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Biomedical subjects

Mitchell H Katz

Publications and source records attributed to Mitchell H Katz.

18 recordsLinked to original sources
PubMed2006

Associations between substance use and sexual risk among very young men who have sex with men.

OBJECTIVE: To determine if an association exists in young men who have sex with men (MSM) between being under the influence of alcohol or drugs during sex and participation in sexual behaviors which increase the risk of human immunodeficiency virus (HIV). STUDY DESIGN: A total of 3492 young MSM were interviewed through the Young Men's Survey, an anonymous, cross-sectional, multisite, venue-based survey conducted from 1994 through 1998 at 194 public venues frequented by MSM aged 15 to 22 years in 7 US cities. RESULTS: The majority of young MSM reported both receptive and insertive anal intercourse, and of these, approximately half reported not using condoms. Report of unprotected receptive anal intercourse at least once in the prior 6 months was associated with being under the influence of alcohol (adjusted odds ratio [AOR]=1.5; 95% confidence interval [CI]=1.2-1.8), cocaine (AOR=1.6; 95% CI=1.1-2.2), amphetamines (AOR=1.5; 95% CI=1.1-2.0) or marijuana during sex (AOR=1.3; 95% CI=1.1-1.6). Report of unprotected insertive anal intercourse at least once in the prior 6 months was associated with being under the influence of alcohol (AOR=1.2; 95% CI=1.0-1.5), cocaine (AOR=1.5; 95% CI=1.1-2.0) or amphetamines (AOR=1.9; 95% CI=1.4-2.6). CONCLUSIONS: HIV prevention strategies for young MSM need to incorporate substance use risk reduction.

Adolescent↗
PubMed2006

Same-sex domestic partnerships and lower-risk behaviors for STDs, including HIV infection.

To determine the association between domestic partnership status and risk behaviors for sexually transmitted diseases, including HIV infection, we analyzed data from a population-based interviewer-administered telephone survey of 2,881 gay men in San Francisco, Los Angeles, New York and Chicago conducted in November 1996 to February 1998. Men in domestic partnerships had a statistically significantly lower prevalence of multiple partnerships, "one-night stands," and unprotected anal intercourse with a non-primary partner than either men with steady partners not identified as domestic partners or men without a steady partner. These findings were independent of age. Men in domestic partnerships had decreased risk behaviors for sexually transmitted diseases, including HIV infection, suggesting but not proving, that conferring legal status to same-sex unions might decrease sexual risk behavior.

Adolescent↗
PubMed2005

Seroconversion following nonoccupational postexposure prophylaxis against HIV.

BACKGROUND: The efficacy of antiretroviral postexposure prophylaxis (PEP) against infection with human immunodeficiency virus (HIV) following occupational exposures has prompted the use of PEP after nonoccupational exposures. There are, however, important differences between occupational and nonoccupational exposures, and the effectiveness of PEP following nonoccupational exposure is unknown. We sought to describe the occurrence and circumstances of HIV seroconversion following nonoccupational PEP. METHODS: HIV uninfected individuals reporting potential sexual or injection drug use exposures to HIV in the preceding 72 h received a 28-day regimen of antiretroviral therapy and counseling in a nonrandomized trial. The level of HIV antibody was measured 12 weeks after PEP initiation. RESULTS: Of 877 exposed subjects, 702 were evaluable 12 weeks after exposure. Seroconversion was detected in 7 subjects (1%; 95% confidence interval, 0.4%-2%). Three seroconverters reported having no exposures after PEP initiation and, thus, probably represent evidence of chemoprophylactic failure. In the other 4 subjects, additional exposures to HIV after PEP initiation or detection of HIV RNA in plasma specimens obtained at baseline precluded determination of the source of seroconversion. No exposure source was available to assess genetic concordance with the seroconverter's virus. CONCLUSIONS: As for occupational exposure, PEP is not completely effective in preventing HIV infection following nonoccupational exposure. Therefore, primary prevention remains essential. In contrast to the occupational setting, the potential source of exposure is rarely available for testing in the nonoccupational setting, and exposures are often not isolated. Thus, it is often impossible to determine whether seroconversion resulted from failure of PEP or from other exposures, posing difficulties for future comparative studies seeking to evaluate the effectiveness of PEP.

Anti-HIV Agents↗
PubMed2005

Clinical decision making during public health emergencies: ethical considerations.

Recent public health emergencies involving anthrax, the severe acute respiratory syndrome (SARS), and shortages of influenza vaccine have dramatized the need for restrictive public health measures such as quarantine, isolation, and rationing. Front-line physicians will face ethical dilemmas during public health emergencies when patients disagree with these measures. Patients might request interventions that are not recommended or for which they are not eligible, or they might object to intrusive or restrictive measures. The physician's primary responsibility in such emergencies is to the public rather than to the individual patient. In public health emergencies, physicians need to address the patient's needs and concerns, recognize their changed roles, and work closely with public health officials. Physicians can still work on behalf of patients by advocating for changes in policies and exceptions when warranted and by mitigating the adverse consequences of public health measures. Before an emergency occurs, physicians should think through how they will respond to foreseeable dilemmas arising when patients disagree with public health recommendations.

Decision Making↗
PubMed2005

The public health response to epidemic syphilis, San Francisco, 1999-2004.

In 1999, the Centers for Disease Control and Prevention launched the National Plan to Eliminate Syphilis. From 1999 to 2003 in San Francisco, early syphilis was epidemic, increasing from 44 cases to 522 cases a year. Syphilis cases were more likely to be in gay or bisexual men, those with human immunodeficiency virus (HIV) infection, those who had anonymous partners, and those who met sex partners on the Internet. Increases in sexual activity and sexual risk behavior in men who have sex with men during this period have been attributed to the improved physical health of HIV-infected men on highly active antiretroviral therapy, HIV treatment optimism, increases in methamphetamine use, and the use of Viagra. The San Francisco Department of Public Health's response to the epidemic included enhanced surveillance, expanded clinical and testing services, provider and community mobilization and sexual health education, and risk factor identification and abatement through investigations, public health advocacy, and treatment. Collaborations with community-based organizations and local businesses were key to the successful implementation of disease-control efforts. A multitude of converging risk factors and new environments contributed to the syphilis epidemic, requiring a comprehensive, innovative, and flexible disease-control strategy.

Contact Tracing↗
PubMed2004

Cost-effectiveness of HIV postexposure prophylaxis following sexual or injection drug exposure in 96 metropolitan areas in the United States.

OBJECTIVES: To evaluate the cost-effectiveness of HIV postexposure prophylaxis (PEP) following sexual or injection-related exposures in 96 metropolitan statistical areas in the United States (MSA). DESIGN: Empirical, model-based cost-effectiveness analysis. METHODS: Epidemiological and population size estimates from the literature were combined with information about the distribution of exposure types, PEP completion rate, proportion of source partners known to be HIV infected, and PEP program costs obtained from a feasibility study of PEP in San Francisco to estimate the cost-effectiveness of hypothetical PEP programs in each of the 96 MSA. The effectiveness of combination antiretroviral therapy following sexual or drug use-related exposures, which is presently not known, was assumed equal to the effectiveness of zidovudine monotherapy in the occupational setting. The main outcome measure was the cost-utility ratio, defined as the cost per quality-adjusted life year (QALY) saved by the PEP intervention. RESULTS: The cost-utility ratios for the 96 MSA ranged from 4137 dollars to 39,101 dollars per QALY saved; only two of the ratios exceeded 30,000 dollars per QALY saved. Combined across the 96 MSA, the hypothetical PEP programs would reach nearly 20,000 clients at a total cost of approximately 22 million dollars. The overall cost-utility ratio across MSA was 12,567 dollars per QALY saved. The majority of the HIV infections prevented by PEP were among men and women who reported receptive anal intercourse exposure. CONCLUSIONS: PEP following sexual or drug use-related exposures could be a cost-effective complement to existing HIV-prevention efforts in most MSA across the United States.

Chemoprevention↗
PubMed2004

HIV RNA testing in the context of nonoccupational postexposure prophylaxis.

BACKGROUND: The specificity and positive predictive value of human immunodeficiency virus (HIV) RNA assays have not been evaluated in the setting of postexposure prophylaxis (PEP). METHODS: Plasma from subjects enrolled in a nonoccupational PEP study was tested with 2 branched-chain DNA (bDNA) assays, 2 polymerase chain reaction (PCR) assays, and a transcription-mediated amplification (TMA) assay. Assay specificity and positive predictive value were determined for subjects who remained negative for HIV antibody for >or=3 months. RESULTS: In 329 subjects examined, the lowest specificities (90.1%-93.7%) were seen for bDNA testing performed in real time. The highest specificities were seen with batched bDNA version 3.0 (99.1%), standard PCR (99.4%), ultrasensitive PCR (100%), and TMA (99.6%) testing. Only the 2 assays with the highest specificities had positive predictive values >40%. For the bDNA assays, increasing the cutoff point at which a test is called positive (e.g., from 50 copies/mL to 500 copies/mL for version 3.0) increased both specificity and positive predictive values to 100%. CONCLUSIONS: The positive predictive value of HIV RNA assays in individuals presenting for PEP is unacceptably low for bDNA-based testing and possibly acceptable for PCR- and TMA-based testing. Routine use of HIV RNA assays in such individuals is not recommended.

Anti-HIV Agents↗
PubMed2004

Use of postexposure prophylaxis against HIV infection following sexual exposure does not lead to increases in high-risk behavior.

BACKGROUND: The effectiveness of postexposure prophylaxis (PEP) following occupational exposure to HIV has prompted advocacy for PEP following sexual or drug-use exposures. OBJECTIVE: To evaluate the concern that the availability of PEP for sexual or drug-use exposures might result in behavioral disinhibition. DESIGN: Non-randomized trial of 397 adults with high-risk sexual or drug-use exposures within the prior 72 h. INTERVENTIONS: Antiretroviral medication for 4 weeks and five counseling sessions. MAIN OUTCOME MEASUREMENTS: Participants were followed for 12 months for repeat request for PEP and for changes compared with pre-enrollment in overall high-risk behavior and the acquisition of sexually transmitted diseases (STD) and HIV. RESULTS: After 12 months following receipt of PEP, the majority of participants (83%) did not request a repeat course of PEP. At 12 months after exposure, 73% of participants reported a decrease compared with baseline in the number of times they had performed high-risk sexual acts; 13% reported no change, and 14% had an increase. Most participants (85%) had no change in the incidence of STD; 8.5% had a decrease and 6.8% an increase. Three homosexual men seroconverted for HIV (none associated with the presenting exposure) for a rate of 1.2/100 person-year, equivalent to rates in San Francisco among all homosexual men. CONCLUSIONS: After receipt of PEP consisting of antiretroviral medication and behavioral counseling following a potential sexual exposure to HIV, most individuals do not increase high-risk behavior. Coupled with prior safety and feasibility data, this lack of behavioral disinhibition suggests that use of PEP should be routinely considered following high-risk sexual exposures.

Adult↗
PubMed2004

Cost-effectiveness of postexposure prophylaxis after sexual or injection-drug exposure to human immunodeficiency virus.

BACKGROUND: The cost-effectiveness of interventions that provide human immunodeficiency virus (HIV) postexposure prophylaxis (PEP) to individuals after sexual or injection-drug use exposures depends on the distribution of exposure routes, prevalence of infection among source partners, adherence to PEP regimens, medical care costs, and prevailing epidemiologic contexts, among other factors. OBJECTIVE: To determine the cost-effectiveness of a comprehensive program to prevent HIV infection after sexual or injection-drug use exposure for 401 persons seeking PEP in an urban community. METHODS: We conducted a retrospective cost analysis to evaluate the cost of the PEP intervention, then combined this information with model-based effectiveness estimates to determine the PEP program's "cost-utility ratio," which is the ratio of net program costs to the total number of quality-adjusted life-years (QALYs) saved by the program. RESULTS: The average cost of the PEP regimen was $1222, and the total cost of the program was $450 970. The PEP program prevented an estimated 1.26 HIV infections, saved 11.74 QALYs, and averted $281 323 in future HIV-related medical care costs. The overall cost-utility ratio was $14 449 per QALY saved. When analysis was restricted to men reporting receptive anal intercourse, the savings in averted HIV-related medical care costs exceeded the cost of the program. The results were generally robust to changes in key parameter values but were sensitive to assumptions about the HIV transmission probability for receptive anal intercourse. CONCLUSIONS: For this study population, HIV PEP was cost-effective by conventional standards and cost-saving for persons seeking PEP after male-male receptive anal intercourse.

Anti-HIV Agents↗
PubMed2004

Management of occupational and nonoccupational postexposure HIV prophylaxis.

The principles of managing patients with recent HIV exposures are similar whether the exposure occurs in an occupational or nonoccupational setting. For both settings, clinicians should 1) assess the likelihood that HIV and other bloodborne viruses will be transmitted as a consequence of the exposure; 2) advise the patient about the risks and benefits of treatment; 3) choose an appropriate antiretroviral treatment regimen (if the decision is made to treat); 4) screen for other illnesses that may complicate treatment or follow-up; 5) counsel patients about the importance of adhering to treatment; 6) promote safe-sex practices and methods to avoid future exposures; 7) follow the patient for potential side effects of treatment; 8) provide follow-up care including repeat HIV testing for seroconversion, surveillance for primary HIV infection, and reinforcement of counseling messages.

Anti-HIV Agents↗
PubMed2003

Multivariable analysis: a primer for readers of medical research.

Many clinical readers, especially those uncomfortable with mathematics, treat published multivariable models as a black box, accepting the author's explanation of the results. However, multivariable analysis can be understood without undue concern for the underlying mathematics. This paper reviews the basics of multivariable analysis, including what multivariable models are, why they are used, what types exist, what assumptions underlie them, how they should be interpreted, and how they can be evaluated. A deeper understanding of multivariable models enables readers to decide for themselves how much weight to give to the results of published analyses.

Biomedical Research↗
PubMed2003

Endemic cryptosporidiosis and exposure to municipal tap water in persons with acquired immunodeficiency syndrome (AIDS): a case-control study.

BACKGROUND: In persons with acquired immunodeficiency syndrome (AIDS), Cryptosporidium parvum causes a prolonged, severe diarrheal illness to which there is no effective treatment, and the risk of developing cryptosporidiosis from drinking tap water in non-outbreak settings remains uncertain. To test the hypothesis that drinking tap water was associated with developing cryptosporidiosis, we conducted a matched case-control study among persons with AIDS in San Francisco. METHODS: Among patients reported to the San Francisco AIDS Registry from May 1996 through September 1998, we compared patients who developed cryptosporidiosis to those who did not. Cases were individually matched to controls based on age, sex, race/ethnicity, CD4+ T lymphocyte count, date of CD4+ count, and date of case diagnosis. Population attributable fractions (PAFs) were calculated. RESULTS: The study consisted of 49 cases and 99 matched controls. In the multivariable analysis with adjustments for confounders, tap water consumption inside and outside the home at the highest exposure categories was associated with the occurrence of cryptosporidiosis (inside the home: odds ratio (OR), 6.76; 95% CI 1.37-33.5, and outside the home: OR 3.16; 95% CI 1.23-8.13). The PAF was 85%; that is, the proportion of cases of cryptosporidiosis in San Francisco AIDS patients attributable to tap water consumption could have been as high as 85%. CONCLUSIONS: Although the results from this observational study cannot be considered definitive, until there is more data, we recommend persons with AIDS, especially those with compromised immune systems, consider avoiding tap water.

AIDS-Related Opportunistic Infections↗
PubMed2002

Characterization of sexually transmitted disease clinic patients with recent human immunodeficiency virus infection.

The serologic testing algorithm for recent human immunodeficiency virus (HIV) seroconversion (STARHS) distinguishes between recent acquisition of HIV infection (seroconversion, on average, in the past 129 days) or long-standing infection. STARHS was offered to sexually transmitted disease clinic patients to estimate HIV incidence and determine correlates of recent infection from October 1998 through December 1999. Of the 5227 patients tested, 116 (2.1%) were HIV infected, and 28 had recent infections. The incidence was highest among homosexual men (5.3%/year; 95% confidence interval [CI], 2.6%-10.0%), those who had HIV-infected partners (8.6%/year; 95% CI, 2.9%-21.1%), and those who had gonorrhea (6.7%/year; 95% CI, 1.5%-20.3%). Among homosexual men, African American (odds ratio [OR], 3.61; 95% CI, 1.13-11.55) or Latino (OR, 3.08; 95% CI, 1.11-8.55) race/ethnicity, and having unprotected anal intercourse (OR, 2.98; 95% CL, 1.20-7.45) or gonorrhea (OR, 3.03 95% CI, 1.07-8.63) predicted the predominance of a recent seroconversion. HIV infections in San Francisco may be shifting from white men who have sex with men to men of color who have sex with men.

Adult↗
PubMed2002

Trends in causes of death among persons with acquired immunodeficiency syndrome in the era of highly active antiretroviral therapy, San Francisco, 1994-1998.

To understand recent temporal trends in acquired immunodeficiency syndrome (AIDS) mortality in the era of highly active antiretroviral therapy (HAART), trends in causes of death among persons with AIDS in San Francisco who died between 1994 and 1998 were analyzed. Among 5234 deaths, the mortality rate for human immunodeficiency virus (HIV)-related or AIDS-related deaths declined after 1995 (P<.01), whereas the mortality rate for non-HIV- or non-AIDS-related deaths remained stable. The proportion of deaths of persons with AIDS associated with septicemia, non-AIDS-defining malignancy, chronic liver disease, viral hepatitis, overdose, obstructive lung disease, coronary artery disease, and pancreatitis increased (P<.05). The standardized mortality ratio was high for these causes in both pre- and post-HAART periods, except for pancreatitis, a possible complication of HAART, which demonstrated an increasing standardized mortality ratio trend after 1996. With increasing AIDS survival, prevention of chronic diseases, assessment of long-term toxicity from HAART, and surveillance for additional causes of mortality will become increasingly important.

AIDS-Related Opportunistic Infections↗
PubMed2002

Risk behaviors and HIV incidence among repeat testers at publicly funded HIV testing sites in San Francisco.

OBJECTIVE: More than 25% of HIV tests are for individuals who have previously been tested. To characterize repeat testers, we 1) estimated the seroincidence of HIV infection, stratified by risk behavior, and examined the association between 2) testing rates and risk level and 3) repeat testing and tester characteristics. METHODS: Records from HIV counseling and testing (C&T) sites were reviewed. Seroincidence was estimated by linking results of current test with date of last reported HIV negative test. A risk hierarchy of behaviors was created. Repeat testing rates were calculated for each risk level strata. Multivariate models explored the association of repeat testing with tester characteristics. RESULTS: The HIV seroincidence among repeaters was 1.3 per 100 person-years (range 0.7-7.0 per 100 person-years). The high-risk level subject had a repeater rate of 92%, with 5.3 tests/person and was more likely (odds ratio = 4.96, 95% confidence interval 3.8-6.5) to have tested two or more times, compared with those in the low risk group. CONCLUSION: The highest users of repeat testing are those who are practicing the highest risk behaviors and have the highest incidence of HIV. This suggests that prevention messages should be modified to more explicitly address the behaviors that are putting individuals at high risk for HIV.

AIDS Serodiagnosis↗
PubMed2002

Impact of highly active antiretroviral treatment on HIV seroincidence among men who have sex with men: San Francisco.

OBJECTIVES: This study assessed the countervailing effects on HIV incidence of highly active antiretroviral treatment (HAART) among San Francisco men who have sex with men (MSM). METHODS: Behavioral risk was determined on the basis of responses to cross-sectional community interviews. HIV incidence was assessed through application of an enzyme-linked immunoassay testing strategy. RESULTS: Use of HAART among MSM living with AIDS increased from 4% in 1995 to 54% in 1999. The percentage of MSM who reported both unprotected anal intercourse and multiple sexual partners increased from 24% in 1994 to 45% in 1999. The annual HIV incidence rate increased from 2.1% in 1996 to 4.2% in 1999 among MSM who sought anonymous HIV testing, and the rate was high (5.3%) but stable in a blinded survey of MSM seeking sexually transmitted disease services. CONCLUSIONS: Any decrease in per contact risk of HIV transmission due to HAART use appears to have been counterbalanced or overwhelmed by increases in the number of unsafe sexual episodes.

Adult↗
PubMed1986

Returning children home: clinical decision making in cases of child abuse and neglect.

Factors that influence the decision to remove children from their parents' care in cases of abuse and neglect were examined by reviewing hospital records of 185 children. Children with physical injuries were more likely to be placed in a foster home or in residential care if they were from poor families, while those with non-physical injuries were more likely to be removed if their families were more affluent. Implications for clinical decision making are considered.

Adolescent↗