Michael S Simberkoff

Publications (4)28.48 Total impact

• Article: Association of increased upper trunk and decreased leg fat with 2-h glucose in control and HIV-infected persons.

  Lisa A Kosmiski, Rebecca Scherzer, Steven B Heymsfield, David Rimland, Michael S Simberkoff, Stephen Sidney, Michael G Shlipak, Peter Bacchetti, Mary L Biggs, Carl Grunfeld
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  ABSTRACT: Changes in body fat distribution and abnormal glucose metabolism are common in HIV-infected patients. We hypothesized that HIV-infected participants would have a higher prevalence of impaired glucose tolerance (IGT) compared with control subjects. A total of 491 HIV-infected and 187 control participants from the second examination of the Study of Fat Redistribution and Metabolic Change in HIV Infection (FRAM) underwent glucose tolerance testing (GTT). Multivariable regression was used to identify factors associated with GTT parameters. The prevalence of impaired fasting glucose (IFG) (>110 mg/dL) was similar in HIV-infected and control participants (21 vs. 25%, P = 0.23). In those without IFG, the prevalence of IGT was slightly higher in HIV-infected participants compared with control subjects (13.1 vs. 8.2%, P = 0.14) and in HIV+ participants with lipoatrophy versus without (18.1 vs. 11.5%, P = 0.084). Diabetes detected by GTT was rare (HIV subjects 1.3% and control subjects 0%, P = 0.65). Mean 2-h glucose levels were 7.6 mg/dL higher in the HIV-infected participants (P = 0.012). Increased upper trunk subcutaneous adipose tissue (SAT) and decreased leg SAT were associated with 2-h glucose and IGT in both HIV-infected and control participants. Adjusting for adipose tissue reduced the estimated effects of HIV. Exercise, alcohol use, and current tenofovir use were associated with lower 2-h glucose levels in HIV-infected participants. In HIV infection, increased upper trunk SAT and decreased leg SAT are associated with higher 2-h glucose. These body fat characteristics may identify HIV-infected patients with normal fasting glucose but nonetheless at increased risk for diabetes.
  Diabetes care 09/2011; 34(11):2448-53. · 8.09 Impact Factor
• Article: Disparities in rates of spine surgery for degenerative spine disease between HIV-infected and uninfected veterans.

  Joseph T King, Adam J Gordon, Melissa F Perkal, Stephen Crystal, Ronnie A Rosenthal, Maria C Rodriguez-Barradas, Adeel A Butt, Cynthia L Gibert, David Rimland, Michael S Simberkoff, Amy C Justice
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  ABSTRACT: Retrospective analysis of nationwide Veterans Health Administration clinical and administrative data. Examine the association between HIV infection and the rate of spine surgery for degenerative spine disease. Combination antiretroviral therapy has prolonged survival in HIV-infected patients, increasing the prevalence of chronic conditions such as degenerative spine disease that may require spine surgery. We studied all HIV-infected patients under care in the Veterans Health Administration from 1996 to 2008 (n = 40,038) and uninfected comparator patients (n = 79,039) matched on age, sex, race, year, and geographic region. The primary outcome was spine surgery for degenerative spine disease, defined by International Classification of Diseases, Ninth Revision procedure and diagnosis codes. We used a multivariate Poisson regression to model spine surgery rates by HIV infection status, adjusting for factors that might affect suitability for surgery (demographics, year, comorbidities, body mass index, combination antiretroviral therapy, and laboratory values). Two hundred twenty-eight HIV-infected and 784 uninfected patients underwent spine surgery for degenerative spine disease during 700,731 patient-years of follow-up (1.44 surgeries per 1000 patient-years). The most common procedures were spinal decompression (50%) and decompression and fusion (33%); the most common surgical sites were the lumbosacral (50%) and cervical (40%) spine. Adjusted rates of surgery were lower for HIV-infected patients (0.86 per 1000 patient-years of follow-up) than for uninfected patients (1.41 per 1000 patient-years; incidence rate ratio 0.61, 95% confidence interval: 0.51-0.74, P < 0.001). Among HIV-infected patients, there was a trend toward lower rates of spine surgery in patients with detectable viral load levels (incidence rate ratio 0.76, 95% confidence interval: 0.55-1.05, P = 0.099). In the Veterans Health Administration, HIV-infected patients experience significantly reduced rates of surgery for degenerative spine disease. Possible explanations include disease prevalence, emphasis on treatment of nonspine HIV-related symptoms, surgical referral patterns, impact of HIV on surgery risk-benefit ratio, patient preferences, and surgeon bias.
  Spine 06/2011; 37(7):612-22. · 2.08 Impact Factor
• Source

  Available from: Joseph Goulet

  Article: Reply to Sogaard et al.

  Maria C Rodriguez-Barradas, Joseph Goulet, Sheldon Brown, Matthew Bidwell Goetz, David Rimland, Michael S Simberkoff, Kristina Crothers, Amy C Justice
  Clinical Infectious Diseases 08/2008; 47(2):295-296. · 9.15 Impact Factor
• Article: Impact of pneumococcal vaccination on the incidence of pneumonia by HIV infection status among patients enrolled in the Veterans Aging Cohort 5-Site Study.

  Maria C Rodriguez-Barradas, Joseph Goulet, Sheldon Brown, Matthew Bidwell Goetz, David Rimland, Michael S Simberkoff, Kristina Crothers, Amy C Justice
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  ABSTRACT: Human immunodeficiency virus (HIV)-infected persons have a high incidence of pneumonia and pneumococcal disease. Benefits of vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPV) among these patients continue to be debated. The impact of PPV vaccination on the incidence of pneumonia events (i.e., the composite of pneumococcal pneumonia and pneumonia due to nonspecified organisms) was examined among participants in the Veterans Aging Cohort 5-Site Study, an ongoing prospective study of HIV-infected patients matched to an HIV-uninfected control group. Dates of PPV vaccination and pneumonia were determined by retrospective review of electronic medical records. Time to events was measured for up to 2 years from PPV vaccination or from enrollment for vaccinated and unvaccinated patients, respectively. Kaplan-Meier and Cox proportional hazards regression methods were used to examine the incidence of pneumonia by HIV infection and PPV vaccination status. Among 692 HIV-uninfected and 934 HIV-infected study participants, 59% were vaccinated with PPV. The 2-year incidence of pneumonia was 6% (97 participants developed pneumonia). HIV-infected patients had a higher rate of pneumonia (hazard ratio, 5.81; 95% confidence interval, 3.15-10.71); overall, vaccinated patients showed a trend toward lower risk of pneumonia (hazard ratio, 0.75; 95% confidence interval, 0.50-1.13). Among HIV-infected patients, after controlling for HIV-specific and other variables, vaccination significantly reduced the risk of pneumonia (hazard ratio, 0.65; 95% confidence interval, 0.42-1.00); current smoking, low hemoglobin level, and low CD4 cell count significantly increased such risk. The effect of PPV vaccination among HIV-uninfected patients was not significant. Among HIV-infected patients, PPV vaccination offered protection against pneumonia. Smoking cessation needs to be pursued as an additional strategy for preventing pneumonia.
  Clinical Infectious Diseases 05/2008; 46(7):1093-100. · 9.15 Impact Factor