Does my patient about to undergo immunosuppressive therapy need antiviral prophylaxis even if she tests positive for hepatitis B surface antibody?

The presence of hepatitis B surface antibody (HBsab) in patients who also test positive for core antibody does not necessarily confer full protection against hepatitis B virus (HBV) reactivation during immunosuppression (incidence 4.3%). 1 This is because despite having HBsab and no HB surface antigen,  a small portion of patients continue to have detectable HBV DNA in the serum and are therefore at risk of reactivation during severe immunosuppression. 2

In fact, the American Gastroenterological Association recommends against using anti-HBs status to guide antiviral prophylaxis in anti-HBc-positive patients. 1

Overall, antiviral prophylaxis may reduce the risk of HBV reactivation by 87% (C.I. 70%-94%). Antiviral drugs with a high barrier to resistance (eg, entecavir) are preferred over lamivudine.

Immunosuppressants often requiring HBV prophylaxis include: 1-3

  • B cell-depleting agents (eg, rituximab, ofatumumab)
  • Anthracycline derivatives (eg, doxorubicin, epirubicin)
  • Prednisone (4 weeks or more)
  • Tumor necrosis factor inhibitors (eg, etanercept, adalimumab, certolizumab, infliximab)
  • Other cytokine or integrin inhibitors (eg, abatacept, ustekinumab, natalizumab, vedolizumab)

Traditional immunosuppressive agents such as azathioprine, 6-mercaptopurine and methotrexate are often considered “low-risk” and do not generally require prophylaxis. 1

Fun Fact: Did you know that hepatitis B virus is very old and probably originated in birds when dinosaurs roamed the earth? 4

References

  1. Reddy KR, Beavers KL, Hammond SP, et al. American Gastroenterological Association Institute Guideline on the prevention and treatment of hepatitis B virus reactivation during immunosuppressive drug therapy. Gastroenterology 2015;148:215-19. https://www.ncbi.nlm.nih.gov/pubmed/25447850
  2. Gigi E, Georgiou T, Mougiou D, et al. Hepatitis B reactivation in a patient with rheumatoid arthritis with antibodies to hepatitis B surface antigen treated with rituximab. HIPPOKATRIA 2013;17:91-93. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738290/
  3. Kim EB, Kim DS, Park SJ, et al. Hepatitis B virus reactivation in a surface antigen-negative and antibody-positive patient after rituximab plus CHOP chemotherapy. Cancer Res Treat 2008;40:36-38. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2699087/
  4. Suh A, Brosius J, Schmitz J, et al. The genome of a Mesozoic paleovirus reveals the evolution of hepatitis B virus. Nature Communications 2013; Article no. 1791. http://www.nature.com/articles/ncomms2798
Does my patient about to undergo immunosuppressive therapy need antiviral prophylaxis even if she tests positive for hepatitis B surface antibody?

Is oral vancomycin prophylaxis (OVP) effective in preventing recurrent Clostridium difficile infection (CDI) in patients requiring systemic antimicrobial therapy (SAT)?

Although OVP is often administered to patients with history of CDI who require SAT, evidence to support this practice has been lacking until recently.

In a 2016 retrospective study of 203 patients with prior history of CDI, those who received OVP (125 mg or 250 mg 2x/daily) during the course of their SAT and for up to 1 week thereafter were significantly less likely to have a recurrence than the non-OVP group (4.2% vs 26.6%, respectively, O.R. 0.12 [C.I. 0.04-0.4]) (1). In this study, the mean interval between prior CDI and initiation of prophylaxis was 6.1 months (1-21 months), and the mean duration of prophylaxis following discontinuation of SAT was 1 day (0-6 days). Similar results have been reported by others (2,3).

Despite their retrospective nature, these studies lend support to the use of OVP in reducing the risk of recurrent CDI in patients who require SAT. It is unclear how long OVP should be continued after SAT is completed, if at all, but common practice is 1-2 weeks.

A randomized-controlled study comparing OVP 125 mg daily for the duration of SAT plus 5 days vs placebo appears to be on the way (4)!

References

  1. Van Hise NW, Bryant AM, Hennessey EK, Crannage AJ, Khoury JA, Manian FA. Efficacy of oral vancomycin in preventing recurrent Clostridium difficile infection in patients treated with systemic antimicrobial agents. Clin Infect Dis 2016; Advance Access published June 17, 2016. Doi.10.1093/cid/ciw401.
  2. Carignan A, Sebastien Poulin, Martin P, et al. Efficacy of secondary prophylaxis with vancomycin for preventing recurrent Clostridium difficile infections. Am J Gastroenterol 2016;111: 1834-40. https://www.ncbi.nlm.nih.gov/pubmed/27619835
  3. Granetsky A, Han JH, Hughes ME, et al. Oral vancomycin is highly effective in preventing Clostridium difficile infection in allogeneic hematopoietic stem cell transplant recipients. Blood 2016;128:2225; http://www.bloodjournal.org/content/128/22/2225?sso-checked=true
  4. https://clinicaltrials.gov/ct2/show/NCT03462459

Disclosure: The author of this post was also a co-investigator of one of the studies cited (ref. 1).

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Is oral vancomycin prophylaxis (OVP) effective in preventing recurrent Clostridium difficile infection (CDI) in patients requiring systemic antimicrobial therapy (SAT)?

Is oral metronidazole (Flagyl®) effective in reducing the risk of recurrent Clostridium difficile infection (CDI)?

To date only 1 study has attempted to evaluate metronidazole’s role in preventing CDI1. This work, however,  has significant shortcomings including its retrospective nature, definition of metronidazole prophylaxis as any dose for reasons other than CDI starting 1-3 days before initiation of the primary antibiotic, undefined duration, less comorbidities in the metronidazole group, and surveillance period for CDI limited to only 7 days following initiation of the primary antibiotic. For these reasons, it is difficult to interpret the results of this study whose conclusion was that metronidazole may protective against CDI2.

In fact, there are several reasons why metronidazole prophylaxis may not be effective in CDI.   First, due to its very high bioavailability, concentrations of metronidazole in formed stool are often undetectable2,3 . Consequently, “preventive” metronidazole in patients at risk of CDI but with formed stools would not be expected to achieve high enough concentrations in the colon to be effective.  In additions, metronidazole itself may be associated with CDI4 and  vancomycin-resistant enterococci5,  and has several potential drug-interactions and adverse effects6 .

References

  1. Rodriguez S, Hernandez MB, Tarchini G, et al. Risk of Clostridium difficile infection in hospitalized patients receiving metronidazole for a non-C difficile infection. Clin Gastroenterol Hepatol 2014;12:1856-61. https://www.ncbi.nlm.nih.gov/pubmed/24681079
  2. Dupont HL. Chemoprophylaxis of Clostridium difficile infections in high-risk hospitalized patients. Clin Gastroenterol Hepatol 2014;12: 1862-63. https://www.ncbi.nlm.nih.gov/labs/articles/24768812/
  3. Bolton RP, Culshaw MA. Faecal metronidazole concentrations during oral and intravenous therapy for antibiotic associated colitis due to Clostridium difficile. Gut 1986;27:1169-1172. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1433873/pdf/gut00370-0065.pdf
  4. Daly JJ, Chowdary KV. Pseudomembranous colitis secondary to metronidazole. Dig Dis Sci 1983;28:573-4.
  5.  Carmeli Y, Eliopoulos GM, Samore MH. Antecedent treatment with different antibiotic agents as a risk factor for vancomycin-resistant enterococcus. Emerg Infect Dis 2002;8:802-807. https://wwwnc.cdc.gov/eid/article/8/8/pdfs/01-0418.pdf
  6. Salvatore M, Meyers BR. Metronidazole. In Mandel, Douglas, Bennett’s Principles and Practice of Infectious Diseases-7th Ed. p. 419-426. 2010, Churchill Livingstone, Philadelphia.

 

 

Is oral metronidazole (Flagyl®) effective in reducing the risk of recurrent Clostridium difficile infection (CDI)?

My bed-bound, debilitated patient is being transferred to a long-term facility (LTF). Should I continue the venous thromboembolism (VTE) prophylaxis she has been receiving in the hospital?

There are no randomized-controlled studies that examine the effectiveness of VTE prophylaxis in debilitated patients following discharge from the hospital, and currently  the literature does not recommend prophylaxis for chronic immobility as a single risk factor for VTE (1). However, given the expected morbidity, potential mortality and hospital readmission associated with VTE,  prophylaxis should be considered in residents of LTFs with the following comorbidities (2):

  • Acute exacerbation of congestive heart failure
  • Acute exacerbation of chronic obstructive pulmonary disease
  • Acute infection (e. g. pneumonia, urosepsis, skin and soft tissue infections, infectious diarrhea)
  • Acute exacerbation of inflammatory/autoimmune diseases
  • Active malignancy
  • Immobility and prior VTE

 

Unless contraindicated, patients should receive prophylactic doses of unfractionated heparin, enoxaparin, or other approved drugs. Mechanical VTE prophylaxis should be used only when the risk of bleeding is considered unacceptably high or when there are drug intolerances or adverse effects.

The need for VTE prophylaxis should be reassessed regularly taking into account patient’s overall health status, mobility, drug tolerance and goals of care.

 

References

  1. Pai M, Douketis JD. Preventing venous thromboembolism in long-term care residents: Cautious advice based on limited data. Cleveland Clin J Med 2010;77: 123-130.  https://www.ncbi.nlm.nih.gov/pubmed/20124270    
  2. Robinson Am. Venous thromboembolism prophylaxis for chronically immobilized long-term care residents. Ann Long-Term Care 2013;10:30. https://www.managedhealthcareconnect.com/article/venous-thromboembolism-prophylaxis-chronically-immobilized-long-term-care-residents
My bed-bound, debilitated patient is being transferred to a long-term facility (LTF). Should I continue the venous thromboembolism (VTE) prophylaxis she has been receiving in the hospital?