Ian Weller

Use of nucleoside reverse transcriptase inhibitors and risk of myocardial infarction in HIV-infected patients enrolled in the D:A:D study: a multi-cohort collaboration

BACKGROUND Whether nucleoside reverse transcriptase inhibitors increase the risk of myocardial infarction in HIV-infected individuals is unclear. Our aim was to explore whether exposure to such drugs was associated with an excess risk of myocardial infarction in a large, prospective observational cohort of HIV-infected patients. METHODS We used Poisson regression models to quantify the relation between cumulative, recent (currently or within the preceding 6 months), and past use of zidovudine, didanosine, stavudine, lamivudine, and abacavir and development of myocardial infarction in 33 347 patients enrolled in the D:A:D study. We adjusted for cardiovascular risk factors that are unlikely to be affected by antiretroviral therapy, cohort, calendar year, and use of other antiretrovirals. FINDINGS Over 157,912 person-years, 517 patients had a myocardial infarction. We found no associations between the rate of myocardial infarction and cumulative or recent use of zidovudine, stavudine, or lamivudine. By contrast, recent-but not cumulative-use of abacavir or didanosine was associated with an increased rate of myocardial infarction (compared with those with no recent use of the drugs, relative rate 1.90, 95% CI 1.47-2.45 [p=0.0001] with abacavir and 1.49, 1.14-1.95 [p=0.003] with didanosine); rates were not significantly increased in those who stopped these drugs more than 6 months previously compared with those who had never received these drugs. After adjustment for predicted 10-year risk of coronary heart disease, recent use of both didanosine and abacavir remained associated with increased rates of myocardial infarction (1.49, 1.14-1.95 [p=0.004] with didanosine; 1.89, 1.47-2.45 [p=0.0001] with abacavir). INTERPRETATION There exists an increased risk of myocardial infarction in patients exposed to abacavir and didanosine within the preceding 6 months. The excess risk does not seem to be explained by underlying established cardiovascular risk factors and was not present beyond 6 months after drug cessation.Methods: Biomarkers, ischemic changes on the electrocardiogram, and rates of various predefined types of cardiovascular disease (CVD) events according to NRTIs used were explored in the Strategies for Management of Anti-Retroviral Therapy (SMART) study. Patients receiving abacavir and not didanosine were compared with those receiving didanosine, and to those receiving NRTIs other than abacavir or didanosine (other NRTIs). Patients randomly assigned to the continuous antiretroviral therapy arm of SMART were included in all analyses (N1⁄42752); for the study of biomarkers, patients from the antiretroviral therapy interruption arm were also included.

Risk of myocardial infarction in patients with HIV infection exposed to specific individual antiretroviral drugs from the 3 major drug classes: the data collection on adverse events of anti-HIV drugs (D:A:D) study

BACKGROUND. The risk of myocardial infarction (MI) in patients with human immunodeficiency virus (HIV) infection has been assessed in 13 anti-HIV drugs in the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study. METHODS. Poisson regression models were adjusted for cardiovascular risk factors, cohort, calendar year, and use of other antiretroviral drugs and assessed the association between MI risk and cumulative (per year) or recent (current or in the past 6 months) use of antiretroviral drugs, with >30,000 person-years of exposure. RESULTS. Over 178,835 person-years, 580 patients developed MI. There were no associations between use of tenofovir, zalcitabine, zidovudine, stavudine, or lamivudine and MI risk. Recent exposure to abacavir or didanosine was associated with an increased risk of MI. No association was found between MI risk and cumulative exposure to nevirapine, efavirenz, nelfinavir, or saquinavir. Cumulative exposure to indinavir and lopinavir-ritonavir was associated with an increased risk of MI (relative rate [RR] per year, 1.12 and 1.13, respectively). These increased risks were attenuated slightly (RR per year, 1.08 [95% confidence interval {CI}, 1.02-1.14] and 1.09 [95% CI, 1.01-1.17], respectively) after adjustment for lipids but were not altered further after adjustment for other metabolic parameters. CONCLUSIONS. Of the drugs considered, only indinavir, lopinavir-ritonavir, didanosine, and abacavir were associated with a significantly increased risk of MI. As with any observational study, our findings must be interpreted with caution (given the potential for confounding) and in the context of the benefits that these drugs provide.

Interactions between HIV and hepatitis B virus in homosexual men : effects on the natural history of infection

Objectives:Hepatitis B virus (HBV) and HIV infections share risk factors; therefore, coinfection is common. Interactions have been reported but controlled studies have been limited. Our objective was to study the effect of HIV infection on the natural history of chronic HBV infection and the reverse effect of the HBV carrier state on HIV infection. Design:Prospective observational cohort study. Setting:Open-access outpatient HIV/genitourinary medicine clinic at a Central London hospital. Patients:Total of 152 untreated homosexual male HBV carriers and 212 HBV surface antigen-negative controls (41.4 and 70.3% HIV-seropositive, respectively). Outcome measures:The rate of loss of serum HBV e antigen (HBeAg) and its reappearance in HIV-infected and HIV-uninfected HBV carriers; serum HBV DNA levels (measured by dot-blot hybridization assay), HBV DNA polymerase activity and liver transaminase activities; the progression of HIV infection to symptomatic disease or AIDS in HIV-infected compared with HBV-HIV coinfected patients. Results:In HIV-infected HBV carriers, serum HBV DNA polymerase activity was higher, alanine aminotransferase was lower and loss of serum HBeAg (mean follow-up, 2.8 years) occurred at a lower rate when compared with HIV-uninfected HBV carriers (estimated relative hazard, 0.39; 95% confidence interval, 0.161–0.942). Concomitant chronic HBV infection had no detectable effect on the rate of progression of HIV disease after correction for lead-time bias. Conclusion:This study strengthens the evidence for a significant effect of HIV infection on the natural history of chronic HBV infection, which by prolonging the period of infectivity could have an important impact on the epidemiology of HBV infection in regions, or patient groups, with high HIV seroprevalence. There was no evidence of an important effect of HBV carriage on HIV disease progression.

Cardio- and cerebrovascular events in HIV-infected persons

Objective: Recent results from the D:A:D Study indicated that the incidence of myocardial infarction (MI) increased by 26% per year of exposure to combination antiretroviral treatment (CART). The present study was performed to investigate whether this risk was similar when including other cardio- and cerebro-vascular disease events (CCVE). Design: D:A:D is an international collaboration of 11 cohorts, following 23 468 HIV-infected patients prospectively at 188 clinics in 21 countries situated in Europe, USA and Australia. Methods: The end-point was the occurrence of a first CCVE during prospective follow-up, defined as the first of: acute MI, invasive cardiovascular procedures, stroke, or death from other cardiovascular disease. Relative rates (RR) for CCVE from Poisson regression models and 95% confidence intervals (CI) are reported. All models are adjusted for other risk factors for CCVE, including age, gender, ethnicity, family history, body mass index, and smoking status as well as cohort and HIV transmission group. Results: Over 36 145 person-years of follow-up, 207 patients experienced at least one CCVE (23.7% fatal). The first event was MI in 126 patients, invasive cardiovascular procedure in 39 patients, stroke in 38 patients, and death from other cardiovascular disease in four patients. The incidence of first CCVE was 5.7 per 1000 person-years [95% confidence interval (CI) 5.0–6.5] and increased with longer exposure to CART (RR per year of exposure, 1.26; 95% CI, 1.14–1.38; P < 0.0001). Conclusion: CART increases the risk of CCVD, and this increase is comparable with how CART affects the risk of MI. This finding is consistent with the hypothesis that atherosclerosis is a side-effect of CART.

HUMAN IMMUNODEFICIENCY VIRUS INFECTION IN TWO COHORTS OF HOMOSEXUAL MEN: NEUTRALISING SERA AND ASSOCIATION OF ANTI-GAG ANTIBODY WITH PROGNOSIS

Sequential sera from 48 subjects infected with human immunodeficiency virus type I (HIV-I) were examined over 36 months for the presence of neutralising antibodies, and for specific anti-gag (p24) and anti-env (gp41) antibodies to HIV-I. Results were interpreted in terms of clinical outcome during the period 1982/3 to 1985/6. HIV-I-infected subjects who remained symptom-free, by comparison with those who manifested AIDS or AIDS-related complex (ARC), had a significantly higher titre of anti-p24 antibodies throughout the 3 years, as measured by competitive enzyme-linked immunosorbent assay and radioimmunoprecipitation. The symptomless subjects also showed a trend towards an increasing neutralising antibody titre with time. There was no relation between anti-gp41 titre and clinical outcome, nor an independent relation between anti-p24 and neutralising titre. A lower or falling titre of anti-p24 antibody was associated significantly with clinical progression, up to 27 months before development of AIDS/ARC.

Response to combination antiretroviral therapy: variation by age.

Objective:To provide information on responses to combination antiretroviral therapy in children, adolescents and older HIV-infected persons. Design and setting:Multicohort collaboration of 33 European cohorts. Subjects:Forty-nine thousand nine hundred and twenty-one antiretroviral-naive individuals starting combination antiretroviral therapy from 1998 to 2006. Outcome measures:Time from combination antiretroviral therapy initiation to HIV RNA less than 50 copies/ml (virological response), CD4 increase of more than 100 cells/μl (immunological response) and new AIDS/death were analysed using survival methods. Ten age strata were chosen: less than 2, 2–5, 6–12, 13–17, 18–29, 30–39 (reference group), 40–49, 50–54, 55–59 and 60 years or older; those aged 6 years or more were included in multivariable analyses. Results:The four youngest age groups had 223, 184, 219 and 201 individuals and the three oldest age groups had 2693, 1656 and 1613 individuals. Precombination antiretroviral therapy CD4 cell counts were highest in young children and declined with age. By 12 months, 53.7% (95% confidence interval: 53.2–54.1%) and 59.2% (58.7–59.6%) had experienced a virological and immunological response. The probability of virological response was lower in those aged 6–12 (adjusted hazard ratio: 0.87) and 13–17 (0.78) years, but was higher in those aged 50–54 (1.24), 55–59 (1.24) and at least 60 (1.18) years. The probability of immunological response was higher in children and younger adults and reduced in those 60 years or older. Those aged 55–59 and 60 years or older had poorer clinical outcomes after adjusting for the latest CD4 cell count. Conclusion:Better virological responses but poorer immunological responses in older individuals, together with low precombination antiretroviral therapy CD4 cell counts, may place this group at increased clinical risk. The poorer virological responses in children may increase the likelihood of emergence of resistance.

Reference ranges and sources of variability of CD4 counts in HIV-seronegative women and men.

BACKGROUND: CD4 lymphocyte counts are used to monitor immune status in HIV disease. An understanding of the variability of CD4 counts which occurs in the absence of HIV infection is essential to their interpretation. The sources and degree of such variability have not been extensively studied. OBJECTIVES: To establish reference ranges for CD4 counts in HIV-seronegative women and heterosexual men attending a genitourinary medicine (GUM) clinic, and to identify possible differences according to gender and cigarette smoking and, in women, any effect of the menstrual cycle, oral contraceptive use and cigarette smoking. DESIGN: Female and heterosexual male patients attending a GUM clinic and requesting an HIV-antibody test were recruited prospectively. Results from an earlier study of CD4 counts in homosexual men were available for comparison. METHODS: Lymphocyte subpopulation analysis on whole blood by flow cytometry. RESULTS: The absolute CD4 count and percentage of CD4 cells (CD4%) were significantly higher in women (n = 195) than heterosexual men (n = 91) [difference between the means 111 x 106/1 (95% CI 41, 180) and 3.1% (1.30, 4.88)]. The absolute CD4 count and CD4% were also significantly higher in smokers (n = 143) than non-smokers (n = 140) [difference 143 (79, 207) and 2.1% (0.43, 3.81)]. Reference ranges for absolute CD4 counts (geometric mean +/- 2SD) were calculated on log transformed data as follows; female smokers 490-1610, female non-smokers 430-1350, heterosexual male smokers 380-1600, heterosexual male non-smokers 330-1280. Among other variables examined, combined oral contraceptive pill use was associated with a trend towards a lower absolute CD4 count. Changes were seen in CD4% with the menstrual cycle. CD4 counts and CD4% did not differ significantly between heterosexual men and homosexual men (n = 45). CONCLUSION: There is a significant gender and smoking effect on CD4 counts. The effects of oral contraceptive use and the menstrual cycle warrant further investigation.

Hepatitis C virus: evidence for sexual transmission.

OBJECTIVE--To determined the prevalence of hepatitis C virus infection and associated risk factors in patients attending a genitourinary medicine clinic, as evidence for sexual transmission. DESIGN--Seroprevalence estimated by reactivity in an enzyme immunoassay for antibodies to C100 protein with supplementary testing with a recombinant immunoblot assay and an assay for hepatitis C virus RNA. SETTING--Outpatient genitourinary medicine clinic in central London. PATIENTS--The panel of 1046 serum samples was from 1074 consecutive patients attending the clinic during November and December 1987 and having blood taken for routine testing for syphilis. Before samples were anonymised demographic and risk factor information was extracted from the clinic notes. Samples had already been tested for antibody to HIV-I and antibody to hepatitis B core antigen. MAIN RESULTS--Significantly more homosexual subjects than heterosexual subjects were positive for hepatitis C antibody determined by enzyme immunoassay alone (19/275 (6.9%) v 8/771 (1.0%), odds ratio 7.14, p less than 0.0001) and also when reactive serum samples were also tested by recombinant immunoblot assay (6/270) (2.2%) v 3/770 (0.4%), odds ratio 5.88, p less than 0.02). There were also significant associations in patients positive for hepatitis C antibody with positivity for antibodies to HIV and to hepatitis B core antigen, lifetime number of sexually transmitted diseases (homosexual men only), and age (all groups combined). Most patients whose serum samples contained specific antibodies to hepatitis C virus were viraemic. CONCLUSIONS--The study provides strong evidence for the sexual transmission of hepatitis C virus. Assays derived from other gene products are desirable to investigate the specificity and sensitivity of the enzyme immunoassay for C100 antibody as a marker of hepatitis C virus infection.

Detection of human herpesvirus 8 Dna in semen from Hiv-infected individuals but not healthy semen donors

Objective:To ascertain the prevalence of Kaposis sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus (HHV) type 8, and cytomegalovirus (CMV) DNA in semen was investigated. Methods:Amplification by nested polymerase chain reaction was used to detect viral DNA sequences in samples from 24 HIV-infected gay men, 15 of them with Kaposis sarcoma (KS), and 115 healthy donors. Results:Six of the 24 HIV-infected patients had detectable HHV-8 DNA in their semen: three of the 15 patients with KS and three of the nine patients without KS. CMV DNA was detected in 20 semen samples from HIV-infected patients. None of the semen samples from healthy donors had detectable HHV-8 DNA and rates of CMV DNA detection were low (3%). Conclusions:The study demonstrates the presence of HHV-8 in semen from HIV-infected individuals with, or at risk, of developing KS and the potential for sexual transmission of the virus. We found no evidence of HHV-8 in the semen of HIV-uninfected donors.

Impaired responsiveness of homosexual men with HIV antibodies to plasma derived hepatitis B vaccine.

Thirty five homosexual men (17 positive for antibody to the human immunodeficiency virus (HIV) and 18 consistently negative) were vaccinated against hepatitis B virus infection. Eight of the 17 seropositive patients failed to develop detectable hepatitis B surface antibody within three months of the third injection compared with only one of the 18 seronegative patients (p less than 0.01). HIV infection is prevalent in the developed world in groups at risk for hepatitis B infection and in certain Third World countries where widespread vaccination programmes exist. This study shows the impact that coincident HIV infection may have on an otherwise efficacious vaccine. The efficacy of this and other vaccines in patients infected with HIV needs to be studied urgently.