Antiretroviral regimens in pregnancy and breast-feeding in Botswana.

BACKGROUND: The most effective highly active antiretroviral therapy (HAART) to prevent mother-to-child transmission of human immunodeficiency virus type 1 (HIV-1) in pregnancy and its efficacy during breast-feeding are unknown. METHODS: We randomly assigned 560 HIV-1-infected pregnant women (CD4+ count, > or = 200 cells per cubic millimeter) to receive coformulated abacavir, zidovudine, and lamivudine (the nucleoside reverse-transcriptase inhibitor [NRTI] group) or lopinavir-ritonavir plus zidovudine-lamivudine (the protease-inhibitor group) from 26 to 34 weeks' gestation through planned weaning by 6 months post partum. A total of 170 women with CD4+ counts of less than 200 cells per cubic millimeter received nevirapine plus zidovudine-lamivudine (the observational group). Infants received single-dose nevirapine and 4 weeks of zidovudine. RESULTS: The rate of virologic suppression to less than 400 copies per milliliter was high and did not differ significantly among the three groups at delivery (96% in the NRTI group, 93% in the protease-inhibitor group, and 94% in the observational group) or throughout the breast-feeding period (92% in the NRTI group, 93% in the protease-inhibitor group, and 95% in the observational group). By 6 months of age, 8 of 709 live-born infants (1.1%) were infected (95% confidence interval [CI], 0.5 to 2.2): 6 were infected in utero (4 in the NRTI group, 1 in the protease-inhibitor group, and 1 in the observational group), and 2 were infected during the breast-feeding period (in the NRTI group). Treatment-limiting adverse events occurred in 2% of women in the NRTI group, 2% of women in the protease-inhibitor group, and 11% of women in the observational group. CONCLUSIONS: All regimens of HAART from pregnancy through 6 months post partum resulted in high rates of virologic suppression, with an overall rate of mother-to-child transmission of 1.1%. (ClinicalTrials.gov number, NCT00270296.)

Predictors of growth and body composition in HIV-infected children beginning or changing antiretroviral therapy.

OBJECTIVES: The aim of the study was to describe growth and body composition changes in HIV-positive children after they had initiated or changed antiretroviral therapy (ART) and to correlate these with viral, immune and treatment parameters. METHODS: Ninety-seven prepubertal HIV-positive children were observed over 48 weeks upon beginning or changing ART. Anthropometry and bioelectrical impedance analysis results were compared with results from the National Health and Nutrition Examination Survey 1999-2002 (NHANES) to generate z-scores and with results for HIV-exposed, uninfected children from the Women and Infants Transmission Study (WITS). Multivariate analysis was used to evaluate associations between growth and body composition and disease parameters. RESULTS: All baseline lean and fat mass measures were below those of controls from NHANES. Weight, height and fat free mass (FFM) index (FFM/height(2)) z-scores increased over time (P = 0.004, 0.037 and 0.027, respectively) and the waist:height ratio z-score decreased (P = 0.045), but body mass index and per cent body fat z-scores did not change. Measures did not increase more than in uninfected WITS controls. In multivariate analysis, baseline height, mid-thigh circumference and FFM z-scores related to CD4 percentage (P = 0.029, P = 0.008 and 0.020, respectively) and change in FFM and FFM index z-scores to CD4 percentage increase (P = 0.010 and 0.011, respectively). Compared with WITS controls, baseline differences in height and mid-thigh muscle circumference were also associated with CD4 percentage. Case-control differences in change in both subscapular skinfold (SSF) thickness and the SSF:triceps skinfold ratio were inversely associated with viral suppression. No measures related to ART class(es) at baseline or over time. CONCLUSIONS: In these HIV-positive children, beginning or changing ART was associated with improved growth and lean body mass (LBM), as indicated by FFM index. Height and LBM related to CD4 percentage at baseline and over time. Altered fat distribution and greater central adiposity were associated with detectable virus but not ART class(es) received.

Safety and efficacy of nevirapine- and efavirenz-based antiretroviral treatment in adults treated for TB-HIV co-infection in Botswana.

BACKGROUND: The safety and efficacy of nevirapine (NVP) and efavirenz (EFV) based highly active antiretroviral treatment (ART) with concurrent anti-tuberculosis treatment in sub-Saharan Africa has not been well established. METHODS: We performed a retrospective study comparing human immunodeficiency virus (HIV) infected adults exposed and not exposed to tuberculosis (TB) treatment with similar baseline HIV-1 RNA levels who were started on ART as part of Botswana's ART Programme. ART regimens, HIV-1 RNA, CD4+ cell count, and liver function tests were reviewed for 12 months following ART initiation. RESULTS: Among 155 patients on ART only and 155 exposed to TB treatment, there was no difference in virologic or immunologic response throughout the first year of ART. Furthermore, there remained no differences in virologic or immunologic outcomes when NVP and EFV groups were stratified by TB treatment exposure status. While more hepatotoxic events occurred in the group exposed to TB treatment than in those not exposed (9% vs. 3%, P = 0.05), there was no difference between patients treated with NVP and those treated with EFV. CONCLUSIONS: Patients co-infected with HIV and TB in Botswana can be treated effectively with either NVP- or EFV-based ART and TB treatment. As hepatotoxic events were more common in the group exposed to TB treatment, liver function tests should be monitored closely.

Pharmacokinetics and safety of nelfinavir when used in combination with zidovudine and lamivudine in HIV-infected pregnant women: Pediatric AIDS Clinical Trials Group (PACTG) Protocol 353.

BACKGROUND: Combination antiretroviral regimens including nelfinavir (NFV) are commonly used in pregnancy. We studied the safety, antiviral effect, and pharmacokinetics of NFV and its M8 metabolite with two dosing regimens in combination with zidovudine (ZDV) and lamivudine (3TC) in HIV-infected pregnant women. METHOD: HIV-infected pregnant women between 14 and 34 weeks gestation received NFV (Cohort 1: 750 mg tid, n = 10; Cohort 2: 1250 mg bid, n = 23) with ZDV and 3TC. Serial blood sampling for NFV concentrations was performed antepartum (AP) and 6 weeks postpartum (PP). Maternal and cord blood samples were also obtained at delivery. NFV and M8 levels were determined by high-performance liquid chromatography. The pharmacokinetic (PK) target was an extrapolated NFV AUC0-24 > 30 mug . h/mL. Mothers were followed frequently for potential clinical and laboratory toxicity. RESULTS: Overall, NFV in combination with ZDV and 3TC was well tolerated. The PK target was met in 3/8 AP and 5/7 PP in Cohort 1 and 17/21 AP and 16/17 PP in Cohort 2. When Cohort 2 NFV PK parameters AP and PP were compared, median Cmax (3.90 microg/mL vs. 5.01 microg/mL, p < .05) and AUC0-24 (56.6 vs. 86.8 microg . h/mL, p < .05) were increased PP and oral clearance (Cl/F; 44.2 vs. 28.8 L/h, p < .05) was decreased PP. The average M8/NFV ratio was increased PP compared to AP (0.085 vs. 0.29, p < .001). Placental transfer of NFV was low with a median cord blood:maternal plasma ratio at delivery of 0.05. Maternal mean CD4+ T cell counts increased significantly and plasma HIV-1 RNA levels decreased from entry to delivery and 6 to 12 weeks postpartum. CONCLUSION: NFV used in combination with ZDV and 3TC was well tolerated in pregnant HIV-infected women and produced a significant improvement in HIV disease parameters. NFV drug exposure is inadequate in most pregnant women receiving 750 mg tid but is much improved with 1250 mg bid. NFV crosses the placenta poorly. The AP increase in NFV oral clearance and decrease in M8/NFV ratio suggest that CYP3A activity increases relative to CYP2C19 activity during pregnancy.

Resource utilization for multidrug-resistant tuberculosis household contact investigations (A5300/I2003).

BACKGROUND: Current guidelines recommend evaluation of the household contacts (HHCs) of individuals with multidrug-resistant tuberculosis (MDR-TB); however, implementation of this policy is challenging. OBJECTIVE: To describe the resource utilization and operational challenges encountered when identifying and characterizing adult MDR-TB index cases and their HHCs. DESIGN: Cross-sectional study of adult MDR-TB index cases and HHCs at 16 clinical research sites in eight countries. Site-level resource utilization was assessed with surveys. RESULTS: Between October 2015 and April 2016, 308 index cases and 1018 HHCs were enrolled. Of 280 index cases with sputum collected, 94 were smear-positive (34%, 95%CI 28-39), and of 201 with chest X-rays, 87 had cavitary disease (43%, 95%CI 37-50) after a mean duration of treatment of 8 weeks. Staff required 512 attempts to evaluate the 308 households, with a median time per attempt of 4 h; 77% (95%CI 73-80) of HHCs were at increased risk for TB: 13% were aged <5 years, 8% were infected with the human immunodeficiency virus, and 79% were positive on the tuberculin skin test/interferon-gamma release assay. One hundred and twenty-one previously undiagnosed TB cases were identified. Issues identified by site staff included the complexity of personnel and participant transportation, infection control, personnel safety and management of stigma. CONCLUSION: HHC investigations can be high yield, but are labor-intensive.

HIV testing uptake among the household contacts of multidrug-resistant tuberculosis index cases in eight countries.

SETTING: The household contacts (HHCs) of multidrug-resistant tuberculosis (MDR-TB) index cases are at high risk of tuberculous infection and disease progression, particularly if infected with the human immunodeficiency virus (HIV). HIV testing is important for risk assessment and clinical management. METHODS: This was a cross-sectional, multi-country study of adult MDR-TB index cases and HHCs. All adult and child HHCs were offered HIV testing if never tested or if HIV-negative >1 year previously when last tested. We measured HIV testing uptake and used logistic regression to evaluate predictors. RESULTS: A total of 1007 HHCs of 284 index cases were enrolled in eight countries. HIV status was known at enrolment for 226 (22%) HHCs; 39 (4%) were HIV-positive. HIV testing was offered to 769 (98%) of the 781 remaining HHCs; 544 (71%) agreed to testing. Of 535 who were actually tested, 26 (5%) were HIV-infected. HIV testing uptake varied by site (median 86%, range 0-100%; P < 0.0001), and was lower in children aged <18 years than in adults (59% vs. 78%; adjusted for site P < 0.0001). CONCLUSIONS: HIV testing of HHCs of MDR-TB index cases is feasible and high-yield, with 5% testing positive. Reasons for low test uptake among children and at specific sites-including sites with high HIV prevalence-require further study to ensure all persons at risk for HIV are aware of their status.

CD4 cell count as a surrogate endpoint in HIV clinical trials: a meta-analysis of studies of the AIDS Clinical Trials Group.

OBJECTIVE: To evaluate initial changes in CD4 cell count as a surrogate endpoint for clinical outcome in HIV-infected patients. DESIGN: Meta-analysis of all relevant Phase II and III randomized clinical trials undertaken by the Adult AIDS Clinical Trials Group. METHODS: Individual patient data were obtained from each clinical trial, and the difference between a pair of treatments in their effect on clinical outcome (AIDS or death, or death alone) during 2 years of follow-up was evaluated. The proportion of treatment effect explained (PTE) was the proportion of this difference explained by the change in CD4 cell count 6 months after starting treatment, evaluated using proportional hazards models. A weighted average PTE across treatment comparisons was obtained. The association between the difference between treatments in clinical outcome, expressed as hazard ratio, and the difference in mean change in CD4 cell count was evaluated using regression analysis. RESULTS: There were 15 clinical trials involving 24 treatment comparisons. The weighted average PTE for both progression to AIDS or death was 0.16 [95% confidence interval (Cl), 0.07-0.26] and for death was 0.10 (95% Cl, 0.00-0.20). There were significant associations between treatment differences in effect on AIDS or death, and on death alone, and the difference in mean change in CD4 cell count. A difference in mean change in CD4 cell count of 30 or 40 x 10(6)/l or more in favor of the test treatment indicated with high probability that there was a corresponding difference in progression to AIDS or death. CONCLUSIONS: The small PTE suggest that other mechanisms of drug action not captured by initial change in CD4 cells are important. CD4 cell count is a weak surrogate endpoint, but has some value as an aid for screening treatments for drug development or preliminary regulatory approval.

The values of quantitative serum HIV-1 RNA levels and CD4 cell counts for predicting survival time among HIV-positive individuals with CD4 counts of < or = 50 x 10(6) cells/l.

OBJECTIVE: To evaluate the HIV-1 RNA level as a predictor of survival time among individuals with advanced AIDS. METHODS: The serum HIV-1 RNA level, the CD4 cell count, and other clinical variables were evaluated at baseline, as predictors of survival time, among 56 retrospectively identified HIV-1 positive individuals with < or = 50 x 10(6) CD4 cells/l who attended the Beth Israel Deaconess Medical Center, Division of Infectious Diseases, between 1 July 1989 and 30 September 1993. RESULTS: During follow-up, 55 of these 56 patients died. The median survival time was 20.5 months. In univariate Cox proportional hazard modeling neither the baseline HIV-1 RNA level nor the CD4 cell count were predictive of survival time. However, in multivariate models longer survival time was associated with the use of trimethoprim-sulphamethoxazole at entry [hazard ratio (HR), 0.42; P = 0.007], whereas shorter survival time was associated with a history of an AIDS-defining illness other than Pneumocystis carinii pneumonia (HR, 2.87; P = 0.007). Correlative analysis revealed a modest correlation of the baseline CD4 cell count with survival time (Spearman p = 0.41; P = 0.002). However, no correlation was found between HIV RNA levels and survival time (P = 0.5). CONCLUSIONS: In this population with very advanced disease, the HIV-1 RNA level was a poor discriminator of survival time, being inferior to the CD4 cell count and to specific clinical variables such as the nature of the prior AIDS-defining illness and the type of Pneumocystis carinii pneumonia prophylaxis employed. Among individuals with advanced AIDS, these data emphasize the relative importance of the CD4 cell count and of specific clinical factors, over the HIV-1 RNA level in predicting survival time.

Neuromuscular function in HIV infection: analysis of a placebo-controlled combination antiretroviral trial. AIDS Clinical Group 175/801 Study Team.

OBJECTIVE: To determine the frequency of peripheral neuropathy and myopathy in HIV-infected subjects enrolled in a combination antiretroviral treatment trial. DESIGN AND METHODS: AIDS Clinical Trial Group (ACTG) protocol 175 was a multicenter, double-blind, placebo-controlled, clinical trial. A total of 2467 subjects were randomized to one of four single or combination regimens, containing zidovudine (ZDV), didanosine (ddl), zalcitabine (ddC), and their respective placebos. Site investigators reported peripheral neuropathy, and the diagnosis of distal symmetrical neuropathy (DSP) was established by the study authors. Myalgia, muscle weakness and creatine phosphokinase (CPK) were prospectively assessed in a subset of the antiretroviral-naive cohort (n = 1067). RESULTS: Of 222 site diagnoses of neuropathy, 109 (49%) were DSP. There was a significant difference between treatment arms for rate of DSP and time to first grade 2 or higher DSP (ZDV-ddC, 6%; ZDV, 4%; ZDV-ddl, 4%; ddl, 3%; P = 0.029). Age and Karnofsky score were significant predictors of DSP. Fifty-six (54%) out of 104 patients with DSP remained on study medication at full (n = 29) or reduced (n = 27) dose within 6 months of developing neuropathy. There was no significant difference between treatment arms in the rate of myalgia or muscle weakness. The median CPK of subjects on ZDV-ddC was significantly higher than other study treatments, although CPK levels did not correlate with symptoms of myopathy. Only six subjects were diagnosed with myopathy during the study (one ZDV-ddl, one ZDV-ddC, and four ddl). CONCLUSIONS: DSP and myopathy may occur with current dosing regimens of combination antiretroviral therapy, and should be diagnosed using stringent criteria. ZDV-ddC was associated with the highest rate of DSP, although features of myopathy were not significantly different between treatment regimens.

The delivery of antisense therapeutics.

Antisense oligonucleotides, ribozymes and DNAzymes have emerged as novel, highly selective inhibitors or modulators of gene expression. Indeed, their use in the treatment of diseases arising from genetic abnormalities has become a real possibility over the past few years. The first antisense drug molecule is now available for clinical use in Europe and USA. However, their successful application in the clinic will require improvements in cellular targeting and intracellular delivery. This review aims to look at recent advances in the in vitro and in vivo delivery of antisense oligodeoxynucleotides and ribozymes.

Meta-analysis of five randomized controlled trials comparing continuation of zidovudine versus switching to didanosine in HIV-infected individuals.

A meta-analysis of the original data from 2411 patients in the ACTG 116A, ACTG116B/117, ACTG175, BMS010 and CTN002 trials was conducted to improve the estimate of the effect of switching from zidovudine to didanosine on rates of clinical progression, to better quantify the rates of neurological events (including AIDS dementia and peripheral neuropathy) and to examine the effects of switching from zidovudine to didanosine among women and racial subgroups. In total, 1012 patients received zidovudine therapy, 557 received high-dose didanosine and 842 received didanosine. The median duration of follow-up was 15 months. Ninety-one percent of patients were male, 78% were white, mean age was 36.5 years. The median CD4 count was 195 cells/mm3 (range: 0-762) and the median duration of prior zidovudine therapy was 14 months (range: 0.1-94). There were 336 deaths and 686 new AIDS-defining illnesses (ADIs) or deaths. After stratification by study and adjusting for baseline CD4 count and presence of an AIDS diagnosis prior to baseline, the relative risks of death associated with switching from zidovudine to high-dose didanosine or to didanosine were 0.94 (P = 0.64) and 0.77 (P = 0.07), respectively. The relative risks of a new ADI or death associated with switching from zidovudine to high-dose didanosine and didanosine were 0.78 (P = 0.01) and 0.66 (P = 0.0001), respectively. There were 21 documented cases of AIDS dementia complex (ADC) during the entire follow-up period. The rates per 100 person years of follow-up were 0.70, 0.65 and 0.41 for the zidovudine, high-dose didanosine and didanosine arms, respectively. There were no significant differences in risks of ADC between treatment arms (zidovudine versus high-dose didanosine: P = 0.30, zidovudine versus didanosine: P = 0.97, didanosine versus high-dose didanosine: P = 0.41). Our data confirm a clinical benefit and CD4 increase associated with a switch from zidovudine to didanosine therapy. No statistical differences were detected between doses of didanosine with respect to survival or progression to a new ADI or death. Furthermore, there was no statistical difference in the frequency of ADC between treatment arms.

Both serum HIV type 1 RNA levels and CD4+ lymphocyte counts predict clinical outcome in HIV type 1-infected subjects with 200 to 500 CD4+ cells per cubic millimeter. AIDS Clinical Trials Group Study 175 Virology Study Team.

To evaluate HIV-1 RNA and CD4+ cell responses to therapy as predictors of clinical progression and to evaluate levels and trends of these markers prior to clinical failure, HIV-1 RNA measurements were retrospectively obtained on subjects who progressed to AIDS or death and a random sample of subjects who did not. Samples were taken from AIDS Clinical Trials Group Study 175, a randomized trial comparing nucleoside analog therapies in subjects with CD4+ cell counts of between 200 and 500 cells/mm3. HIV-1 RNA and CD4+ cell count independently predicted clinical progression. Risk of subsequent progression is best captured by the change to the last measured value for CD4+ cell count and the area under the curve minus baseline, a measure of viral replication over time, for HIV-1 RNA. Subjects who failed had lower CD4+ cell counts, greater rates of CD4+ cell decline, and higher HIV-1 RNA levels, but not greater rates of HIV-1 RNA increase than subjects who did not. Subjects who maintained more than 200 CD4+ cells/mm3 and fewer than 10,000 copies of HIV-1 RNA per milliliter had low risk of progression. During the first few months of therapy, treatments are best monitored by regular HIV-1 RNA and less frequent CD4+ cell measurements. Thereafter, both markers should be monitored on a similar schedule to identify rapidly declining CD4+ cell counts, or adverse levels of either. These results further delineate the prognostic significance of HIV-1 RNA and CD4+ cell count and should help to better define their utility in the practice setting.

Virologic and CD4 cell response to zidovudine or zidovudine and lamivudine following didanosine treatment of human immunodeficiency virus infection.

To optimize nucleoside reverse transcriptase inhibitor (nRTI) antiretroviral therapy, 137 subjects who had been treated with didanosine monotherapy for more than 3 years in the AIDS Clinical Trials Group (ACTG) 175 study were randomized to zidovudine and didanosine (dual therapy) or zidovudine, didanosine, and lamivudine (triple therapy). Evaluation of early (8 week) change in HIV plasma RNA demonstrated that addition of lamivudine and zidovudine provided significantly greater virologic suppression compared to the addition of zidovudine alone (mean decrease of 1.27 vs. 0.74 log(10) copies/ml, n = 108, p = 0.007). Both dual and triple therapy provided significant long-term decreases (from study entry to mean at Weeks 40 and 48) in HIV plasma RNA: 0.62 and 0.86 log(10) copies/ml, respectively (n = 110). However, the difference between treatments was not significant (p = 0.16). At 48 weeks, 26% of subjects starting study treatment had <500 copies/ml of plasma HIV RNA. The CD4 count response was greater at 4 weeks for triple versus dual therapy: a mean increase of 51 vs. 12 CD4 cells/ml(3) (n = 126, p = 0.039). The difference at Weeks 40 and 48 was not significant (a 22 cell increase vs. a 1 cell decrease, n = 129, p = 0.41). Zidovudine and didanosine treatment, with or without lamivudine, was well tolerated and only 2 of 137 (1.5%) of study participants developed an AIDS-defining event over 48 weeks.

Effect of lamivudine in HIV-infected persons with prior exposure to zidovudine/didanosine or zidovudine/zalcitabine.

Nucleoside analog-based regimens remain an integral component of combination therapy for use in both antiretroviral treatment-naive and experienced HIV-infected patients. To further define treatment responses to new antiretroviral therapy in patients with long-term experience to dual nucleoside analog therapy (zidovudine [ZDV] plus didanosine [ddI] or ZDV plus zalcitabine [ddC]), 325 subjects derived from the AIDS Clinical Trials Group (ACTG) 175 trial were randomized to three different combination regimens: (1) continuation of ZDV + ddI or ZDV + ddC (continuation arm), (2) addition of 3TC to ZDV + ddI or ZDV + ddC (addition arm), or (3) a switch to ZDV + 3TC therapy (switch arm). Both the addition and switch arms sustained significantly greater short-term (baseline to week 4) mean CD4+ cell count increases compared with the continuation arm (+36, +28 versus -4 cells/mm3; p = 0.012) and long-term CD4+ cell count responses (baseline to weeks 40/48: +32, +19 versus -9 cells/mm3; p = 0.003). Superior short-term (baseline to week 8) mean decreases in plasma HIV RNA (p < 0.001) were achieved by both the addition and switch arms (0.53 log10 and 0.54 log10 copies/ml, respectively) compared with the continuation arm (0.13 copies/ml) whereas no differences in long-term virologic suppression were observed (p = 0.30). At week 48, no differences were observed in the proportions of subjects who had HIV RNA levels below 500 copies/mL: 18% of subjects in each treatment arm (3-way p = 1.0). Overall, the treatments were well tolerated and only nine subjects (3%) died or developed one or more AIDS-defining events. While this study confirms the intrinsic antiretroviral activity of 3TC, only modest marker changes and limited short-term viral suppression are seen with incremental addition of the drug. The current approach of using 3TC in maximally suppressive regimens is preferred.

Within-subject diastolic blood pressure variability: implications for risk assessment and screening.

Because of variability in diastolic blood pressure within an individual, repeated measurements increase precision in assessing an individual's underlying mean pressure and so also aid risk classification. Data from a cohort of 11,299 middle-aged men is used to model the variability in diastolic pressure between annual measurements. A simple model with pressure normally distributed about an underlying mean with standard deviation increasing with level fits the data very well. In modelling risk of cardiovascular mortality, a strong association is found with observed diastolic pressure level but not to trends in or variability between observed values. The effect of regression dilution is clear with the risk relationship appearing greater as one uses the mean of an increasing number of measurements. A method of adjusting for this regression dilution is described so giving an estimate of the relationship with underlying mean diastolic pressure. Using this survival model and the model for blood pressure variability, a method is presented for estimating both underlying mean pressure and absolute risk of cardiovascular disease given a sequence of blood pressure measurements from screening. This allows a sequential strategy for determining whether (a) antihypertensive intervention is desirable, (b) no further screening is necessary, or (c) further screening would aid the assessment, and emphasizes the need to consider blood pressure in the context of multiple risk factors.

Intrahousehold allocation of energy intake among children under five years and their parents in rural Bangladesh.

OBJECTIVE: This study assesses intrahousehold allocation of energy in rural Bangladesh and tests the hypothesis that, when daily energy intake is adjusted for energy expenditure, no age or gender bias will be apparent in intrahousehold energy allocation. DESIGN: Data were collected at two-month intervals over a one year study. SETTING: Four villages in Matlab Thana, rural Bangladesh. SUBJECTS: Two hundred and seven children up to 5 y of age and their 145 mothers and 123 fathers. INTERVENTIONS: Data included six measurements of observed 24 h dietary energy intake and physical activity recorded from waking to sleeping. Total daily energy expenditure was derived using the factorial method. RESULTS: Women's energy intake ranged from 75-88% of the FAO/WHO recommended energy intake over the six periods of data collection, significantly less (P < 0.0001) than the men's (range 89-114%). Although the women had moderate levels of physical activity, frequent pregnancies and long lactation periods increased their energy needs. Among children no longer breast fed, energy consumption, unadjusted for energy expenditure, provided 86-108% of the FAO/WHO recommended energy intake by weight. CONCLUSIONS: Women consistently received less of their energy requirements than either their children or their husbands.

PIP: Data collected during 1977-78 in 4 villages in Matlab Thana, Bangladesh, on 207 children under 5 years of age and their 145 mothers and 123 fathers were used to investigate the hypothesis that, when daily energy intake is adjusted for energy expenditure, energy needs are met and no age or gender bias will be evident in intrahousehold energy allocation. During the 12-month study period, data were collected every 2 months on 24-hour dietary energy intake and physical activity. Women's energy intake ranged from 75% to 88% of the Food and Agriculture Organization (FAO)/World Health Organization (WHO) recommended intake, even though their physical activity levels, frequent pregnancies, and long lactation periods increased their energy needs. Men's energy intake ranged from 89% to 114% of the FAO/WHO standard. Among weaned children, energy consumption, unadjusted for energy expenditure, provided 86-108% of the recommended energy intake by weight. The finding that fathers generally met their energy requirements is assumed to reflect their role as producers of the family's food supply. Feeding men during periods of peak agricultural labor demand, even at the expense of lower intakes for their wives and children, may be perceived as essential to the household's survival. Agricultural and income generation programs to increase total energy availability to households, family planning services to diminish the burden of childbearing, and enhanced educational opportunities for women all have the potential to help mothers meet their energy needs.

Adjusting for regression toward the mean when variables are normally distributed.

Many studies use the same variable, for example blood pressure in studies of antihypertensive treatments, to identify subjects to be included in the study and to evaluate the effects of a treatment. As a consequence, if not properly accounted for, the effect of regression toward the mean can confound the evaluation of treatment effects if the study has no randomized control group. In this paper we review the methods that have been proposed for adjusting for the effect of regression toward the mean when the variable of interest is assumed to be normally distributed. Maximum likelihood estimation and moment-based estimation are considered, including more recent methods which can be applied when repeated measurements on each subject are available.

Magnetic resonance imaging as a surrogate outcome for multiple sclerosis relapses.

BACKGROUND: Magnetic resonance imaging (MRI) of lesions in the brain may be the best current candidate for a surrogate biological marker of clinical outcomes in relapsing remitting multiple sclerosis (MS), based on its role as an objective indicator of disease pathology. No biological surrogate marker has yet been validated for MS clinical outcomes. OBJECTIVE: The objective of this study was to use a multi-phased study to determine if a valid surrogate relationship could be demonstrated between counts of contrast enhancing lesions (CELs) and occurrence of relapses in MS. METHODS: We examined correlations for the concurrent and predictive relationship between CELs over 6 months and MS relapses over the same 6 months and an additional 6 months (total: 12 months), using available data on untreated patients from a large clinical trial and natural history database. RESULTS: Concurrent and predictive correlations were inadequate to justify continuation of this study to the planned additional phases required to demonstrate a surrogate relationship between CELs and MS relapses. CONCLUSIONS: Confidence intervals for correlations between CELs and MS relapses exclude the possibility that CELs can be a good surrogate for relapses over the time scales we investigated. Further exploration of surrogacy between MRI measures and MS clinical outcomes may require improved datasets, the development of MRI techniques that couple better to clinical disease, and the ability to test a wide range of imaging- and clinically-based hypotheses for surrogacy.

Regression dilution in the proportional hazards model.

The problem of regression dilution arising from covariate measurement error is investigated for survival data using the proportional hazards model. The naive approach to parameter estimation is considered whereby observed covariate values are used, inappropriately, in the usual analysis instead of the underlying covariate values. A relationship between the estimated parameter in large samples and the true parameter is obtained showing that the bias does not depend on the form of the baseline hazard function when the errors are normally distributed. With high censorship, adjustment of the naive estimate by the factor 1 + lambda, where lambda is the ratio of within-person variability about an underlying mean level to the variability of these levels in the population sampled, removes the bias. As censorship increases, the adjustment required increases and when there is no censorship is markedly higher than 1 + lambda and depends also on the true risk relationship.

Reporting Bayesian analyses of clinical trials.

Many clinicians wrongly interpret p-values as probabilities that treatment has an adverse effect and confidence intervals as probability intervals. Such inferences can be validly drawn from Bayesian analyses of trial results. These analyses use the data to update the prior (or pre-trial) beliefs to give posterior (or post-trial) beliefs about the magnitude of a treatment effect. However, for these methods to gain acceptance in the medical literature, understanding between statisticians and clinicians of the issues involved in choosing appropriate prior distributions for trial reporting needs to be reached. I focus on two types of prior that deserve consideration. The first is the non-informative prior giving standardized likelihood distributions as post-trial probability distributions. Their use is unlikely to be controversial among statisticians whilst being intuitively appealing to clinicians. The second type of prior has a spike of probability mass at the point of no treatment effect. Varying the magnitude of the spike illustrates the sensitivity of the conclusions drawn to the degree of prior scepticism in a treatment effect. With both, graphical displays provide clinical readers with the opportunity to explore the results more fully. An example of how a clinical trial might be reported in the medical literature using these methods is given.