Prophylactic Antibiotics Don’t Prevent Poststroke Pneumonia

Prophylactic antibiotics don’t prevent poststroke pneumonia or reduce mortality, even in patients who have stroke-induced dysphagia and are at high risk of aspiration, according to a report published in the Lancet.

In a prospective open-label cluster-randomized clinical trial, researchers randomly assigned 37 stroke units in the United Kingdom to give new patients either prophylactic antibiotics for 7 days plus standard stroke care (564 patients) or standard stroke care alone (524 patients). All study participants were considered “unsafe to swallow” because they had impaired consciousness, they failed a bedside swallow test, or they had a nasogastric tube, said Lalit Kalra, Ph.D., of the department of basic and clinical neurosciences and the Institute of Psychiatry, Psychology, and Neuroscience at King’s College, London, and his associates.

Each hospital was allowed to choose which prophylactic antibiotics to use according to their local guidelines, as well as which dosage and route of administration. The primary outcome was the incidence of post-stroke pneumonia within 2 weeks of hospitalization, which was assessed by two separate methods: a statistician masked to treatment assignment diagnosed pneumonia according to a criteria-based hierarchical algorithm, and a local treating physician diagnosed pneumonia according to clinical findings.

According to the algorithm, poststroke pneumonia developed in 13% of patients given prophylactic antibiotics and 10% of the control group, for an OR of 1.21. According to the clinical findings, poststroke pneumonia developed in 16% of the intervention group and 15% of the control group, for an OR of 1.01. By either definition, prophylactic antibiotics failed to reduce the incidence of poststroke pneumonia, the investigators said (Lancet 2015;386:1835-44).

In addition, all-cause mortality at 14 days (10%) and at 90 days (39%) was not significantly different between the two study groups. And there was no significant difference in the percentage of patients with good functional outcomes. Prophylactic antibiotics were associated with longer hospital stays than standard treatment.

On the positive side, prophylactic antibiotics did reduce the number of nonpneumonia infections, especially urosepsis.

Adverse effects, including cases of Clostridium difficile-positive diarrhea and MRSA colonization, were rare and occurred in equal numbers across the two study groups.

The findings indicate that routine use of antibiotics to prevent poststroke pneumonia “cannot be recommended and should be used judiciously ... in patients after stroke who are managed on stroke units, even if they are at high risk of aspiration,” Dr. Kalra and associates said.

The most likely explanation for this study’s negative findings is that prophylactic antibiotics “do not add to existing preventive measures such as positioning, regular suction, swallowing techniques, modified diets, and early initiation of antibiotics” if patients are suspected of developing pneumonia. It also is possible that poststroke pneumonia is not just a straightforward infection but a complex respiratory syndrome stemming from multiple bacterial, chemical, and immunologic causes that might not respond to antibiotics alone, they added.

This study was funded by the U.K. National Institute for Health Research. Dr. Kalra and associates reported having no relevant financial disclosures.

Prophylactic antibiotics don’t prevent poststroke pneumonia or reduce mortality, even in patients who have stroke-induced dysphagia and are at high risk of aspiration, according to a report published in the Lancet.

In a prospective open-label cluster-randomized clinical trial, researchers randomly assigned 37 stroke units in the United Kingdom to give new patients either prophylactic antibiotics for 7 days plus standard stroke care (564 patients) or standard stroke care alone (524 patients). All study participants were considered “unsafe to swallow” because they had impaired consciousness, they failed a bedside swallow test, or they had a nasogastric tube, said Lalit Kalra, Ph.D., of the department of basic and clinical neurosciences and the Institute of Psychiatry, Psychology, and Neuroscience at King’s College, London, and his associates.

Each hospital was allowed to choose which prophylactic antibiotics to use according to their local guidelines, as well as which dosage and route of administration. The primary outcome was the incidence of post-stroke pneumonia within 2 weeks of hospitalization, which was assessed by two separate methods: a statistician masked to treatment assignment diagnosed pneumonia according to a criteria-based hierarchical algorithm, and a local treating physician diagnosed pneumonia according to clinical findings.

According to the algorithm, poststroke pneumonia developed in 13% of patients given prophylactic antibiotics and 10% of the control group, for an OR of 1.21. According to the clinical findings, poststroke pneumonia developed in 16% of the intervention group and 15% of the control group, for an OR of 1.01. By either definition, prophylactic antibiotics failed to reduce the incidence of poststroke pneumonia, the investigators said (Lancet 2015;386:1835-44).

In addition, all-cause mortality at 14 days (10%) and at 90 days (39%) was not significantly different between the two study groups. And there was no significant difference in the percentage of patients with good functional outcomes. Prophylactic antibiotics were associated with longer hospital stays than standard treatment.

On the positive side, prophylactic antibiotics did reduce the number of nonpneumonia infections, especially urosepsis.

Adverse effects, including cases of Clostridium difficile-positive diarrhea and MRSA colonization, were rare and occurred in equal numbers across the two study groups.

The findings indicate that routine use of antibiotics to prevent poststroke pneumonia “cannot be recommended and should be used judiciously ... in patients after stroke who are managed on stroke units, even if they are at high risk of aspiration,” Dr. Kalra and associates said.

The most likely explanation for this study’s negative findings is that prophylactic antibiotics “do not add to existing preventive measures such as positioning, regular suction, swallowing techniques, modified diets, and early initiation of antibiotics” if patients are suspected of developing pneumonia. It also is possible that poststroke pneumonia is not just a straightforward infection but a complex respiratory syndrome stemming from multiple bacterial, chemical, and immunologic causes that might not respond to antibiotics alone, they added.

This study was funded by the U.K. National Institute for Health Research. Dr. Kalra and associates reported having no relevant financial disclosures.

Prophylactic antibiotics don’t prevent poststroke pneumonia or reduce mortality, even in patients who have stroke-induced dysphagia and are at high risk of aspiration, according to a report published in the Lancet.

In a prospective open-label cluster-randomized clinical trial, researchers randomly assigned 37 stroke units in the United Kingdom to give new patients either prophylactic antibiotics for 7 days plus standard stroke care (564 patients) or standard stroke care alone (524 patients). All study participants were considered “unsafe to swallow” because they had impaired consciousness, they failed a bedside swallow test, or they had a nasogastric tube, said Lalit Kalra, Ph.D., of the department of basic and clinical neurosciences and the Institute of Psychiatry, Psychology, and Neuroscience at King’s College, London, and his associates.

Each hospital was allowed to choose which prophylactic antibiotics to use according to their local guidelines, as well as which dosage and route of administration. The primary outcome was the incidence of post-stroke pneumonia within 2 weeks of hospitalization, which was assessed by two separate methods: a statistician masked to treatment assignment diagnosed pneumonia according to a criteria-based hierarchical algorithm, and a local treating physician diagnosed pneumonia according to clinical findings.

According to the algorithm, poststroke pneumonia developed in 13% of patients given prophylactic antibiotics and 10% of the control group, for an OR of 1.21. According to the clinical findings, poststroke pneumonia developed in 16% of the intervention group and 15% of the control group, for an OR of 1.01. By either definition, prophylactic antibiotics failed to reduce the incidence of poststroke pneumonia, the investigators said (Lancet 2015;386:1835-44).

In addition, all-cause mortality at 14 days (10%) and at 90 days (39%) was not significantly different between the two study groups. And there was no significant difference in the percentage of patients with good functional outcomes. Prophylactic antibiotics were associated with longer hospital stays than standard treatment.

On the positive side, prophylactic antibiotics did reduce the number of nonpneumonia infections, especially urosepsis.

Adverse effects, including cases of Clostridium difficile-positive diarrhea and MRSA colonization, were rare and occurred in equal numbers across the two study groups.

The findings indicate that routine use of antibiotics to prevent poststroke pneumonia “cannot be recommended and should be used judiciously ... in patients after stroke who are managed on stroke units, even if they are at high risk of aspiration,” Dr. Kalra and associates said.

The most likely explanation for this study’s negative findings is that prophylactic antibiotics “do not add to existing preventive measures such as positioning, regular suction, swallowing techniques, modified diets, and early initiation of antibiotics” if patients are suspected of developing pneumonia. It also is possible that poststroke pneumonia is not just a straightforward infection but a complex respiratory syndrome stemming from multiple bacterial, chemical, and immunologic causes that might not respond to antibiotics alone, they added.

This study was funded by the U.K. National Institute for Health Research. Dr. Kalra and associates reported having no relevant financial disclosures.