A measurement strategy to obtain the right information from the right people at the right time is necessary. A comprehensive patient outcome ascertainment would require tremendous resources at a population level, therefore, a sampling-based approach of representative patients presents a feasible and affordable way to ascertain outcomes of HIV lost-to-follow-up (LTFU) patient.

The true clinical outcomes in a random, but numerically small, sample of patients lost-to-follow-up (LTFU) can be found through patient tracking in the community. These outcomes in a small but representative sample can provide an efficient and unbiased estimate in all patients. Once incorporated into survival analysis through a probability weight [6], this approach can be used to correct estimates of mortality, retention in care, and identify epidemiologically valid determinants of important patient outcomes. Indeed, the measurement of outcomes is the simple biggest barrier to the roll-out of valid epidemiology. Without outcomes, the use of patient and clinic factors is limited to cross-sectional and descriptive estimates.

Drawing from HIV clinics in East Africa where a sampling-based approach was applied, CIDRZ conducted the Bill & Melinda Gates Foundation-funded Better Information for Health in Zambia (BetterInfo) study from 2015 - 2016 to better understand the outcomes of 5000 patients who were considered LTFU and to identify the drivers for their engagement or disengagement from HIV care in 30 randomly sampled public health facilities across Lusaka, Southern, Eastern and Western Provinces of Zambia. See Annex 1: BetterInfo Protocol.

The BetterInfo study was implemented in public-health facilities where CIDRZ has been implementing its key activities in HIV/AIDS, Tuberculosis, and health systems strengthening. BetterInfo employed a sampling-based survey methodology with all research participants and collected blood specimens from a sub-sample of patients in Lusaka province where the CIDRZ laboratory is located. See Annex 2: STATA Code for Sampling and Analysis and Annex 3: Blood Sample Collection.

 Before participating in the research study, participants were given sufficient information about the BetterInfo study including risks and benefits in the language they understood. Those who voluntarily decided to take part in the study were requested to give consent through a written informed consent process and to sign an Informed Consent Form. See Annex 4: Informed Consent Form. Every effort was made by the BetterInfo study staff to keep research participant information confidential and private.

During implementation of BetterInfo, various barriers and facilitators were encountered, therefore if this sampling-based approach is adopted it would be important to learn the lessons herein and strategies for data management and quality control. See Annex 5: Key Implementation Advice and Annex 6: Data Management and Quality Control.