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Biomedical subjects

Donald R Hoover

Publications and source records attributed to Donald R Hoover.

At least 19 recordsLinked to original sources
PubMed2006

Quantitative analysis of HIV-1 variants with the K103N resistance mutation after single-dose nevirapine in women with HIV-1 subtypes A, C, and D.

INTRODUCTION: We used a sensitive point mutation assay, LigAmp, to detect and quantify K103N-containing variants in African women who received single-dose nevirapine (NVP) to prevent mother-to-child HIV-1 transmission. METHODS: Plasma for testing was collected 6 to 8 weeks postpartum from 301 women (144 subtype A, 63 subtype C, and 94 subtype D). RESULTS: The portion of women with 0.5% or more K103N-containing variants was lowest for subtype A (60/144, 41.7%) and highest for subtype C (44/63, 69.8%; P < 0.0001). K103N was rarely detected in pre-NVP samples. In a multivariate model, K103N detection was associated with HIV-1 subtype (C > A), after adjusting for log10 delivery viral load, the number of days between NVP dosing and sample collection, age, and parity. Among women with K103N detected: (1) the median %K103N was lower for subtype A (2.2%) than C (11.7%, P = 0.0001) or D (5.5%, P = 0.04), and (2) in a multivariate linear model, higher log10 (%K103N) was associated with HIV subtype (C > A, P = 0.0001; D > A, P = 0.01; and C vs D, no difference), but not other factors. CONCLUSIONS: After administration of single-dose NVP, K103N was detected more frequently and at higher levels in women with subtypes C and D than A. Further studies are needed to evaluate the clinical significance of NVP-resistant variants in this setting.

Amino Acid Substitution↗
PubMed2006

Association between the replication capacity and mother-to-child transmission of HIV-1, in antiretroviral drug-naive Malawian women.

Replication capacity and transmission of human immunodeficiency virus (HIV)-1 in antiretroviral drug-naive Malawian women who had subtype C infection were investigated. Infant children of these women received either 1 dose of nevirapine or 1 dose of nevirapine plus 1 week of daily doses of zidovudine. PhenoSense HIV was used to determine replication capacity in 49 women whose infants were infected with HIV-1 and in 47 women whose infants were uninfected by 6-8 weeks of age. Mean replication capacity was higher in transmitters than in nontransmitters (P=.01). In a multivariate model, higher replication capacity was associated with transmission (odds ratio, 1.45 for each 10% increase in replication capacity [95% confidence interval, 1.11-1.90]; P = .0063), after adjustment for maternal HIV-1 load and other factors.

Adult↗
PubMed2006

Higher in utero and perinatal HIV infection risk in girls than boys.

OBJECTIVE: This study analyzed mother-to-child HIV transmission rates by sex and exposure time for babies born to HIV-infected, untreated African women. METHODS: Data were analyzed from 2 independent studies done in Malawi during the 1990s. Infections were established by polymerase chain reaction on blood samples. Odds ratios (ORs) for transmission were examined by period at risk: in utero (infected in umbilical cord blood), perinatal (infected in 1st postnatal blood > or =4 weeks), and postnatal (later postnatal infection). RESULTS: Among 1394 singleton births, girls were more likely to become infected than boys. For in utero transmission, the OR was 1.4 (95% CI: 0.9 to 2.2). For transmission during early life (umbilical cord blood not available) the OR was 2.7 (95% CI: 1.5 to 4.9). However, transmission risks in the perinatal and postnatal infection periods did not differ in boys and girls. Among 303 tested twin-birth pairs, girls were at higher risk than boys for in utero (OR: 2.6; 95% CI: 1.2 to 5.8) and perinatal (OR: 1.9; 95% CI: 1.0 to 3.7) infection. Recognized mother-to-child transmission risk factors did not explain the higher risk of infection in girls. CONCLUSIONS: Girls were at higher risk of early (in utero and perinatal) HIV infection than boys. It is proposed that minor histocompatibility reactions between maternal lymphocytes and infant Y chromosome-derived antigens reduce the risk of HIV transmission in boys.

Disease Susceptibility↗
PubMed2006

Development of nevirapine resistance in infants is reduced by use of infant-only single-dose nevirapine plus zidovudine postexposure prophylaxis for the prevention of mother-to-child transmission of HIV-1.

We analyzed the development of nevirapine (NVP) resistance in human immunodeficiency virus type 1 (HIV-1)-infected Malawian infants who received regimens containing single-dose NVP (SD-NVP) for the prevention of mother-to-child transmission (MTCT) of HIV-1. All infants received SD-NVP, and some randomly received zidovudine (ZDV) as well. Mothers did or did not receive SD-NVP on the basis of when they arrived at the hospital for delivery. In infants 6-8 weeks of age, NVP resistance was less frequent when infants had received SD-NVP plus ZDV and mothers had not received SD-NVP than when infants had received SD-NVP alone and mothers had received SD-NVP (4/15 [27%] vs. 20/23 [87%]; P < .001). The risk of MTCT of HIV-1 was comparable with these regimens. Infant-only prophylaxis also eliminates the development of NVP resistance in mothers.

Anti-Retroviral Agents↗
PubMed2006

Factors associated with poor immunologic response to virologic suppression by highly active antiretroviral therapy in HIV-infected women.

Virologic response to highly active antiretroviral therapy (HAART) typically results in a substantial rise in CD4 cell counts. We investigated factors associated with poor CD4 response among HIV-infected women followed at 6-monthly intervals in the Women's Interagency HIV Study. Women with nadir CD4 counts < 350 cells/mm3 who achieved at least 6 months of plasma HIV RNA < 400 copies/ml were studied. Demographic, clinical, and treatment factors were compared between immunologic nonresponders, defined as the lower quartile of CD4 count change after two visits with virologic suppression (< 56 cell/mm3; n = 38), and the remaining group of responders (n = 115). Immunologic nonresponders had lower baseline HIV RNA levels and higher CD4 counts, more frequently used HAART 6 months prior to achieving consistent viral suppression, and more commonly had HIV RNA levels > 80 but < 400 copies/mL at both suppressive visits (21 vs. 7.8%, p = 0.024). In multivariate analysis, higher CD4 count and lower HIV RNA level at the last presuppressive visit were associated with immune nonresponse. We conclude that higher baseline CD4 count and lower HIV RNA level were associated with poor immunologic response to HAART in women with virologic suppression for at least 6 months. Persistent low level viremia may also contribute.

Adult↗
PubMed2006

Bimodal virological response to antiretroviral therapy for HIV infection: an application using a mixture model with left censoring.

STUDY OBJECTIVE: To assess whether HIV RNA levels (log(10) scale) in highly active antiretroviral therapy (HAART) treated population have a bimodal distribution, suggesting optimal or suboptimal response to HAART. METHODS: The study population from two ongoing cohort studies comprised 564 men (4785 person visits) and 1173 women (8675 person visits) with known dates of HAART initiation and with HIV RNA measurements before and after initiation. Values below detection limit of assays were treated in the analysis as left censored. Maximum likelihood methods were used to estimate parameters and to determine possible bimodality of HIV RNA distributions. RESULTS: A two component mixture model fitted HIV RNA levels significantly better than did a single component distribution at different years from HAART initiation in both therapy experienced and therapy naive patients. In the fifth year after HAART initiation, 32% of men and 44% of women had HIV RNA in the higher component with medians of 5247 and 9253 copies/ml, respectively, suggesting suboptimal virological response to HAART, which was associated with poor adherence and lower frequency of CCR5 heterozygous genotype. CONCLUSION: The bimodal distribution of HIV RNA persisted during the years after HAART initiation. The high occurrence of suboptimal virological response at the fifth year after HAART initiation underscore the needs for careful monitoring and patient education about the importance of treatment adherence. This data analysis overcomes limitations of measurement techniques of observations having values below detection limits and serves to characterise the dynamics of the virological response to therapies.

Adult↗
PubMed2006

The impact of breastfeeding on the health of HIV-positive mothers and their children in sub-Saharan Africa.

OBJECTIVE: We assessed the impact of breastfeeding by women infected with human immunodeficiency virus (HIV)-1 on their morbidity and risk of mortality and on the mortality of their children. METHODS: We analysed longitudinal data from two previous randomized clinical trials of mother-to-child transmission of HIV conducted between April 2000 and March 2003 in the Republic of Malawi, Africa. Mothers infected with HIV, and their newborns, were enrolled at the time of their child's birth; they then returned for follow-up visits when the child was aged 1 week, 6-8 weeks and then 3, 6, 9, 15, 18, 21 and 24 months. Patterns of breastfeeding (classified as exclusive, mixed or no breastfeeding), maternal morbidity and mortality, and mortality among their children were assessed at each visit. Descriptive and multivariate analyses were performed to determine the association between breastfeeding and maternal and infant outcomes. FINDINGS: A total of 2000 women infected with HIV were enrolled in the original studies. During the 2 years after birth, 44 (2.2%) mothers and 310 (15.5%) children died. (Multiple births were excluded.) The median duration of breastfeeding was 18 months (interquartile range (IQR)=9.0-22.5), exclusive breastfeeding 2 months (IQR=2-3) and mixed feeding 12 months (IQR=6-18). Breastfeeding patterns were not significantly associated with maternal mortality or morbidity after adjusting for maternal viral load and other covariates. Breastfeeding was associated with reduced mortality among infants and children: the adjusted hazard ratio for overall breastfeeding was 0.44 (95% confidence interval (CI)=0.28-0.70), for mixed feeding 0.45 (95% CI=0.28-0.71) and for exclusive breastfeeding 0.40 (95% CI=0.22-0.72). These protective effects were seen both in infants who were infected with HIV and those who were not. CONCLUSION: Breastfeeding by women infected with HIV was not associated with mortality or morbidity; it was associated with highly significant reductions in mortality among their children.

Adult↗
PubMed2005

Resistance after single-dose nevirapine prophylaxis emerges in a high proportion of Malawian newborns.

The administration of single-dose nevirapine to women in labor and their infants can prevent HIV-1 mother-to-child transmission. We examined nevirapine resistance in infants who were HIV-1 infected despite single-dose nevirapine prophylaxis, including 18 Ugandan infants (HIVNET 012 trial, nine subtype A and nine subtype D) and 23 Malawian infants (NVAZ trial, all subtype C). Nevirapine resistance was more frequent in infants with subtype C than with subtypes A and D (87 versus 50%, P = 0.016).

Anti-HIV Agents↗
PubMed2005

Individual variation in CD4 cell count trajectory among human immunodeficiency virus-infected men and women on long-term highly active antiretroviral therapy: an application using a Bayesian random change-point model.

The authors evaluated population- and individual-level CD4-positive T-lymphocyte (CD4 cell) count trajectories over a 7-year period (July 1995-March 2004) following initiation of highly active antiretroviral therapy (HAART) in the Multicenter AIDS Cohort Study and the Women's Interagency HIV Study. The study population included 404 human immunodeficiency virus (HIV)-infected men and 609 HIV-infected women who 1) had a CD4 cell count measurement available from their last pre-HAART study visit, 2) provided at least four post-HAART CD4 cell count measurements, and 3) reported HAART usage for at least 80% of the post-HAART visits. The CD4 cell count trajectory was analyzed by means of a Bayesian random change-point model. The results indicated that CD4 cell count trajectories for long-term frequent HAART users can be well modeled with change points at both the population and individual levels. At the population level, regardless of CD4 cell count before HAART initiation, the gains in CD4 cell count ended approximately 2 years after HAART initiation in both men and women. At the individual level, 35% of men in the Multicenter AIDS Cohort Study versus 25% of women in the Women's Interagency HIV Study had a statistically significant change in CD4 cell count trajectory within 7 years after HAART initiation.

Adult↗
PubMed2005

Nevirapine (NVP) resistance in women with HIV-1 subtype C, compared with subtypes A and D, after the administration of single-dose NVP.

OBJECTIVE: In the Human Immunodeficiency Virus (HIV) Network for Prevention Trials (HIVNET) 012 trial in Uganda, 6-8 weeks after single-dose nevirapine (SD-NVP), NVP resistance mutations were detected at a higher rate in women with HIV-1 subtype D than in women with subtype A. Here, we evaluate the rate of NVP resistance mutations in women with subtype C. METHODS: NVP resistance mutations were detected using the ViroSeq HIV-1 Genotyping System. RESULTS: The portion of women with any NVP resistance mutation was higher in those with subtype C (45/65 [69.2%] in the NVP and zidovudine trial, Malawi) than in those in the HIVNET 012 trial with either subtype A (28/144 [19.4%]; P<.0001) or subtype D (35/97 [36.1%]; P<.0001). In a multivariate model, subtype (C vs. A: odds ratio [OR], 8.73 [95% confidence interval {CI}, 4.29-17.76]; C vs. D: OR, 3.38 [95% CI, 1.65-6.93]) and viral load at delivery (OR, 2.35 [95% CI, 1.62-3.40]) independently predicted NVP resistance mutations, but maternal age, parity, and time between SD-NVP and the 6-8-week visit did not. CONCLUSIONS: The rate of NVP resistance mutations after SD-NVP was significantly higher in women with HIV-1 subtype C than in women with subtype A or D. Studies are needed to assess the clinical significance of this finding.

Adult↗
PubMed2005

Sex-based differences in T lymphocyte responses in HIV-1-seropositive individuals.

Sex-based differences in the levels of human immunodeficiency virus 1 (HIV-1) RNA in plasma could be associated with differences in the strength of HIV-1-specific CD8(+) T cell responses. CD8(+) effector responses in 18 men and 15 women were measured 0-2 years (time A) and 5-7 years (time B) after seroconversion. CD8(+) effector responses were seen in 7 (39%) of 18 men and 2 (13%) of 15 women at time A (P=.13) and in 12 (67%) of 18 men and 10 (67%) of 15 women at time B (P=.99). At time B, the strength of CD8(+) effector responses correlated with the number of CD4(+) lymphocytes in women ( rho =-0.68; P=.005) but not in men ( rho =-0.14; P=.58). The level of HIV-1 RNA was not associated with the strength of CD8(+) effector responses according to sex, but there was a sex-based difference in the correlation between the strength of CD8(+) effector response and the number of CD4(+) lymphocytes.

Adult↗
PubMed2005

Gender differences in perinatal HIV acquisition among African infants.

OBJECTIVE: We investigated gender-specific risks of mother-to-child transmission (MTCT) at birth and at 6 to 8 weeks among infants born to HIV-infected African women. DESIGN: Follow-up study of infants enrolled in 2 randomized, phase III, clinical trials to prevent MTCT, conducted in Blantyre, Malawi, in southeast Africa. METHODS: Infants were enrolled at birth and monitored postnatally, and their HIV status was assessed at birth and at 6 to 8 weeks (assessment beyond 6-8 weeks is ongoing). Statistical analyses were stratified according to gender, and comparisons were made with descriptive, univariate, and multivariate statistical tests. MTCT was estimated at birth and at 6 to 8 weeks among infants who were not infected at birth. RESULTS: Overall, 966 boys and 998 girls were enrolled. The rate of HIV transmission at birth was 9.5% (187 of 1964 infants). However, at birth significantly more girls (12.6%) than boys (6.3%) were infected with HIV. This association remained significant after controlling for maternal viral load and other factors. Among infants who were uninfected at birth, 8.7% (135 of 1554 infants) acquired HIV by 6 to 8 weeks; of these infants, more girls acquired HIV (10.0%), compared with boys (7.4%). CONCLUSIONS: Female infants may be more susceptible to HIV infection before birth and continuing after birth. Alternatively, in utero mortality rates of HIV-infected male infants may be disproportionately higher and thus more HIV-infected female infants are born. In areas of sub-Saharan Africa, where HIV infection rates are high among women of reproductive age, the magnitude of the gender transmission differences observed in this study could have clinical, preventive, and demographic implications.

Birth Weight↗
PubMed2004

Herpes zoster in women with and at risk for HIV: data from the Women's Interagency HIV Study.

BACKGROUND: Herpes zoster occurs at all CD4 cell counts in HIV-infected adults. It was hypothesized that even in the era of highly active antiretroviral therapy (HAART), zoster risk is higher in HIV-infected than uninfected women. METHODS: Generalized estimating equations modeled self-reported occurrence of zoster between semiannual visits among 1832 HIV-infected and 489 HIV-uninfected women in the Women's Interagency HIV Study followed for up to 7.5 years. RESULTS: A total of 337 (18.4%) HIV-infected and 7 (1.4%) HIV-uninfected women reported zoster at some time during follow-up. Using HIV-infected women with CD4 >750 cells/microL as the reference category, the odds ratios for reporting zoster since the prior visit were: 1.43 (95% CI 0.86-2.37) for CD4 500-749 cells/microL, 2.07 (95% CI 1.27-3.38) for CD4 350-499 cells/microL, 2.72 (95% CI 1.66-4.46) for CD4 200-349 cells/microL, and 3.16 (95% CI 1.92-5.18) for CD4 <200 cells/microL, compared with 0.11 (95% CI 0.046-0.26) for HIV-uninfected women. In multivariate analyses using visits from all HIV-infected women and only those who initiated HAART, lower CD4 cell count was more strongly associated with zoster incidence than were other clinical indicators. CONCLUSIONS: Herpes zoster is associated with degree of immunosuppression in HIV-infected women, but even women with high CD4 counts are at greater risk of zoster than HIV-uninfected women.

Adult↗
PubMed2004

Case-control study of diabetes mellitus in HIV-infected patients.

BACKGROUND: Diabetes mellitus (DM) is more prevalent among patients with HIV infection. Besides protease inhibitors (PIs), other factors may contribute to the development of DM. OBJECTIVE: To assess characteristics associated with the development of DM in HIV-infected persons. METHODS: We conducted a case-control study in an urban HIV clinic among patients with incident DM (49 cases) matched to 2 controls (n = 98) on age +/-5 years, race, sex, and length of clinic follow-up. There was a second set of unmatched controls (n = 196). RESULTS: Compared with matched controls, case patients had higher mean body mass index (BMI; 30.0 vs. 25.3 kg/m, matched odds ratio [OR] = 1.20; P < 0.001), higher alanine aminotransferase (ALT; 66 vs. 44 U/L, OR = 1.12 per 10 U/L; P = 0.013), and stronger family history of DM (50% vs. 29%, OR = 3.30; P = 0.009). Hepatitic C virus coinfection and PI use were not significant factors. In unmatched controls, there was no significant difference in age, sex, or ethnicity. In multivariate analyses, BMI (OR = 1.13 per kg/m; P = 0.012), family history (OR = 5.55; P = 0.014), and ALT (OR = 1.16; P = 0.012) were associated with DM. CONCLUSION: These findings suggest a complex interaction among genetic factors, body composition, and liver injury in the pathogenesis of DM in HIV-infected patients.

Adult↗
PubMed2004

Reimbursement denial and reversal by health plans at a university hospital.

PURPOSE: Denial and downgrading of reimbursement for hospital days are two strategies utilized by health plans to maintain profitability. The goal of this study was to describe patterns of discounted reimbursement at a university hospital. METHODS: We performed a retrospective cohort study of consecutive per diem patients hospitalized in 1999. We defined a discounted day as a day fully denied or downgraded and a reversal day as a day reimbursed at a higher level after appeal. The study outcomes included the probability of a discounted day and the probability of a discounted day to be later reversed. Covariance logistic regression was used to compare these outcomes by plan and physician specialty after adjusting for age, sex, race, length of stay, and diagnosis. Correlations with plan characteristics were analyzed. RESULTS: Of 59,265 hospital days, 6074 days (10.2%) were initially denied or downgraded. On appeal, 1755 discounted days (28.9%) were reversed. The percentage of days discounted per plan ranged from 1.2% to 18.8% (P <0.001), whereas the percentage of discounted days that were later reversed ranged from 23.2% to 85.3% (P <0.001). The qualitative magnitude of these associations and statistical significance were unchanged in adjusted models. Strong correlations were found between the adjusted odds ratio for a discounted day and net profit margin (R = 0.81) and medical loss ratio (R = -0.77). CONCLUSION: Denials and downgrades are frequent, with marked variation by health plan. More profitable plans had higher denial and discount rates. Evidence-based standards for denials and downgrades are needed to maintain optimal patient care and the fiscal health of hospitals and health plans.

Adult↗
PubMed2004

Association between renal disease and outcomes among HIV-infected women receiving or not receiving antiretroviral therapy.

BACKGROUND: The associations of proteinuria and an elevated creatinine level with progression to acquired immunodeficiency syndrome (AIDS) and death in the era of highly antiretroviral therapy (HAART) have not been fully described. METHODS: This analysis includes 2038 human immunodeficiency virus (HIV)-infected women from the Women's Interagency HIV Study. Time to the development of a new AIDS-defining illness (ADI) and death was modeled using proportional hazards regression before the widespread availability of HAART and after initiation of HAART. RESULTS: Of the 2038 subjects, the 14.1% of women with proteinuria had lower CD4 lymphocyte counts and higher viral loads (P<.0001 for all) at baseline and before initiation of HAART. Before the widespread availability of HAART, proteinuria was associated with an increased risk for development of ADI (hazard ratio [HR], 1.37; P=.005), and proteinuria and an elevated creatinine level were both associated with an increased risk of death (for proteinuria: HR, 1.35 [P=.04]; for creatinine: HR, 1.72 per decrease in the inverse unit [P=.02]). Among women initiating HAART, an elevated creatinine level remained associated with an increased risk of development of ADI (HR, 1.54 per decrease in the inverse unit; P=.03), and proteinuria and an elevated creatinine level were associated with an increased risk of death (for proteinuria: HR, 2.07 [P=.005]; for creatinine: HR, 1.96 per decrease in the inverse unit [P=.04]). CONCLUSIONS: Proteinuria and an elevated creatinine level were associated with an increased risk of death and development of ADI. These associations may reflect the direct role of the kidney in modulating HIV disease, or they may act as markers of greater comorbidity.

Adult↗
PubMed2004

Nevirapine and zidovudine at birth to reduce perinatal transmission of HIV in an African setting: a randomized controlled trial.

CONTEXT: Antenatal counseling and human immunodeficiency virus (HIV) testing are not universal in Africa; thus, women often present in labor with unknown HIV status without receiving the HIVNET 012 nevirapine (NVP) regimen (a single oral dose of NVP to the mother at the start of labor and to the infant within 72 hours of birth). OBJECTIVE: To determine risk of mother-to-child transmission of HIV when either standard use of NVP alone or in combination with zidovudine (ZDV) was administered to infants of women tested at delivery. DESIGN, SETTING, AND PARTICIPANTS: A randomized, open-label, phase 3 trial conducted between April 1, 2000, and March 15, 2003, at 6 clinics in Blantyre, Malawi, Africa. The trial included all infants born to 894 women who were HIV positive, received NVP intrapartum, and were previously antiretroviral treatment-naive. Infants were randomly assigned to NVP (n = 448) and NVP plus ZDV (n = 446). Infants were enrolled at birth, observed at 6 to 8 weeks, and followed up through 3 to 18 months. The HIV status of 90% of all infants was established at 6 to 8 weeks. INTERVENTION: Mothers received a 200-mg single oral dose of NVP intrapartum and infants received either 2-mg/kg oral dose of NVP or NVP (same dose) plus 4 mg/kg of ZDV twice per day for a week. MAIN OUTCOME MEASURES: HIV infection of infant at birth and 6 to 8 weeks, and adverse events. RESULTS: The mother-to-child transmission of HIV at birth was 8.1% (36/445) in infants administered NVP only and 10.1% (45/444) in those administered NVP plus ZDV (P =.30). A life table estimate of transmission at 6 to 8 weeks was 14.1% (95% confidence interval [CI], 10.7%-17.4%) in infants who received NVP and 16.3% (95% CI, 12.7%-19.8%) in those who received NVP plus ZDV (P =.36). For infants not infected at birth and retested at 6 to 8 weeks, transmission was 6.5% (23/353) in those who received NVP only and 6.9% (25/363) in those who received NVP plus ZDV (P =.88). Almost all infants (99%-100%) were breastfed at 1 week and 6 to 8 weeks. Grades 3 and 4 adverse events were comparable; 4.9% (22/448) and 5.4% (24/446) in infants receiving NVP only and NVP plus ZDV, respectively (P =.76). CONCLUSIONS: The frequency of mother-to-child HIV transmission at 6 to 8 weeks in our 2 study groups was comparable with that observed for other perinatal HIV intervention studies among breastfeeding women in Africa. The safety of the regimen containing neonatal ZDV was similar to that of a standard NVP regimen.

AIDS Serodiagnosis↗