LTFU presents even more challenging obstacles that require special consideration and approaches [6, 7].

Established in 2003, TAHOD is a collaborative observational cohort study involving 18 sites in the Asia-Pacific region (see Acknowledgement). Detailed methods have been published previously [17]. Briefly, each site recruited approximately 200–300 HIV-infected patients, with recruitment based on a consecutive series of patients regularly attending a given site from a particular start-up time. Ethical approval for the study was obtained from the University of New South Wales Ethics Committee, Western Institutional Review Board, and respective local ethics committee from each TAHOD participating site.

In March 2007, there were 2565 patients in the database. 1061 patients were subsequently enrolled in TAHOD up to March 2010. A total of 3626 patients from TAHOD who had follow-up visits in the clinic were included in this analysis. During the study period (from March 2007 to March 2010), there were 54 patients who died and considered to have complete followup.

We found that an interval of 180 days between clinic visits was the best-performing definition of LTFU based on sensitivity and specificity in identifying true LTFU. By this definition, we observed that approximately one in five patients in our cohort would miss clinic visits for more than 180 days and so become defined as LTFU. Among these patients in our cohort close to half eventually returned to followup, with half becoming truly lost to HIV-related treatment and care.

With rapid scaleup of antiretroviral treatment, it is essential to study factors that predict loss to followup and identify patients at risk of loss to treatment and care, particularly in resource-limited settings. At the treatment and care level, this can maintain efficacy of antiretroviral therapy and avoid adverse events. At the program evaluation level, the impact of loss to followup on overall treatment outcome, disease progression, and survival can then be accounted for with appropriate statistical adjustments. Collaboration with HIV treatment programs in other regions in studies on LTFU and in particular standardisation of LTFU definitions are essential for reporting and program evaluation.