Contemporary disengagement from antiretroviral therapy in Khayelitsha, South Africa: A cohort study.

BACKGROUND: Retention in care is an essential component of meeting the UNAIDS "90-90-90" HIV treatment targets. In Khayelitsha township (population ~500,000) in Cape Town, South Africa, more than 50,000 patients have received antiretroviral therapy (ART) since the inception of this public-sector program in 2001. Disengagement from care remains an important challenge. We sought to determine the incidence of and risk factors associated with disengagement from care during 2013-2014 and outcomes for those who disengaged. METHODS AND FINDINGS: We conducted a retrospective cohort study of all patients ≥10 years of age who visited 1 of the 13 Khayelitsha ART clinics from 2013-2014 regardless of the date they initiated ART. We described the cumulative incidence of first disengagement (>180 days not attending clinic) between 1 January 2013 and 31 December 2014 using competing risks methods, enabling us to estimate disengagement incidence up to 10 years after ART initiation. We also described risk factors for disengagement based on a Cox proportional hazards model, using multiple imputation for missing data. We ascertained outcomes (death, return to care, hospital admission, other hospital contact, alive but not in care, no information) after disengagement until 30 June 2015 using province-wide health databases and the National Death Registry. Of 39,884 patients meeting our eligibility criteria, the median time on ART to 31 December 2014 was 33.6 months (IQR 12.4-63.2). Of the total study cohort, 592 (1.5%) died in the study period, 1,231 (3.1%) formally transferred out, 987 (2.5%) were silent transfers and visited another Western Cape province clinic within 180 days, 9,005 (22.6%) disengaged, and 28,069 (70.4%) remained in care. Cumulative incidence of disengagement from care was estimated to be 25.1% by 2 years and 50.3% by 5 years on ART. Key factors associated with disengagement (age, male sex, pregnancy at ART start [HR 1.58, 95% CI 1.47-1.69], most recent CD4 count) and retention (ART club membership, baseline CD4) after adjustment were similar to those found in previous studies; however, notably, the higher hazard of disengagement soon after starting ART was no longer present after adjusting for these risk factors. Of the 9,005 who disengaged, the 2 most common initial outcomes were return to ART care after 180 days (33%; n = 2,976) and being alive but not in care in the Western Cape (25%; n = 2,255). After disengagement, a total of 1,459 (16%) patients were hospitalized and 237 (3%) died. The median follow-up from date of disengagement to 30 June 2015 was 16.7 months (IQR 11-22.4). As we included only patient follow-up from 2013-2014 by design in order to maximize the generalizability of our findings to current programs, this limited our ability to more fully describe temporal trends in first disengagement. CONCLUSIONS: Twenty-three percent of ART patients in the large cohort of Khayelitsha, one of the oldest public-sector ART programs in South Africa, disengaged from care at least once in a contemporary 2-year period. Fifty-eight percent of these patients either subsequently returned to care (some "silently") or remained alive without hospitalization, suggesting that many who are considered "lost" actually return to care, and that misclassification of "lost" patients is likely common in similar urban populations. A challenge to meeting ART retention targets is developing, testing, and implementing program designs to target mobile populations and retain them in lifelong care. This should be guided by risk factors for disengagement and improving interlinkage of routine information systems to better support patient care across complex care platforms.

Developing program theory for purveyor programs.

BACKGROUND: Frequently, social interventions produce less for the intended beneficiaries than was initially planned. One possible reason is that ideas embodied in interventions are not self-executing and require careful and systematic translation to put into practice. The capacity of implementers to deliver interventions is thus paramount. Purveyor organizations provide external support to implementers to develop that capacity and to encourage high-fidelity implementation behavior. Literature on the theory underlying this type of program is not plentiful. Research shows that detailed, explicit, and agreed-upon program theory contributes to and encourages high-fidelity implementation behavior. The process of developing and depicting program theory is flexible and leaves the researcher with what might be seen as an overwhelming number of options. METHODS: This study was designed to develop and depict the program theory underlying the support services delivered by a South African purveyor. The purveyor supports seventeen local organizations in delivering a peer education program to young people as an HIV/AIDS prevention intervention. Purposive sampling was employed to identify and select study participants. An iterative process that involved site visits, a desktop review of program documentation, one-on-one unstructured interviews, and a subsequent verification process, was used to develop a comprehensive program logic model. RESULTS: The study resulted in a formalized logic model of how the specific purveyor is supposed to function; that model was accepted by all study participants. CONCLUSION: The study serves as an example of how program theory of a 'real life' program can be developed and depicted. It highlights the strengths and weakness of this evaluation approach, and provides direction and recommendations for future research on programs that employ the purveyor method to disseminate interventions.