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Biomedical subjects

D R Hoover

Publications and source records attributed to D R Hoover.

125 records · Page 7Linked to original sources
PubMed1992

The progression of untreated HIV-1 infection prior to AIDS.

Using a case-control study of untreated men, we investigated the physical, mental, and economic effects of human immunodeficiency virus (HIV-1) infection prior to the diagnosis of acquired immunodeficiency syndrome (AIDS). Beginning 2 to 2.5 years prior to AIDS, case subjects reported more of 12 HIV-1 related symptoms and during the year prior to AIDS, at least 30.6 extra days of these symptoms than did control subjects. Within the 6 months preceding AIDS, case subjects' unemployment rose to 9% (P < or = .05) and depression to 34.2% (P < or = .001). At 6 to 12 months and within 6 months before AIDS, 17.1% and 31.5%, respectively, were anemic, while 37.7% and 64.7% had CD4+ counts less than 200 x 10(6)/L. Diagnosing AIDS at CD4+ counts less than 200 x 10(6)/L could significantly reduce pre-AIDS morbidity. Other implications of these findings are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Effect of CD4+ cell count measurement variability on staging HIV-1 infection.

A single CD4+ cell count (CD4) measurement is often used to stage HIV-1 infection, decide when to initiate prophylactic therapy and inform patients, and may soon even define AIDS onset. Documentation of the reliability and validity of employing CD4 for the above purposes in a population-based setting is needed. We utilized data from 4,954 homosexual/bisexual men followed over 6 years, with CD4 testing at 6 month intervals, to study the timing of CD4-based staging of HIV-1 disease and quantify and evaluate the potential impact of CD4 measurement error. The median time from seroconversion to first CD4 test below 500 x 10(6)/L or clinical AIDS was 1.70 years, and the first CD4 test below 200 x 10(6)/L or clinical AIDs was 5.29 years. The time from first testing less than 500 x 10(6)/L to clinical AIDS in untreated men was 5.55 years. With confirmatory retesting, these times were significantly lengthened. The 95% confidence ranges for the true CD4 state in individuals with measured CD4 of 500 and 200 x 10(6)/L are at least (297 x 10(6), 841 x 10(6)/L) and (118 x 10(6), 337 x 10(6)/L), respectively. Without confirmatory retesting, individuals with true CD4 remaining at 700 x 10(6) and 280 x 10(6)/L have at least a 40% chance for one of five CD4 measurements to fall below guideline limits of 500 x 10(6) and 200 x 10(6)/L, respectively. Confirmatory retesting can reduce these probabilities to as low as 4%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Estimating the 1978-1990 and future spread of human immunodeficiency virus type 1 in subgroups of homosexual men.

The authors studied the historical spread of human immunodeficiency virus type 1 (HIV-1) infection in homosexual/bisexual men and projected its future spread in these men using data from an AIDS-free cohort recruited during late 1984 in Baltimore, Maryland; Chicago, Illinois; Los Angeles, California; and Pittsburgh, Pennsylvania. Dates of preentry seroconversion in HIV-1 seroprevalent men were estimated using study entry values of hematologic variables influenced by HIV-1 infection. The authors used survival methods incorporating truncation to determine numbers/dates of seroconversion for men with a pre-1984 AIDS diagnosis who were selectively excluded by design from the 1984 AIDS-free cohort. Overall, the annual seroconversion hazard rose progressively from 0.4% in 1978 to 13.8% in 1983, dropped to 4.6% in 1985, and remained relatively stable at 1.1-2.2% from 1986 to 1990. By January 1990, almost 46% of men who were seronegative in 1978 had seroconverted. The authors estimated historical rates of spread by city, age, education, and ethnicity to examine the effects of these factors in the early and continuing stages of the HIV-1 epidemic. There were striking differences among cities with respect to pre-1985 seroconversion rates but not with respect to post-1985 seroconversion rates. Age, education, and ethnicity were all associated with 1978-1990 seroconversion rates. Future seroconversion among homosexual men was predicted assuming that the "stabilized" 1986-1990 hazards (stratified by age) observed here will be representative of future rates. Truncated Kaplan-Meier methods gave the probability of a seronegative 20-year-old man's remaining seronegative in subsequent years. Such a man has a 20.2% chance of seroconverting before reaching the age of 25 years (a 4.4% yearly hazard). The annual hazard drops to 2.5% between 25 and 30 years, to about 1.5% between 30 and 45 years, and to 1.0% between 45 and 55 years. The overall probability of seroconversion prior to age 55 years is about 50%, with seroconversion still continuing at and after age 55. Given that this cohort consists of volunteers receiving extensive anti-HIV-1 transmission education, the future seroconversion rates of the general homosexual population may be even higher than those observed here.

Adult↗
PubMed1991

The unseen sample in cohort studies: estimation of its size and effect. Multicenter AIDS Cohort Study.

Recruitment of disease-free subjects into cohort studies and measurement of their time from exposure/infection to disease selectively excludes individuals (the unseen sample) who had earlier exposure and who have shorter times to disease. The unseen and observed samples may differ in other characteristics in addition to incubation period and exposure/infection time. For data with known truncation times, we develop non-parametric maximum likelihood estimates of the size, exposure/infection dates and distribution of incubation time in the unseen sample. We provide procedures to estimate and compensate for the biasing effects due to exclusion of the unseen sample in descriptive and survival analysis. We give consistency properties of these estimates and assess variability using bootstrap methods. One can use imputation to derive the above estimates from data with unknown truncation times that have been estimated parametrically. Application is made to an AIDS cohort study of over 5000 homosexual men. Important estimates obtained from this application are the annual seroconversion rates from 1978 to 1983, not otherwise obtainable in this study population.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Epidemiologic patterns of upper respiratory illness and Pneumocystis carinii pneumonia in homosexual men.

The relationship between self-reported upper respiratory illness symptoms (URI) and human immunodeficiency virus Type 1 (HIV-1) was examined in homosexual men using semiannual visits from 1984 to 1988. Temporal and geographic patterns of Pneumocystis carinii pneumonia (PCP) diagnosis in these men during the same time period are also described. URI, including acute sinusitis, was reported more often by 916 HIV-1-seropositive participants than by 2,161 seronegative participants (32.21 versus 28.86% p less than 0.001). For 387 seropositive subjects who progressed to acquired immunodeficiency syndrome (AIDS), the proportion reporting URI peaked one visit pre-AIDS at a level significantly higher than matched control subjects (0.45 versus 0.28, p less than or equal to 0.001). The peak was higher for those with PCP as an initial diagnosis. Reported URI peaked in winter and troughed in summer, and PCP diagnosis rates peaked and troughed 4 months later, respectively. Cities with the highest reported rates of URI also had the highest proportions of AIDS cases with PCP as an initial diagnosis. No temporal or geographic patterns were observed for other HIV-1-related symptoms or non-PCP AIDS diagnoses. These patterns suggest the possibility of a person-to-person transmission of P. carinii similar to that of other respiratory pathogens, which would imply a need to consider stricter methods to prevent nosocomial transmission of this pathogen in inpatient and outpatient settings. Further investigation of these issues is needed.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The association of blood pressure levels and change in renal function in hypertensive and nonhypertensive subjects.

We compared the changes in serum creatinine levels over time after a mean follow-up of 9.8 years in essential hypertensive (EH, n = 56) and control (n = 59) male veteran subjects. All subjects had normal serum creatinine levels (62 to 124 mumol/L) and "normal" urinalysis results on entry into the study. Subjects with comorbid renal diagnoses and diabetes mellitus were eliminated from the analysis. Although not statistically significant, the rate of change in the serum creatinine concentration over time was greater in the EH cohort compared with the control cohort (1.08 +/- 4.8 vs 0.027 +/- 3.5 mumol/L per year). The difference was especially marked in black EH subjects vs black control subjects (1.60 +/- 6.2 mumol/L per year vs -0.21 +/- 3.3 mumol/L per year). When age, race, body mass index, and a diagnosis of EH were entered into a logistic regression analysis, EH subjects had a statistically significantly greater rate of decline in renal function than did control subjects (1.5 +/- 8.3 mumol/L per year). When mean time-averaged systolic blood pressure for each subject was also included in the logistic regression analysis, only systolic time-averaged blood pressure was statistically significant (0.063 +/- 0.029 mumol/L per year). We conclude that in the absence of clinically detected parenchymal renal disease, EH subjects have a greater rate of decline in renal function than do nonhypertensive subjects. Time-averaged blood pressure is predictive of the change in serum creatinine concentration not only in EH subjects but also in nonhypertensive subjects. Thus, preservation of renal function may require a blood pressure lower than the currently accepted normotensive range.

Blood Pressure↗
PubMedDate not supplied

Using multiple decrement models to estimate risk and morbidity from specific AIDS illnesses. Multicenter AIDS Cohort Study (MACS).

A simple non-parametric approach is developed to simultaneously estimate net incidence and morbidity time from specific AIDS illnesses in populations at high risk for death from these illnesses and other causes. The disease-death process has four-stages that can be recast as two sandwiching three-state multiple decrement processes. Non-parametric estimation of net incidence and morbidity time with error bounds are achieved from these sandwiching models through modification of methods from Aalen and Greenwood, and bootstrapping. An application to immunosuppressed HIV-1 infected homosexual men reveals that cytomegalovirus disease, Kaposi's sarcoma and Pneumocystis pneumonia are likely to occur and cause significant morbidity time.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

The effectiveness of interventions on incubation of AIDS as measured by secular increases within a population.

Methods are developed to estimate and test for the impact of intervention use on a population's survival function (time to AIDS). Each participant's history is divided into J + 1 components: omega 0 occurring before the intervention is available and omega 1 to omega J occurring later, as the intervention becomes successively more available. Distribution free truncated Kaplan-Meier models based on time since exposure fit separately to the risk sets/outcomes in omega 0 to omega J directly show the changing patterns of survival. Multivariate proportional hazards models can be used to adjust for covariates. Application of these methods indicates that availability of proven anti-AIDS interventions may have delayed time to AIDS by 8 months in an educated HIV-1 infected homosexual cohort with good access to medical care.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Alcohol consumption as a cofactor in the progression of HIV infection and AIDS.

Alcohol consumption as a cofactor in the progression of HIV infection was examined in 1,446 homosexual and bisexual HIV + men enrolled in the Multicenter AIDS Cohort Study who had a minimum of three visits. Two measures of drinking were employed: initial level, and pattern during the study period. Outcome measures included AIDS-related symptoms and AIDS diagnosis. Level of drinking at entry to the study was not significantly associated with either AIDS-related symptoms at final visit or with AIDS diagnosis. However, men who decreased drinking were more likely to report thrush, fatigue, weight loss, and diarrhea at their final visit. Most likely, these men decreased drinking as a result of failing health, not because their drinking pattern influenced symptom onset. These data support earlier reports that found no relationship between alcohol consumption and progression to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Attitudes of adolescent/young adult women toward human papillomavirus vaccination and clinical trials.

Human papillomavirus (HPV) is the most common sexually transmitted infection. It often inflicts adolescents and young adults shortly after onset of sexual activity. More than 30 types of HPV infect the anogenital area; some HPV types cause cervical cancer in women decades after infection, whereas other types cause genital warts in both men and women within a year after infection. Vaccines are being developed against oncogenic and wart-producing HPV. Knowledge of HPV and attitudes toward HPV vaccination/clinical trial participation among 60 female adolescents and young adults were evaluated. Knowledge of HPV in this group was limited, but almost all participants would be interested in receiving vaccines that prevented cervical cancer and genital warts. Only 30% were likely to participate in an HPV clinical trial that required shots and pelvic examinations. A key motivating factor for clinical trial participation was the potential for a vaccine to help other women.

Adolescent↗
PubMedDate not supplied

Early intervention for human immunodeficiency virus in Baltimore Sexually Transmitted Diseases Clinics. Impact on gonorrhea incidence in patients infected with HIV.

BACKGROUND: High incidences of sexually transmitted diseases (STD) after posttest counseling have been documented in patients diagnosed with human immunodeficiency virus (HIV) in Baltimore STD clinics. In July 1991, the authors instituted an HIV early intervention program providing long-term medical care and social work services. This study compares the incidence of gonorrhea after post-HIV+ test counseling in patients diagnosed with HIV before and after the institution of the early intervention program. METHODS: Medical records of a cohort composed of all patients newly diagnosed with HIV and those who underwent posttest counseling for HIV in 1991 to 1993 in two Baltimore STD clinics were reviewed. Patients were offered early intervention medical and social work services. Gonorrhea incidence in this cohort was compared to a historical cohort diagnosed and counseled for post-HIV+ testing in 1988 to 1989 who were not offered early intervention services. RESULTS: The mean follow-up time was 418 days (range, 26 to 703 days). After post-HIV+ test counseling, gonorrhea developed in 39 of 468 (8.3%) men in the 1989 cohort and 13 of 400 (3.3%) men in the 1991 to 1993 cohort. Controlling for variable length of follow-up, the 1991 to 1993 cohort had a relative risk of 0.442 for the development of gonorrhea during the study period (95% confidence interval, 0.225 to 0.790; P = 0.006). Incident gonorrhea after post-HIV+ test counseling also was associated with a prevalent gonorrhea condition at the time of HIV diagnosis (RR = 3.02; 95% CI, 1.75 to 5.23; P = 0.0001) and failure to return for post-HIV+ test counseling as scheduled (RR = 2.27; 95% CI, 1.17-4.43; P = 0.013). After adjustment for gonorrhea at the time of HIV diagnosis and failure to return for scheduled posttest counseling, the difference in gonorrhea incidence between men in the two cohorts remained statistically significant (RR = 0.494; 95% CI, 0.260 to 0.941; P = 0.032). In comparison, overall gonorrhea rates in Baltimore changed little between 1988 and 1993. No significant difference was found in gonorrhea incidence in women, which may have been the result of active gonorrhea screening during the 1991 to 1993 period, which was not performed in 1988 to 1989. CONCLUSIONS: Providing clinical care to persons with HIV may facilitate the reduction of high-risk behaviors that lead to incident STDs and further HIV transmission.

Adult↗
PubMedDate not supplied

Immunologic parameters of multiple chemical sensitivity.

Immunologic abnormalities have long been advanced as a potential mechanism for multiple chemical sensitivity (MCS). An immunologic mechanism is supported in part by the systemic nature of the symptoms reported, the complex interactions known to exist between the immune system and other systems, and limited experimental evidence. However, there are both theoretical grounds for doubting an immunologic mechanism in MCS and methodological constraints in many of the studies that have been conducted in humans. The authors discuss the structure and function of the immune system as it potentially applies to MCS, the uses and limitations of immunologic testing, and the evidence for immunologic theories of MCS. They describe recent work to validate some of the immunologic tests used in MCS and consider opportunities for further research.

Humans↗
PubMedDate not supplied

Stage of behavior change for condom use: the influence of partner type, relationship and pregnancy factors.

A theoretical model was used to examine the influence of relationship factors, pregnancy intentions, contraceptive behavior and other psychosocial characteristics on stages of behavior change in condom use among heterosexual black women of reproductive age. Data from an inner-city street survey compared women who were not contemplating condom use, women who were attempting to use condoms or had used them consistently for short periods of time, and those who had achieved long-term consistent use. Women's relationship with their main partner appears to be an important factor in understanding their use of condoms both with main partners and with other partners. For condom use with the main partner, factors such as emotional closeness and partner support were significant predictors of the likelihood that women would be attempting to use condoms rather than not contemplating use. Cohabitation and the belief that condom use builds trust were significant predictors of long-term consistent condom use. Having a regular or main partner was strongly associated with intentions to use condoms with other partners. Women who wanted to become pregnant were much less likely to intend to use condoms with their main partner, and women using oral contraceptives were less likely to be long-term consistent condom users.

Adolescent↗