Cohort studies: to what extent can they inform treatment guidelines?

Development and application of a new measure of engagement in out-patient HIV care

OBJECTIVES

Commonly used measures of engagement in HIV care do not take into account that the frequency of attendance is related to changes in treatment and health status. This study developed a new measure of engagement in care (EIC) incorporating clinical factors.

METHODS

We conducted semi-structured interviews with eight HIV physicians to identify factors associated with the timing of patients' next scheduled appointments. These factors informed the development of an algorithm to classify each month of follow-up as "in care" (on or before the time of the next expected attendance) or "out of care" (after the time of the next expected attendance). The EIC algorithm was applied to data from the UK Collaborative HIV Cohort (UK CHIC) study, a large clinical cohort study.

RESULTS

The interviews indicated that time to next appointment varied depending on psychosocial and physical comorbidities, and clinical factors (time since diagnosis, AIDS diagnosis, treatment status, CD4 count and viral load). The resulting EIC algorithm was applied to 44 432 patients; 83.9% of the 3 021 224 person-months were "in care". Greater EIC was independently associated with older age, white ethnicity, HIV acquisition through sex between men, current use of antiretroviral therapy (ART), a higher nadir CD4 count, later calendar year and being seen at the clinic for the first time within the last year.

CONCLUSIONS

This algorithm describing engagement in HIV care incorporates a time-updated measure of patients' treatment and health status. It adds to the options available for measuring this key performance indicator.

REACH: a mixed-methods study to investigate the measurement, prediction and improvement of retention and engagement in outpatient HIV care

Background

Antiretroviral therapy (ART) benefits individuals living with human immunodeficiency virus (HIV) through reduced morbidity and mortality, and brings public health gains through a reduction in HIV transmission. People living with human immunodeficiency virus (PLWH) need to know their HIV status and engage in HIV care in order for these individual and public health benefits to be realised.

Objective

To explore, describe and understand HIV outpatient attendance in PLWH, in order to develop cost-effective interventions to optimise engagement in care.

Design

A mixed-methods study incorporating secondary analysis of data from the UK Collaborative HIV Cohort (UK CHIC) study and primary data collection.

Methods

Phase 1 – an engagement-in-care (EIC) algorithm was developed to categorise patients as in care or out of care for each month of follow-up. The algorithm was used in group-based trajectory analysis to examine patterns of attendance over time and of the association between the proportion of months in care before ART initiation and post-ART mortality and laboratory test costs. Phase 2 – a cross-sectional survey was conducted among patients attending seven London HIV clinics. Regular attenders (all appointments attended in past year), irregular attenders (one or more appointments missed in past year) and non-attenders (recent absence of ≥ 1 year) were recruited. A ‘retention risk tool’ was developed to identify those at risk of disengaging from care. Individual in-depth interviews and focus groups were conducted with PLWH. Phase 3 – key informant interviews were conducted with HIV service providers. Interventions were developed from the findings of phases 2 and 3.

Results

Plots from group-based trajectory analysis indicated that four trajectories best fitted the data. Higher EIC is associated with reduced mortality but the association between EIC before starting ART, and post-ART mortality [relative hazard (RH) per 10% increase in EIC 0.29, 95% confidence interval (CI) 0.18 to 0.47] was attenuated after adjustment for fixed covariates and post-ART cluster of differentiation 4 counts and viral loads (RH 0.74, 95% CI 0.42 to 1.30). Small differences were found in pre-ART EIC and the costs of post-ART lab tests. The final model for the retention risk tool included age at diagnosis, having children, recreational drug use, drug/alcohol dependency, insufficient money for basic needs and use of public transport to get to the clinic. Quantitative and qualitative data showed that a range of psychological, social and economic issues were associated with disengagement from care. The negative impact of stigma on attendance was highlighted. Interventions were proposed that support a holistic approach to care including peer support, address stigma by holding clinics in alternative locations and involve training staff to encourage attendance.

Conclusions

The study shows the adverse health impacts of disengaging from HIV care and demonstrates the importance of the wider health and social context in managing HIV effectively. Although phase 1 analysis was based on UK data, phases 2 and 3 were limited to London. The interventions proposed are supported by the data but their cost-effectiveness requires testing. Future research is needed to evaluate the interventions, to validate our retention risk tool across populations and settings, and to fully analyse the economic costs of disengaging from HIV care.

Funding

The National Institute for Health Research Health Services and Delivery Research programme. The UK CHIC study is funded by the Medical Research Council UK (grant numbers G0000199, G0600337, G0900274 and M004236).

Clinical and Virologic Outcomes After Changes in First Antiretroviral Regimen at 7 Sites in the Caribbean, Central and South America Network

BACKGROUND

HIV-infected persons in resource-limited settings may experience high rates of antiretroviral therapy (ART) change, particularly because of toxicity or other nonfailure reasons. Few reports address patient outcomes after these modifications.

METHODS

HIV-infected adults from the 7 Caribbean, Central and South America network clinical cohorts who modified >1 drug from the first ART regimen (ART-1) for any reason thereby starting a second regimen (ART-2) were included. We assessed cumulative incidence of, and factors associated with, death, virologic failure (VF), and regimen change after starting ART-2.

RESULTS

Five thousand five hundred sixty-five ART-naive highly active ART initiators started ART-2 after a median of 9.8 months on ART-1; 39% changed to ART-2 because of toxicity and 11% because of failure. Median follow-up after starting ART-2 was 2.9 years; 45% subsequently modified ART-2. Cumulative incidences of death at 1, 3, and 5 years after starting ART-2 were 5.1%, 8.4%, and 10.5%, respectively. In adjusted analyses, death was associated with older age, clinical AIDS, lower CD4 at ART-2 start, earlier calendar year, and starting ART-2 because of toxicity (adjusted hazard ratio = 1.5 vs. failure, 95% confidence interval: 1.0 to 2.1). Cumulative incidences of VF after 1, 3, and 5 years were 9%, 19%, and 25%. In adjusted analyses, VF was associated with younger age, earlier calendar year, lower CD4 at the start of ART-2, and starting ART-2 because of failure (adjusted hazard ratio = 2.1 vs. toxicity, 95% confidence interval: 1.5 to 2.8).

CONCLUSIONS

Among patients modifying the first ART regimen, risks of subsequent modifications, mortality, and virologic failure were high. Access to improved antiretrovirals in the region is needed to improve initial treatment success.

Virologic and immunologic outcome of HAART in Human Immunodeficiency Virus (HIV)-1 infected patients with and without tuberculosis (TB) and latent TB infection (LTBI) in Addis Ababa, Ethiopia

BACKGROUND

HIV/TB coinfection remains a major challenge even after the initiation of HAART. Little is known about Mycobacterium tuberculosis (Mtb) specific immune restoration in relation to immunologic and virologic outcomes after long-term HAART during co-infections with latent and active TB.

METHODS

A total of 232 adults, including 59 HIV patients with clinical TB (HIV + TB+), 125 HIV patients without clinical TB (HIV + TB-), 13 HIV negative active TB patients (HIV-TB+), and 10 HIV negative Tuberculin Skin TST positive (HIV-TST+), and 25 HIV-TST- individuals were recruited. HAART was initiated in 113 HIV + patients (28 TB + and 85 TB-), and anti-TB treatment for all TB cases. CD4+ T-cell count, HIV RNA load, and IFN-γ responses to ESAT-6/CFP-10 were measured at baseline, 6 months (M6), 18 months (M18) and 24 months (M24) after HAART initiation.

RESULTS

The majority of HIV + TB- (70%, 81%, 84%) as well as HIV + TB + patients (60%, 77%, 80%) had virologic success (HIV RNA < 50 copies/ml) by M6, M18 and M24, respectively. HAART also significantly increased CD4+ T-cell counts at 2 years in HIV + TB + (from 110.3 to 289.9 cells/μl), HIV + TB- patients (197.8 to 332.3 cells/μl), HIV + TST- (199 to 347 cells/μl) and HIV + TST + individuals (195 to 319 cells/μl). Overall, there was no significant difference in the percentage of patients that achieved virologic success and in total CD4+ counts increased between HIV patients with and without TB or LTBI. The Mtb specific IFN-γ response at baseline was significantly lower in HIV + TB + (3.6 pg/ml) compared to HIV-TB + patients (34.4 pg/ml) and HIV + TST + (46.3 pg/ml) individuals; and in HIV-TB + patients compared to HIV-TST + individuals (491.2 pg/ml). By M18 on HAART, the IFN-γ response remained impaired in HIV + TB + patients (18.1 pg/ml) while it normalized in HIV + TST + individuals (from 46.3 to 414.2 pg/ml).

CONCLUSIONS

Our data show that clinical and latent TB infections do not influence virologic and immunologic outcomes of ART in HIV patients. Despite this, HAART was unable to restore optimal TB responsiveness as measured by Mtb specific IFN-γ response in HIV/TB patients. Improvement of Mtb-specific immune restoration should be the focus of future therapeutic strategies.

Prospective observational study comparing three different treatment regimes in patients with Clostridium difficile infection

In a hospital-based, prospective cohort study, the effects of the three standard treatment regimens for mild Clostridium difficile infection (CDI), oral (p.o.) metronidazole at 500 mg three times/day, intravenous (i.v.) metronidazole at 500 mg three times/day, and oral (p.o.) vancomycin at 250 mg four times/day, were compared with respect to the risk of occurrence of complications, sequelae, and all-cause death within 30 days after the date of starting treatment. Differences in the incidence of these outcomes were tested by χ² or Fisher's exact tests. A Poisson regression model was performed to control for possible confounding effects of sex, age, and severity of comorbidity categorized according to the Charlson comorbidity index. The highest mortality was observed in the metronidazole i.v. group, with a mortality rate 38.1% (16/42) compared to mortality rates of 7.4% (9/121) in the metronidazole p.o. group and 9.5% (4/42) in the vancomycin p.o. group (P < 0.001). After adjustment for possible effects of sex, age (> 65 years), and severity of comorbidity, the relative risk of a 30-day fatal outcome for patients receiving metronidazole i.v. was 4.3 (95% confidence interval [CI] = 1.92 to 10; P < 0.0001) compared to patients treated with metronidazole p.o. and 4.0 (95% CI = 1.31 to 5.0; P < 0.015) compared to patients treated with vancomycin p.o. There were no significant differences in the risk of complications between the three treatment groups. This study generates the hypothesis that treatment with i.v. metronidazole is inferior to the oral alternatives metronidazole and vancomycin.