Participation in clinical studies among patients infected with HIV-1 in a single treatment centre over 12 years

HIV research trials versus standard clinics for antiretroviral-naïve patients: the outcomes differ but do the patients?

Exclusion criteria for HIV treatment-naïve drug trials can be stringent and selection bias exists, making it difficult to extrapolate results into the 'real world' clinical situation. We aim to compare the demographics, virological outcomes and psychosocial complexity in adult HIV-infected treatment-naïve patients from our cohort initiating combination antiretroviral therapy (cART) in research trials versus standard clinics. In our unit from 2006 to 2011, 1202 standard clinic and 69 research trial patients initiated cART; every eighth standard clinics patient was included to create a standard clinics:research trials patient ratio of 2:1. Notes were retrospectively reviewed for patient demographics, attendance rates and virological outcomes. Data from 221 antiretroviral-naïve patients starting cART were analysed: 152 standard clinic patients and 69 from research trials. In the research trials group, there was an overrepresentation of men (p = 0.041), men who have sex with men (p < 0.001), patients of white ethnicity (p = 0.01), employed patients (p = 0.01) and patients using excessive alcohol (p = 0.02). There was equal representation of drug use, depression and referral to psychology, psychiatry and social work in both groups. The research trials group at baseline had significantly higher CD4 counts (p < 0.001), lower viral loads (p = 0.01) and more patients achieved undetectable viral loads at three (p < 0.001), six (p < 0.001) and 24 months (p = 0.033). There is a prevailing common preconception that participants in clinical trials are uncomplicated, unlike their 'real-life' counterparts. We demonstrated important similarities in psychosocial complexity as well as differences in demographics and virological outcomes in trial and non-trial patients. Clinicians need to be aware of these discrepancies to ensure the facilitation of a heterogeneous population participating in research trials.

Regional variation in HIV clinical trials participation in the United States

OBJECTIVES

To ensure generalizability of clinical research results, it is important to enroll a heterogeneous population that is representative of the target clinical population. Earlier studies have found regional variation in participation in human immunodeficiency virus (HIV) clinical trials, with the lowest rates seen in the southern United States. Rates of new HIV diagnoses are highest in the South, highlighting the need for in-depth understanding of disparities in clinical trial participation. We evaluated whether regional variation in study participation remains, and describe factors that facilitate or prevent HIV clinical trial participation by region.

METHODS

A one-time, anonymous, bilingual, self-administered survey was conducted among HIV-infected adults receiving HIV care at all 47 domestic AIDS Clinical Trials Group clinical research sites, with a goal of completing 50 surveys per site. χ(2) tests were used to evaluate differences in knowledge of and participation in HIV clinical trials by region, including Northeast, Midwest, South, and West regions. Multivariable logistic regression was used to estimate odds ratios and 95% confidence intervals (CIs) for the effect of region on knowledge of and participation in HIV clinical trials.

RESULTS

Of 2263 completed surveys, 2125 were included in this analysis. The proportion of respondents in the South who reported knowledge of studies (66%) was significantly lower than in the Northeast (76%), Midwest (77%), and West (73%) (P = 0.001). Respondents in the South also were the least likely group to report ever having tried to or having participated in a research study (51%) compared with respondents in the Northeast (60%), Midwest (57%), and West (69%; P < 0.001). After adjusting for age, sex, education, race/ethnicity, tobacco use, and alcohol use, the odds ratio for knowledge of and participation in clinical trials for the Northeast (1.36; 95% CI 1.07-1.72) and West (1.85; 95% CI 1.39-2.45) remained significant compared with the South. African American respondents in the South were the most likely population group to report not understanding research studies (15%) as a reason for not participating, compared with the Northeast (9%), Midwest (8%), and West (6%; P < 0.001).

CONCLUSIONS

Significant regional variations in knowledge of and participation in HIV clinical trials exist. Our results suggest that increasing awareness and understanding of research studies, particularly among African Americans in the South, may facilitate HIV clinical trial participation that is more representative of the HIV-infected population across the United States.

Factors associated with past research participation among low-income persons living with HIV

We described influences on past research participation among low-income persons living with HIV (PLWH) and examined whether such influences differed by study type. We analyzed a convenience sample of individuals from a large, urban clinic specializing in treating low-income PLWH. Using a computer-assisted survey, we elicited perceptions of research and participating in research, barriers, benefits, "trigger" influences, and self-efficacy in participating in research. Of 193 participants, we excluded 14 who did not identify any type of study participation, and 17 who identified "other" as study type, resulting in 162 cases for analysis. We compared results among four groups (i.e., 6 comparisons): past medical participants (n=36, 22%), past behavioral participants (n=49, 30%), individuals with no past research participation (n=52, 32%), and persons who had participated in both medical and behavioral studies (n=25, 15%). Data were analyzed using chi-square tests for categorical variables and ANOVA for continuous variables. We employed a multinomial probit (MNP) model to examine the association of multiple factors with the outcome. Confidence in ability to keep appointments, and worry about being a 'guinea pig' showed statistical differences in bivariate analyses. The MNP regression analysis showed differences between and across all 6 comparison groups. Fewer differences were seen across groupings of medical participants, behavioral participants, and those with no past research experience, than in comparisons with the medical-behavioral group. In the MNP regression model 'age' and level of certainty regarding 'keeping yourself from being a guinea pig' showed significant differences between past medical participants and past behavioral participants.

Different baseline characteristics and different outcomes of HIV-infected patients receiving HAART through clinical trials compared with routine care in Mexico

BACKGROUND

The efficacy of antiretroviral therapy (ART) has been established through clinical trials (CTs). However, selection bias and differences can limit their applicability to the general population.

METHODS

All treatment-naive HIV-infected patients who began ART in routine care (RC) between 2000 and 2008 were compared with all patients who initiated ART through a CT in terms of incidence of virological failure (VF), increase in CD4(+) count, mortality rate, and loss to follow-up (LTFU).

RESULTS

At baseline, the RC group had less years of education, higher unemployment rate, higher proportion of females (14.2 vs. 5.7%; P < 0.01), lower median CD4(+) (97 vs. 158 cells/μL; P < 0.01), and lower proportion of patients with hemoglobin >12 g/dL (74 vs. 83%, P = 0.04). VF at week 48 was less frequent in the CT compared with the RC group (1.8% vs. 6.21%, P = 0.02). In multivariate analysis, participation in CT [odds ratio (OR): 0.20, 95% confidence interval (CI): 0.04 to 0.91, P = 0.03], hemoglobin >12 g/dL (OR: 0.29, 95% CI 0.09-0.89, P = 0.03), and receiving an optimal highly active antiretroviral therapy regimen (OR: 0.09, 95% CI: 0.01 to 0.52, P < 0.01) remained associated with lower risk of VF. All cause mortality was 0.017 (95% CI: 0.002 to 0.122) versus 0.094 (95% CI: 0.053 to 0.17) deaths per 1000 person-days in the CT group and in the RC group, respectively (P = 0.05). No differences were found in the proportion of patients LTFU.

CONCLUSIONS

Receiving ART through CT was associated with lower probability of VF, lower mortality (probably related to less severe clinical characteristics at baseline), and similar rates of LTFU than RC.

Determinants of access to experimental antiretroviral drugs in an Italian cohort of patients with HIV: a multilevel analysis

Background

Identification of the determinants of access to investigational drugs is important to promote equity and scientific validity in clinical research. We aimed to analyze factors associated with the use of experimental antiretrovirals in Italy.

Methods

We studied participants in the Italian Cohort of Antiretroviral-Naive Patients (ICoNA). All patients 18 years or older who had started cART (≥ 3 drugs including at least two NRTI) after their enrolment and during 1997-2007 were included in this analysis. We performed a random effect logistic regression analysis to take into account clustering observations within clinical units. The outcome variable was the use of an experimental antiretroviral, defined as an antiretroviral started before commercial availability, in any episode of therapy initiation/change. Use of an experimental antiretroviral obtained through a clinical trial or an expanded access program (EAP) was also analyzed separately.

Results

A total of 9,441 episodes of therapy initiation/change were analyzed in 3,752 patients. 392 episodes (360 patients) involved an experimental antiretroviral. In multivariable analysis, factors associated with the overall use of experimental antiretrovirals were: number of experienced drugs (≥ 8 drugs versus "naive": adjusted odds ratio [AOR] = 3.71) or failed antiretrovirals(3-4 drugs and ≥ 5 drugs versus 0-2 drugs: AOR = 1.42 and 2.38 respectively); calendar year (AOR = 0.80 per year) and plasma HIV-RNA copies/ml at therapy change (≥ 4 log versus < 2 log: AOR = 1.55). The probability of taking an experimental antiretroviral through a trial was significantly lower for patients suffering from liver co-morbidity(AOR = 0.65) and for those who experienced 3-4 drugs (vs naive) (AOR = 0.55), while it increased for multi-treated patients(AOR = 2.60). The probability to start an experimental antiretroviral trough an EAP progressively increased with the increasing number of experienced and of failed drugs and also increased for patients with liver co-morbidity (AOR = 1.44; p = 0.053). and for male homosexuals (vs heterosexuals: AOR = 1.67). Variability of the random effect associated to clinical units was statistically significant (p < 0.001) although no association was found with specific characteristics of clinical unit examined.

Conclusions

Among patients with HIV infection in Italy, access to experimental antiretrovirals seems to be influenced mainly by exhaustion of treatment options and not by socio-demographic factors.

Antiretroviral treatment interruption leads to progression of liver fibrosis in HIV-hepatitis C virus co-infection

OBJECTIVE

Despite potential negative consequences, HIV/hepatitis C virus (HCV) co-infected patients may discontinue antiretroviral treatment (ART) for several reasons. We examined the impact of ART interruption on liver fibrosis progression in co-infected adults, using the aspartate aminotransferase-to-platelet ratio index (APRI) as a surrogate marker of liver fibrosis.

METHOD

Data were analyzed from a multisite prospective cohort of 541 HIV-HCV co-infected adults. ART interruption was included as a time-updated variable and defined as the cessation of all antiretrovirals for at least 14 days. The primary endpoint was the development of an APRI score at least 1.5. Time-dependent Cox proportional hazards regression and inverse probability-of-treatment weighting (IPTW) in a marginal structural model were used to evaluate the association of baseline and time-varying covariates with developing significant fibrosis.

RESULTS

Patients were followed for a median of 1.02 years; 10% (n = 53) interrupted ART and 10% (n = 53) developed significant fibrosis. After accounting for potential confounders, including CD4 T-cell count, HIV viral load, baseline APRI score, age and gender, the hazard ratio for ART interruption was 2.52 (95% confidence interval 1.20-5.28). Use of IPTW resulted in a similar effect estimate, suggesting that mediation by time-varying confounders was negligible.

CONCLUSION

ART interruption was associated with an increased risk of fibrosis progression in HIV-HCV co-infection that was only partially accounted for by HIV viral load and CD4 T-cell counts. Our findings suggest that liver disease progression observed in ART-treated co-infected patients is partly due to the consequences of treatment interruptions.

Recruitment of HIV/AIDS treatment-naïve patients to clinical trials in the highly active antiretroviral therapy era: influence of gender, sexual orientation and race

BACKGROUND

In the USA, women, racial/ethnic minorities and persons who acquire HIV infection through heterosexual intercourse represent an increasing proportion of HIV-infected persons, and yet are frequently underrepresented in clinical trials. We assessed the demographic predictors of trial participation in antiretroviral-naïve patients.

METHODS

Patients were characterized as trial participants if highly active antiretroviral therapy (HAART) was initiated within a clinical trial. Prevalence ratios (PRs) were obtained using binomial regression.

RESULTS

Between 1996 and 2006, 30% of 738 treatment-naïve patients initiated HAART in a clinical trial. Trial participation rates for men who have sex with men (MSM), heterosexual men, and women were respectively 36.5, 29.6 and 24.3%. After adjustment for other factors, heterosexual men appeared less likely to participate in trials compared with MSM [PR 0.79, 95% confidence interval (CI) 0.57, 1.11], while women were as likely to participate as MSM (PR 0.97, 95% CI 0.68, 1.39). The participation rate in Black patients (25.9%) was lower compared with non-Black patients (37.5%) (adjusted PR 0.80, 95% CI 0.60, 1.06).

CONCLUSIONS

In our clinical setting, gender did not appear to impact participation in HIV treatment trials, but Black patients were slightly less likely to participate in these trials. Considering the substantial proportion of HIV-infected patients who are Black, future trials need to consider strategies to incorporate such underrepresented populations.

Comparative efficacy versus effectiveness of initial antiretroviral therapy in clinical trials versus routine care

BACKGROUND

The applicability of clinical trial findings (efficacy) to the routine care setting (effectiveness) may be limited because of study eligibility criteria and volunteer bias. Although well-chronicled in many conditions, the efficacy versus effectiveness of antiretroviral therapy (ART) remains understudied.

METHODS

A retrospective study of the University of Alabama at Birmingham 1917 Clinic Cohort evaluated ART-naive patients who started ART from 1 January 2000 through 31 December 2006. Patients received ART through clinical trials or routine care. Multivariable logistic and linear regression models were fit to evaluate factors associated with virological failure (virological failure was defined as a viral load >50 copies/mL) and change from baseline CD4+ cell count 6 and 12 months after ART initiation. Sensitivity analyses evaluated the impact of missing data on outcomes.

RESULTS

Among 570 patients starting ART during the study period, 121 (21%) enrolled in clinical trials, and 449 (79%) received ART via routine care. ART receipt through routine care was not associated with viral failure at either 6 months (odds ratio [OR], 1.00; 95% confidence interval [CI], 0.54-1.86) or 12 months (OR, 1.56; 95% CI, 0.80-3.05) in primary analyses. No statistically significant differences in CD4+ cell count responses at 6 and 12 months were observed.

CONCLUSIONS

Although marked differences in efficacy versus effectiveness have been observed in the therapeutic outcomes of other conditions, our analyses found no evidence of such divergence among our patients who initiated antiretroviral therapy for human immunodeficiency virus infection.

Determinants of participation in HIV clinical trials: the importance of patients' trust in their provider

PURPOSE

To investigate the factors that contribute to willingness to participate in HIV clinical trials and to determine the impact of a brief intervention on willingness to participate.

METHODS

115 consecutive outpatients receiving HIV primary care participated in this prospective study. Each patient completed a questionnaire about clinical trials and met with a research assistant who discussed the purpose of clinical trials. After the educational intervention, participants completed a second questionnaire and responses from the two surveys were compared.

RESULTS

115 patients were enrolled (56% had previously enrolled in a clinical trial; 50% of whom were currently enrolled in a trial); 92% would consider participating in a future clinical trial. Increased patient trust in the provider was associated with increased willingness to participate in a trial. After the intervention, 94% indicated that they would be willing to be contacted about a clinical trial for which they may be eligible and 85% preferred to be contacted by their primary physician.

CONCLUSIONS

Patients' trust in their provider may predict willingness to participate in clinical trial. Providing HIV-infected patients and their providers with information about HIV clinical trials at the site where they receive care may increase participation rates in HIV clinical trials.

Decisions to participate in research: views of underserved minority drug users with or at risk for HIV

Under-representation of minority populations, particularly African Americans, in HIV/AIDS research is problematic because African Americans bear a greater disease burden from HIV/AIDS. Studies of motivations for participating in research have emphasized factors affecting individuals' willingness to participate and barriers to participation, especially in regard to HIV vaccine research. Little is known about how underserved minority drug users perceive research and their decisions to participate. This study describes African American drug users' perceptions of research participation and their decisions to participate based on three kinds of hypothetical HIV/AIDS-related clinical studies. In-depth, qualitative interviews were conducted with 37 underserved, African American crack cocaine users, recruited from participants already enrolled in three different behavioral HIV prevention studies. Interviews were recorded, transcribed, coded for themes and sub-themes and analyzed using directed and conventional content analysis. Participants' decisions to take part in research often involved multiple motivations for participating. In addition, decisions to participate were characterized by four themes: a desire for information; skepticism and mistrust of research and researchers; perceptions of medical care and monitoring within a study; and participant control in decisions to participate or decline participation. Lack of adequate information and/or medical care and monitoring within a study were related to mistrust, while the provision of information was viewed by some individuals as a right and acknowledgement of the participant's contribution to the study. Participants perceived, rightly or wrongly, that medical monitoring would control some of the risks of a study. Participants also described situations of exerting control over decisions to enter or withdraw from a research study. Preliminary findings suggest that continuous communication and provision of information may enhance enrollment and adherence. Further exploration of decisions to participate in research will add to the understanding of this complex phenomenon and enhance the ability of individuals with HIV/AIDS to benefit from research.

Unmeasured confounding caused slightly better response to HAART within than outside a randomized controlled trial

OBJECTIVE

To compare the outcome of highly active antiretroviral therapy (HAART) in HIV-infected patients initiating equivalent regimens within and outside a randomized controlled trial (RCT).

STUDY DESIGN AND SETTING

The Danish Protease Inhibitor Study (DAPIS) was a national multicenter RCT comparing initial treatment with indinavir, ritonavir, or saquinavir/ritonavir during 96 weeks. From the Danish HIV Cohort Study we identified all patients initiating one of these protease-inhibitor-based HAART regimens: 425 patients within DAPIS and 677 outside the trial. We compared viral load, CD4 count response, and mortality.

RESULTS

At weeks 96 and 240, trial participants were more likely than nonparticipants to have undetectable viral load (adjusted odds ratio [adOR] 1.28 [95% CI=0.94-1.74] and 1.70 [95% CI=1.16-2.50]) and a CD4 increase > or =100 cells/microl (adOR 1.37 [95% CI=1.03-1.82] and 1.53 [95% CI=1.04-2.25]). For antiretroviral-experienced, but not for antiretroviral-naïve patients, trial participants had a lower risk of death (mortality rate ratio [MRR]=0.46 [95% CI=0.27-0.77]) than nonparticipants. This effect was moderated in adjusted analyses (MRR=0.60 [0.33-1.07]).

CONCLUSIONS

Compared to nontrial patients, trial participants had better response to HAART. The differences were small defying the notion that results obtained in RCTs are unachievable in routine clinical practice.

The feasibility of clinical endpoint trials in HIV infection in the highly active antiretroviral treatment (HAART) era

BACKGROUND

Planning clinical-endpoint trials in patients with HIV remain difficult as long-term follow-up of many patients is required. Cohort studies of patients with HIV can provide key estimates of the likely disease progression, required sample size and follow-up.

OBJECTIVES

To verify the assumptions used in designing ESPRIT, a large randomized clinical trial assessing the clinical benefit of interleukin-2 treatment in patients with HIV infection, to use EuroSIDA to mimic the inclusion criterion of ESPRIT in order to compare the observed event rate in ESPRIT with the projected rate in EuroSIDA, and to project the required length of ESPRIT.

METHODS

Patients in EuroSIDA who satisfied the ESPRIT recruitment criteria were selected. Patients were followed from baseline to new AIDS or death.

RESULTS

The incidence of clinical progression in the selected EuroSIDA patients (N = 4482) was 1.5 per 100 PYFU (95% CI 1.3-1.7), and did not increase with increasing time from baseline, contrary to what was assumed in the design of the ESPRIT trial. In ESPRIT (N = 4150), for which the comparative data remain blinded, the incidence was 1.1 per 100 PYFU (95% CI 0.9-1.3), with no increase over time. The average follow-up required to complete ESPRIT and accrue the 320 events required by protocol would be seven years, 10 months using the projected rates from the EuroSIDA study, and seven years, 11 months if the observed event rate in ESPRIT continued unchanged.

LIMITATIONS

Differences between patients recruited to observational studies or clinical trials cannot always be adjusted for.

CONCLUSIONS

Event rates in EuroSIDA were similar in the first two years to those used in the design of ESPRIT, but did not increase over time, leading to an increase in the expected duration of ESPRIT. Clinical endpoint trials in HIV infection remain feasible, and large cohort studies are critical to the planning and ongoing assessment of design assumptions in such trials. The underlying assumptions of the clinical trial should be re-examined to ensure the original trial assumptions remain valid.

Lopinavir/Ritonavir or Efavirenz plus two Nucleoside Analogues as First-Line Antiretroviral Therapy: A Non-Randomized Comparison

Background

Although efavirenz (EFV) and lopinavir/ritonavir (LPV/r) are both recommended antiretroviral agents for combination therapy in drug-naive HIV-infected patients, no randomized comparison of their efficacy and tolerability is available yet. A multi-cohort prospective observational comparative study was performed.

Methods

Efficacy was examined comparing time to virological failure, CD4 recovery and clinical progression. Tolerability was examined comparing time to treatment discontinuation for any reason and for toxicity and time to liver enzymes or lipid alterations. Survival analysis was conducted by an intent-to-treat principle using the Kaplan–Meier method, and standard and weighted Cox regression models.

Results

A total of 674 antiretroviral-naive patients starting a two nucleoside reverse transcriptase inhibitor regimen plus either EFV ( n=481) or LPV/r ( n=193) were examined. At baseline, patients starting LPV/r had higher HIV RNA and lower CD4+ T-cell counts. There was no difference in the adjusted hazards of virological failure (LPV/r versus EFV relative hazard [RH] 1.16, 95% confidence intervals [CI]: 0.58–2.32, P=0.67), CD4 recovery (RH=0.93, 95% CI: 0.66–1.30, P=0.66), clinical progression (RH=1.64, 95% CI: 0.70–3.84, P=0.25), drug discontinuation for toxicity (RH=0.92, 95% CI: 0.51–1.64, P=0.76) and for any reason, and rates of liver enzyme and total/low density lipoprotein (LDL) cholesterol elevation. In contrast, the rate of triglycerides elevations (>1 NCEP Adult Treatment Panel III category increase) was higher in the LPV/r group (RH=1.69, 95% CI: 1.14–2.50; P=0.01). Models weighted for the inverse of conditional probability of receiving either drug applied to the efficacy endpoints yielded similar results. CD4 recovery with both drugs was also similar in the lowest CD4 strata.

Conclusions

Our analysis suggests similar efficacy and tolerability for EFV- or LPV/r-based first-line antiretroviral regimens. LPV/r was associated with higher rates of hypertriglyceridaemia.

Genotypic Resistance and Immunologic Outcomes Among HIV-1-Infected Women With Viral Failure

OBJECTIVES

To describe the prevalence of specific protease inhibitor (PI) and nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance mutations and the relationship between the presence of these mutations and immunologic outcomes following PI/NNRTI initiation among a cohort of HIV-1-infected women.

METHODS

Viral genotypic resistance testing was done for 366 women enrolled in the Women's Interagency HIV Study at the visit immediately prior to 1st reported use of PI or NNRTI (baseline) and at the visit approximately 1 year after PI/NNRTI initiation. We modeled the changes in CD4+ T-cell counts and HIV RNA levels approximately 1 year after therapy initiation as a function of baseline and follow-up markers, type of antiretroviral therapy used, and resistance mutations.

RESULTS

At baseline, 52% of women showed only nucleoside reverse transcriptase inhibitor (NRTI) mutations, 38% showed no mutations, and 10% showed PI or NNRTI mutations. Only 40% of women showed viral response (HIV-1 RNA < or = 80 copies/mL) 1 year after initiating a PI or NNRTI. Among those without a viral response, 54% developed PI or NNRTI mutations. NNRTI (among those with baseline NRTI mutations) and PI resistance mutations were associated with better CD4+ cell count changes (mean increase of 118 cells/mm3 and 64 cells/mm3, respectively, as compared with viral nonresponders with no PI or NNRTI mutations).

CONCLUSIONS

In this population-based cohort, virologic failure with PI or NNRTI resistance was common. Viremia with these resistance mutations was associated with preserved CD4+ T-cell count responses, providing evidence of reduced virulence or viral fitness.

Reasons for stopping antiretrovirals used in an initial highly active antiretroviral regimen: increased incidence of stopping due to toxicity or patient/physician choice in patients with hepatitis C coinfection

Low adherence and toxicities among HIV-positive patients starting highly active antiretroviral therapy (HAART) can lead to discontinuation of therapy and treatment failure. Little is known about hepatitis C (HCV) status and discontinuation of HAART. Poisson regression was used to determine factors related to discontinuation of any part of an initial HAART regimen due to treatment failure (TF) or toxicities and patient/physician choice (TOX), and to investigate the relationship between HCV and discontinuation of a HAART regimen in 1198 patients staring HAART after 1999 from the EuroSIDA study. At 1 year after starting HAART, 70% of patients remained on their original regimen, 24% had changed, and 6% were off all treatment. The most frequent reason for discontinuation was toxicities (30.4%). There was no change over time in the proportion of patients discontinuing after stratification by reason for discontinuation (p = 0.18). Of patients 190 stopped at least one antiretroviral drug used in their initial HAART regimen due to toxicities; the toxicity reported did not vary according to HCV status (p = 0.90). Anti-HCV seropositive patients had a higher incidence of discontinuation due to TOX (IRR 1.46, 95% CI 1.13-1.88, p = 0.0042) compared to patients without HCV. Patients with HCV were more likely to discontinue all or part of their HAART regimens due to toxicity or patient/physician choice. Managing adverse events must remain a key intervention in maintaining HAART. There is a need for further studies to describe the relationship between HCV, specific antiretrovirals, and different treatment strategies.

Reasons for stopping antiretrovirals used in an initial highly active antiretroviral regimen: increased incidence of stopping due to toxicity or patient/physician choice in patients with hepatitis C coinfection

Low adherence and toxicities among HIV-positive patients starting highly active antiretroviral therapy (HAART) can lead to discontinuation of therapy and treatment failure. Little is known about hepatitis C (HCV) status and discontinuation of HAART. Poisson regression was used to determine factors related to discontinuation of any part of an initial HAART regimen due to treatment failure (TF) or toxicities and patient/ physician choice (TOX), and to investigate the relationship between HCV and discontinuation of a HAART regimen in 1198 patients staring HAART after 1999 from the EuroSIDA study. At 1 year after starting HAART, 70% of patients remained on their original regimen, 24% had changed, and 6% were off all treatment. The most frequent reason for discontinuation was toxicities (30.4%). The incidence of any discontinuation was significantly lower after 1999 compared to before [incidence rate ratio (IRR) 0.43; 95% CI 0.35-0.53, p < 0.0001], this pattern was most marked for toxicities (IRR 0.28; 95% CI 0.20-0.39, p < 0.0001) and patient/physician choice (IRR 0.49; 95% CI 0.33-0.73, p < 0.0001). Patients with HCV had a higher incidence of discontinuation due to TOX (IRR 1.46, 95% CI 1.13-1.88, p = 0.0042) compared to patients without HCV. Patients with HCV were more likely to discontinue all or part of their HAART regimens due to toxicity or patient/physician choice. Managing adverse events must remain a key intervention in maintaining HAART. There is a need for further studies to describe the relationship between HCV, specific antiretrovirals, and different treatment strategies.

The Problems Faced When Assessing the Prevalence and Incidence of Antiretroviral-Related Toxicities

Although the dramatic effect of highly active antiretroviral therapy (HAART) in reducing morbidity and mortality must not be underestimated, it is also important to consider the incidence and prevalence of HAART-related toxicities. Although several studies have investigated HAART-related toxicities, there has been great variety between them in the reported incidence and prevalence rates of these toxicities. Various factors, including whether the study type was a clinical trial or an observational study, the definition of the toxicity endpoints, the demographic characteristics of the study populations and the effect of calendar year on analyses, may all influence the rates observed. We investigated the possible explanations for the differences in the incidence and prevalence rates of HAART-related toxicities between studies, focussing on metabolic and hepatotoxic disorders.

Pitfalls of assessing hepatotoxicity in trials and observational cohorts

The relationship between the use of antiretroviral drugs and the development of hepatic abnormalities has been documented in both randomized controlled trials (RCTs) and observational database studies. Both types of study design are known to have limitations when addressing this issue. Whereas RCTs may enroll a population that is at lower risk for the development of hepatotoxicity, thus underestimating the possible effect of antiretroviral therapy on hepatic abnormalities, observational databases may encompass information from a more heterogeneous group of patients, allowing the drugs to be assessed in a more realistic situation. However, a number of possible biases associated with the use of observational data may limit the conclusions that can be drawn from such studies. I describe some of the benefits and limitations of RCTs and observational data sets when drawing conclusions about the relationship between antiretroviral therapy and the development of hepatic abnormalities.

Virological rebound after suppression on highly active antiretroviral therapy

OBJECTIVE To determine the rate of virological rebound and factors associated with rebound among patients on highly active antiretroviral therapy (HAART) with previously undetectable levels of viraemia. DESIGN An observational cohort study of 2444 patients from the EuroSIDA study. METHODS Patients were followed from their first viral load under 400 copies/ml to the first of two consecutive viral loads above 400 copies/ml. Incidence rates were calculated using person-years of follow-up (PYFU), Cox proportional hazards models were used to determine factors related to rebound. RESULTS Of 2444 patients, 1031 experienced virological rebound (42.2%). The incidence of rebound decreased over time; from 33.5 in the first 6 months after initial suppression to 8.6 per 100 PYFU at 2 years after initial suppression (P < 0.0001). The rate of rebound was lower for treatment-naive compared with treatment-experienced patients. In multivariate models, patients who changed treatment were more likely to rebound, as were patients with higher viral loads on starting HAART. Treatment-naive patients were less likely to rebound. Among pretreated patients, those who were started on new nucleosides were less likely to rebound. CONCLUSION The rate of virological rebound decreased over time, suggesting that the greatest risk of treatment failure is in the months after initial suppression. Treatment-naive patients were at a lower risk of rebound, but among drug-experienced patients, those who added new nucleosides had a lower risk of rebound, as were patients with a good immunological response.

Reasons for modification and discontinuation of antiretrovirals: results from a single treatment centre

OBJECTIVE

To describe the reasons for, and factors associated with, modification and discontinuation of highly active antiretroviral therapy (HAART) regimens at a single clinic.

SUBJECTS

A total of 556 patients who started HAART at the Royal Free Hospital were included in analyses. Modification was defined as stopping or switching any antiretrovirals in the regimen, whereas discontinuation was defined as the simultaneous stopping of all antiretrovirals included in the initial regimen. Reasons were classified as immunological/virological failure (IVF) and toxicities and patient choice/poor compliance (TPC).

RESULTS

The median CD4 count at starting HAART was 171 x 10(6) cells/l and viral load 5.07 log copies/ml. During a median follow-up of 14.2 months, 247 patients (44.4%) modified their HAART regimen, 72 due to IVF (29.1%) and 159 due to TPC (64.4%) and a total of 148 patients (26.6%) discontinued HAART. Older patients were less likely to modify HAART [relative hazard (RH), 0.73 per 10 years; P = 0.0008], as were previously treatment-naive patients (RH, 0.65; P = 0.0050), those in a clinical trial (RH, 0.64; P = 0.027) and those who started nelfinavir (RH, 0.57; P = 0.035). Patients who started with four or more drugs (RH, 2.21, P < 0.0001), who included ritonavir in the initial regimen (RH, 1.41; P = 0.035) or who had higher viral loads during follow-up (RH per log increase, 1.51; P < 0.0001) were more likely to modify HAART.

CONCLUSIONS

There was a high rate of modification and discontinuation of HAART regimens in the first 12 months, particularly due to toxicities, patient choice or poor compliance.